Analysis of factors driving stream water composition and synthesis of management tools-A case study on small/medium Greek catchments

ArticleinScience of The Total Environment 362(1-3):205-41 · July 2006with 182 Reads 
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Abstract
Twenty-nine small- and mid-sized permanent rivers (thirty-six sites) scattered throughout Greece and equally distributed within three geo-chemical-climatic zones, have been investigated in a seasonal base. Hydrochemical types have been determined and spatio-temporal variations have been interpreted in relation to environmental characteristics and anthropogenic pressures. Multivariate statistical techniques have been used to identify the factors and processes affecting hydrochemical variability and the driving forces that control aquatic composition. It has been shown that spatial variation of aquatic quality is mainly governed by geological and hydrogeological factors. Due to geological and climatic variability, the three zones have different hydrochemical characteristics. Temporal hydrological variations in combination with hydrogeological factors control seasonal hydrochemical trends. Respiration processes due to municipal wastewaters, dominate in summer, and enhance nutrient, chloride and sodium concentrations, while nitrate originates primarily from agriculture. Photosynthetic processes dominate in spring. Carbonate chemistry is controlled by hydrogeological factors and biological activity. A possible enrichment of surface waters with nutrients in "pristine" forested catchments is attributed to soil leaching and mineralisation processes. Two management tools have been developed: a nutrient classification system and a rapid prediction of aquatic composition tool.

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  • ... The objective of the present work is to connect the physicochemical status of river Epis with the composition of olive oil mill waste waters during the winter period. The Greek River Nutrient Classification system, Skoulikidis et al. (2006), was used in order to classify the stations into quality classes before, during and after the production period in order to evaluate whether and to what extend the system recovers. The results could constitute a useful tool for local authorities and the local administration in the planning of water resources management. ...
    ... The Greek River Nutrient Classification system was used, (Skoulikidis et al., 2006) in order to assess the physico-chemical quality of the river water and assign the quality classes of the stations [5]. ...
    ... According to the Greek Nutrient Classification System (Skoulikidis et al., 2006) the quality of all the stations examined before the olive oil production period of 2008-2009 (09/2008) was classified as high. At the end of November, the station E2 was classified as moderate, due to the extremely elevated values of ammonium (N-NH4 0.70mg/l) and the low concentration of dissolved oxygen (4.95mg/l) ( Table 4). ...
    Conference Paper
    Full-text available
    The production of olive oil has been of paramount importance from the ancient years until today in the Mediterranean region which is responsible for the 97% of the worldwide production. Around 80-84% of this production belongs to European countries where Greece (402.703tn/year) is the third in a row after Spain (890.100tn/year) and Italy (614.950tn/year). In the study area, Messinia – South Peloponnese, quantities of the order of 50.000 tn are annually produced, mainly from three phase olive oil industries, which correspond to the production of 250.000 tn of olive oil mill waste waters. According to the literature from 100kg of olive fruit 100-120lt of omww are generated. In this study the physicochemical status of river Epis, which is located at the western, most productive part of Messinia, is connected for the first time to the composition of these wastes. River Epis receives great quantities of untreated olive oil mill waste waters annually coming from nearby industries. Chemical parameters such as phenols, ammonium, nitrites, phosphates and certain heavy metals that have been in the past identified to be present in the waste were recorded during and after three olive oil production periods in the water column. High concentration of phenols (414μg/l, 12/2010) and considerable amounts of ammonia (9,5μΜ) were recorded before the estuaries of the river during December of 2010, where olive oil production reaches a peak. It is worth mentioning that the coastal area was also charged with phenols during December (96μg/l) while in the springs of the river a much lower concentration was recorded (1,7μg/l). The N:P ratio was greater (25) than the theoretical value (16:1) implying an input of inorganic nitrogen into the gulf. Total organic carbon was also found higher than the other rivers studied. Concerning the concentrations of trace metals the mean Mn concentration in the water body of Epis was found to be 72.46μg/l, during three productive periods, while much lower concentrations were recorded in other rivers studied (8.9-34μg/l). An extreme Mn value (486μg/l) was recorded during December of 2008 in the water column and rather elevated values of Ni and Cu were also detected at the same period. The sediment analysis confirmed the ecosystem's enrichment in trace metals. Calculating the sediment enrichment factor (SEF) towards Al we observed high values for Mn and Cr and rather elevated values for Ni and Cu. Furthermore, olive oil wastes contain high quantity of phenols (0,5-8g/l), high C.O.D. values (up to 170g/l) and appreciable amounts of certain trace metals. Taking into account that the coastal areas consist one of the most mercurial ecosystems, special attention should be given in the riverine area of Epis.
  • ... In order to classify the physicochemical status of the river sites, the river nutrient classification system (NCS) [Skoulikidis et al., 2006; Table 1] was applied for nutrients and the Norwegian system for dissolved oxygen [Cardoso et al., 2001; Table 1]. ...
    ... The highest average nitrate, ammonium, and phosphate concentrations were measured at P8-P10 and at Sokratous-Verginas stations, and they were classified as of bad quality based on the nutrient classification system [Skoulikidis et al., 2006; Table 1]. ...
    ... Spatial Coliforms, e) Total PAH and f) Total Phenols concentrations in Pikrodafni stream (Yellow and red lines represent the threshold values for each nutrient in order for every water sample to be classified as of moderate and bad chemical quality, respectively[Skoulikidis et al., 2006] ...
    Preprint
    Full-text available
    The impact and occurrence of human-induced pollution sources have been investigated in one of the few remaining urban streams located in Attica, Greece. Baseline information is provided on the presence and concentration of physicochemical parameters, nutrients, total coliforms, hydrocarbons and phenols in 12 key points along the Pikrodafni stream. The aim was to evaluate the relative importance of key water quality variables and their sources. Indicator substances (i.e. concentrations of nitrate, ammonium, phosphate and total coliforms in certain stations indicating wastewater exposure; PAHs indicating petroleum sources) successfully related the water quality variables to pollution sources. Furthermore, a pollution pressure map has been developed with the activities identified from in-situ visits and Google Earth surveys, while the statistical analysis (CA and PCA) has contributed to the further exploration of the relative magnitude of pollution sources effects. Our results underline initially the importance of diffuse pollution management accompanied by the necessity for continuous environmental monitoring and the application of legal and environmental restoration actions if water quality is to be improved according to WFD 2000/60/EC.
  • ... Ο Αλιάκµονας ανήκει στην υδροχηµική ζώνη ΙΙ (Skoulikidis et al., 2006), που χαρακτηρίζεται από υψηλές ποτάµιες συγκεντρώσεις µαγνησίου, πυριτίου και οξυανθρακικών, ως αποτέλεσµα της αποσάθρωσης βασικών/υπερβασικών πετρωµάτων. Τα νερά του κυρίου ρου, ανήκουν στον πλέον κοινό ελληνικό χηµικό τύπο, τον ασβεστούχο διτανθρακικό (Ca > Mg > Na > K – HCO3 > SO4 > Cl), όπου η συγκέντρωση του µαγνησίου είναι ελαφρώς µικρότερη αυτής του ασβεστίου (2,06 και 2,29 meq/l αντίστοιχα), ενώ η ψηλή ιοντική σχέση Νa + /Cl -(1,5) φανερώνει την επίδραση της αποσάθρωσης των όξινων µαγµατικών και µεταµορφωµένων πετρωµάτων της λεκάνης απορροής. ...
    ... Αγροτικής Ανάπτυξης και Τροφίµων, η µέση υπερετήσια (1980-2000) συγκέντρωση θρεπτικών στη θέση Ιλαρίων είναι: 0,68 mg/l N-NO 3 , 8,2 µg/l N- NO 2 , 0,14 mg/l N-NH 4 και 0,02 mg/l P-PO 4 . Με βάση τις παραπάνω συγκεντρώσεις, και σύµφωνα µε σύστηµα ταξινόµησης Ελληνικών ποταµών (Skoulikidis et al. 2006), η κατάσταση του ποταµού στη θέση αυτή ως προς τα νιτρικά τα νιτρώδη, την αµµωνία και τον ολικό φώσφορο είναι καλή (κοντά στα όρια καλής/ µέτριας κατάστασης). Αν και σύµφωνα µε τους Voutsa et al. (1995) οι συγκεντρώσεις των βαρέων µετάλλων που προσδιορίστηκαν στα νερά του Αλιάκµονα βρέθηκαν χαµηλές, οι Karamanis et al. (2006), που µελέτησαν τους ποταµούς Αλιάκµονα, Πηνείο, Αχελώο, Καλαµά και Λούρο, διαπίστωσαν µέγιστη συγκέντρωση Ζn (224.8 µg/L) στον Αλιάκµονα στη θέση Πόρος. ...
    ... Cardoso et al., 2001). 2. Συγκεντρώσεις (mg/l) και κατάταξη ποιότητας θρεπτικών (σύµφωνα µε τους Skoulikidis et al., 2006) στον κύριο ρου και σε παραποτάµους του άνω Αλιάκµονα (από τα ανάντη προς τα κατάντη) σε διάφορες χρονικές περιόδους στο διάστηµα 1983 – 2007. υπόγειο δυναµικό της συγκεκριµένης λεκάνης δεν µπορεί να είναι ιδιαιτέρως υψηλό αφού οι υδρογεωλογικές συνθήκες ευνοούν περισσότερο την άµεση απορροή (βασική και επιφανειακή απορροή). ...
    Technical Report
    Full-text available
    This report describes the organization and analysis of information acquired during seasonal fish sampling for one year, coupled with recording of abiotic parameters and shows the results of data processing: assessment of fish species’ composition, distribution and abundance and the study of their biological and ecological attributes. Moreover, macroinvertebrate sampling was conducted and samples were analyzed in order to characterize the ecological situation in the main section of the upper reaches of the River Aliakmonas and certain major tributaries. At the same time, an assessment of the nature and quality of the physical structure of the upper reaches of the River Aliakmonas was recorded, using the River Habitat Survey, RHS.
  • ... Ranges of values for the major measured parameters in water samples from the three streams are presented in Table 1. Also in Table 1 are given the respective median values from Greece Mainland Rivers (Skoulikidis et al. 2006) for comparison. The latter values are representative of water quality in more 'pristine' environments, away from urban centres, however they belong in the same geological and climatic zone with respect to national spatial scale. ...
    ... With respect to measured nutrient concentrations of NO3and PO4 3-, collected data show a high degree of variability related to seasonal fluctuations as well as presence of point sources along the flow path of the studied streams ( Figure 2). When compared to the Nutrient Classification System developed by Skoulikidis et al. (2006), most samples fall within the 'moderate' to 'bad' quality categories. .This is probably related to the existence of greenhouse farms adjacent to the sampling points which use fertilizers and pesticides, that possibly leak into the river. ...
    ... Summary of concentration ranges for major water parameters in the studied streams. Median values of river water from mainland Greece(Skoulikidis et al. 2006) are also given for comparison. ...
    Article
    Full-text available
    The geochemistry of three urban streams in Athens was analysed and compared on the basis of major elements and heavy metals content in water and active sediment. The studied streams of Kifissos, Podoniftis and Pikrodafni run through the Athens basin of a total area of 540 km2 but differ with respect to the origin of their headwaters i.e., Parnitha, Penteli and Hymettus mountains. The main aim of the study was to determine the geochemical signature of water and sediment within the Athens hydrological basin and evaluate the effect of natural and anthropogenic environment on these water courses. A total of 56 stream water samples were obtained and analysed for major anions, cations and heavy metals (Mn, Cr, Cu, Zn, Pb) as well as nitrate and phosphate concentrations. Active stream sediments were collected at 22 locations along the streams and were analysed for heavy metals (Pb, Zn, Cu, Mn, Cr, Ni, Cd). Results indicated that rock weathering, rather than atmospheric or pollution influx is the dominant process affecting the major ion geochemistry of stream flow in the urban setting. However, Kifissos and Podoniftis waters had higher nitrate and phosphate concentrations indicating greater influence by anthropogenic activities. In general the quality characteristics of water and sediment in the study area were found to be in a good state regarding the studied parameters.
  • ... The vast majority of the Evrotas hydrographical network belongs to the most representative hydrochemical river type found in Greece (Ca > Mg > Na > K-HCO3 > SO4 > Cl; [76]), mainly resulting from the dissolution of carbonate rocks. Situated within the southern part of geographical zone No. 3, the ERB presents an example of the influence of dry climatic conditions on river hydrochemistry; in contrast to the rivers located at the northern part of this zone, the Evrotas River is characterised as very hard (median total hardness 307 mg/L CaCO 3 ) and highly mineralised (median total dissolved ion concentration 491 mg/L). ...
    ... Initial floods also caused substantial sediment mobilisation and flushing of epsomite-type salts, which are very soluble [84]. Colours represent nitrate quality classes (blue high, green good, yellow moderate and orange poor quality) according to the Greek Nutrient Classification System [76]. Dotted line represents the mean annual N-NO 3 concentration ...
    ... Sampling sites and water bodies are classified using a five-class system (high, good, moderate, poor, bad), which combines physicochemical, hydromorphological and biological data [93], appropriately collected to comply with the requirements of the WFD. In Greece, the physicochemical quality is classified within the Nutrient Classification System [76] and hydromorphological assessment within the River Habitat Survey (RHS) method [94]. The biological quality classification is derived from the lowest observed quality class among the four biological quality elements (BQEs): fish, benthic macro-invertebrates, diatoms and macrophytes. ...
    Chapter
    This chapter is the outcome of a 10-year ecological monitoring survey in the Evrotas River Basin (ERB). Synthesising the main outcomes of past and ongoing research projects, it presents an overview of the basin’s geographical, geological, hydrological and ecological features, focused on the ecological status according to the Water Framework Directive 2000/60/EC, and assesses the degree of environmental degradation caused by the major pollution sources and other anthropogenic pressures. Chemical, hydromorphological and biological data from studies carried out in the ERB during the past decade are integrated to derive spatial and temporal trends in environmental degradation. Despite the numerous sources of organic and inorganic pollution, which include, inter alia, olive mill and fruit juice processing wastewaters and agricultural, industrial and urban runoffs, the overall ecological degradation of the ERB is assessed as moderate and is located mainly at the downstream half of the basin, where the anthropogenic activities become intensified. However, the major impact in the ERB during the last decades has been the over-exploitation of the surface and groundwater resources for irrigation, which has resulted in the artificial desiccation of large parts of the basin’s hydrological network. Despite the aforementioned issues, the aquatic benthic biota of the basin shows high resilience, but the fish fauna is severely affected by hydrological and morphological alteration. Biomonitoring, conservation and management responses to drought and pollution require approaches, which account for spatial and temporal variability. Within this perspective, a programme of measures is proposed, aiming at preserving and restoring the basin’s water resources and aquatic ecosystem.
  • ... For the assessment of the chemical-physicochemical quality of river water, the following standards were applied: for pH, the Directive, 2006/44/EC concerning fish conservation, for DO, we used 8, 6 and 4 mg l −1 as the boundaries between high -good, good -moderate and moderate -poor quality, respectively (Karavokyris et al., 2009). Finally, we applied the Nutrient Classification System (NCS) according to Skoulikidis et al. (2006) for the assessment of nutrient quality. ...
    ... Values below the limits of investigation were also used for the calculation of the average, dis: discharge, p: pools, T: water temperature, cond: conductivity, pCO 2 : partial pressure of carbon dioxide, ppmv: parts per million volume partial pressure, DO: dissolved oxygen, % eq cond: % equivalent conductivity, CO 3 was 0 in all samplings, ΤΝ: total dissolved nitrogen, TP: total dissolved phosphorus, CV: coefficient of variation, flood x /av: parameter ratio between flood events and annual average. Colors represent the quality status of nutrients according to Skoulikidis et al. (2006), where blue = high quality, green = good quality and yellow = moderate quality. 3.4. ...
    ... St: station, av: average, dis: discharge, p: pools, con p: connected pools, dis p: disconnected pools, mpd: mean pool depth, T: water temperature, cond: conductivity, DO: dissolved oxygen, pCO 2 : partial pressure of carbon dioxide, ppmv: parts per million volume partial pressure, ΤΝ: total dissolved nitrogen, TP: total dissolved phosphorus, CV: coefficient of variation. Colors represent the quality status of specific nutrients according to Skoulikidis et al. (2006), where blue = high quality, green = good quality and yellow = moderate quality. daily water temperature and pH coincided with minimum daily DO (Fig. 5) a feature that cannot be explained by the effect of photosynthesis or respiration alone. ...
  • ... High concentrations of nitrates (NO 3 − ), ammonium (NH 4 + ) and phosphorus (P-PO 4 3− ) can cause eutrophication to rivers resulting in algal blooms (Rabalais, 2002) and disturbance of natural nutrient cycles and food webs (Galloway and Cowling, 2002;Rabalais, 2002). In Greece, for the selection of reference sites as to nutrient concentration, the Nutrient Classification System (NCS) proposed by Skoulikidis et al. (2006) was chosen. Thresholds used in NCS for inorganic nitrogen from nitrites, nitrates and ammonium are lower than values proposed by other Mediterranean countries Munné et al., 2006) in the MedGIG (Feio et al., 2014b) and Central-Baltic Europe [e.g. ...
    ... N-NO 3 − values vary between 2 and 6 mg l −1 according to Pardo et al. (Pardo et al., 2012) in the Central-Baltic region. According to Skoulikidis et al. (2006), the higher threshold for the inorganic phosphorus could be induced by natural processes leading to higher background levels. Subsequently, the biological criterion to choose the reference sites was based on at least good quality sites as to the Hellenic assessment method (SemiHES ≥ 4). ...
    ... Selected criteria for the construction of the three reference databases. 1 Feio et al. (2014a), 2 Environment Agency (2005), 3 Raven et al. (1998), 4Skoulikidis et al. (2006),5 Artemiadou and Lazaridou (2005). ...
    Article
    During the last decades, a great number of indices have been developed throughout Europe to fulfil the requirements of the Water Framework Directive (WFD) and to assess the ecological impacts of anthropogenic pressures. The development of a methodology for assessing the ecological quality status of Greek rivers and streams was urgently needed because the existing European indices were not adapted efficiently to the particular hydrological and climatic conditions of this Mediterranean region. After selecting the most appropriate typo-logical system, four systems were tested using a different number of reference samples based on a vast number of criteria from impaired to at least impaired sites. The most suitable typological system was found to be the river types (IC) from the Mediterranean Intercalibration exercise. Reference or minimally disturbed sites to evaluate the Ecological Quality Ratio (EQR) for each river type were selectedpreviously to the development and selection of the most appropriate metrics or biotic index based on benthic communities for the assessment of the ecological quality of the rivers. In this frame, 42 European metrics and indices, were tested against a) their response to three quality gradients (undisturbed, slightly disturbed and disturbed), b) their acquisition of a low interquartile coefficientand c) a low Spearman's correlation between the metrics and indices. Hence, 9 metrics and indices were examined for their response to human pressures and the Hellenic Evaluation System 2 (HESY2) was se-lectedand successfully intercalibrated with the assessment methods of the other countries, using the option of indirect comparison based on near-natural reference sites (reference benchmarking). This index showed a significant correlation with some anthropogenic pressures (e.g. P-PO 4 3− , artificial and agricultural areas) in all IC types. HESY2 estimates also more than 86% of the moderate samples correctly and beside this, it provides a precise, explicit and simply applicable assessment of the ecological quality status in Greek streams and rivers. HESY2 is applied for the assessment of the ecological quality in Greek running waters and will be further justified considering the results of the forthcoming National Monitoring Program (2017-2022).
  • ... Afin de classer l'état physico-chimique des sites fluviatiles étudiés, le Système de Par rapport aux teneurs en P-PO4 (0.0005-0.013 mg/l), l'état physico-chimique est très bon au niveau des deux stations et pendant toute la période de l'échantillonnage ( Figure 150). Figure 150: Variation spatio-temporelle de la teneur en P-PO4 au niveau des stations fluviatiles par rapport aux valeurs seuils de Skoulikidis et al. (2006) Par rapport aux teneurs en N-NO3 (0.173-0.723 mg/l), l'état physico-chimique de l'eau des deux stations fluviatiles est bon à très bon sauf au niveau de la station R2 durant le mois de novembre 2016, l'état est moyen ( Figure 151). ...
    ... Variation spatio-temporelle de la teneur en N-NO3 au niveau des stations fluviatiles par rapport aux valeurs seuils deSkoulikidis et al. (2006) Variation spatio-temporelle de la teneur en N-NO2 au niveau des stations fluviatiles par rapport aux valeurs seuils deSkoulikidis et al. (2006) 1.3. BactériologieLes valeurs de coliformes et streptocoques fécaux dans l'eau des deux stations fluviatiles durant toute la période d'échantillonnage (mai 2016 à août 2017) s'échelonnent entre 35 249 et 5000 UFC pour les coliformes d'une part et entre 2 et 600 UFS pour les streptocoques d'autre part. ...
    ... Variation spatio-temporelle de la teneur en N-NO3 au niveau des stations fluviatiles par rapport aux valeurs seuils deSkoulikidis et al. (2006) Variation spatio-temporelle de la teneur en N-NO2 au niveau des stations fluviatiles par rapport aux valeurs seuils deSkoulikidis et al. (2006) 1.3. BactériologieLes valeurs de coliformes et streptocoques fécaux dans l'eau des deux stations fluviatiles durant toute la période d'échantillonnage (mai 2016 à août 2017) s'échelonnent entre 35 249 et 5000 UFC pour les coliformes d'une part et entre 2 et 600 UFS pour les streptocoques d'autre part. ...
    Thesis
    Le but principal de cette étude est de comprendre le fonctionnement de la zone interface, continuum terre-mer au Liban. Suite à l’anthropisation spécifiquement la construction des barrages, les apports du fleuve vers la mer en termes de quantité et qualité, sont modifiés de nos jours. Le fleuve Ibrahim, ayant le débit le plus important parmi les fleuves libanais, interrompu par trois barrages, a été choisi comme étude de cas représentant les fleuves côtiers libanais. Les différents paramètres retenus ont permis de dégager des résultats intéressants. Au niveau de l’eau de surface marine le panache fluvial est décelé par l’étude des paramètres hydrologiques des masses d’eaux superficielles. Les résultats montrent aussi que l’apport fluviatile est le contributeur principal en nutriments au niveau de la région côtière durant la saison humide, élucidé par les teneurs en nitrates et silice dissoute. D’autre part, le transfert des particules de la zone côtière vers le large, à travers la pente continentale, se fait par l’intermédiaire de couches néphéloïdes.L’origine des sédiments et de leurs constituants est mise en relief en analysant plusieurs paramètres sédimentaires. La combinaison des paramètres granulométriques et géochimiques organiques et inorganiques et l’application des tests statistiques a permis de distinguer entre deux environnements de dépôt. (1) Les environnements littoraux (≤ 30 m) ou zone de « bypass » où le sable fin et la matière organique autochtone dominent. (2) Les environnements profonds (≥ 60 m) ou zones de dépôts où la fraction fine et la matière organique allochtone dominent.Sur l’ensemble du suivi l’état chimique de l’eau du fleuve au niveau des deux stations échantillonnées, déduit des teneurs en nutriments et macrofaune benthique, est considéré comme bon à très bon d’après les normes internationales Finalement, l’analyse des éléments traces métalliques confirme la faible contribution anthropique dans les stations marines et fluviatiles échantillonnées malgré la densité de population croissante au niveau de la région côtière Libanaise.
  • ... Physicochemical quality of the river tributaries was classified according to the Nutrient Classification Scheme (Skoulikidis et al. 2006) while for the lake, the OECD (1982), EPA (2000) and ECOFRAME (Moss et al. 2003) classification systems were applied. According to the OECD (1982) classification system, lakes are classified based on their water transparency, phosphorus and chlorophyll concentrations into five categories. ...
    ... The high nitrate concentration in PLC4 was mostly attributed to fish aquaculture facilities located just upstream the sampling site. Nevertheless, the nitrate concentrations overall were considered to be relatively low and the water quality status of the streams was classified as high, according to the adopted nutrient classification scheme (Skoulikidis et al. 2006), during the whole sampling period. ...
    ... , 0.22 mg/l PO 4 3-) could be attributed to the aforementioned fish aquaculture facilities (Karitsiotis stream). Based on the phosphate concentrations, apart from PLC1 and PLC4, which were classified as bad and poor water quality status, respectively, in July 2009, the rest of the stream sites varied from high to good, taking into consideration the threshold values (Skoulikidis et al. 2006). ...
    Article
    Human activities such as agriculture and tourism impose significant pollution threats in protected lake catchments worldwide. Plastira Lake is a highly touristic, artificial lake which is protected under the Natura 2000 European protection network. In this paper, the impacts from human activities, land uses and soil erosion on the lake’s water quality have been identified and quantified. Hydro-morphological and physicochemical data were collected bimonthly in 17 sites, both in the lake and in the associated catchment’s tributaries. Moreover, a soil erosion model was applied to estimate the annual soil erosion potential of the study catchment and identify its relationship with specific metal concentrations in the lake. A statistical analysis was conducted in order to ascertain the existence of a potential relationship between the basin’s total nitrogen (TN) and phosphorus (TP) loads and the relevant TN and TP concentrations in the lake. The results revealed the significant effects of human pressures in the lake catchment, the magnitude of which is still relatively low. The lake’s trophic status is mesotrophic with a tendency to eutrophy, and the existing soil erosion regime affects through the river tributaries, the lake’s phosphorus and Fe balance.
  • ... The seawater chlorophyll-a concentrations were determined with a TURNER 00-AU-10U fluorometer according to the method of Holm-Hansen et al. (1965), modified by Welschmeyer (1994). To classify the physicochemical status of the river's sites, the River Nutrient Classification System (Skoulikidis et al., 2006; Table 1) was applied for nutrients and the Norwegian system for dissolved oxygen (Cardoso et al., 2001; Table 1). In order to decide if a marine area is in "Good Environmental Status" (GES), it is necessary to establish threshold values for key parameters, in order to distinguish between acceptable (good) and unacceptable (not good) environmental conditions. ...
    ... KR1, KR2, KR3, KR4 and KR7 stations had higher dissolved oxygen levels than KR5, KR6 and KR8 stations, in which water was characterized as of good (KR5) and moderate quality (KR6-KR8), respectively. Nitrate concentrations were higher in stations KR2, KR3, KR4 and KR5 during the entire sampling period, while their water quality status was characterized as moderate (Table 4) according to Skoulikidis et al. (2006). The highest average nitrite, ammonium, and phosphate concentrations were measured at KR6, KR7, and sometimes at KR8 stations where the intensification of the pollutant pressures (agriculture, wastewater treatment plant output) were detected (Fig. 2). ...
    ... The average nutrients' variation regarding the stations located at the river estuary (KR7, KR8) and the sea stations (KR9-KR13), have been cross-examined in order to identify the potential influence of the Fig. 3. Temporal variation of river samples' nutrients for wet (1st column) and dry (2nd column) sampling periods (The blue, green, yellow, orange and red lines represent the threshold values for each nutrient in order each water sample to be classified as of high, good, moderate, poor and bad quality (Skoulikidis et al., 2006)). (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) ...
    Article
    Taking into consideration the Water Framework Directive's requirements, water samples were collected monthly and/or bimonthly between 2014 and 2015 from Spercheios River, its estuary and the adjacent Maliakos Gulf in order to assess the quality of these water bodies. A study on dissolved nitrate, nitrite, ammonium, phosphate and chlorophyll-a concentrations was carried out, to investigate the impact between the river and the associated coastal area and assess the nutrient loads based on water flows from Spercheios River into the marine system.Furthermore a seasonal distribution of nutrient concentrations have been studied, dividing the sampling period into dry and wet season according to the river's discharges.
  • ... The assessment of the environmental status of the river and marine waters followed the five-step classification scheme according to the WFD guidelines. Physicochemical assessment of the river was based on the five-step scale of Skoulikidis et al. (2006) for nitrates, nitrites, ammonium and phosphates, and Cadorso et al. (2001) for dissolved oxygen in the freshwater samples. The assessment of the trophic status and the ecological quality of coastal waters was based on the five-step quality scale, extrapolated from the computation of the Eutrophication Index (ΕΙ) of Primpas et al. (2010), which involves nitrates, nitrites, ammonia, phosphates and chl-a concentrations. ...
    ... Taking into consideration the average values of DO and nutrient concentrations, the overall physicochemical status of downstream stations KR7 and KR8 in Spercheios river, for the entire sampling period (2014)(2015), was assessed according to Skoulikidis et al. (2006) and Cardoso et al. (2001) (Fig. 10A). The bad quality at KR7 for both ammonium and phosphates is a strong indication of the impacts of the Lamia city waste water treatment plant that outflows near this site. ...
    ... The Eutrophication Index (ΕΙ) by Primpas et al. (2010) was another step forward and the extrapolated five-step ecological scale, which has been developed for the oligotrophic waters of the eastern Mediterranean and has been widely used ever since, mainly because it combines both pressures (nutrients) and responses (chl-a) in its formula. For river waters in Greece, a combined five-step quality scale by Skoulikidis et al. (2006) and Cardoso et al. (2001) is used extensively and is based on physicochemical characteristics. Both scales aim to assess and classify the physicochemical status of river waters in one of the five quality levels suggested by the WFD. ...
    Article
    This paper examines the response of phytoplankton and potentially harmful species to river inflows in an eastern Mediterranean coastal area, within the context of environmental status assessment suggested by the European Commission’s Water Framework Directive (WFD, 2000/60/EC) and the Marine Strategy Framework Directive (MSFD, 2008/56/EC). The spatio-temporal distribution of phytoplankton communities and biomass (as chlorophyll a), potentially harmful species, nutrient levels, dissolved oxygen, salinity and temperature were studied. A marginal good to moderate physicochemical status was assigned to downstream of River Spercheios that flows into Maliakos Gulf. Silicates and nitrates were indicated as proxies of freshwater influence in Maliakos Gulf, whereas ammonium, nitrites and phosphates as proxies of pollutants from non-point sources. Phytoplankton biomass and abundances reached high levels throughout Maliakos Gulf inter-seasonally. High silicates favoured the dominance of Diatoms. The potentially harmful species bloomed frequently, with higher levels in the estuary, and they were associated with low salinity, thus demonstrating the riverine influence on them. Pseudo-nitzschia was the most frequent potentially harmful genus with an interesting strong linkage with low silicates and nitrates. Maliakos Gulf demonstrated an overall mesotrophic condition and failed to achieve good ecological status.
  • ... Water quality monitoring at a river basin scale is a necessary approach in order to identify the dominant pollution pressures and design appropriate restoration measures where necessary. The recently introduced European Water Framework Directive (2000/60/EC) provides the legislative framework for analyzing the water related pressureimpacts relationships at a basin level and apply ecological monitoring schemes to ensure the achievement of good ecological status of the European water bodies by the year 2015 [1,2,3]. However, establishing water quality classification systems by estimating the reference conditions for each water body type is a difficult scientific task requiring long water chemical and biological data-series [3]. ...
    ... The recently introduced European Water Framework Directive (2000/60/EC) provides the legislative framework for analyzing the water related pressureimpacts relationships at a basin level and apply ecological monitoring schemes to ensure the achievement of good ecological status of the European water bodies by the year 2015 [1,2,3]. However, establishing water quality classification systems by estimating the reference conditions for each water body type is a difficult scientific task requiring long water chemical and biological data-series [3]. The particular scientific effort attempted to identify the dominant pressures at Spercheios river catchment and provide an insight on the spatiotemporal fluctuations of significant water quality parameters in the specific area. ...
    ... The water quality status for nutrients in the various sites in Spercheios river, according to Skoulikidis et al. [3] classification system, varies significantly. In particular, for NO 3 , Sp4 has a poor quality status in September 2009, while most of the sampling sites have moderate to bad status during the summer periods and good quality status during the high flow periods. ...
    Conference Paper
    Full-text available
    Identifying the dominant pollution pressures and establishing the associated pressure – impact relationship in a river catchment is a prerequisite for integrated water resources management according to the Water Framework Directive (2000/60/EC). Sperchios River is located in Central Greece, close to the historic area of Thermopyles. Sperchios catchment has a total extent of 1828 km 2 , with a mean altitude of 636 m and includes many ecologically important areas that are protected under the framework of Natura 2000 network (Oiti mountain, Sperchios river valley and Maliakos gulf). However, the particular river constitutes the recipient of substantial agrochemical loads from intensively cultivated areas in the Prefecture of Fthiotida as well as wastewater from nearby villages, cities and small industries. This has progressively led to the environmental degradation of the area and particularly of the river's water quality which constitutes a threat for the biological resources of both the river and Maliakos gulf. The Institute of Inland Waters of the Hellenic Centre for Marine Research undertook a project in 2009 to monitor the water quality status of Sperchios river, identify the pollution sources of the particular catchment and propose relevant management and mitigation measures. The results indicated that the central part of the catchment can be characterized as of moderate to poor water quality as far as nitrates are concerned. This illustrates a strong influence from agrochemicals that becomes evident in the river during the end of irrigation period (September). Additionally, in the lower part of the river (6 km upstream of the deltaic area), relatively high concentrations of NO2 and PO4 are observed which degrade the water quality status for the specific parameters to moderate – poor. The sudden increase of the particular parameters is caused probably by a nearby industrial facility (paper factory) that discharges effluents in a Sperchios tributary. The water quality status gets improved as we move towards Maliakos gulf due to the natural attenuation processes of the river Delta. Thus, the measurements of nutrients close to Sperchios outlet classify the river as of good chemical status in the particular area. Therefore, according to the Water Framework Directive, management and restoration measures should be designed and applied, immediately, in order to reestablish the good water quality status in the entire river. For this purpose, the irrigation abstractions from the river should be lowered through water saving schemes (eg underground canals and drop irrigation infrastructure) and alternative sources of water (recycling and small scale reservoirs) should be established. Moreover, agroenvironmental measures should be also promoted in the broader area (agrochemicals monitoring in the soil and adaptive fertilizing) to reduce the pollution pressures and the nutrient loads in the area.
  • ... Thus, in order to extensively survey the current extent of pollution in the study area, both water and bottom sediment samples were collected and analyzed (Forstner et al., 1983). Measured contaminant concentrations provide sufficient data for an environmental survey (Temnerud et al., 2005), however, the deviation of some chemical parameters from the well established correlations with geological properties (Skoulikidis et al., 2006) could also carry beneficial information. Statistical methods (Massart et al., 1983) have been proved indispensible in finding correlations between chemical parameters (Singh et al., 2005), which also facilitates the projection of chemical data to geographical characteristics (Lambrakis et al., 2004). ...
    ... The boiled-down and Ward's hierarchical cluster analysis (Massart et al., 1983). The correlation between certain chemical properties and the cluster structure of the samples are discussed in the view of the geological characteristics of the study area (Skoulikidis et al., 2006). MS Excel 2003, SPSS 11.5 and instrument controlling software were used for data treatment. ...
    ... Ward's cluster analysis classified the 19 samples into 4 clusters. Then dendogram of the cluster structure can be seen in Figure 2. The first 2 clusters represent the hydrographical structure of the study area (Skoulikidis et al., 2006) the fourth contains sites where traces of contamination were detected: E/3, E/5, E/6, E/15, E/17. Samples E/2 and E/18, which form the third cluster, are unique in a way that no other samples ...
    Article
    Full-text available
    A one-time environmental analytical study was carried out concerning small watercourses in the source region of Ier (Ér) Stream, a tributary to Barcǎu (Berettyó) River, in order to explore the extent of contamination and to identify main pollution sources. More than 70% of this land belonged to the marsh of Ier (Ér) before the 1960's when water control of the area resulted in a vast network of well-defined small watercourses. Water and bottom sediment samples were collected from 22 sampling sites on streams. The samples of both types were analyzed in accordance with the current Hungarian Standards. The chemical data were evaluated by principal component analysis and Ward's hierarchical cluster analysis and found to be in good correlation with the geological and hydrological characteristics of the study area. Evidence for anthropogenic contamination was found in 3 water samples out of the 22 collected.
  • ... In Greece, water quality and hydromorphological monitoring of all river and catchment sizes is systematically implemented on the last decades compared to other countries [18]. Based on Reference [18], till the early 2000s, approximately 35% of the total Greek runoff that enters the sea from river basins had unknown hydrological and hydrochemical regimes. ...
    ... In Greece, water quality and hydromorphological monitoring of all river and catchment sizes is systematically implemented on the last decades compared to other countries [18]. Based on Reference [18], till the early 2000s, approximately 35% of the total Greek runoff that enters the sea from river basins had unknown hydrological and hydrochemical regimes. Unfortunately, due to a lack of data, especially for small and medium catchments, the majority of the studies that deals with the water quality and the hydromorphological variability are only focused at catchment scale [15,[19][20][21][22][23][24][25]. ...
    ... Thus, our dataset consisted of 1002 records containing information on nine physicochemical and fifteen hydromorphological variables ( Table 2). In addition, the nutrient quality classification score (NCS) for each site was calculated according to the Nutrient-quality Classification System [18]. NCS was developed to fill the gap of chemical classification of small and intermediate Greek rivers influenced by nutrient pollution. ...
    Article
    Full-text available
    European rivers are under ecological threat by a variety of stressors. Nutrient pollution, soil erosion, and alteration in hydrology are considered the most common problems that riverine ecosystems are facing today. Not surprisingly, river monitoring activities in Europe have been intensified during the last few years to fulfil the Water Framework Directive (WFD) requirements. With this article, we present a nationwide assessment of the water quality and hydromorphological variability in Greek Rivers based on the results of the national monitoring program under the WFD. Water quality and hydromorphological data from 352 sites belonging to 221 rivers were explored with principal component analysis (PCA) to identify main environmental gradients and the variables that contribute the most to the total variance. Nitrate, phosphate, ammonium and electrical conductivity were identified as the most important water chemistry parameters, and typical vector-based spatial data analysis was applied to map their spatial distribution at sub-basin scale. In addition, we conducted simple linear models between the aforementioned parameters and the share of land uses within the basin of each sampling site in order to identify significant relationships. Agriculture was the most important land use affecting the nitrate and electrical conductivity, while artificial surfaces were the best predictor for phosphate and ammonium. Concerning the hydromorphological variability, fine types of substrate and discharge were the variables with the highest contribution to the total variance. Overall, the results of this article can be used for the preliminary assessment of susceptible areas/rivers to high levels of nutrient pollution that can aid water managers to formulate recommendations for improvement of further monitoring activities. Furthermore, our findings implicate the need for enhancement of agri-environmental measures and reduction of point-source pollution in disturbed areas to avert the risk of further environmental degradation under the anticipated global change.
  • ... Η λεκάνη του Αλιάκµονα διαµορφώθηκε κατά την Αλπική Ορογένεση µε τεκτονικά φαινόµενα και αποτελεί µέρος ενός µεγάλου τεκτονικού βυθίσµατος που χωρίζεται σε επιµέρους κλιµακωτά βυθίσµατα, του Αλιάκµονα, του Λουδία και των Γιαννιτσών (39). Σύµφωνα µα τους Hinsbergen et al. (2005), κατά το Κατώτερο Μειόκενο-Πλειόκενο (πριν περίπου 4-8 εκ. ...
    ... Ο Αλιάκµονας ανήκει στην υδροχηµική ζώνη ΙΙ (Skoulikidis et al. 2006), που χαρακτηρίζεται από υψηλές ποτάµιες συγκεντρώσεις µαγνησίου, πυριτίου και οξυανθρακικών, ως αποτέλεσµα της αποσάθρωσης βασικών/υπερβασικών πετρωµάτων. Τα νερά του κυρίου ρου, ανήκουν στον πλέον κοινό ελληνικό χηµικό τύπο, τον ασβεστούχο διτανθρακικό (Ca > Mg > Na > K -HCO3 > SO4 > Cl), όπου η συγκέντρωση του µαγνησίου είναι ελαφρώς µικρότερη αυτής του ασβεστίου (2,06 και 2,29 meq/l αντίστοιχα), ενώ η µοριακή σχέση Νa + /Cl -(1.5) µαρτυρά την επίδραση της αποσάθρωστης των όξινων µαγµατικών και µεταµορφωµένων πετρωµάτων της λεκάνης απορροής. ...
    ... Η µέση υπερετήσια (1980-2000) συγκέντρωση θρεπτικών στη θέση Ιλαρίων είναι: 3,64 mg/l N-NO 3 , 8,2 µg/l N-NO 2 , 0,14 mg/l N-NH 4 0.02 mg/l P-PO 4 . Με βάση τις παραπάνω συγκεντρώσεις, και σύµφωνα µε σύστηµα ταξινόµησης Ελληνικών ποταµών (Skoulikidis et al. 2006), η ποιότητα του ποταµού στη θέση αυτή είναι κακή ως προς τα νιτρικά και µέτρια ως προς τα νιτρώδη, την αµµωνία και τον ολικό φώσφορο. Σύµφωνα µε τα δεδοµένα και αποτελέσµατα των Skoulikidis et al. (2002) και το παραπάνω σύστηµα ταξινόµησης, η ποιότητα 16 σταθµών της υπολεκάνης απορροής του Ιλαρίωνα κυµαίνεται από υψηλή (3 σταθµοί στον άνω ρου), καλή (10 σταθµοί), µέτρια (2 σταθµοί) έως ανεπαρκή (1 σταθµός: εκροή λίµνης Καστοριάς). ...
    Technical Report
    Full-text available
    The project aims at proposing conservation actions for the ichthyofauna of Aliakmonas river, at the Development Area of the Hydroelectric Dam Ilarionas and so far entailed: (1) Collection of all available ichthyological, hydrological, physicochemical and biological data and also data on human impacts on the study area and (2) Preliminary sampling for the establishment of a network of stations, upstream and downstream of the dam.
  • ... To that effort, the (2002). In Greece the development of a classification system concerning fresh waters has taken place, named the Greek River Nutrient Classification System (GR_NCS) established by Skoulikidis (2006) & modified by Laschou (2010). This system is used in order to assess the physico-chemical status of the rivers and assign the quality class in which each station belongs. ...
    ... Also in Rhodes island (S. Aegean sea), the only fish species present in the rivers is Ladigesocypris ghigii species, a fact that raises concerns about the classification of the rivers (Gritzalis, 2006). ...
    Article
    Full-text available
    SUMMARY The purpose of the present work is to highlight serious problems resulting from the classification processes in the five grade quality scale as the EU Directive (2000/60/EC) requires concerning water and especially river ecosystems. We were led in this study upon the ascertainment of an imbalance which appeared at regular intervals by the various research programs being elaborated in Greece. Thus, after an experience which originated from studies conducted in hundreds of sampling stations, in different river types, in all seasons of the year and from contemplating the impact of different types of pollutants and especially the issue of reference conditions, the need for a different approach in the area of classification was revealed. Therefore, using this data and taking into account various parameters such as biodiversity, especially macroinvertebrate fauna, chemical and physico-chemical characteristics and of course hydro-morphology, we recognize and focus on the problem, wherein the weak points are being highlighted and subsequently a number of concrete solutions are being proposed. Of course, it should be taken into consideration seriously, that an undisturbed system and specifically an undisturbed river is a difficult concept, since from ancient times the modifications and arrangements of the rivers were a common phenomenon, which was accompanied by a variety of environmental descriptions. This procedure was essential and concerned human health, a regime that also applies today as it is evidenced by the recordings of various environmental conditions and extreme climatic events in conjunction with the various pollution loads.
  • ... Lower values were proposed by Smith et al. (2007; 0.98 mg/l) and Smith and Tran (2012; 0.3 mg/l) for wadeable rivers, based on the responses of invertebrates of large rivers and on diatoms and invertebrates, respectively. Skoulikidis et al. (2006;0.22 mg/l) found an even lower value for invertebrates of high-quality streams in Greece. An excess of nitrate can lead to waters clogged with fastgrowing algae and macrophytes (Hilton et al., 2006), while for animals the main toxic action of nitrate is the conversion of oxygen-carrying pigments, such as hemoglobin and hemocyanin, to forms incapable of carrying oxygen (Camargo et al., 2005). ...
    ... For orthophosphates our threshold (0.06) is slightly higher than the value proposed by Pardo et al. (2012) for the Central-Baltic European streams (0.04 mg/l) but close to the one proposed for Spanish Mediterranean streams (0.052) by Sanchéz-Montoya et al. (2012) and lower than the 0.1 mg/l proposed by Birk et al. (2012) for large rivers in good condition. Conversely, Skoulikidis et al. (2006) found a much higher threshold value of 0.125 mg/l. Low oxygen concentrations (b 35%) induce sublethal effects on macroinvertebrates, such as suppressed drift, but usually not mortality, which only occurs at very low saturation levels (b10%) for most insects and b 20% for mayflies (Connoly et al., 2004). ...
  • ... mg SRP/L with an average of 0.04 mg SRP/L. Skoulikidis et al. (2006) have proposed a Nutrient Classification System (NCS) for small/medium sized rivers in Greece based on annual average concentrations from 36 sites throughout Greece. According to this system, the river is classified as of moderate quality in relation to nitrates (0.6-1.3 mg N/L) and ammonium (0.06-0.20 mg N/L) and of high quality in relation to TP (0.17-0.22 mg TP/L). ...
    ... According to this system, the river is classified as of moderate quality in relation to nitrates (0.6-1.3 mg N/L) and ammonium (0.06-0.20 mg N/L) and of high quality in relation to TP (0.17-0.22 mg TP/L). Under other classifications, e.g., the nutrient quality classes in French and Italian rivers (Skoulikidis et al., 2006), the Louros river would be placed between a "Good" and "Moderate" class. At the same river and sub-catchments, macrophyte data (taxon name and abundance class) were collected and the IBR (Indice Biologique Macrophytique en Rivière -Macrophyte Biological Index for Rivers) was calculated by Manolaki et al. (2011) according to the methodology proposed by Haury et al. (2006). ...
    Article
    Full-text available
    When designing and implementing agri-environmental policies to reduce nutrient loss, action programmes may falsely address areas where the nutrient issue from agricultural activity is not currently important and is not likely to become so in the future (a false positive), or may fail to address areas where the agricultural nutrient issue is currently important or may likely become so in the future (a false negative). Based on a case study of the Louros watershed in Greece, this work identifies database and modelling sources of false positives and negatives and proposes a decision making process aimed at minimizing the possibility of committing such errors. The baseline is well simulated and shows that the Louro's watershed falls behind a Good Environmental Status, at least marginally. Simulated mitigation measures show that the river's status can be upgraded to “Good”, at least as concerns nitrates and ammonium. Simulated climate change does not seem to exert an important positive or negative effect. Land use changes forecasting considerably less cultivated area have a significant effect on Total Phosphorous but not on nitrates or ammonium concentrations. The non-linearity between nutrient disposition (inputs) and nutrient concentration in downstream water bodies (output) and the many factors that affect the nutrient disposition-transportation-concentration chain, highlights the importance of simulating the effects of mitigation actions and of future climate and land use changes before adopting and establishing agri-environmental measures.
  • ... Lower values were proposed by Smith et al. (2007; 0.98 mg/l) and Smith and Tran (2012; 0.3 mg/l) for wadeable rivers, based on the responses of invertebrates of large rivers and on diatoms and invertebrates, respectively. Skoulikidis et al. (2006;0.22 mg/l) found an even lower value for invertebrates of high-quality streams in Greece. An excess of nitrate can lead to waters clogged with fastgrowing algae and macrophytes (Hilton et al., 2006), while for animals the main toxic action of nitrate is the conversion of oxygen-carrying pigments, such as hemoglobin and hemocyanin, to forms incapable of carrying oxygen (Camargo et al., 2005). ...
    ... For orthophosphates our threshold (0.06) is slightly higher than the value proposed by Pardo et al. (2012) for the Central-Baltic European streams (0.04 mg/l) but close to the one proposed for Spanish Mediterranean streams (0.052) by Sanchéz-Montoya et al. (2012) and lower than the 0.1 mg/l proposed by Birk et al. (2012) for large rivers in good condition. Conversely, Skoulikidis et al. (2006) found a much higher threshold value of 0.125 mg/l. Low oxygen concentrations (b 35%) induce sublethal effects on macroinvertebrates, such as suppressed drift, but usually not mortality, which only occurs at very low saturation levels (b10%) for most insects and b 20% for mayflies (Connoly et al., 2004). ...
    Conference Paper
    The Mediterranean Rivers Geographic Intercalibration Group developed a 3-step approach that allowed the characterization of the best available condition of four Mediterranean common stream types, regarding organic contamination and nutrients, hydrological and morphological alterations and land use. For this purpose, a common database composed of 7 member states national reference sites sampled for invertebrates, diatoms and macrophytes was used, with an initial number of 929 sample records gathered in different seasons, but mainly in spring. After a first step, the analyses of reference sites, classified with no-impact for hydromorphological changes, revealed that medium- size streams (100-1000 km 2) with highly seasonal hydrological regime are the most affected by extensive agriculture in the catchment, while non-siliceous rivers (e.g., calcareous river bed) are the most affected by intensive agriculture. Small rivers (<100 km 2) are those with a higher % of semi-natural areas. Based on the previous sites selection, the 90th percentile (or/and the 10th percentile in case of inverse variables) was used to calculate threshold values for pressure variables by type. The results indicated a lower threshold value for DO (60%) in RM5 streams compared with the other stream types, which can be attributed to temporary streams’ natural characteristics, and was therefore retained for this stream type. For the remaining parameters (ammonium, nitrate, phosphate, total P, % of artificial areas, % of intensive and extensive agriculture, % of semi-natural areas) the differences between types were minimal and common limits were established. These values were further used to select the list of reference sites to be used in the Intercalibration Exercise within the Mediterranean areas
  • ... In this paper, the data series set contains 2376 records. In this way, a number of successively 10 methods of analysis were considered, in order to identify the main relationships and the causal 11 connection between the measured parameters (Skoulikidis et al., 2006;Li et al., 2008). 12 ...
    ... These substantial changes indicate the existence of groups of factors that combine differently and 19 present temporal changes (Skoulikidis et al., 2006). The dependent variables were chosen for each 20 group factor, taking into account the chemical interdependencies: e.g. ...
    Article
    Full-text available
    This paper presents the research on the temporal variability of water quality parameters for the most important river system in Romania and Europe – the River Danube. The data on the river water quality had been obtained between January 1990-December 1998. Using statistical methods as Principal Component Analysis (PCA) and Factor Analysis (FA), all the samples data sets were classified in order to determine seasonal variability of the water quality state parameters and to identify the key quality factors that cause variability. These procedures showed that more than 70% of the total variance can be explained by three main factors: a) the first factor (F1) is designated as tutorial involves inorganic human influence type and flow variations and provides a natural buffer system perspective of the ecosystem; b) the second factor (F2) is designated as the trophic factor; c) the third factor (F3) is related to the impact of anthropogenic activities. The analysis revealed that the weight of the three main factors is not the same during the year. This work highlights two major aspects: the first one is due to the fact that the site of research is the meeting point of the borders of three countries: Moldova, Ukraine and Romania. The second significant issue is caused by the fact that the study was conducted in the predeltaic area of the Danube Delta. This study carried out during 10 years, highlights the auto-epuration capacity of the Danube River. Researches of this type are extremely useful because there are no other previous studies of this complexity.
  • ... Finally, in order to investigate the reliability of the methodological approach, the output map was contrasted with the results of the National Monitoring Program 2012-2015 of the water status in Greece [88]. More specifically, for each of the 299 monitoring stations of the aforementioned project the quality status was estimated based on the Nutrient Classification System (NCS) [89] modified to also include dissolved oxygen concentrations [90] (Table 4) and after averaging each status. Then, the quality class of each station was contrasted to the class describing the need for river water quality monitoring. ...
    ... Quality status in rivers based on the Nutrient Classification System (NCS)[89] (copyright permission see Supplementary Materials) and dissolved oxygen concentrations[90]. ...
    Article
    Full-text available
    Water quality indices that describe the status of water are commonly used in freshwater vulnerability assessment. The design of river water quality monitoring programs has always been a complex process and despite the numerous methodologies employed by experts, there is still no generally accepted, holistic and practical approach to support all the phases and elements related. Here, a Geographical Information System (GIS)-based multicriteria decision analysis approach was adopted so as to contribute to the design of the national network for monitoring of water quality parameters in Greece that will additionally fulfill the urgent needs for an operational, real-time monitoring of the water resources. During this cost-effective and easily applied procedure the high priority areas were defined by taking into consideration the most important conditioning factors that impose pressures on rivers and the special conditions that increase the need for monitoring locally. The areas of increased need for automatic monitoring of water quality parameters are highlighted and the output map is validated. The sites in high priority areas are proposed for the installation of automatic monitoring stations and the installation and maintenance budget is presented. Finally, the proposed network is contrasted with the current automatic monitoring network in Greece.
  • ... Also, Kastro was not so impacted in order to be grouped together with the other site of Katsambas river (Chora). The main source of ammonia, phosphate and total phosphate are municipal wastewaters (Skoulikidis et al. 2006). Thus, human influence affects the hydrochemical quality of Samothraki's streams. ...
    Article
    Full-text available
    The European Landscape Convention (ELC 2000) defines landscape as “an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors.” The Convention promotes raising awareness of the value of so-called living landscapes, yet there are very few tools for assessing the conditions or quality of landscapes on the ground. A more participatory approach for appreciating and protecting landscapes is needed to provide support to communities in dealing with landscape change and associated threats and challenges.This work aims to introduce and apply a simple site-based assessment tool which guides evaluators such as students, public bodies and scientists. This visual assessment protocol is similar to rapid visual assessment protocols such as SVAP (Bjorkland et al. 2001), which are now used for monitoring streams and river riparian areas world-wide. Mediterranean insular cultural landscapes such as on Samothraki are especially difficult to assess with precision and accuracy due to the diverse natural history fabric and the influence of humans on the landscape for many centuries (Terkenli 2001). Our effort combines a qualitative and semi-quantitative assessment for landscape assessment and explores ways to validate the field protocol application
  • ... For the evaluation and classification of the physicochemical (Ph) quality of the sites, the Nutrient Classification System (NCS) was used (Skoulikidis et al., 2006). The index equally considers chemical quality based on nutrient concentrations nitrate (NO 3 ), nitrite (NO 2 ), ammonium (NH 4 ) and phosphate (PO 4 ). ...
  • ... As a result of increased carbonate rock dissolution, Greek rivers are enriched in solutes compared to European ones [14]; almost half of the variance of chemical data of major rivers was attributed to carbonate rock dissolution, while the remaining was explained by pollution, biological activity, and acid silicate rock weathering [9]. Greek and Balkan rivers belong to three north-south-extending hydrochemical zones, which simultaneously present distinct geological and climatic features [15,16]. Samothraki Island belongs to a zone with prevailing acid silicate rocks, minimum precipitation, river basins with high stream densities, narrow and shallow riverbeds, and relative low solute concentrations with high sulphate levels [17]. ...
    Article
    Full-text available
    Due to its rough, mountainous relief, Samothraki remains one of the last minimally disturbed islands in the Mediterranean. This paper examines the hydrogeochemical regime of the island’s surface waters as it results from geological, morphological, and hydro(geo)logical controls within a frame of minimally disturbed environmental conditions. Shallow, cracked groundwater aquifers, in combination with steep slopes and predominant weathering resistant rocks, bring about flashy stream regimes with remarkably low solute concentrations. Streams and springs revealed hydrochemical similarities. Contrary to streams chiefly draining sedimentary rocks, streams underlined by granite and ophiolite rocks do not respond hydrochemically to geochemical differences. Using ion proportions instead of concentrations, geochemical fingertips of magmatic stream basins were detected. Atmospheric inputs largely affect stream and spring composition, e.g., by 75% regarding sodium. Only 20% of dissolved oxygen and pH variance was assigned to biological activity, while nutrient levels were consistent with the undisturbed conditions of the island, except nitrate. Small mountainous springs and brooks fed by restricted, cracked groundwater aquifers with perennial flow, despite scarce summer rainfalls, may be fueled by cloud and fog condensation. High night-day stream flow differences, high atmospheric humidity predominately occurring during the night, and low stream water travel times point out toward this phenomenon.
  • ... However, there is no generally accepted definition for small, medium and large catchment sizes in the literature. For the purpose of Level 1 metaanalysis, the catchment boundary is defined by using Northern Ireland Water Framework Directive (2005) and Skoulikidis et al. (2006) as the references, with the small catchment size defined as 0 to 100 km 2 , the medium catchment size as 100 to 1000 km 2 and the large catchment size as above 1000 km 2 . ...
    Article
    Hydrological models play a significant role in modeling river flow for decision making support in water resource management. In the past decades, many researchers have made a great deal of efforts in calibrating and validating various models, with each study being focused on one or two models. As a result, there is a lack of comparative analysis on the performance of those models to guide hydrologists to choose appropriate models for the individual climate and physical conditions. This paper describes a two-level meta-analysis to develop a matching system between catchment complexity (based on catchment significant features CSFs) and model types. The intention is to use the available CSFs information for choosing the most suitable model type for a given catchment. In this study, the CSFs include the elements of climate, soil type, land cover and catchment scale. Specific choices of model types in small and medium catchments are further explored with all CSFs information obtained. In particular, it is interesting to find that semi-distributed models are the most suitable model type for catchments with the area over 3000 km2, regardless of other CSFs. The potential methodology for expanding the matching system between catchment complexity and model complexity is discussed. This article is protected by copyright. All rights reserved.
  • ... Numerous factors have an influence on trace element and uranium concentration in natural water, such as type of the aquifer, redox conditions, acidity/alkalinity, CO 2 and O 2 concentration, temperature, and presence of inorganic and organic compounds, colloids (Chabaux et al. 2008;Porcelli 2008). On the other hand, the increased levels of trace elements and radioactivity in natural waters could be the result of the past or current anthropogenic activities, including practices due to activities producing technologically enhanced naturally occurring radioactive material (TENORM) sources, like mining and phosphate industry (Chalupnik et al. 2001;Perianez 2005), or increased use of phosphate fertilizers (Skoulikidis et al. 2006). ...
    Article
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    Concentrations of 46 elements, including major, trace, and rare earth elements, and (238)U in Croatian tap waters were investigated. Selected sampling locations include tap waters from various hydrogeological regions, i.e., different types of aquifers, providing insight into the range of concentrations of studied elements and (238)U activity concentrations in Croatian tap waters. Obtained concentrations were compared with the Croatian maximum contaminant levels for trace elements in water intended for human consumption, as well as WHO and EPA drinking water standards. Concentrations in all analyzed tap waters were found in accordance with Croatian regulations, except tap water from Šibenik in which manganese in concentration above maximum permissible concentration (MPC) was measured. Furthermore, in tap water from Osijek, levels of arsenic exceeded the WHO guidelines and EPA regulations. In general, investigated tap waters were found to vary considerably in concentrations of studied elements, including (238)U activity concentrations. Causes of variability were further explored using statistical methods. Composition of studied tap waters was found to be predominately influenced by hydrogeological characteristics of the aquifer, at regional and local level, the existing redox conditions, and the household plumbing system. Rare earth element data, including abundances and fractionation patterns, complemented the characterization and facilitated the interpretation of factors affecting the composition of the analyzed tap waters.
  • ... Also elevated values of phenols, a characteristic compound of olive oil mill wastewaters, have been recorded downstream of Pamisos R. in recent former studies [5]. Additionally, according to the physicochemical classification of Greek and Balkan Rivers in quality classes, pursuant to the Greek River Nutrient Classification System [6], Pamisos R. has been classified as 'Bad' towards nitrates [7]. The physicochemical status of its estuaries was classified as 'Good' during 2012; however, according to the biological classification, it was classified as 'Poor' and it is currently subject to degradation [8]. ...
    Article
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    Abstract The Pamisos river basin, located at the southern part of Peloponnese, covers an area of 619 Km2 and is the biggest river area in the Prefecture of Messinia. A key feature is its rural character, dominated by olive groves. A characteristic of a smaller river, Lygdou, which joints Pamisos R. exactly before its estuaries, is the presence of an industrial zone within its catchment area. A great number of the active industries are located near the confluence with Pamisos R. Six sampling sites were established for nutrient analysis at the downstream portion and the estuaries of Pamisos R. and the stoichiometric nutrients balance was calculated. Nitrates were rather higher during the dry period while the concentration of ammonia was recorded higher during the wet period. The station of Lygdou seems to curry the highest load of almost all nutrient species, with extremely elevated values of phosphates, nitrates and ammonia, thus charging the estuaries of Pamisos R. with considerable amounts of nutrients. The N:P ratio was found to be much higher than the theoretical value indicating that phosphorus is the limiting factor for phytoplankton growth during the dry period. The results indicate that great quantities of both nitrogen and phosphorus are transferred towards the mouth of Pamisos river and the Messinian Gulf. The large agricultural areas present in combination with the great olive oil activity and the vast quantities of olive oil wastewaters generated annually are responsible for the enrichment of the ecosystem with these elements.
  • ... Classification of the Chemical-Physicochemical status of Arkadikos R. took place according to the Greek River Nutrient classification system [21,22]. The classification system of the chemical-physicochemical status of the rivers applied constitutes a development of the classification system developed by Skoulikidis 2006 [21] and refers to geographical zone 3 to which the study area belongs [22]. ...
    Article
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    ABSTRACT Various quality assessment methods have been developed over the past decades in order to estimate the pollution loads and their impact on river water quality, by taking into account among other things the analysis of pressures, including the discharges coming from small industries and the leaching from adjacent croplands. In the present research we considered such methods for assessing quality with a special emphasis on monitoring, as the European Directive of 2000/60/EU requires. The aim of the study is to determine both the physicochemical and biological status of the river and link it to the current pressures. As an indicative ecosystem, River Arkadikos was chosen, located in Messinia Prefecture which flows into Kyparissiakos Gulf and receives great quantities of olive oil wastewater annually. This constitutes the major issue concerning river pollution in the prefecture since no treatment method is currently applied and the wastes result in nearby streams. Several chemical parameters were recorded such as total phenols, pesticide residues of 90 active substances, trace metals, nutrients and particulate organic carbon. Subsequently, the assessment method of river quality, River Habitat Survey was applied and the STAR_ICMi biological indicator was calculated. The downstream part of Arkadikos R., as it is evident from the physicochemical and biological results, was found to be severely downgraded during the winter period of 2011 which can be partly attributed to the impact of olive oil waste waters. The system seems to recover during spring, since the values of the parameters were drastically decreased but the pollution burden is shifted towards pesticides whose values were recorded elevated. KEYWORDS: river, pollution, habitat survey, nutrients, pesticides.
  • ... The station was also classified according to the Greek River Nutrient Classification System (Laschou, 2010). Aquatic macroinvertebrate organisms were sampled with the worldwide used method of RIVPACS (Armitage et al., 1983; Alba-Tercedor Classification according to the Greek River Nutrient Classification system: The chemical and physicochemical characteristics were recorded and the station was classified pursuant to Tables 1 and 2 according to the Greek River Nutrient Classification system, Laschou (2010), which constitutes a development of the Skoulikidis et al. (2006) classification system and refers to geographical zone 3 in which the study area belongs (Fig. 2). ...
    Article
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    The wetland of Aghios Floros is located in the Prefecture of Messinia (S. W. Peloponnese, Greece) and occupies a small area, covered permanentlywith water. Flooding of the surrounding area is defended by an artificial channel that discharge large quantity of water into Pamisos River in whose river basin the Aghios Floros station belongs. At the sampling site various physico-chemical and conventional pollution parameters as well as hydrochemical variables were measured during the wet and the dry period of 2011. The hydromorphological and multihabitat approach of RIVPACS method was applied in situ, which gives an overall image of the landscape. The site was classified as 'Good' according to the Greek River Nutrient Classification System (GR.NCS) and the benthic macroinvertebrate fauna assemblages that dominated the area pointed out a 'Good' biological status as well. The biotic and abiotic sample processing, carried out in compliance with the demands of the Water Framework Directive, in general revealed high ecological status of the station. Specifically, a rich diversity and abundance of some macroinvertebrate families was recorded and regarding the aquatic flora the area is dominated by the water lilies species of Nymphaea alba which are unique in the area of Peloponnese.
  • ... Water samples were collected in plastic bottles (250 mL), stored at 4°C, transferred to the lab, and analyzed for major ions (Cl À 2 , NO À 3 , NO À 2 , NH þ 4 , PO 3 À 4 , and SO 2 À 4 ) and total suspended solids (TSS) using a HACH Lange-DR2800 Spectrophotometer. Chemical classification of sites according to the requirements of the Water Framework Directive 2000/60/EC was achieved by the application of the Nutrient Classification System (Skoulikidis et al., 2006), in which sites are classified into one of five chemical quality classes according to the concentration of N-NNO À 3 , N-NH þ 4 , N-NO À 2 , and P-PO 3 À 4 . Two alternative approaches were applied, calculating (i) the least chemical quality, expressed as the lowest observed quality class among the four nutrient concentrations and (ii) the mean chemical quality, calculated by assigning a score at each nutrient quality class and averaging. ...
    Article
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    Freshwater macroinvertebrates face numerous stressors at different spatial scales, challenging river managers to identify the most appropriate, to initiate a successful river restoration. To address this, 45 samples from 13 sites located in a regulated and temporary Mediterranean river network were analyzed. Sites were separated according to hydrology and classified into four zones based on land use. Chemical analysis was undertaken prior to macroinvertebrate sampling, and a chemo-biological classification was performed. Canonical correspondence analysis (CCA) and analysis of similarities were used to identify statistical differences between the various groups. Unacceptable quality according to the Water Framework Directive 2000/60/EC was revealed for 60% of samples. Significant correlations were detected between land use and biological indices. Agriculture was the major factor influencing macroinvertebrate distribution, and significant taxonomic differences were identified between natural and agriculturally impacted sites. Flow regime alterations from water regulation and desiccation resulted in significant reduction in macroinvertebrate density. The small difference between explained/unexplained variance (45%/55%, CCA) suggests that land use and local in-stream factors together influence macroinvertebrate assemblages. We conclude that in regulated/temporary rivers, land use and flow-related pressures exert strong influence on freshwater invertebrates and should be given equal importance as local in-stream factors, for sustainable river restoration.
  • ... Several authors question the validity of the law of average stream lengths if Strahler's segment-ordering technique is applied [25,[27][28][29]. In fact, the relation does not hold closely for individual streams [30]. In order to obtain Horton's stream lengths ratio, R L using Strahler's ordering, it is essential to use the cumulative mean stream length method [25]. ...
    Article
    In this study, ten Indiana basins were selected to investigate their geomorphologic characteristics. The drainage area of these basins covers a wide range. Stream networks of these basins are classified according to both Strahler’s and Shreve’s ordering systems. Based on these ordering systems, more than twenty primary and secondary geomorphologic parameters were determined for each study basin. Horton’s laws of stream numbers, stream length and stream area were checked and found valid for these Indiana basins. Values of cumulative drainage area were used to investigate the exceedance probability distribution of mean annual discharge and energy fluxes in the study watersheds. The results of the study show that discharge and energy fluxes were found to follow power law distributions. Exponent of the resulting power laws does not show the universality suggested by previous investigations.
  • ... ,主要包括以下几个环节:1)利用非点源污 染评估工具识别关键源区。经验模型和机制性模型能够 对流域内非点源污染的关键源区进行划分,并对不同 BMPs 类型及其污染物削减效率进行较好的表征。如 SWAT ( soil and water assessment tool ) [5] 、 AGNPS (agricultural nonpoint source pollution model) [6] 、HSPF (hydrological simulation program-fortran) [7] 、输出系数 模型 [8] 、磷指数 [9] 等;2)利用经济评估模型对不同空间 位置的 BMPs 成本进行分析。随着计算机技术的发展, 多数研究均通过构建 BMPs 初选评估体系或 BMPs 数据 库的方式来辅助实现 [10] ,可在很大程度上提高优化算法 的运行效率和评估准确性;3)利用最优化算法程序解决 流域非点源污染最佳管理措施的成本—效益的最优化求 解问题。其主要通过广泛的、非线性的以及非连续性的 解空间的寻优运算 [11] 。有学者对此类问题进行了研究, 但还存在一些不足,如 Gitau 等的研究虽然获取了小尺 度区域的最优 BMPs 配置方案,但并未解决多目标决策 问题,且未提供最优化方案的成本—效益曲线 [12] ;相比 较而言,Bekele 等的研究虽然有关于成本—效益曲线的 相关描述,但是仅仅是针对于 BMPs 成本与泥沙负荷量 之间的关系,因此其在 BMPs 的类型选择方面就具有较 大的局限性 [13] ;Arabi 等的研究虽然提供了不同污染物削 减效率及其 BMPs 成本之间的成本—效益曲线,但是其 环境目标是以污染物的加权负荷量来表示的,因此在其 研究中并未对不同营养物质的削减效率进行较为明确的 表示 [14] ;Rabotyagov 等的研究工作与之前几位学者的工 作之间有较大的不同,其以 3 个决策标准的最小化为基 础,提供了不同营养物质的成本—效益评估曲线 [15] ...
    Article
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    Eutrophication caused by the enrichment of nutrients from diffusing sources is degrading surface water quality throughout the world, while an increased loss of agricultural nutrients is a growing concern for water quality in drinking water areas of Beijing. Best management practices (BMPs) have been proven to actually reduce nitrogen (N), phosphorus (P) and sulfur (S) pollutant loads from agricultural areas. However, in a watershed with multiple farms and multiple BMPs feasible for implementation, it becomes a daunting task to choose the right combination of BMPs that provides maximum pollution reduction with least implementation costs. Several studies have shown that best BMPs are effective in controlling water pollution. However, those issues affecting water quality need water management plans that take into consideration BMPs selection, placement and affordability. In this study, a framework of "Risk assessment - Planning and zoning - differentiated management" was developed, and it included three tools: 1) A new "risk assessment" tool was introduced for potential loads estimation of N, P and S pollution in BeiZhai small watershed by analyzing social economic data, land use, soil type, water and soil conservation practices and agricultural management measures under current conditions, and then the critical source area was identified according to the pollution loads based on GIS technology; 2) A multi-criteria index ranking system for the BMPs was devised. First, each individual second-level index was assigned a numeric value that was based on site characteristics and information on LIDBMPs. The quantified indices were normalized and then integrated to obtain the score for each first-level index. The final evaluation score of each BMP was then calculated based on the scores for the first-level indices. Finally, the appropriate BMP types for a specific installation site were determined according to the rank of the final evaluation scores, and furthermore the final scores could be served as a first screen and selective reference for the BMP placement and optimization in next step; 3) Three typical areas with different spatial scales were extracted from the BeiZhai small watershed, and a Non-dominated Sorting Genetic Algorithm (NSGA-II) was selected as an optimization engine to evaluate the optimal fitness of each BMP combination based on the initial pollutant loadings, targets of pollutant reduction and the costs of BMPs implemented at different spatial scales. The results indicated that: 1) Potential risk evaluation of non-point source pollution in the study area proved that the potential of non-point source pollution was closely related with land use patterns affected by human activities; 2) Comprehensive index values for different measures in a descending order were constructed wetlands, infiltration basin, green roof, wet detention pond and porous pavement, and these could be used as the main practices for the BMP planning; 3) The pollutants loads were reduced by 45% while the total cost (TC) was 574 560 yuan for watershed scale, the pollutants loads were reduced by 46% while the TC reached to 374 660 yuan for the community scale, the total N and P load was reduced by 65% while the TC reached to 1 518 yuan for the farm scale. Therefore, this framework can be served as a decision-making support for non-point source pollution control in the upper watershed of Huairou Reservoir.
  • ... NH 4 (mg L À1 ) concentration was determined using a Skalar automatic analyzer. Ecological quality assessment based on nutrients was made following Skoulikidis et al. (2006). ...
    Article
    Full-text available
    The extreme seasonal environmental variation of intermittent rivers has a profound effect on freshwater fish communities. Yet, few studies have examined the consequences of the seasonal cycles of flooding and drying to fish condition and reproduction in these ecosystems. In this study, we compared the body condition, reproduction and diet of two chub populations from two adjacent sites (a perennial and an intermittent site) on the main stem of a Mediterranean river (Evrotas River, S. Greece). The study was conducted in spring 2017, three months after flow resumption and before the onset of chub reproductive period. Condition (net weight adjusted for length) of fish did not differ significantly between the two sites, despite lower aquatic macroinvertebrate availability at the intermittent site. Fish at the intermittent site compensated for the lower aquatic prey availability by increasing their feeding intensity and by shifting to higher terrestrial prey consumption. In addition, chub liver weight (adjusted for length) and gonadal weight (adjusted for length) were significantly higher at the intermittent site, indicating higher somatic and reproductive investment. These results highlight the resilience of fish populations inhabiting streams with extreme variation in flow, due to natural and/or anthropogenic drought.
  • ... Based on the Nutrient Classification System (NCS) (Skoulikidis et al., 2006), the chemicalphysicochemical quality of the streams ranged between high and good, except of two sites on Lakkoma and Katsambas streams, which ranged between moderate and poor, due to the impact of untreated municipal wastes. ...
    Conference Paper
    Full-text available
    Samothraki is a northern Aegean island with unique natural features. The island supports extensive perennial flowing streams, many small wetlands and ancient riparian woodlands; these ecosystems are scarce in the smaller Aegean islands. Focusing on the island’s freshwaters during the last fifteen years, HCMR has investigated 20 stream basins, 21 cold springs, 2 hot springs, 15 wetlands and 12 micro-wetlands. Our focus on the island gave rise to a cooperation agreement between HCMR and the Municipality of Samothraki aiming in establishing an observatory for long-term research, education and conservation. This initiative has formed a linking network among scientists which we call Samothraki Nature Observatory.
  • ... In view of the spatial and time variations in the hydrochemistry of surface waters, regular monitoring programs are required for reliable estimates of the water quality; thus, a large number of methodologies have been developed to assess ecological quality of running waters (Singh et al. 2004;Skoulikidis et al. 2004;Shrestha and Kazama 2007;Varol et al. 2012). For chemical-physicochemical quality assessment, various methods have been developed, such as classification systems (House and Ellis 1987;Skoulikidis et al. 2006), pollution indices/metrics (Brown et al. 1972;Skoulikidis et al. 2004), and emission-based models (i.e., empirical developed equations on nutrient emissions from various land uses) (Kronvang et al. 2003;Dodds and Oakes 2004;Woli et al. 2004). ...
    Article
    Full-text available
    In this work, a comparative study on the water quality characteristics of two in-line water reservoirs (artificial lakes) in Aliakmon River (Western Macedonia, Greece) is performed. Polyfytos Reservoir and Ilarion Reservoir were created in 1975 and 2012 respectively, in order to serve the homonymous hydroelectric stations. In young artificial lakes, severe deterioration of water quality may occur; thus, the monitoring and assessment of their water quality characteristics and their statistical interpretation are of great importance. In order to evaluate any temporal or spatial variations and to characterize water quality of these two in-line water reservoirs, water quality data from measurements conducted from 2012 to 2015 were statistically processed and interpreted by using a modified National Sanitation Foundation water quality index (WQI). The water physicochemical characteristics of the two reservoirs were found to be generally within the legislation limits, with relatively small temporal and spatial variations. Although Polyfytos Reservoir showed no significant deviations of its water quality, Ilarion Reservoir exhibited deviations in total Kjeldahl nitrogen, nitrite nitrogen, total suspended solids, and turbidity due to the inundated vegetation decomposition. The conducted measurements and the use of the modified NSFWQI revealed that during the inundation period of Ilarion Reservoir, its water quality was “moderate” and that the deviations were softened through time, leading to “good” water quality during its maturation period. Three years since the creation of Ilarion Reservoir, water quality does not match that of Aliakmon River (feeding water) or that of the stabilized reservoir (Polyfytos Reservoir), whose quality is characterized as “high.” The use of a WQI, such as the proposed modified NSFWQI, for evaluating water quality of each sampling site and of an entire water system proved to be a rapid and relatively accurate assessment tool.
  • ... The STAR_ICMi multimetric index (Buffagni et al. 2007) was used to assess the biological status of the sites. For the evaluation and classification of the physicochemical status, the Nutrient Classification System (Skoulikidis et al. 2006) was used that includes two indices; the organic pollution index (N-NO2-, N-NH4+ dissolved oxygen and BOD 5 ) and the chemical pollution index (N-NO3-, P-PO43-, total P and total phenols). For the ecological status classification, the worst quality element (biological and physicochemical) was considered according to REFCOND (2003). ...
    Conference Paper
    Full-text available
    Within the past half century Mediterranean rivers have experienced a runoff decrease of about 20% and in many cases natural flow has disappeared. Water scarcity can be attributed either to natural climate variability (meteorological droughts) or to direct (water resources exploitation) and indirect (climate change) anthropogenic pressures or a combination of both. Apart from water scarcity, many freshwater ecosystems in Mediterranean countries have to countenance and tackle the problem of olive mill wastewater (OMW) pollution, which is one of the major and most challenging organic pollutants in these countries and when discharged in receiving waterways, may cause severe adverse effects. In this study, the influence of potential water scarcity to the ecological status of streams receiving OMW and its interaction with the self-purification capacity of such streams was evaluated. For this purpose, several sampling sites of different typological character (i.e. mountainous vs. lowland; permanent vs. intermittent) were selected and monitored upstream and downstream the outflow of olive oil mills. Water quality and aquatic communities were severely deteriorated during the wastewater discharge period. Streams receiving OMW ranged from moderate to bad ecological status according to stream typology and adverse effects were more pronounced at lowland intermittent streams, than mountainous and permanent ones. The typology (i.e. slope, altitude) and hydrology of the stream site (i.e. perennial or intermittent) and the intensity and volume of the wastewater were the most important determinants of self-purification processes. The outcomes of this study demonstrate that the capacity of the streams for reducing the effects of polluting substances through internal mechanisms of self-purification will be significantly affected under water scarcity and climatic change.
  • ... The Directive renders monitoring of temporary rivers mandatory, even though their hydrological and biogeochemical behaviors are still not well understood (Jacobson et al. 2004). Temporary river ecosystems, which were not included in previous water legislation, are extremely sensitive to inputs of domestic and agricultural water, both point and non-point sources of pollution (Skoulikidis 2008;Skoulikidis et al. 2006). In this context, water quality indexes (WQI) appear to be a practical way to evaluate and compare the level of chemical contamination of different water bodies in different geographic locations (Barcelo-Quintal et al. 2013). ...
    Article
    Full-text available
    Water quality indexes (WQI) are a practical way to evaluate and compare the level of chemical contamination of different water bodies and to spatially and temporally compare levels of pollution. The purpose of this study was to check if these indexes are appropriate for intermittent rivers under arid and semi-arid climates. A literature review enabled the comparison of 25 water quality indexes to discern their capability to evaluate spatial (inter and intra catchment) and temporal (high and low water flow conditions) variations in water quality in three Mediterranean intermittent rivers: the River Vène (France) and the Oued Fez and the River Sebou (Morocco). Hierarchical cluster analysis identified groups of WQI with similar behavior and brought to light the 6 most distinguishing indexes. Whatever the hydrological conditions at the two sites, both the ME-MCATUHE and NCS indexes, which were developed for Morocco and Greece, and the CCMEWQI and BCWQI indexes, which were developed for non-arid or semi-arid zones, gave appropriate water quality evaluations.
  • ... For example, both landscape and geological factors in the US have a strong influence on stream chemistry during summer stormflows when hydrological connections are strongest, than during autumn baseflows, when only geological influences are significant Pionke et al. 1999). Pollutant concentrations for different sites and environmental phases can therefore be highly variable spatially and temporally, and evaluations and interpretations have to be carried out carefully (Interlandi and Crockett 2003;Skoulikidis et al. 2006;Ayoko et al. 2007). ...
  • ... In circumstances where excess P results in greater biomass, waters may become hypoxic as plants die off and the decomposing biomass causes further decline in the amount of DO. Phosphorus in surface waters not impacted by human activities is generally very small (<10 µg/L soluble reactive phosphorus, SRP); this is generated by the natural bio-geo-cycling of phosphorus [5]. This low level of naturally occurring P is important and is usually sufficient to maintain " normal " biological productivity in aquatic systems. ...
    Article
    Full-text available
    An oversupply of Phosphorus in water bodies accelerates growth of algae and higher forms of plant life to produce undesirable impacts on overall water quality. Phosphorus inputs to surface waters arise from a variety of point and nonpoint sources. However much of the P is contributed by agricultural runoff and outfall of treated (or untreated) wastewater in receiving water-bodies. Point sourced-P inputs to waters have considerably decreased in recent years, at least partly driven by regulatory requirements, e.g. the EU Water Framework Directive. This has largely been achieved by removing P from treated wastewaters at sewage treatment works (STWs). Studies have shown that introducing an additional treatment step (“P-stripping”) can significantly reduce P in STW outfalls. Given P deposits are depleting, there is much interest in phosphorus recovery from wastewaters. A few STWs have already started to recover P as struvite (NH4MgPO4.6H2O) mineral – a substitute for commercially produced P-fertilizers. This requires major investment and is not economically viable at small STWs. Nonetheless it is a major breakthrough in terms of P recovery and its use. Effluents from sewage treatment works (STW) can often contain a complex mixture of residual microcontaminants, not removed during wastewater treatment. Organic micro-pollutants have been found in rivers receiving STW effluents. Such residual contaminants have become the focus of an emerging field of water quality study and are collectively referred to as pharmaceuticals and other personal healthcare products, PPHCPs. Many of these chemicals have the ability to effect the hormonal signaling of organisms and are called endocrine disrupting compounds (EDC). Such chemicals have shown some of the most damaging biological effects in aquatic organisms. Biological effects in the aquatic environment are typically related to the development of intersex in fish. Recent research shows the use of STW practices such as upgrading from using a combined trickling filter contact process to activated sludge treatment, ozonation, membrane filtration and use of suspended biofilm reactors reduces the amount of EDCs in waste effluent. It is thus possible to remove contaminants from STW effluents, but it will not be possible without major infrastructure improvements. This paper presents the challenges and prospects of P and micro-organic pollutants in surface waters.
  • Conference Paper
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    River Epis is located in southwestern Peloponnese, its basin covers an area of 61.6 km2, it is open to the Messinian bay from the east and its main feature is its rural character. The vast majority of the industrial units in the area is held by olive mills (76%), most of which operate at three phases producing large quantities of wastewaters which are discharged into the aquatic environment. The average annual olive oil production in the prefecture is 50.000tn, the majority of which takes place in the western part of the prefecture where the studied river basin belongs. Classification of the river, shortly before its estuaries, into quality classes took place based on biological indicators, specifically according to STAR ICMi index, which is accepted across Europe, as well as according to the indexes BMWP, IBMWP (Spanish Version) and ASPT, using the RIVPACS methodology which is based on multi-habitats and provides information concerning hydrogeomorphology, riparian conditions, anthropogenic pressures and land uses. The water quality of river Epis was found to be significantly disturbed and far beyond the 'Good status' that all river sites should attain by 2015 as the EU Directive 2000/60/EC requires. The station was classified as Poor during the wet period of 2013 and as Moderate during the dry period based on all the indicators except ASPT according to which its status was classified as Bad during the wet period. The use of benthic macroinvertebrates, which constitutes the most prevalent method for estimating the quality of inland waters in Europe for decades, pointed out the severity of the situation and at the same time it was also proven that olive mill wastewaters may cause dramatic effects on aquatic fauna.
  • Conference Paper
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    River Lygdou is located at the southwestern Peloponnese, its river basin covers an area of 18,7 km2 and its address is north-south and open to the Messinian Bay from the south. The morphological relief is characterized as flat based on Dikau’s grading and the average altitude is 9.5m. The specific water catchment area is dominated by agricultural activities and the majority of crops are annuals. The rice fields are met at 27.4%, the permanently irrigated land at a rate of 24.8% while olive groves and complex culture systems follow with smaller percentages. Two distinctive features of the basin are the presence of an industrial area, which occupies the 4.8%, and the existence of a CORINE biotope section within the Lygdou river catchment area. This water system is strongly influenced by the surrounding agricultural land as demonstrated by the study of the physicochemical parameters and particularly the study of the benthic fauna. The aquatic macroinvertebrate organisms were collected by the RIVPACS method which is based on multi-habitats. This data was inserted in the AQEMdip 2.6 database, created through the European projects of AQEM and STAR and subsequently was transferred in the ASTERICS program in order to calculate the STAR biotic indices and the indicators BMWP, IBMWP (Spanish Version) and ASPT. On the basis of the biological results no improvement was recorded during the dry period of 2013, in comparison to the wet, something that was observed regarding the chemical and physicochemical results and the biological status of the station was classified as 'poor' based on most of the above indicators.
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    Increasing demand for irrigation water leads to reuse treated wastewater as an alternative source, especially in countries facing water scarcity. Besides its benefits, wastewater reuse in irrigation may pose health and environmental risks if applied in an uncontrolled manner. There exist a number of wastewater reuse standards and guidelines for agricultural irrigation in various countries. In this study, available guidelines and standards were reviewed and classified according to microbiological parameters, metal concentrations in reused water, and irrigation water quality parameters. These are presented for various countries with the aim of providing an insight to authorities, institutions, and decision-makers. Upon investigation of the set values, it is seen that the quality limits differ from country to country, and that implementing a single standard seems to be difficult due to national and/ or local circumstances. In parallel to scientific evidence and technological advances, continuous improvement in revising/ expanding the existing standards and guidelines is expected. Besides, control and monitoring of efficient reuse applications along with training of the public should be encouraged.
  • Article
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    This review presents the main results of a 10-year research study conducted in a Mediterranean intermittent basin (Evrotas River). By assembling the main outcomes of past and ongoing research projects, this study provides an overview of multiple stressor effects, with emphasis on water scarcity , focusing on hydro-biogeochemical processes, as well as on spatial and temporal variations in benthic macroinvertebrates and fish fauna. The major impact in the basin has been the over-exploitation of surface and groundwater resources, which, in combination with droughts, has resulted in the recurrent artificial desiccation of large parts of the hydrological network. The response to intermittency of the macroinvertebrate fauna is characterized by high resilience through various drought-resistant evolutionary mechanisms, with assemblages recovering successfully after recurrent droughts. However, when pollution is evident in combination with drought, effects on benthic species richness, abundance, and assemblage structure can be severe. Similarly, pollution and water stress may result in massive fish mortalities due to hypoxic conditions, with fish populations requiring long periods to recover. However, the fish fauna appears to be relatively resilient to drought-driven reach-scale desiccation, and ultimately recovers, provided that aquatic refugia are available to supply colonists and that there are no physical barriers impeding recolonisation. Appropriate conservation measures are urgently required to address the effects of recurrent bouts of water stress, as well as of other stressors on the freshwater communities of the Evrotas River, both at the level of water management and of water policy and at the local and the national level.
  • Conference Paper
    Full-text available
    Karyas River is located in the prefecture of Messinia, in southwest Peloponnese, its catchment covers an area of 65.3 km2 and the surrounding region is dominated by complex farming systems (20.4%) and olive groves (13.1%). The average altitude in the catchment is 331.5m and the mean slope of the terrain is 8.0ο. The related pressures are primarily the olive mill wastewater disposals and the burden from fertilizers and pesticides that comes from the surrounding croplands. The chemical and physicochemical classification of the station was carried out according to the Greek River Nutrient Classification System under which each quality element takes a value depending on its concentration and the average of these values defines the class in which the station belongs. Alongside, a classification of the station was held on the basis of several biological indicators (STAR ICMi, BMWP, IBMWP-Spanish Version and ASPT) by implementing the modified AQEM protocol during the sampling of benthic macroinvertebrates. The biological results, which capture in a greater depth and with higher accuracy the image that prevails in a station in comparison with the chemical parameters, highlighted the degradation that is present by classifying the station either as poor or bad, during winter and spring of 2013 according to most of the above indicators. The few macroinvertebrate families found were in low abundance and the species recorded are considered to be resistant towards pollution. The physicochemical classification showed that the water quality is downgraded during the wet period and the slight improvement during the dry period indicates that pollution could be seasonal. Contrary the biological results indicated that no improvement takes place in the river’s status during the dry period.
  • Article
    The study aimed at the attempt to identify and to evaluate the interaction intensity, and to classify the sources of river waters nutrients in the catchment of upper river Narew within Narew National Park (north-eastern Poland). The studies were carried out on Narew river within borders of Narew National Park, where 5 measurement-control points were localized as well as one near estuaries of its 5 tributaries (Awissa, Czaplinianka, Horodnianka, Turosnianka and Suprasl). Factor analysis (FA) from multi-dimensional group was applied for statistical processing of study results, because it iscommonly used to describe and explore a large number of data. concentrations of analyzed chemicals depended on a water sampling point that was under anthropopression and geogenic conditions. Studies and results from analyses (FA and CA) allowed for identifying the main sources of river Narew nutrients within Narew National Park. These are: tributaries of river Narew, point and distributed runoffs, as well as shallow ground waters that transport components having anthropogenicand partially geogenic-lithologic origin. River Turosnianka supplies the largest loads of studied parameters to river Narew within Narew National Park boundaries. River Suprasl is the most contaminated tributary of river Narew.
  • Article
    Full-text available
    As a tool for stock identification the body morphology and the free amino acid (FAA) profile variability were determined among farmed rainbow trout Oncorhynchus mykiss (Walbaum 1792) from different geographical areas throughout Greece, using geometric morphometrics and Reversed Phase-High-Performance Liquid Chromatography. Significant intraspecific body shape variation was detected among the fish stocks of different origin. Canonical Variate Analysis distinguished populations into two groups being consistent to a great extent with a previous population genetics study. General linear models did not support an association of haplotypes and diet with shape. However, shape was significantly correlated with origin, water temperature, geological-chemical-climatic zones, histidine and arginine. Therefore, morphological variation was primarily driven by environmentally induced differences among these zones being the result of phenotypic plasticity. Environmental cues and rearing conditions played the pivotal role in comparison to broodstock origin. Specimens presented different FAA profiles depending on their geographical origin. Principal Component Analysis showed a division between eastern and western Greece which might be owed to the existence of climatic fluctuations affecting the abiotic factors. This combined approach offers an important tool for stock identification thus assisting environmental risk assessments in evaluation of potential ecological effects and fostering research excellence in sustainable aquaculture management.
  • Chapter
    Full-text available
    In this chapter, the characteristics and environmental impacts of wastewaters from the major agricultural industries on the river ecosystems of Greece are reviewed and discussed, focusing especially on olive mills, orange juice processing factories and cheese processing factories. The high organic load, suspended solids and nutrients of these wastewaters, as well as their toxicity, have deteriorated river water quality and the ecological status of many running waters of Greece. Among the most common effects are eutrophication, the decline of fish and invertebrate populations, species richness loss and the consequent reduction of the river capacity for moderating the effects of polluting substances through internal mechanisms of self-purification. The organic load of the wastewaters, substrate contamination (sewage bacteria) and distance from the wastewater discharge outlet appear to be the most important factors affecting macroinvertebrate assemblages, while typology (i.e. slope, altitude), hydrology (i.e. permanent, intermittent), intensity and volume of the wastewater are the most important determinants of self-purification processes. As these industries are usually located near small-sized streams that are not significantly considered in the Water Framework Directive 2000/60/EC, there is a need for including them in monitoring and assessment schemes as they may considerably contribute to the pollution load of the river basin. Finally, guidelines to manage these wastes through technologies that minimise their environmental impact and lead to a sustainable use of resources are also critical.
  • Chapter
    This chapter provides an overview on the hydrogeochemical and pollution characteristics of Greek rivers and attempts to interpret the origin and spatio-temporal variability of their composition as it emerges from various natural factors and processes and human interference. Despite the highly variable physicogeographic and geological conditions of the country, river basins may be hydrogeochemically classified into three main geographical zones with distinct geological, climatic and hydrological features. River hydrogeochemical properties mainly depend on geochemical, hydromorphological and climatic factors. Catchment geology directly controls solute concentrations and major ion portions and influences hydrological and hydrogeological factors. The latter indirectly control water temperature and solute concentrations, as well as pH and carbonate equilibrium together with biological activity. In certain river basins, anthropogenic pressures (i.e. inadequately treated municipal wastes, agrochemicals, agro-industrial and mining effluents) affect aquatic quality, whereas water resources management (i.e. water overexploitation for irrigation and dam operation) alters the hydrological regime, thus indirectly influencing solute concentration. In general, rivers located in western Greece as well as mountainous rivers and streams range from “pristine” to satisfactory conditions. On the contrary, lowland sections of large rivers are at a greater risk due to a variety of pressures, such as agriculture, agro-industry, mining, (illegal) building, and tourism. Despite the great number of internationally important sites in river basins and, the recent, major efforts made in implementing the WFD, Greek rivers are still threatened from insufficient implementation of environmental legislation and ad-hoc management practices. The economic crisis may set environmental conservation at the expense of economic development and/or change socio-economical attitudes. thus pushing environmental conservation forward.
  • Chapter
    The Sava river is the third longest Danube tributary, and the largest by discharge. The length of the Sava River from its main source in the western Slovenian mountains to its mouth into the Danube in Belgrade is about 944 km (ISBRC 2009). It runs through four countries (Slovenia, Croatia, Bosnia and Herzegovina, and Serbia), and connects three of the four capitals: Ljubljana in Slovenia, Zagreb in Croatia, and Belgrade in Serbia. The fourth capital—Sarajevo, in Bosnia and Herzegovina—also lies within the Sava River Basin. The basin, with an area of 97,713 km2, covers considerable parts of Slovenia, Croatia, Bosnia and Herzegovina, Serbia and Montenegro, and a small portion of Albanian territory. With its average discharge of about 1564 m3/s, the Sava River represents the most important Danube tributary, contributing almost 25% to the Danube’s total discharge at their confluence in Belgrade. The Sava River is very important for the Danube River Basin also for its outstanding biological and landscape diversity. One of the first order, main and right tributaries of the Sava River is the Drina. The Drina basin is 20,320 km2 and its total length some 346 km, with Albania’s share of the basin about 179 km2 or 0.2% (ISBRC 2009).
  • Chapter
    Full-text available
    The spring waters of the Sierra Nevada result from the attack of high CO2 soil waters on typical igneous rocks and hence can be regarded as nearly ideal samples of a major water type. Their compositions are consistent with a model in which the primary rock-forming silicates are altered in a closed system to soil minerals plus a solution in steady-state equilibrium with these minerals. Isolation of Sierra waters from the solid alteration products followed by isothermal evaporation in equilibrium with the earth's atmosphere should produce a highly alkaline Na-HCO3-CO3 water; a soda lake with calcium carbonate, magnesium hydroxysilicate, and amorphous silica as precipitates.
  • Article
    The concentrations of several nutrients in a stream draining a large montane ecosystem in northern Utah, USA were monitored over a 2-yr period. Stream discharge (cubic metres per day) accounts for much of the variation in the concentration of the most common nutrients. When the concentration of each nutrient is plotted logarithmically against stream discharge and the points are joined in a time sequence, a locus or trajectory is obtained which varies more between ions than between years for the same ion. These patterns of nutrient flux appear to be controlled largely by the magnitude of stream discharge and the relative contributions of groundwater flow, overland flow, and interflow. Plant uptake, supply of exchangeable ions, and equilibrial dynamics of the calcium carbonate system also influence the shape of the trajectories and give rise to much of the differences between trajectories for different ions. The trajectories for less common ions are more variables than those for abundant entities. Available data indicate that trajectories are observed in other ecosystems but are only seen clearly in watersheds with a simple annual pattern of streamflow. These patterns of nutrient flux occur for each significant rise and fall in stream discharge and are not observed distinctly in ecosystems with frequent changes in streamflow. The characteristic and recurring form of trajectories suggests that these patterns represent an important and general property of some ecosystem and that they may provide a basis for a theoretical approach to ecosystem nutrient dynamics.
  • Article
    River water quality is highly variable by nature due to environmental conditions such as basin lithology, vegetation and climate. In small watersheds spatial variations extend over orders of magnitude for most major elements and nutrients, while this variability is an order of magnitude lower for major basins. A standard river water for use as reference is therefore not applicable. As a consequence natural waters can possibly be unfit for various human uses, even including drinking. The Water Quality (WQ) concept has greatly evolved since the beginning of the century in accordance with expanding water uses and analytical developments. Even in well developed countries the dissolved heavy metal measurements in rivers are not very reliable while dissolved organic micro-pollutants are even rarely analysed routinely. Major WQ problems have been identified according to river basin size, including organic pollution, salinity, total suspended solids, heavy metals, eutrophication, nitrate, organic micro-pollutants, acidification. They generally occurred in this order over a period of about 100 years in the industrialized countries. Historical records of WQ are rare but can be established indirectly through studies of lake sediments. When proper control action is taken at an early stage, numerous examples of WQ recovery have been found in rivers for most of the common pollution problems. Future WQ problems will mostly derive from mine tailings and toxic waste disposal in both developed and developing countries, industrial accidents and organic micropollutants which emerge faster than our analytical capacities. The newly industrializing countries will face all the above-mentioned problems within a very short time period without having the means to cope with them one at a time. River studies point out the global alteration of the biogeochemical cycles of many major elements and nutrients (S, Na, K, N, P). For heavy metals such as lead, present estimates of global river loads emphasize the role of interim storage on land, thus delaying downstream pollution problems.
  • Article
    To better understand the biogeochemical factors affecting seasonal variations of major Greek river water composition, multivariate analyses on four seasonal data matrices of thirteen major Greek rivers and tributaries have been applied. The main factors governing river water composition were "carbonate dissolution", which is the most important factor in spring, autumn and winter, and "pollution", which is most important in summer. Less important factors are "biological activity", which predominates during the dry seasons and "sodium chloride enrichment", which slightly influences river waters, primarily in spring, due to flushing processes. The Greek river catchments are characterized by different climatic, hydrographic, morphologic, petrographic and vegetative features and varying pollution impact. Nevertheless, biogeochemical processes controlling river composition appear to follow certain common seasonal trends, as they would be a part of an integrated ecosystem.
  • Article
    In the preface the authors state, as reasons for producing this book, the need for an appropriate undergraduate-level text on water chemistry and the desire to provide broader coverage of atmospheric and environmental chemistry than is found in other existing books on this topic. They have attempted to write a book that could be understood by almost anyone with an elementarv knowledge of science, yet could still serve as a source of geochemical and environmental data for researchers in a variety of fields. The authors have succeeded admirably in achieving these difficult goals.
  • Article
    Full-text available
    The SCOPE`/UNEP project "Transport of Carbon and Minerals in Major World Rivers" was initiated to acquire a detailed understanding of the riverine part of the global carbon cycle quantitatively and qualitatively. Two approaches were followed: (i) initiating sampling and water quality analyses in major rivers for a full hydrological year to obtain a new set of original data, and (ii) inspecting and synthesizing existing data records and pursuing specila field experiments on the local and regional scale. While the first approach led to an internnational cooperation - the first results of which are presented as separate chapters in the present volumen - the outcome of the second approach is subject of this study. Central issue is the CO2 pressure of fresh waters and its development and causes both spatially (between source and sea) and temporally (with respect to seasonal and long-term fluctuation). The free CO2 of fresh waters mediates between the organic and inorganic carbon pools. Its concentration and pressure changes are related to the interplay of respiration and photosynthesis and serve as a critial parameter for the variety of inorganic and organic riverine processes. Such processes and theri influence on the PCO2 are discussed in the light of the complexity of the carbon system for a series of case studies from shallow groundwaters, lakes, rivers, and estuaries. Field analyses an existing data records of European, North- and South American rivers are examined. The case studies cover examples from a wide range of settings, i.e. geologically, hydrologically, climatically, and economically.The economic aspect is of special value when nutrient pollution of rivers and the anthropogenically induced CO2-fixation in the coastal seas are discussed. The data record presented here allows the calculation of long-term transport rates for carbon and nutrients in major natural and industrialized rivers and reveals the manitude of interannual changes in discharge and flux rates.
  • Article
    Full-text available
    Computer technique has its applications in speleology. The commission for physico-chemistry of karst should try to establish a program librara, collecting programs concerning standard calculations and procedures from among its members. The here presenten program uses temperature, pH, alkalinity, total hardness, calcium, and magnesium as input data. It calculates besides standard transformations, pPCO2 and the saturation indices with respect to calcite, dolomite and gypsum, with and without allowing for neutral ion pairs. The calculations are not presenten here again, as they can be found easily in the literature. The program language is Fortran IV.
  • Article
    Full-text available
    Extraordinary flood conditions caused by the 1982 El Nino/Southern Oscillation (ENSO) climatic anomaly. Under, and with a flow 75% higher than the long-term mean, the river exported a total organic C (TOC) load of 8.43 Tg yr-1 (3.0 g m-2 yr-1) of which 89% was accounted for by dissolved organic C (DOC) and the remainder by particulate organic C (POC). Under normal hydrological conditions, however, the Parana has a TOC load that is roughly half of that determined during the ENSO-triggered flood (4.43 Tg yr-1, 1.6 g m-2 yr-1), but with a very different DOC:POC ratio (63:37). In July-August 1985 the Parana was sampled along a reach of over 1300 km. At the time of sampling, the Paraguay River supplied ~68% of the POC load, 59% of the labile particulate load (LPOC), and 71% of the DOC entering the middle reach of the Parana. Carbohydrates in LPOC appear to become more abundant than amino acids in the lower reaches, probably due a significant input from the floodplain of the Parana. -from Authors
  • Article
    Extraordinary flood conditions caused by the 1982 El Nino/Southern Oscillation (ENSO) climatic anomaly. Under, and with a flow 75% higher than the long-term mean, the river exported a total organic C (TOC) load of 8.43 Tg yr-1 (3.0 g m-2 yr-1) of which 89% was accounted for by dissolved organic C (DOC) and the remainder by particulate organic C (POC). Under normal hydrological conditions, however, the Parana has a TOC load that is roughly half of that determined during the ENSO-triggered flood (4.43 Tg yr-1, 1.6 g m-2 yr-1), but with a very different DOC:POC ratio (63:37). In July-August 1985 the Parana was sampled along a reach of over 1300 km. At the time of sampling, the Paraguay River supplied ~68% of the POC load, 59% of the labile particulate load (LPOC), and 71% of the DOC entering the middle reach of the Parana. Carbohydrates in LPOC appear to become more abundant than amino acids in the lower reaches, probably due a significant input from the floodplain of the Parana.
  • Article
    Methods of estimating excess partial pressures of carbon dioxide in river waters using pH and Gran alkalinity measurements are considered using data from several UK lowland rivers covering a spectrum of industrial, urban and agricultural catchments. Two simple equations are shown to be eminently suitable except for the most demanding accuracies at pH values greater than 9 when carbonate and hydroxide ions as well as calcium complexes with bicarbonate, carbonate and hydroxide become larger. The most basic of these equations, which simply allows for the averaged effects of temperature and ion activity, is
  • Article
    Full-text available
  • Article
    The effect of ion pairing on water analyses is examined. Significant changes in composition details and saturation indices can occur in waters of moderate-to-high sulfate content. Revised estimates of the equilibrium constants for gypsum and dolomite for various temperatures are presented.
  • Article
    1] The partial pressure CO 2 (pCO 2) in streams and rivers reflects both internal carbon dynamics and external biogeochemical processes in terrestrial ecosystems. CO 2 is typically supersaturated in streams because rates of organic matter decomposition exceed photosynthetic uptake, and because of inflow of CO 2 supersaturated ground waters. Using the U.S. Geological Survey's NASQAN database, we calculated pCO 2 and dissolved inorganic carbon (DIC) concentration in 417 streams and rivers distributed across the contiguous United States over a 22-year period. In addition to demonstrating widespread supersaturation and distinct regional variation in pCO 2 across the U.S., our analysis revealed that pCO 2 significantly declined 78.4 ppmv y À1 from 1973 to 1994. This decline is not attributable to changes in terrestrial weathering or in-stream processes, but instead suggests large-scale declines in terrestrial CO 2 production and import into aquatic ecosystems during this 22-year period.
  • Chapter
    Full-text available
    Europe occupies 6.94% of the total land surface of Earth and contributes 7.4% of total continental runoff. Even though these figures appear small, Europe nevertheless plays an important role for global biogeochemical cycle due to its high chemical weathering rate, it high population density, its intensive agriculture and its highly developed industry. (from conclusions)
  • Article
    This article starts from the representative water analyses for major rock types commonly found on the continents. A theoretical world average is then set up on the basis of global outcrop proportions and compared to the observed composition. After discussion, this theoretical average is apportioned into the individual contributions from various minerals and rocks. As the water analyses are mostly derived from a previous study of unpolluted monolithologic French watersheds, this approach is called the Temperature Stream Model.
  • Article
    Elevated atmospheric inputs of NH4+ and NO3– have caused N saturation of many forest ecosystems in Central Europe, but the fate of deposited N that is not bounded by trees remains largely unknown. It is expected that an increase of NO3– leaching from forest soils may harm the quality of groundwater in many regions. The objective of this study was to analyze the input and output of NH4+ and NO3– at 57 sites with mature forest stands in Germany. These long-term study sites are part of the European Level II program and comprise 17 beech, 14 spruce, 17 pine, and 9 oak stands. The chloride balance method was used to calculate seepage fluxes and inorganic N leaching below the rooting zone for the period from 1996 to 2001. Nitrogen input by throughfall was significantly different among most forest types, and was in the order: spruce > beech/oak > pine. These differences can be largely explained by the amount of precipitation and, thus, it mirrors the regional and climatic distribution of these forest types in Germany. Mean long-term N output with seepage was log-normal distributed, and ranged between 0 and 26.5 kg N ha–1 yr–1, whereby 29 % of the sites released more than 5 kg N ha–1 yr –1. Leaching of inorganic N was only significantly lower in the pine stands (P < 0.05) compared with leaching rates of the spruce stands. Median N output : input ratio ranged between 0.04 and 0.11 for the beech, oak, and pine stands, while the input : output ratio of the spruce stands was 0.24, suggesting a higher risk of NO3– leaching in spruce forests. Following log-transformation of the data, N input explained 38 % of the variance in N output. The stratification of the data by the C : N ratio of the O horizon or the top mineral soil revealed that forests soils with a C : N ratio < 25 released significantly more NO3– (median of 4.6 kg N ha–1 yr–1) than forests with a C : N ratio > 25 (median of 0.8 kg N ha–1 yr–1). The stratification improved the correlation between N input and N output for sites with C : N ratios < 25 (r2 = 0.47) while the correlation for sites with C : N ratios > 25 was weaker (r = 0.21) compared with the complete data set. Our results suggest that NO3– leaching may increase in soils with wide C : N ratios when N deposition remains on a high level and that the potential to store inorganic N decreases with C : N ratios in the O horizons becoming more narrow. Nitratauswaschung aus Waldböden: eine Analyse von Dauerbeobachtungsflächen in Deutschland Erhöhte NH4+- und NO3–-Einträge haben zu einer N-Sättigung vieler Wälder in Mitteleuropa geführt. Der Verbleib des deponierten Stickstoffs, der nicht in den Bäumen gebunden ist, ist jedoch weitgehend unbekannt. Es wird angenommen, dass ein Anstieg der NO3–-Auswaschung aus Waldböden die Grundwasserqualität in vielen Regionen gefährdet. In dieser Studie wurden die Eintrags- und Austragsraten von NH4+ und NO3– von 57 Waldflächen in Deutschland analysiert. Diese Dauerbeobachtungsflächen sind Teil des europäischen Level-II-Programms und setzen sich aus 17 Buchen-, 14 Fichten-, 17 Kiefern- und 9 Eichenbeständen zusammen. Die Cl–-Bilanz-Methode wurde angewandt, um die Sickerwassermengen unterhalb des Wurzelraumes für die Periode von 1996 bis 2001 zu berechnen. Die N-Einträge waren in vielen Waldtypen signifikant unterschiedlich und zeigten folgende Ordnung: Fichte > Buche/Eiche > Kiefer. Diese Unterschiede können weitgehend mit der Niederschlagsmenge erklärt werden und spiegeln somit die regionale und klimatische Verteilung dieser Waldtypen in Deutschland wider. Der mittlere, langjährige N-Austrag war log-normal verteilt and variierte zwischen 0 und 26,5 kg N ha–1 a–1, wobei 29 % der Flächen mehr als 5 kg N ha–1 a–1 freisetzten. Nur die Kiefernbestände wiesen eine signifikant (P < 0,05) geringere NO3–-Auswaschung auf als die Fichtenbestände. Der Median des Verhältnisses N-Austrag : N-Eintrag lag zwischen 0,04 und 0,11 für die Buchen-, Eichen- bzw. Kiefernbestände, während die Fichtenbestände ein Verhältnis von 0,24 aufwiesen und damit ein höheres Risiko der NO3–-Auswaschung darstellen. Nach Logarithmierung der Daten konnte der N-Eintrag zu 38 % die Varianz der N-Austräge erklären. Die Stratifizierung der Daten nach dem C:N-Verhältnis der Humusauflage oder dem obersten Mineralboden ergab, dass Waldböden mit einem C:N-Verhältnis < 25 (Median von 4,6 kg N ha–1 a–1) signifikant mehr NO3– freisetzten als Wälder mit einem C:N-Verhältnis > 25 (Median von 0,8 kg N ha–1 a–1). Im Vergleich zu dem gesamten Datensatz verbesserte die Stratifizierung der Daten nur die Beziehung zwischen N-Eintrag und N-Austrag für Flächen mit einem C:N-Verhältnis < 25 (r2 = 0,47) während die Beziehung für Flächen mit einem C:N-Verhältnis > 25 schwächer (r = 0,21) war. Unsere Ergebnisse deuten darauf hin, dass die NO3–-Auswaschung in deutschen Wäldern mit weiten C:N-Verhältnissen in der Humusauflage zunehmen kann, sofern die N-Deposition auf einem hohen Niveau verbleibt. Ferner kann das Potenzial der Wälder, anorganischen N zu speichern, mit enger werdenden C:N-Verhältnissen in den Humusauflagen abnehmen.
  • Article
    SUMMARY1Two pH electrodes and a thermistor were used to record conditions in the surface of Esthwaite Water every 15 min over a 12-month period. Combined with approximately weekly measurements of alkalinity they allowed inorganic carbon speciation to be calculated.2Large changes in pH from 7.1 to nearly 10.3, and hence in concentrations of inorganic carbon species, were measured over a year. Carbon speciation and pH varied on a diel, episodic and seasonal basis. Diel variation of up to pH 1.8 was recorded, although typical daily variation was between 0.03 and 1.06 (5 and 95 percentiles). Daily change in concentration of inorganic carbon varied between 4 and 63 mmol m-3 (5 and 95 percentiles).3During lake stratification, episodes of high pH, typically of 1–2 weeks' duration were interspersed with episodes of lower pH. These changes appeared to relate to the weather: e.g. low wind velocity, high pressure, low rainfall and high sunshine hours correlated with periods of high pH.4Seasonal progression of carbon depletion generally followed stratification and the development of high phytoplankton biomass. When the lake was isothermal, the phytoplankton biomass caused relatively small amounts of carbon depletion.5During autumn, winter and spring, the lake had concentrations of CO2* (free CO2) up to 0.12 mol m-3 which is nearly seven times the calculated atmospheric equilibrium concentration so the lake will accordingly be losing carbon to the atmosphere. In contrast, during periods of elevated pH the concentration of CO2* was reduced close to zero and the lake will take up atmospheric CO2. The rates of transfer between water and the atmosphere were estimated using a chemical equilibrium model with three boundary layer thicknesses. The calculations show that over a year the lake loses CO2 to the atmosphere with the current mean atmospheric level of 360 μmol mol-1, at between 0.28 and 2.80 mol m-2 yr-1. During elevated pH, rates of CO2-influx increased up to nearly tenfold as a result of chemical-enhancement by parallel flux of HCO-3. Input of CO2* to the lake from the catchment is suggested to be the main source of the carbon lost to the atmosphere.6The turnover time for CO2 between the air and water was calculated to be 1 year for the gross influx and 3.3 years for the net flux. These values are less than the average water residence time of 0.25 years, which indicates that over a year inflow from streams is a more important source of inorganic carbon than the atmosphere.7Influx of CO2 from the atmosphere was calculated to be roughly equivalent to between 1 and 4% of the rates of production in the water during mid-summer indicating that this source of inorganic carbon is not a major one in this lake.8Influx of CO2 from the hypolimnion was estimated on one occasion to be 6.9 10-9 mol m-2 s-1 using transfer values based on mass eddy-diffusion. These rates are equivalent to 23% of the rate of influx of CO2 from the atmosphere on this occasion which suggests that the hypolimnion is probably a small source of inorganic carbon to the epilimnion. The exception appears to be during windy episodes when pH is depressed. Calculations based on depth-profiles of CO2* and HCO-3 suggest that the measured changes in pH can be accounted for by entrainment of hypolimnetic water into the epilimnion.9The solubility product for calcite was exceeded by up to about sixfold which, although insufficient to allow homogeneous precipitation, may have allowed heterogeneous precipitation around algal particles.
  • Article
    Establishing reference nutrient conditions for rivers and streams is necessary to assess human impact on aquatic ecosystems and protect water quality and biotic integrity. Several methods have been proposed: (1) percentiles from statistical distributions of all rivers and streams in a region or dataset, (2) reference stream approaches, and (3) modeling river networks from existing reference streams. We propose an additional statistical method to estimate the influence of anthropogenic land uses on lotic nutrient concentrations. First, we quantify regional variation by using analysis of covariance, where total nitrogen or total phosphorus is the dependent variable, region is the categorical predictor, and percentage of anthropogenic land use (e.g., cropland, urban land) is the covariate. This allows for the aggregation of regions if there is not a significant regional effect, or if there is a significant regional effect, identifies the need to analyze regions separately. Second, we develop multiple linear regression models with best-model techniques in which anthropogenic land-use classifications are the independent variables, and the logarithms of in-stream nutrient concentrations are the dependent variables. The intercept of these regression models (i.e., expected nutrient concentration in the absence of human activities assuming linear extrapolation to the origin) represents the reference nutrient concentrations. This analysis suggests that larger percentages of cropland and urban land have strong positive influences on in-stream nutrient concentrations, both in eastern Kansas and across the conterminous United States. The most appropriate method for regions may depend on the relative availability of reference sites and other data sources. The covariance/reference approach offers a potential method for regions with limited numbers of reference sites. © 2004, by the American Society of Limnology and Oceanography, Inc.
  • Article
    Soils derived from a number of different parent materials (lithologies) and developed along a climatic gradient, manifested by the altitudinal succession of natural vegetation zones (Mediterranean, sub-Mediterranean, Mountainous and Pseudoalpine), were sampled throughout mainland Greece. In soils derived from siliceous parent materials low in clay, acidity increase and percent base saturation decreases from the Mediterranean to the Pseudoalpine vegetation zones. Clay illuviation is found mainly in soils developed in the Mediterranean and the sub-Mediterranean zones. No such changes are apparent in clayey soils rich in bases. Organic matter content of the mineral portion of the soil profile increases by a factor of 2 with a decrease in mean annual air temperature of about 10°C. The pattern of change in clay and soil organic matter content with climate is in relatively good agreement with soil development trends in the area, when soil profiles are named according to the FAO-Unesco soil map of the world. Concentrations of Ca and Mg decrease and those of total N, total and extractable P, K, Fe, Mn and Zn increase from the Mediterranean to the Mountainous zone. Within the same zone, however, concentrations of N, Ca, K, Fe, Mn and Zn decrease, but those of Mg, total and extractable P increase with soil depth. The concentrations of most macro- and micronutrients in the humic horizon are several times higher than those in the mineral portion of the soil profile due to biological enrichment.
  • Article
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