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Etat de santé de l’environnement côtier dans les deux sites prévus pour l’installation des stations de dessalement de l’eau de mer dans la baie d’Agadir : Etudes physico-chimique, écotoxicologique et biologique.
Abstract
This work aims to study the impact of the installation of seawater desalination plant in Agadir bay by drawing up the initial health state of two marine ecosystems Tifnit-Douira and Cap Ghir receiving desalination plants. Thus, a multidisciplinary study was conducted in the sentinel species Mytilus galloprovincialis, combining two complementary approaches: i) the chemical approach (physico-chemistry and chemical detection of pollutants); and (ii) the biological approach (ecotoxicological study of multi-biomarker response and reproductive biology). An inventory of macro-phyto/zoo-benthic species associated with mussel beds was also carried out to assess the biodiversity of these ecosystems.
Our results related to the physicochemical approach in the two studied stations reveal values that oscillate between: 16.24 and 21.61 °C for seawater temperature; 7.39 and 8.73 for pH; 43.15 and 65.16 mS/cm for conductivity and between 27.40 and 43.75 PSU for salinity. TDS and dissolved oxygen values vary between 21.14 to 31.88 and 4.33 to 8.14 mg/l respectively. These parameters follow monthly fluctuations in the two studied ecosystems due to the marine environmental responses to changes in daily and weekly climatic conditions and also to seasonal hydrodynamic factors (currents, swell and upwellings).
The study of metal pollution in both ecosystems has shown that their concentrations undergo monthly, seasonal and annual fluctuations depending on the dosed element. Cd, Pb and Cu recorded relatively high levels (2.28, 2.50 and 6.86 mg/kg respectively) with comparable annual profiles between the two stations. While Arsenic (As) oscillates between 7.97 and 12.60 mg/kg without reaching the toxicity threshold of 14 mg/kg. The measured values are significantly high, especially at Cap Ghir with a stability of the values throughout the study period. This attests to the presence of Arsenic in a natural way in the Atlantic marine ecosystem. The results obtained for the major metal elements studied showed maximums of 6.33, 145.51 and 285.74 mg/kg respectively for Mn, Fe and Zn. The revealed annual patterns appear similar between the two ecosystems with moderate seasonal fluctuations.
Biomarker response measures, Acetylcholinesterase (AChE), Glutathione-S-Transferase (GST), Catalase (CAT) and Malondialdehyde (MDA) in Mytilus galloprovincialis, have been shown to be present in measurable and inducible amounts. In addition, response levels fluctuate respectively between 1.94 to 8.85; 3.74 to 36.91; 3.52 to 17.94 and 1.13 to 5.91 nmol/mg protein. This is explained by the response of these molluscs, to variations in environmental conditions as well as to the presence of certain contaminants including heavy metals mainly Cadmium, and consequently to the physiological disturbances of the species during its development cycle.
The study of reproductive cycle in the mussel Mytilus galloprovincialis, testifies to a continuous sexual activity throughout the year with periods of collective egg-laying coinciding with spring and summer. The number of these collective gametic release varies between two to three periods depending on the environmental conditions, especially variations in seawater temperature. This results in a lack of collective sexual rest period in these mussel populations. The sex ratio study shows a balance between males and females of 1.14:1 in Tifnit-Douira, and it varies between 1.12:1 to 1.18:1 in Cap Ghir. The histological study allowed the detection of a single case of hermaphroditism, revealed for the first time in mussel populations in the Agadir bay.
The values of the condition index are high (>60) in Mytilus galloprovincialis of the studied stations during all seasons even during laying periods. The favorable conditions of the environment allow a continuous allometric and weight growth throughout the year. Regarding biological diversity, both stations have a very high diversity of Macro-Phyto/Zoo-benthic species. Indeed, the animal kingdom is rather dominated by Crustaceans and Gastropods, while Chromophytes and Rhodophytes are the most dominant in the plant kingdom.
All these results prove the well-balanced state of the environment in the two studied ecosystems Tifnit-Douira and Cap Ghir; and that permanent monitoring should be realized to protect their health state from the impact of desalination plants.
Keywords: Mytilus galloprovincialis, Agadir Bay, Cap Ghir, Tifnit-Douira, Desalination, Biomarkers, Marine ecosystem, Heavy metals, Reproductive cycle, Biodiversity, Biomonitoring.
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Water is an essential component of our economics and is at the centre of economic and social development. It is vital to maintain health, grow food, manage the environment and create jobs. There is a close link between water and economic growth of country. Lack of water is a barrier to sustainable socioeconomic development, lack of development is a barrier to solving water problems. Water can affect basic human well being and the productivity, scarcity of water, lack of collection and distribution systems can lead to extraordinary consumption of energy in gathering daily water needs. Domestic water supply serves as a basic component of welfare in its role as a direct consumer commodity, it also functions as an element of socioeconomic infrastructure. Water contributes to a wide variety of natural productive process, including directly productive activities such as food production and manufacturing operations and as an element of basic economic infrastructure. Employment in the water sector remains relatively limited; the potential growth for jobs in water sector is particularly changes from region to region. The water resources are limited in India, but growing demand of water due to increasing population, urbanization and industrialization. India's multidimensional water development has contributed significantly to the promotion of the country's economic growth. Water resources development can contribute to economic growth during both construction and operational stages.
The taxonomic information about macroalgal species along the Atlantic coast of Morocco is sparse and, in most cases, related to historical records. The aim of the present study is to catalogue the subtidal and intertidal red seaweeds inhabiting three coastal areas nearby Essaouira city, extended between 31° 52′ N−9° 75′ W North and 31° 49′ N −9° 76′ W South. It is the first revised and updated checklist of Rhodophyceae for almost 18 years on the Atlantic Moroccan coastline. A total of 196 taxa belonging to 104 genera was recorded, with an increase of 22% in species compared to previous studies. Additionally, the new benthic macroalgal species collected in the different seasons of the year are shown as well as a comparative analysis of the Ecological State Groups (ESG) of the new records with their Recovery Index (RI) among the three sampled coastal areas.
The present study aims to update the red seaweed species in the intertidal zone of the Atlantic coast of Sidi Bouzid, a seaside resort near El Jadida City (Morocco) from 2016 to 2018. A particular interest was given to the new species recorded for the first time in the Moroccan coasts. The results obtained have shown an important red algal diversity in comparison to previous studies with 32 species of seaweeds that were found for the first time in this coastal area. A total of 156 species was recorded andrepresented by 35 families of red algae, where the largest number of these species belonged to Ceramiales order with 73 species, as well as 20 species of the order Gigartinales and 10 species for the Gelidiales and Corallinales orders. Among them, two epiphytes, Aglaothamnion tripinnatum and Gaillona gallica, are cited for the first time for the Moroccan coastline.
Alien Mediterranean mussels Mytilus galloprovincialis, Pacific oysters Crassostrea gigas and indigenous Cape mussels Choromytilus meridionalis were used as sentinel biomonitors of inorganic pollutants in Saldanha Bay, South Africa. Neutron activation analysis was used to determine the concentrations of 33 macro and microelements in the soft tissues of molluscs. The Mediterranean mussels significantly demonstrated the higher accumulation ability to S, Se and Br than the Pacific oysters, whereas the Pacific oysters - to Fe, Cu, Zn and As. The Cape mussels are more sensitive to Mn and As and the Mediterranean mussels were sensitive to Zn and Se.
Turkey borders three seas and the most populous locations are squeezed into the coastal territories. Thus, organisms living in these aquatic territories are under longstanding anthropogenic pressure. Hence, this study investigated the consumption outcomes leading to potential child and adult health risks along with the spatial distribution of As, Cd, Cr, Cu, Ni, Pb, V, and Zn in the Mediterranean mussels (Mytilus galloprovincialis) sampled at 23 different stations from the Black Sea, the Sea of Marmara, and the Aegean Sea coastal waters of Turkey. The mean concentrations of trace elements found in the Mediterranean mussels followed Zn (39.75 mg kg−1) > Cu (1.95 mg kg−1) > As (1.84 mg kg−1) > Pb (0.99 mg kg−1) > Ni (0.65 mg kg−1) > Cr (0.62 mg kg−1) > V (0.47 mg kg−1) > Cd (0.08 mg kg−1). Factor analysis revealed that trace elements were mostly derived from anthropogenic sources. Pb values were found to be above the permissible European Union limits at 10 sampling stations. While the estimated weekly intake did not exceed the Joint FAO/WHO Expert Committee on Food Additives limits, the target hazard quotient for As was found >1 for children. The lifetime cancer risk (CR) for adults and children was unacceptable (>10−4) at high consumption rates for As according to US Environmental Protection Agency. Monte Carlo simulation confirmed a CR to adult (62.98%) and children (97.24%) mussel consumers caused by As.
The present work is a part of the impact study of the tourist resort "Taghazout Bay" installation on the coast of Taghazout (North of the Agadir bay). The purpose of this study is to assess the initial state of the macro-zoobenthic structure present in the intertidal sands at the three study stations over the 2016 and 2017 seasons. The biological approach is accompanied by the study of some physico-chemical parameters of the seawater (temperature, pH, salinity and dissolved oxygen) and the study of the sediment (grading structure, classification, and contents in organic matter). PCA analysis identified a perfect correlation between physico-chemical parameters. The sediment contains three grading classes only (Medium sand, fine sand, and very fine sand), very well classified with normal proportions of organic matter. The study of intertidal benthic macrofauna of the sandy substrate shows ten species and spatiotemporal variations with a clear dominance of the bivalve species Donax trunculus. We notice, from the DIMO model, that the variation profile of the spring and summer (2016 and 2017) shows a community dynamics called "Diversity type". In winter and in autumn, they know an "Evenness type". The rank-frequency diagram explains that the benthic community of Taghazout sandy coast exists in the stage "Pioneer 1". The ascending hierarchical clustering gave three logical gatherings of seasons. The faunistic structure of this benthic community revealed the shape M>C>P. We also notice that there is diversity in regimes in this ecosystem.
The Moroccan Mediterranean coast between Nador and Al Hoceima is known for its ideal environment that promotes ecological evolution as well as distinctive biodiversity. In this shoreline, a marine protected area for the conservation of the biological richness is under consideration. In this context, the present study was carried out to assess the environmental health based on water physicochemical parameters, sediment granulometry, and geochemical analysis of heavy metals. For this purpose, water and surface sediment samples were collected from ten locations in the seabed. The analysis of the physicochemical parameters of seawater shows that they are of good quality and within the international standards. The granulometric analysis demonstrated a diversity of facies represented by sandy mud, silt, and clay with a low percentage of organic matter, indicating a favorable environment for the reproduction and growth of marine fauna. The analysis of heavy metal concentrations, Pb, Cr, Cd, Cu, Ni, and Zn, were below the natural average values. Furthermore, the contamination indices: pollution load index (PLI), modified contamination degree (mCd), geoaccumulation index (Igeo), the potential ecological risk index (RI), and mean ERM quotient (M-ERM-Q) indicated that the study area is beyond any metallic contamination. Consequently, the study area is a favorable habitat for marine fauna and thus it can perfectly host a marine protected area. The obtained results in this work can be used as a reference state for marine protected areas.
The aquatic environment is the final sink of various pollutants including metals, which can pose a threat for aquatic organisms. Waterborne metal mixture toxicity might be influenced by environmental parameters such as the temperature. In the present study, common carp were exposed for 27 days to a ternary metal mixture of Cu, Zn, and Cd at two different temperatures, 10 and 20°C. The exposure concentrations represent 10% of the 96 h-LC50 (concentration lethal for the 50% of the population in 96 h) for each metal (nominal metal concentrations of Cu: 0.08 μM; Cd: 0.02 μM and Zn: 3 μM). Metal bioaccumulation and toxicity as well as changes in the gene expression of enzymes responsible for ionoregulation and induction of defensive responses were investigated. Furthermore the hepatosomatic index and condition factor were measured as crude indication of overall health and energy reserves. The obtained results showed a rapid Cu and Cd increase in the gills at both temperatures. Cadmium accumulation was higher at 20°C compared to 10°C, whereas Cu and Zn accumulation was not, suggesting that at 20°C, fish had more efficient depuration processes for Cu and Zn. Electrolyte (Ca, Mg, Na, and K) levels were analyzed in different tissues (gills, liver, brain, muscle) and in the remaining carcasses. However, no major electrolyte losses were observed. The toxic effect of the trace metal ion mixture on major ion uptake mechanisms may have been compensated by ion uptake from the food. Finally, the metal exposure triggered the upregulation of the metallothionein gene in the gills as defensive response for the organism. These results, show the ability of common carp to cope with these metal levels, at least under the condition used in this experiment.
The majority of tissue-specific environmental quality standards (EQSs) considering metal tolerance are prior to the chemical-specific EQSs in aquatic organisms. However, metal baseline levels in marine organisms were very scarce. We explored the correlation between Hg, Cd, Pb, Cu, and Zn concentrations in water or sediments and those metal concentrations in marine organisms (crustacean, mollusc, and fish) by generalized additive models (GAMs) and executed a meta-analysis of Hg, Cd, Pb, Cu, and Zn contents in those three organisms by implementing cumulative frequency distribution analysis of individual metal distribution in a heavy metal-contaminated semi-enclosed Bay, China. Results showed that the average contents of Hg, Cd, Pb, Cu, and Zn were 0.042±0.01, 0.38±0.22, 1.72±0.65, 3.61±1.01, and 16.08±6.33 μg/L in water; 0.064±0.02, 0.42±0.04, 20.54±7.76, 28.97±3.90, and 96.74±35.11 μg/g dw in sediment; and 0.0049±0.0028, 0.52±0.28, 0.24±0.15, 11.05±6.95, and 21.12±4.47 μg/g dw in crustacean, 0.015±0.0087, 0.24±0.17, 0.08±0.02, 0.37±0.35, and 10.62±6.79 μg/g dw in mollusc; and 0.0038±0.0028, 0.065±0.05, 0.32±0.19, 2.01±0.59, and 16.04±4.97 μg/g dw in fish. The mercury content in mollusc presented a negative correlation with mercury content in sediment, while the content of other metals (Cd, Pb, Cu, and Zn) in organisms showed positive correlations with the content of those metals in water or sediment. We further obtained tissue-baseline-C5% in crustacean, mollusc, and fish which were 1.191, 3.341, and 0.014 μg/g dw for Cu; 0.013, 0.072, and 0.033 μg/g dw for Cd, 0.015, 0.027, and 0.052 μg/g dw for Pb; 9.515, 14.422, and 0.056 μg/g dw for Zn; and 0.0009, 0.004, and 0.0035 μg/g dw for Hg, respectively. However, there were no obvious relationships of the 4d-NOEC in laboratory toxicity tests with C5%, as well as C50% and 4d-LC50 or tolerance index a for Cu, Cd, Pb, Zn, and Hg in organisms. Our results pointed out the controversy of laboratory sensitive species toxicity results for deriving chemical-specific EQSs with field studies. We advocated to set up the metal concentration baselines in aquatic organisms and further served the tissue-specific EQSs, which are essential basis for geochemical recordings, bio-monitoring, and semi-enclosed bay management in the world.
Graphical abstract
In the Gulf of California; mineral deposits have contributed to high metal contents in coastal environments. This study examined cadmium; lead; copper; zinc; and iron contents in three fish species; Kyphosus vaigiensis (herbivore), Stegastes rectifraenum (omnivore), and Balistes polylepis (carnivore) at two mining sites. Metal concentrations were analyzed by atomic absorption spectrophotometry and stable nitrogen and carbon isotopes were estimated using mass spectrophotometry. Also, we assessed the risk to human health from the consumption of these three species based on permissible limits; although only two of them (Kyphosus and Balistes) are consumed as food. Metal concentrations differed among fish species; except for iron. The highest concentrations of metals were not always recorded in the species at the highest trophic level; i.e., Balistes. The highest concentrations (dry weight) recorded were cadmium (0.21 ± 0.03 µg g−1) and lead (1.67 ± 0.26 µg g−1), in S. rectifraenum; copper (1.60 ± 0.49 µg g−1) and zinc (67.30 ± 8.79 µg g−1), in B. polylepis; and iron (27.06 ± 2.58 µg g−1), in K. vaigiensis. Our findings show that each element accumulates differently in particular marine organisms; depending on the physiology of the species and the biogeochemistry of its habitat; which in turn is affected by the anthropogenic activities in adjacent areas. No risk of heavy metals toxicity is expected from the human consumption of the species and sites studied
The occurrence of 21 trace elements in native Mediterranean mussel (Mytilus galloprovincialis) from the Calich Lagoon, a typical brackish area of the northwest of Sardinia (Italy), was investigated. The seasonal variation of metals in bivalves was considered, and the highest values were found in spring and summer; in particular, a high significant (P < 0.001) temporal variation was reported for silver (Ag) and mercury (Hg). The highest and similar concentrations were registered for aluminium (Al, mean 32 mg kg−1wet weight), iron (Fe, mean 32 mg kg−1 w. w.), and zinc (Zn, mean 25 mg kg−1 w. w.). The maximum limits set by European Regulations for cadmium (Cd), mercury (Hg), and lead (Pb) were never exceeded. Speciation analysis revealed negligible risk related to inorganic arsenic (iAs). Therefore, M. galloprovincialis confirmed its role as suitable bioindicator to monitor the contamination of coastal environments. Although the recommended tolerable weekly intake (TWI) was not exceeded, the levels of aluminium should be carefully evaluated in monitoring plans in the studied lagoon.
Graphical abstract
The mussel Perna perna is one of the most used bioindicators of coastal areas and the most economically exploited species in Brazil through mariculture. In the present study, P. perna was used to investigate metal pollution in the estuarine area of Vitória Bay. Four sampling sites were located along an estuarine branch of Vitória Bay and stations were sampled during three campaigns. Trace metals in the tissues of P. perna were evaluated as well as dissolved trace metals and other ancillary variables in the water column. Dissolved Cd, Pb, Cu, Ni, and Fe concentrations surpassed the tolerance limits stablished by legislation in all the sampling campaigns. P. perna exhibited concentrations in disagreement with the Brazilian legislation for Cr and As. A general trend of higher concentrations in outer stations was observed for most metals, what suggested the occurrence of flocculation process in the lower estuary, reducing the concentrations of dissolved elements and increasing their bioavailability for the biota through the particulate form. Cd was highlighted with elevated concentrations in dissolved fraction but not detected in P. perna, probably due to chlor-complex formation under influence of more saline waters. Al, Ba, Mn, Fe, Cu, Zn, Ni, Cr, Pb, and As were considered bioavailable, once they were accumulated in the mussels’ tissues. Hazard index (HI) and target cancer risk (TCR) showed that the consumption of mussels from the study area offers health risk issues, being iron and arsenic the main contributors for the high indexes.
Surface sediments from Khnifiss lagoon (Morocco) were analyzed to evaluate the contamination degree of the area. Concentrations of V, Cr, Co, Ni, Cu, Zn, As, Cd, Hg, and Pb were determined on samples taken during the summer and the autumn of 2016. On the whole, higher concentrations were found in the summer season. The results revealed the following average concentrations (mg/kg), reported in descending order: Zn (51.7 ± 31.3) > V (38.8 ± 24.7) > Cr (26.6 ± 17.8) > Ni (16.5 ± 5.47) > As (8.50 ± 2.00) > Cu (6.60 ± 3.81) > Pb (6.13 ± 3.46) > Co (3.57 ± 2.09) > Cd (0.16 ± 0.11) > Hg (0.006 ± 0.001). Organic matter showed a positive significant correlation with some trace metals (mainly V, Cr, Co, Zn, Cd, Pb). Three pollution indices were calculated: Enrichment Factor (EF), Index of Geo−accumulation (Igeo), and Pollution Load Index (PLI). Minimal enrichments (for Zn, As, and Cd) were detected at some sampling points. Overall indices showed that the Khnifiss sediments can be classified as not contaminated, and that the trace metals amounts found are ascribable to the geogenic origin. The results of this work can be used as a starting point for further evaluations of trace metals distribution in Moroccan lagoons.
This study reports, for the first time, different physico-chemical analyses, of Mediterranean mussels (Mytilus galloprovincialis) from harvesting areas in the Montenegro coast of the Adriatic Sea, in order to evaluate the influence of origin on different parameters and assessed the quality of shellfish grown in this area. The Boka Kotorska Bay is situated in Montenegro, in the southeastern part of the Adriatic Sea The mussel samples were collected at the same time in the spring of 2019 at six locations in Boka Kotorska Bay, Montenegro: Kotor and Tivat Bays. Biomet-ric parameters, percentage of meat, condition index, proximate composition, sensory evaluation and lipid profiles of mussels were studied. The concentrations of some micro and macro elements and heavy metals in mussels, were also analyzed. Significant differences were found between mussels from different locations. Mean biometric parameters of mussels grown in Sv.Nedjelja, were considerably higher than in mussels grown elsewhere.. Protein, lipid, ash and gly-cogen content were varied from 7.80 to 10.26%; 1.36 to 2.18%; 1.73 to 3.34% and 12.81 to 15.38%, respectively. Gas chromatographic analysis showed that polyunsaturated fatty acids (PUFAs) were dominant lipids in mussels (37.56 to 41.08%), followed by monounsaturated (MUFAs) (30.52 to 38.31%) and saturated (SFAs) (21.89 to 29.45%) fatty acids. Fatty acid profiles were investigated and revealed high contents of n-3 PUFAs and high n-3/n-6 ratios in all mussels from Montenegro In the mussel samples high concentrations of K, Mg, Ca, and Na, and much lower concentrations of Fe, Mn, Zn, and Cu were found. Some of toxic elements (As, Pb, Hg and Cd) were determined also.. The qualitative sensory assessment showed that all mussels were acceptable. All mussels in the current study achieved scores of 3 or more out of 5 in the qualitative category. Data on biochemical composition and quality indices of the mussels cultured in the Boka Kotorska Bay demonstrated that these products could be accepted well by consumers and could compete with other currently available mussels from other locations in Adriatic Sea.
The mosses are widely used as sentinels of the lead pollution from road traffic, for their morphological and physiological properties (the absence of root system and tissue developed conductors). Indeed, the mosses are used to estimate concentrations of lead emitted by vehicles in the atmosphere of the city of Tiaret (west Algeria); such was the object of this research. Mosse Bryum argenteum is used in this study, as a bio-monitor passive of trace element which is emitted by road traffic. The results show that the city of Tiaret is polluted, because the lead levels (Pb) in Bryum argenteum are considerably high (584 µg/g). Résumé Les mousses sont couramment utilisées comme sentinelles de la pollution métallique atmosphérique, à cause de leurs propriétés morphologiques et physiologiques (l'absence de système racinaire et de 106 tissus conducteurs développés). En effet, les mousses sont utilisées pour évaluer les concentrations du plomb émis par les véhicules dans l'atmosphère de la ville de Tiaret (Ouest Algérien); tel fut l'objet de ce travail de recherche. La mousse Bryum argenteum est utilisée, dans cette étude, en tant que bio-moniteur passif des éléments traces métalliques qui sont émis par le trafic routier. Les résultats obtenus montrent que la ville de Tiaret est pollué puisque les teneurs du plomb (Pb) dans Bryum argenteum sont considérablement élevés (584 µg/g).
Marine bivalve molluscs, such as scallops, mussels and oysters, are crucial components of coastal ecosystems, providing a range of ecosystem services, including a quarter of the world’s seafood. Unfortunately, due to human activity, coastal marine areas often suffer from metal contamination. We establish that increased levels of metal pollution (zinc, copper and lead) in sediments near the Isle of Man, resulting from historical mining, strongly correlate with significant weakening of shell strength in king scallops, Pecten maximus. This weakness increases mortality during fishing and leaves individuals more exposed to predation. Comparative structural analysis revealed that shells from the contaminated area were thinner and exhibited a pronounced mineralisation disruption parallel to the shell surface within the foliated region of both the top and bottom valves. Our data suggest that these disruptions caused reduced fracture strength and hence increased mortality, even at subcritical contamination levels with respect to current international standards. This hitherto unreported effect is important since such non-apical responses rarely feed into environmental quality assessments, with significant implications for population survival. Hence, our findings highlight the impact of metal pollution on shell mineralisation in bivalves, and urge a reappraisal of currently accepted critical contamination levels.
The objective of this study was to monitor the bacteriological contamination of the seawater of the marine fisheries of the coastal Agadir, Morocco. The study was focused on the diagnosis on the pollution in heavy metals, such as cadmium, lead, and mercury in five zones: the port of Imi Ouaddar fish boarding (zone Z1), the old port of Agadir (zones Z2 and Z3), the port of Agadir Marina (zone Z4), and the estuary of Oued Souss (zone Z5). The analyses were done by testing physicochemical parameters (such as pH, temperature, dissolved oxygen, salinity and conductivity) as well as microbiological and atomic adsorption analyses. The experimental results showed that the values of the physicochemical parameters were almost the same in all zones, while the microbial conditions were different, in which this is due to the existence of heavy metals. The more heavy metal concentrations affected the condition of microbes in the sea water, confirmed by the number of Escherichia coli. This study demonstrated the importance of controlling concentration of heavy metals for better sustainability of environment.
The accumulation levels of elements (Al, As, Li, Mg, Mn, S, Si, Ti, and V) in the soft tissue of mussels (Mytilus galloprovincialis), collected monthly in 2016, from Junuary to December, from sampling sites of the mussel farming facilities installed in the coastal areas of Al Hoceima, were investigated. The studied element levels were determined by using Inductively Coupled Plasma — Optical Emission Spectrometry (ICP-OES 720-ES). Descending order of the average element concentrations in soft tissue of M. galloprovincialis was S > Mg > Si> Al > Mn > Ti > As >V > Li. Element contents (Al, As, Mg, S and V) in tissue of mussels were significantly different (P < 0.05) between seasons, being highest in winter and lowest in summer. Strong correlations were observed between studied elements and chlorophyll a, indicating the importance of food for metal bioaccumulation in mussels in this period of the season. The observed strong correlations for metal levels in tissues of mussels can be explained by their common sources, which are associated with anthropogenic effects. The detected seasonal variations of investigated element concentrations in soft tissues of M. galloprovincialis could be attributed to physicochemical parameters such as temperature, salinity, dissolved oxygen, nutrients and food availability, as well as the biological status of the mussel. This study may provide basic information for detecting the current pollution status of investigated elements in Al Hoceima coasts from the Moroccan Mediterranean Sea using M. galloprovincialis as biological indicators.
This study used the integrated biomarker response (IBR) index approach to assess the ecological risks of heavy metals in different regions of Dianchi Lake, combined with active monitoring and passive monitoring. The contents of five heavy metals (Cu, As, Cd, Hg, and Pb) and six biomarkers (acetylcholinesterase, sodium-potassium ATPase, metallothionein, superoxide dismutase, glutathione peroxidase, and malondialdehyde) in the muscles of crucians (Carassius auratus) were measured to calculate the IBR value. The results indicate that the contents of heavy metal in the fish under active monitoring and passive monitoring were rather low and did not exceed the National Food Safety Standards of China. The IBR value of day 14 of active monitoring correlated with the heavy metal Cd content in the fish, suggesting a potential risk of Cd pollution in the aquatic environment of Dianchi Lake. The IBR values obtained for different regions of the lake on day 14 can be arranged in the following order: West S3 (9.24) > East S1 (3.97) > South S2 (2.39) > North S4 (0.36). These results suggest a potential risk of heavy metal contamination in the western part of Dianchi Lake.
Anthropogenic contaminants in the marine environment often biodegrade slowly, bioaccumulate in organisms, and can have deleterious effects on wildlife immunity, health, reproduction, and development. In this study, we evaluated tissue toxicant concentrations and pathology data from 83 odontocetes that stranded in the southeastern United States during 2012–2018. Mass spectrometry was used to analyze blubber samples for five organic toxicants (atrazine, bisphenol-A, diethyl phthalates, nonylphenol monoethoxylate [NPE], triclosan), and liver samples were analyzed for five non-essential elements (arsenic, cadmium, lead, mercury, thallium), six essential elements (cobalt, copper, manganese, iron, selenium, zinc) and one toxicant mixture class (Aroclor¹²⁶⁸). Resultant data considerably improve upon the existing knowledge base regarding toxicant concentrations in stranded odontocetes. Toxicant and element concentrations varied based on animal demographic factors including species, sex, age, and location. Samples from bottlenose dolphins had significantly higher average concentrations of lead, manganese, mercury, selenium, thallium, and zinc, and lower average concentrations of NPE, arsenic, cadmium, cobalt, and iron than samples from pygmy sperm whales. In adult female bottlenose dolphins, average arsenic concentrations were significantly higher and iron concentrations were significantly lower than in adult males. Adult bottlenose dolphins had significantly higher average concentrations of lead, mercury, and selenium, and significantly lower average manganese concentrations compared to juveniles. Dolphins that stranded in Florida had significantly higher average concentrations of lead, mercury, and selenium, and lower concentrations of iron than dolphins that stranded in North Carolina. Histopathological data are presented for 72 animals, including microscopic evidence of Campula spp. and Sarcocystis spp. infections, and results of Morbillivirus and Brucella spp. molecular diagnostic testing. Sublethal cellular changes related to toxicant exposure in free-ranging odontocetes may lead to health declines and, in combination with other factors, may contribute to stranding.
In this study, we conducted a noncarcinogenic risk assessment of consuming vegetables and fruits grown in two old mining areas from the Banat area of Southern Carpathians (Romania), Moldova Veche (M) and Rusca Montana (R) and in a nonpolluted reference area located near the village of Borlova (Ref). Concentrations of Fe, Mn, Zn, Cu, Ni, Cd and Pb in soils and commonly eaten vegetables and fruits were measured and used for calculating the weighted estimated daily intake of metals (WEDIM), the target hazard quotients (THQ) and the total target hazard quotients (TTHQ) for normal daily consumption in adults. Levels of certain metals in soils and plants from the R area (Pb) and the M area (Cu) were higher than those measured in the Ref area—and often exceeded normal or even alert-threshold levels. TTHQs for the R area (1.60; 6.03) and the M area (1.11; 2.54) were above one for leafy vegetables and root vegetables, respectively, suggesting a major risk of adverse health effects for diets, including these vegetal foodstuffs. Moreover, THQ and TTHQ indicated a higher population health risk for the R area than for the M area, with the Ref area being a safe zone.
Cadmium (Cd) is a toxic non-essential transition metal that poses a health risk for both humans and animals. It is naturally occurring in the environment as a pollutant that is derived from agricultural and industrial sources. Exposure to cadmium primarily occurs through the ingestion of contaminated food and water and, to a significant extent, through inhalation and cigarette smoking. Cadmium accumulates in plants and animals with a long half-life of about 25–30 years. Epidemiological data suggest that occupational and environmental cadmium exposure may be related to various types of cancer, including breast, lung, prostate, nasopharynx, pancreas, and kidney cancers. It has been also demonstrated that environmental cadmium may be a risk factor for osteoporosis. The liver and kidneys are extremely sensitive to cadmium’s toxic effects. This may be due to the ability of these tissues to synthesize metallothioneins (MT), which are Cd-inducible proteins that protect the cell by tightly binding the toxic cadmium ions. The oxidative stress induced by this xenobiotic may be one of the mechanisms responsible for several liver and kidney diseases. Mitochondria damage is highly plausible given that these organelles play a crucial role in the formation of ROS (reactive oxygen species) and are known to be among the key intracellular targets for cadmium. When mitochondria become dysfunctional after exposure to Cd, they produce less energy (ATP) and more ROS. Recent studies show that cadmium induces various epigenetic changes in mammalian cells, both in vivo and in vitro, causing pathogenic risks and the development of various types of cancers. The epigenetics present themselves as chemical modifications of DNA and histones that alter the chromatin without changing the sequence of the DNA nucleotide. DNA methyltransferase, histone acetyltransferase, histone deacetylase and histone methyltransferase, and micro RNA are involved in the epigenetic changes. Recently, investigations of the capability of sunflower (Helianthus annuus L.), Indian mustard (Brassica juncea), and river red gum (Eucalyptus camaldulensis) to remove cadmium from polluted soil and water have been carried out. Moreover, nanoparticles of TiO2 and Al2O3 have been used to efficiently remove cadmium from wastewater and soil. Finally, microbial fermentation has been studied as a promising method for removing cadmium from food. This review provides an update on the effects of Cd exposure on human health, focusing on the cellular and molecular alterations involved.
Les inondations ont constitué durant ces dix dernières années un risque majeur pour le territoire national, surtout pour les villes situées au pied de la montagne. La ville de Khénifra est un exemple de ces villes qui connaissent en permanence des inondations; dites parfois catastrophiques (dégâts matériels, pertes en vie humaine) ; avec une fréquence d'une année sur cinq (F1/5). Il faut reconnaître que la ville de Khénifra est confrontée au risque d'inondation, du fait de sa situation de cuvette, entourée par quatre grandes montagnes et traversée par l'oued Oum Er Rbia ; l'un des fleuves les plus importants du Maroc ; et ses affluents (9 Châabats) et vue son climat favorable (hiver humide et orages en été). Ce phénomène est certainement lié à l'augmentation des entrées pluviométriques sur l'ensemble de la ville, ce qui provoque le débordement des eaux de l'oued Oum Er Rbia et le ruissellement des châabats. La présente étude consiste à analyser les variations des événements pluvieux à travers une analyse statistique des données pluviométriques de la station de Tarhat pour une chronique de 27 ans (1985-2011). L'objectif principal est d'extraire l'ensemble des informations qui peuvent nous renseigner sur les caractéristiques pluviométriques de cette période, de déterminer les tendances pluviométriques, d'extraire les variabilités pluviométriques, d'identifier les extrêmes pluviométriques qui sont à l'origine de toutes les catastrophes qui se sont produites dans la ville de Khénifra et de définir le rôle des hauteurs pluviométriques, pour apporter des explications concernant les inondations que connait la ville. Abstract The floods have made over the past ten years a major threat to the country, especially in the towns at the foot of the mountain. City Khénifra is an example of the cities that are constantly flooding, sometimes called catastrophic (damage, loss of life) with a frequency of one year to five (F1/5). Admittedly City Khénifra faces the risk of flooding due to its bowl situation, surrounded by four big mountains and crossed by the Oum Er Rbia; one of the most important rivers of Morocco; and its tributaries (9 châabats) and for its favorable climate (wet winter and thunderstorms in summer). This is certainly linked to the increase in rainfall inputs throughout the city, causing the water overflow the Oum Er Rbia and runoff châabats. This study is to analyze the variations of rainfall events through a statistical analysis of rainfall data of Tarhat station for chronic 27 years (1985-2011). The main objective is to extract all the information that can inform us about the rainfall characteristics of this period, to determine rainfall patterns, extract rainfall variability, identify rainfall extremes that are the source of all the disasters that have occurred in the city of Khénifra and define the role of rainfall amounts, to provide explanations for the floods that knowledge.
A novel sensitive method for the detection of acetylcholinesterase inhibitors is presented by using unmodified gold nanoparticle coupled with dynamic light scattering (DLS). The hydrolysis of acetylcholine (ACh) mediated by acetylcholinesterase (ACHE) yields the choline, which influences the gold nanoparticles (AuNPs) aggregation, and triggered the increase of their average diameter. The inhibition of the enzyme by pesticides (paraoxon) produces lower yields of choline, leading to less or no AuNP aggregate formation. This study is the first to describe a homogeneous AuNPs-based DLS nanosensor for ultrasensitive detection of paraoxon by measuring ACHE activity. The average diameter and count rate of unmodified AuNPs decreased with the increasing concentration of paraoxon, with a detection limit of 75.5 pmol.L⁻¹. These results suggest that this DLS assay based on unmodified AuNPs could be used in the future for measuring ACHE activity and for non-selective detection of trace amounts of all ACHE inhibitors.
L'inventaire bibliographique des Chlorophyceae et Phaeophyceae marines benthiques du littoral marocain a révélé 213 espéces dont 93 Chlorophyceae (6 ordres, 15 familles et 31 genres) et 110 Phaeophyceae (11ordres, 20 familles et 50 genres).
Les hydrocarbures aromatiques polycycliques (HAP) sont des cancérigènes ubiquitaires, produits en mélanges complexes dont la composition varie en fonction de la source d’émission. Classées substances prioritaires de par leur abondance et leur génotoxicité, l’exposition aux HAP des populations se fait notamment par voie cutanée au cours des activités professionnelles. La surveillance biologique de l’exposition (SBE) tient compte de l’absorption cutanée en plus de l’inhalation et identifie les situations d’exposition à risque. Pour estimer l’exposition au Benzo[a]pyrène (B[a]P), cancérogène certain pour l’homme, le dosage du 3-hydroxybenzo[a]pyrène (3-OHB[a]P) et du (±)trans-anti-B[a]P-tétraol (B[a]P-tétraol) a été récemment proposé. L’objectif de cette thèse était d’étudier l’absorption et le métabolisme cutanés du B[a]P mais aussi des mélanges d’HAP en vue de d’améliorer la compréhension de leur génotoxicité et de développer des biomarqueurs pertinents pour estimer les risques sanitaires. La première partie de ce travail a consisté au développement d’un modèle cutané ex vivo simple mais réaliste à partir d’explants de peau humaine. Après la mise au point des méthodes d’extraction et d’analyse adéquates, la toxico-cinétique et le métabolisme cutané de faibles doses de B[a]P ont été étudiés. La pénétration cutanée et le métabolisme du B[a]P sont inversement proportionnels à la dose appliquée. Cependant, les voies de métabolisation sont impactées différemment. Alors que la production du 3-OHB[a]P issu des voies de détoxication est dose-dépendante, la formation du B[a]P-tétraol, produit de l’hydrolyse du métabolite cancérogène ultime du B[a]P, est rapidement saturée. Le B[a]P-tétraol est donc le biomarqueur le plus pertinent pour estimer le risque cancérogène au B[a]P. De plus, la proportion de B[a]P non-métabolisé traversant la peau est extrêmement limitée indiquant que la toxicité de ce composé s’exprime essentiellement localement. La deuxième partie de ce travail a consisté en une synthèse bibliographique centrée sur la biotransformation de 7 autres HAP cancérogènes permettant d’identifier 16 métabolites d’intérêt commercialisés. In fine, le dosage de 10 de ces métabolites, impliqués dans les voies de bioactivation ou de détoxication de 5 HAP, a pu être développé en GC-MS/MS. Le dosage urinaire de ces nouveaux biomarqueurs devrait permettre d’améliorer la SBE des populations aux HAP cancérogènes. Dans la dernière partie de ce travail, l’impact de la composition de mélanges synthétiques ou industriels (extraits de brai de houille et de coke de pétrole) à différentes doses sur l’absorption et le métabolisme cutanés des HAP furent évalués en présence ou non de rayonnements ultraviolets (UV). La pénétration des HAP diminue quand la complexité du mélange et la dose augmentent. Alors que les UV amplifient la pénétration des HAP lors de l’application des mélanges industriels, ils n’ont pas d’effet sur le B[a]P appliqué seul ou sur les mélanges synthétiques. Leur bioactivation décroit sous l’influence des mélanges et des UV, provoquant une accumulation de HAP non-métabolisés dans la peau ce qui pourrait retarder la survenue des effets génotoxiques. A l’instar du B[a]P, la toxicité des autres HAP cancérogènes semble être essentiellement locale et dépendre du scénario d’exposition cutanée. Ce travail souligne l’importance de l’étude des mélanges du fait d’interactions plus complexes que de simples effets additifs.
Au Nord comme au Sud, l’accès à l’eau, que celle-ci soit à usage domestique ou agricole, devient de plus en plus difficile pour les populations pauvres, alors que les différents types d’exclusion se combinent pour accentuer les inégalités. Pour comparer les processus actuellement en cours sur les cinq continents et tenter d’inverser ces tendances, l’IRD a organisé en 2005 des rencontres à l’université d’Agadir avec l’appui du CRDI et de la Ford Fondation. Les chercheurs, décideurs et responsables d’ONG réunis à cette occasion proposent dans le présent CD un cadre d’action et invitent les pouvoirs publics à renouveler les politiques publiques et répondre aux revendications locales.
Arsenic (As) and As speciation in marine bivalves have been widely investigated. However, little is known about the bioaccumulation and biotransformation of inorganic As in different tissues of scallops. Therefore, the tissue-specific accumulation, biotransformation and subcellular partitioning of As were investigated in Chlamys farreri following 12 d inorganic As [arsenite (AsⅢ) and arsenate (AsⅤ)] exposure and 30 d depuration. Total As levels were highest in the kidneys and lowest in the adductor muscle after 12 d exposure for both As (Ⅲ) and As (Ⅴ) treatment groups, and the bioavailability of As (Ⅲ) was significantly higher than that of As (Ⅴ) for C. farreri. After 30 d elimination, total As levels were significantly decreased to the control levels. The subcellular fate of As in five different tissues was similar for different inorganic As treatment groups. The greatest proportion of As was found in the metallothionein-like protein fraction (MTLP) and the second was the cellular debris (CD). A little part of As (Ⅲ) could be oxidized to As (Ⅴ) in the gill and digestive gland for As (Ⅲ) treatment groups, and the reduction of As (Ⅴ) to As (Ⅲ) happened in the gill and kidney under As (Ⅴ) exposure. Although a high methylation activity was found in C. farreri, it varied in different tissues with different inorganic As species exposure. The present results indicated that exposure to As (Ⅲ) and As (Ⅴ) could induce different responses in bioaccumulation and biotransformation in five tissues of C. farreri.
In this paper a novel methodology to assess the risk of marine litter (ML) pollution in the Mediterranean Sea is implemented. In this approach, the hazard component is estimated using a state-of-the-art 3D modeling system, which allows the simulation of floating and sinking ML particles; the exposure component is defined from biodiversity estimates; and the vulnerability is related to ML ingestion rates of each species. The results show that the hot-spots for the ML risk concentrate in the coastal regions, and are mainly conditioned by the biodiversity in the region. A dedicated analysis on the marine protected areas shows that the risk therein is controlled by the proximity to ML sources and that their present-day protection levels are not effective in the case of ML pollution. Only a reduction of ML at the sources could reduce the impact of ML pollution in protected areas.
Although soft-bottoms are the largest ecosystem on Earth in terms of area, only a small percentage of their macrobenthos has been studied and most of its species are not yet described. Herein, the most up-to-dated comprehensive inventory and the broad-scale baseline of the soft-sediment macrozoobenthos in semi-enclosed coastal systems (SECS) of the Moroccan Atlantic and Mediterranean coasts (3500 km) is presented. In total, 496 species (7 phyla, 21 classes, 65 orders and 201 families) were recorded among which 95 species were exlusively Mediterranean, 99 species were Atlantico-Mediterranean SECS and 302 species exclusively Atlantic.
The best multivariate model, explaining 33% of the total variation observed in benthic assemblages’ composition, included the type of the SECS (estuaries vs lagoons vs bay), the marine ecoregion (Atlantic vs Mediterranean), the surface of the SECS and the environmental features (minimal temperature, minimal and maximal salinity) as predictors of benthic macrofauna composition in the Moroccan SECS. In contrast to the general latitudinal diversity gradient (LDG) pattern, our results showed that species richness and taxonomic diversity showed no relationship with latitude. Such differences in benthic macrofaunal composition across a large scale could result from the fact that each ecosystem has its own specific characteristics, which implies an individualistic approach to ecosystem ecology.
The sample of the 12 SECS considered in this study covers most of the range of variation along the coasts of Morocco. The current compilation is relevant in such poorly known area at the global scale and fulfills a knowledge gap on benthic macrofauna in SECS of the Southern part of the North-Eastern Atlantic and Mediterranean ecoregions. However, the knowledge gained here is insufficient to address perceived shortfalls in knowledge of biodiversity, its importance to ecosystem function, and the threats and consequences of disturbance by anthropogenic activities.
Engineered nanoparticles including ZnO nanoparticles (nZnO) are important emerging pollutants in aquatic ecosystems creating potential risks to coastal ecosystems and associated biota. The toxicity of nanoparticles and its interaction with the important environmental stressor (such as salinity variation) are not well understood in coastal organisms and require further investigation. Here, we examined the interactive effects of 100 μg l⁻¹ nZnO or dissolved Zn (as a positive control for Zn²⁺ release) and salinity (normal 15, low 5, and fluctuating 5–15) on bioenergetics and intermediate metabolite homeostasis of a keystone marine bivalve, the blue mussel Mytilus edulis from the Baltic Sea. nZnO exposures did not lead to strong disturbances in energy or intermediate metabolite homeostasis regardless of the salinity regime. Dissolved Zn exposures suppressed the mitochondrial ATP synthesis capacity and coupling as well as anaerobic metabolism and modified the free amino acid profiles in mussels indicating that dissolved Zn is metabolically more damaging to the Baltic Sea mussels than nZnO. The environmental salinity regime strongly affected metabolic homeostasis and altered physiological and biochemical responses to nZnO or dissolved Zn in the mussels. Exposure to low (5) or fluctuating (5-15) salinity affected the physiological condition, energy metabolism and homeostasis, as well as amino acid metabolism in M. edulis. Generally, fluctuating salinity (5-15) appeared bioenergetically less stressful than constantly hypoosmotic stress (salinity 5) in M. edulis indicating that even short (24 h) periods of recovery might be sufficient to restore the metabolic homeostasis in this mussel species. Notably, the biological effects of nZnO and dissolved Zn became progressively less detectable as the salinity stress increased. These findings demonstrate that habitat salinity must be considered in the biomarker-based assessment of the effects of nanopollutants on coastal organisms.
Trophic transfer of metals has been well researched in aquatic food webs; however, most studies have examined the presence of metal residuals in the entire body of marine organisms and but not in specific tissues. In this study, we determined the concentrations of Cu, Cr, Pb, Zn, Cd, and Ni in various organs of 17 marine species, including crustaceans, gastropods, bivalves, and fishes, with different trophic levels (TLs), which were collected from the Liaodong Bay, China, in July 2019. Results showed that the liver, gill, and muscle tissues of marine species are ideal indicators for analyzing Cu, Cr, Pb, Zn, Cd, and Ni contamination in marine environments. Page: 2
When the entire bodies of these marine species were considered, a bio-dilution in Cu, Cr, Pb, Zn, Cd, and Ni was observed in the studied food web. In contrast, the metal tissue-specific bio-magnification in the entire studied food web showed different results. In the liver and gill tissues, negative correlations were found between the concentrations of cadmium and TLs, while copper bio-dilution was also observed in gill tissue. In the muscle tissues, Cu, Pb, and Ni showed bio-dilution and trophic magnification factors of Cu, Pb, and Ni ranged from 0.44 to 0.73. This study highlights the importance of tissue-specific considerations to obtain further accurate information on metal trophodynamics and trophic transfers in marine food webs, thereby enhancing the risk assessment of many elements in wildlife and human health.
Arsenic (As) causes cancer and non-cancer health effects in humans. Previous research revealed As concentrations over 200 μg g⁻¹ in lake sediments in the south-central Puget Sound region affected by the former ASARCO copper smelter in Ruston, WA, and significant bioaccumulation of As in plankton in shallow lakes. Enhanced uptake occurs during summertime stratification and near-bottom anoxia when As is mobilized from sediments. Periodic mixing events in shallow lakes allow dissolved As to mix into oxygenated waters and littoral zones where biota reside. We quantify As concentrations and associated health risks in human-consumed tissues of sunfish [pumpkinseed (Lepomis gibbosus) and bluegill (Lepomis macrochirus)], crayfish [signal (Pacifastacus leniusculus) and red swamp (Procambarus clarkii)], and snails [Chinese mystery (Bellamya chinensis)] from lakes representing a gradient of As contamination and differing mixing regimes. In three shallow lakes with a range of arsenic in profundal sediments (20 to 206 μg As g⁻¹), mean arsenic concentrations ranged from 2.9 to 46.4 μg g⁻¹ in snails, 2.6 to 13.9 μg g⁻¹ in crayfish, and 0.07 to 0.61 μg g⁻¹ in sunfish. Comparatively, organisms in the deep, contaminated lake (208 μg g⁻¹ in profundal sediments) averaged 11.8 μg g⁻¹ in snails and 0.06 μg g⁻¹ in sunfish. Using inorganic As concentrations, we calculated that consuming aquatic species from the most As-contaminated shallow lake resulted in 4-10 times greater health risks compared to the deep lake with the same arsenic concentrations in profundal sediments. We show that dynamics in shallow, polymictic lakes can result in greater As bioavailability compared to deeper, seasonally stratified lakes. Arsenic in oxygenated waters and littoral sediments was more indicative of exposure to aquatic species than profundal sediments, and therefore we recommend that sampling methods focus on these shallow zones to better indicate the potential for uptake into organisms and human health risk.
Algal diversity in aquatic environments can help assess the health status of ecosystems, provide information about invasions of new species and inform species diversity changes according to environmental conditions. An algal diversity survey (2016–19) of Nador Lagoon (northern Morocco) revealed the presence for the first time of the brown alga Cystoseira aurantia . Since 2015 this alga has been found in high abundance in the northwestern part of the lagoon, mainly around Attalayoun and Nador City. The thalli of larger specimens reached 60 cm in length, and all plants present were free-floating. The species was collected from the water surface to depths not exceeding 2 cm. Floating patches were usually found suspended above sandy and muddy substrates. Increased abundance of this species in the lagoon corresponds with new physico-chemical conditions and ecological parameters, principally resulting from increased water ventilation and improved water quality since 2012. The new communities of C. aurantia may offer a novel resource for the lagoon but high abundance could pose future threats to attached vegetation such as seagrasses and benthic algae by shading and the accumulation of organic detritus. Attention is drawn to taxonomic issues involving C. aurantia .
In the present study, microplastic-associated biofilms were cultivated in an urban lake and a reservoir using virgin expanded polystyrene (PS). The uptake of Pb(II) onto both natural (suspended particles and surficial sediment) and anthropogenic (virgin microplastics and microplastic-associated biofilms) solid substrates was investigated and compared as a function of contact time, pH, and ionic strength in batch adsorption experiments. The adsorption isotherms revealed that biofilms enhanced the adsorption capacity of Pb(II) onto microplastics; however, natural substrates still exhibited a higher capacity. Ionic strength and pH significantly influenced the adsorption of Pb(II) onto all of the solid substrates. Under neutral conditions, competitive adsorption of Pb(II) was observed between anthropogenic solid substrates and natural substrates, which may further alter the distribution of Pb(II) among these solid substrates. The combined toxicity tests of Pb(II) and each solid substrate were carried out using Daphnia magna, the results indicated biofilm enhanced the combined toxicity of Pb(II) and microplastics. Therefore, biofilms not only intensified the vector role of microplastics in the migration of heavy metals in freshwater, but also enhanced their combined toxicity, which may have further potential ecological risks to freshwater ecosystems.
Arsenic is a naturally occurring metalloid and one of the few metals that can be metabolized inside the human body. The pervasive presence of arsenic in nature and anthropogenic sources from agricultural and medical use have perpetuated human exposure to this toxic and carcinogenic element. Highly exposed individuals are susceptible to various illnesses, including skin disorders; cognitive impairment; and cancers of the lung, liver, and kidneys. In fact, across the globe, approximately 200 million people are exposed to potentially toxic levels of arsenic, which has prompted substantial research and mitigation efforts to combat this extensive public health issue. This review provides an up-to-date look at arsenic-related challenges facing the global community, including current sources of arsenic, global disease burden, arsenic resistance, and shortcomings of ongoing mitigation measures, and discusses potential next steps.
This paper provides the current state of knowledge available from the literature regarding the use of copper sulphate (CuSO4) in culture of freshwater and marine fish as related to toxicity, growth performance, physiology, immunity, histomorphology and antiparasitic treatment. From this review, I have assessed and discussed all of these factors, as well as the potential strategies available for use in fish farming. Acute toxicity (96h-LD50) to CuSO4 varies widely among fish species (0.001–730 mg/L) depending on various water quality factors, and many fish species are sensitive to concentrations near those required for controlling and treating parasite infections. Acute exposure to CuSO4 may lead to mortality while sublethal exposure in different organism causes changes in feeding and swimming behaviour, growth performance, histomorphology of gills, liver, kidney, and spleen, hematology, blood biochemistry, the antioxidant defense system, and oxygen consumption. After exposure to copper sulphate, copper ions often accumulate in the gills, liver, kidney and spleen, and in the gills provokes changes in mucus and chloride cells, hyperplasia and/or hypertrophy of primary and/or secondary lamellae, edema of the gill epithelium, and lamellar fusion. Long and short-term exposure to copper sulphate may negatively affect the body growth of fish exposed, and control and treat ectoparasite infections that are discussed here. Copper sulphate may be a chemotherapeutic for controlling and treating ectoparasites in farmed fish because of its effectiveness and low cost.
In 2008–2018, 1458 georeferenced samples of clams and 343 of mussels were harvested in Italy from classified areas along Marche coast and analyzed within food-safety monitoring plans. Pb, Cd, V, Ni, Cr, and As median levels (mg kg⁻¹) were 0.09, 0.08, 0.29, 0.77, 0.35, and 2.35 in clams and 0.16, 0.15, 0.46, 0.48, 0.25, and 3.34 in mussels. The reported levels were comparable with the published ones, and Hg always fell below LOQ (0.025 mg kg⁻¹). Pb and Cd datasets, based on quarterly results, show a decreasing trend in clams and constant baseline value for mussels. Time-trends and forecasting models represent an asset to predict emerging food safety/security risks. The metal levels in mussels and clams from the same area allow environmental safety assessment and thus enable the evaluation of contaminants in both water column and sediment. Monitoring of elements that are not regulated may help in preserving food and environmental safety.
The Swan Lagoon is a national nature reserve and an important spawning ground in China. In this study, we evaluated the concentration of heavy metals (Cd, Cr, Cu, Pb, and Zn) in different aquatic organisms (aquatic plants, crustaceans, mollusks, and fish), in order to examine their trophic transfer in food web. The results showed that the concentrations of Cd, Cu, Pb, and Zn were considerably higher in mollusks, whereas Cr concentrations were significantly higher in aquatic plants than in mollusks, crustaceans, and fish (p < 0.01). Heavy metals exhibit different patterns of trophic transfer in food web. Cd, Cr, Cu, and Pb tended to be efficiently biodiluted with increasing trophic levels in food web (trophic magnification factor, TMF < 1; p < 0.05). The concentration of Zn increased with increasing trophic level; however, it exhibited a TMF of only 1.03, and was not significantly correlated with δ15N (p > 0.05), indicating neither biomagnification or biodilution in the food web.
During the spring season, trace metal concentrations of cadmium (Cd) and copper (Cu) were investigated in surficial fine-grained sediments and the blue mussel Mytilus galloprovincialis. The study was conducted on the Atlantic coast of Morocco at two selected points along Safi shores, a supposed clean station and a recognized metal-contaminated one. The main objectives were to assess the pollution status of these two stations and to highlight the environmental and human risks associated with metal contamination. The bioavailability and the bioaccumulation of the selected metals, several physiological and biometric parameters of mussels were assessed at both sampling stations. As expected, the station located near industry plants showed the highest metal concentrations in the two compartments and was associated with lower values in the physiological and biometric indices. At the mussel scale, inter-station and inter-tissue variations in metal concentrations were observed showing a preferential accumulation within the digestive gland. Besides, strong reliable negative relations of Cd and Cu concentrations were obtained with physiological indices. Surprisingly, a significant occurrence of both selected metals was recorded at the location assumed as a reference station. Therefore, the hypothesis that this station presumed to be clean and currently used as a control station must be reconsidered. As for the risk for the consumer, the estimated daily intake (EDI) of Cd and Cu indicated a potential health risk through mussel consumption since the EDI values were markedly above the international guidelines and threshold levels for human consumption. Finally, our data were compared to those previously obtained along the Safi coastline (NW Morocco) and other geographical regions, including the Mediterranean and western Atlantic areas within the temperate zone.
Indo-Pacific humpback dolphins (Sousa chinensis) reside in shallow coastal waters where they are exposed to potentially toxic elements (PTEs) through dietary intake. We quantitatively assessed the risk posed by eight PTEs to the health of S. chinensis by determining their concentration in 13 fish species. The fish species represented the primary prey of S. chinensis in the South China Sea. Zn and Mn were the most dominant elements in fish at all sampling locations with concentrations ranges of 19.93–67.63 mg kg −1 dry weight (dw) and 1.52–68.2 mg kg −1 dw, respectively. The highest Zn concentration in fish was found in Coilia mystus (72.65 mg kg−1 dw) followed by Liza carinatus (62.57 mg kg−1 dw). At Jiangmen, Zn concentration was significantly lower in benthopelagic fish than in pelagic fish (p < 0.05, one-way ANOVA), while no significant difference was observed in other metals. The health risk posed by dietary intake assessed using the toxicity reference value showed that PTEs did not a significant health risk to S. chinensis. In contrast, the risk quotient (RQ) based on reference doses ranged from 2.17 to 54.63 in prey fish that were contaminated with Zn and Cr indicating a potential health risk to S. chinensis in the South China Sea. The number of PTEs that posed a health risk varied between sites with seven out of eight PTEs above the threshold at Jiangmen and six out of eight at Zhanjiang and Qinzhou. This study showed fish niche and location may influence the health risk posed by consumption of PTE-contaminated fish.
The contamination of aquatic systems with arsenic (As) is considered to be an internationally-important health
and environmental issue worldwide, affecting over 115 countries globally. Arsenic contamination of aquatic
ecosystems is a global threat as it can enter the food chain from As-rich water and cause harmful impacts on the
humans and other living organisms. Although different factors (e.g., pH, redox potential, iron/manganese oxides,
and microbes) control As biogeochemical cycling and speciation in water systems, the significance of algal species
in biotransformation of As is poorly understood. The overarching attribute of this review is to briefly elaborate
various As sources and its distribution in water bodies and factors affecting As biogeochemical behavior in aqueous
ecosystems. This review elucidates the intriguing role of algae in biotransformation/volatilization of As in
water bodies under environmentally-relevant conditions. Also, we critically delineate As sorption, uptake, oxidation
and reduction pathways of As by algae and their possible role in bioremediation of As-contaminated water
(e.g., drinking water, wastewater). The current review provides the updated and useful framework for government
and water treatment agencies to implement algae in As remediation programs globally.
Objective
To determine mercury (Hg), arsenic (As) and selenium (Se) in six fish species of the Oman Sea and assess the health risk of Hg and As.MethodsLECO AMA 254 Advanced Mercury Analyzer according to ASTM, standard no. D 6722, was applied to analyze Hg, and ICP-MS model HP-4500 was used to measure As and Se concentrations in fish samples.ResultsThe mean concentrations of studied elements ranged from 0.12 ± 0.03 to 0.39 ± 0.11 µg g−1 wet weight (ww) for Hg, 0.74 ± 0.37 to 3.30 ± 1.39 µg g−1 ww for As and 0.621 ± 0.16 to 1.54 ± 0.48 µg g−1 ww for Se. A significant correlation (r = 0.65, p < 0.001) was seen between Se and Hg molar concentrations in all samples of fish. The means of Se-to-Hg molar ratios were in the range 8.98–13.40 in mackerel tuna and black pomfret, respectively. The negative significant correlation (r = − 0.27, p < 0.03) was obtained between Se-to-Hg molar ratio and length of fish species. The means of selenium health benefit value (HBVSe) were ranged from 7.12 in Indo-Pacific king mackerel to 17.66 in Narrow-barred mackerel, respectively. The maximum of estimated weekly intake (EWI) for Hg and As was calculated 1.95 μg kg−1 week−1 in mackerel tuna and 0.49 μg kg−1 week−1 in Javelin grunter, respectively. HQHg was exceeded 1 in mackerel tuna and Narrow-barred mackerel, but HQAs was below 1 for all fish species.Conclusion
Since the interactions between Se and Hg, assessing Hg concentration in fish alone is incompetent. Consumers of these fish species are not at high risk of Hg and As exposure. Individuals who frequently eat fish should choose fish species with lower Hg levels, shorter length and high HBVSe, particularly if they are among sensitive groups.
This book provides an inventory of water resources, describes water challenges, and suggests methodologies and technologies for integrated water resources management in the UAE. It also summarizes efforts of water conservation and management, and modern approaches for improvement of water resources management and decision-making related to this valuable resource. The authors are specialized in geology and hydrogeology and have been teaching and conducting scientific research on water resources in the UAE for the last three decades.
This book represents the main reference on water resources in the UAE for academia, researchers, professionals, students and the general public.
This review highlights arsenic (As) and selenium (Se) sources in the environment, their uptake in the soil-plant system, interactions between these metals and the associated toxicity in major biological compartments, which may assist in addressing the hazardous impacts associated with As and Se contamination. The interaction between As and Se is a critical factor for a detailed systematic understanding of the transportation, environmental fate, and associated toxicological effects of these metalloids in plants, animals, and humans. Arsenic and Se induce cytotoxicity and genotoxicity through the generation of reactive oxygen species (ROS). Compared to arsenite (AsIII), methylated arsenicals, including methylarsonous acid (MAsIII) and dimethylarsinous acids (DMAsIII), exhibit more cytotoxic and genotoxic potential to inhibit more potent enzymes and activate the protein AP˗1, which is a critical marker of genetic stability. Methylated AsIII and its associated metabolites are well-known potential carcinogens that induce toxicity by blocking Se metabolism pathway. The imbalance of Se compounds can lead to the generation of ROS, which can inhibit or decrease genomic stability. The As and Se nexus also affect cellular signalling through activation of transcription factors such as NFҡB and AP-1.
The impact of reject brine chemical composition and disposal from Al Asyah inland desalination on soil and groundwater was evaluated. The reject brine is disposed directly into a surface impoundment in a permeable soil with low clay content. Samples were collected from four evaporation ponds and chemically analyzed. The total dissolved salts (TDS) and the concentration of radioactive constituents were quantified. The results indicate high concentrations of TDS in the evaporation ponds where it ranges from 9650 to 15,460 mg/l. The majority of TDS include sodium chlorides produced throughout the isolation process of fresh water from brine. Moreover, the radioactive isotopes of radium-226 and radium-228 have been identified with total concentrations of 78.89 and 198.77 (pCi/l), respectively. These concentrations may be increased over time due to increasing of radon accumulation in the filtration sands. These results indicate that these constituents are above the standards set by the Gulf Cooperation Council and the Saudi National standards for drinking water and effluents discharged into the desert. Hence, reducing of the environmental impact resulting from both the radioactive materials and the ratio of salinity in water is of utmost importance for Al Asyah plant. Furthermore, the continuous monitoring of the effects of radioisotopes on the validity of the adjacent groundwater is highly recommended.