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Environmental risk dynamics of pesticides toxicity in a Mediterranean micro-estuary
Abstract
Pesticides are potentially toxic to aquatic systems, even at low concentration, depending on their individual ecotoxicological properties and their mixture composition. Thus, to evaluate possible ecological stress due to pesticide load, a thorough assessment of the potential toxicity of pesticide mixtures is required. Here we report water discharge and quality data of an eastern Mediterranean micro-estuary (Alexander stream), targeting the temporal distribution of a pesticide mixture. Over 150 water samples were collected during 2 hydrological years representing base-flow and flood conditions. On average, each water sample contained 34 and 45 different pesticides with peak concentrations of 1.4 μg L⁻¹ of Imidacloprid and 55 μg L⁻¹ of Diuron during base-flow and flood events, respectively. Pesticide mixtures were potentially toxic to benthic invertebrates and algae during flood events, surpassing the toxicity benchmark with medians of 110% and 155%, respectively. The herbicide Diuron and the insecticide Imidacloprid were the main pesticides responsible for the high potential toxicity during flood events. The falling limb of the flood hydrographs was found to inflict the highest stress on the estuarine environment due to elevated toxicity combined with prolonged residence time of the water. Examination of the potential chronic toxicity of single compounds showed continuous stress for plants, algae, amphibians, crustaceans, insects and fish from nine pesticides. Our data show that the ecosystem of the Alexander micro-estuary is under a continuous chronic stress with acute peaks in potential toxicity during flood events and the period that follows them. We propose that analyzing a small set of flood-tail samples is needed for the evaluation of small estuarine ecosystems risk during the rainy season. From a management perspective, we suggest better control of application practices for Diuron in the watershed to minimize the stress to the estuarine ecosystem.
... 60 metric tons of dissolved inorganic nitrogen and 2.7 metric tons of phosphorus (Suari et al., 2017). The discharge also carries significant amounts of pesticides (Topaz et al., 2020a), pharmaceuticals (Topaz et al., 2020b), and possibly other pollutants to the nearby sea (Suari et al., 2019b;Topaz et al., 2018Topaz et al., , 2020aTopaz et al., , 2020b. Although the Alexander Stream and the other Israeli coastal streams supply significant amounts of nutrients and pollutants to a highly oligotrophic marine environment, little is known regarding their dispersal in the coastal environment. ...
... 60 metric tons of dissolved inorganic nitrogen and 2.7 metric tons of phosphorus (Suari et al., 2017). The discharge also carries significant amounts of pesticides (Topaz et al., 2020a), pharmaceuticals (Topaz et al., 2020b), and possibly other pollutants to the nearby sea (Suari et al., 2019b;Topaz et al., 2018Topaz et al., , 2020aTopaz et al., , 2020b. Although the Alexander Stream and the other Israeli coastal streams supply significant amounts of nutrients and pollutants to a highly oligotrophic marine environment, little is known regarding their dispersal in the coastal environment. ...
... Several papers (Topaz et al., 2018(Topaz et al., , 2020a(Topaz et al., , 2020b have shown that floodwater and suspended sediments carry elevated concentrations of pesticides and pharmaceuticals. These organic pollutant mixtures have high potential of acute toxicity to most taxonomic groups in the estuary. ...
... In addition, herbicides are also used to kill algae in mariculture. Therefore, the detection rate for herbicides in inshore waters is high, pollution is very high, and these residues threaten the survival of marine organisms and the health of marine ecosystems (McKenzie et al., 2020;Ouyang et al., 2019;Topaz et al., 2020). Triazine herbicides are the most widely used herbicides (De Souza et al., 2007;Xie et al., 2019). ...
... Most studies have focused on the toxic effects of a single herbicide on phytoplankton (Qiu et al., 2013;Smedbol et al., 2018;Zhao et al., 2017). However, studies have shown that many types of herbicides coexist in the marine environment (Ojemaye et al., 2020;Topaz et al., 2020;Zheng et al., 2016). The interaction of the low-concentration components of the triazine herbicide mixture produces a more serious combined toxicity effect (Faust et al., 2001). ...
Triazine herbicides are widely used in agricultural production, and large amounts of herbicide residue enter the ocean through surface runoff. In this study, the toxicities of the triazine herbicides atrazine, prometryn and terbutryn (separately and mixed) to Phaeodactylum tricornutum were investigated. The EC50 values of atrazine, prometryn and terbutryn were 28.38 μg L⁻¹, 8.86 μg L⁻¹, and 1.38 μg L⁻¹, respectively. The EC50 of an equitoxic mixture of the three herbicides was 0.78 TU, indicating that they had synergistic effects. The equitoxic mixture accumulated in P. tricornutum, which damaged chloroplast and mitochondria structures and significantly decrease the biomass, levels of key cellular components (such as chlorophyll a (chl a), carbon (C) and nitrogen (N) content, fatty acid content) and the effective photochemical quantum yield of photosystem II (PSII, ∆Fv/Fm). The mixture also downregulated key genes in the light response (PsbD, PetF), dark response (PGK, PRK), tricarboxylic acid (TCA) cycle (CS, ID, OGD, and MS) and fatty acid synthesis (FABB, SCD, and PTD9). P. tricornutum partially alleviates the effects of the mixture on photosynthesis and fatty acid synthesis by upregulating PetD, PsaB, RbcL and FabI expression. The triazine herbicide mixture reduced the biomass and nutritional value of marine phytoplankton by inhibiting photosynthesis and energy metabolism.
... Therefore, organism diversity can be affected directly and indirectly by pesticides since bays are the ultimate recipients of agricultural nonpoint source pollution from riverine catchments (Ouyang et al. 2019) and act like a sink for large volumes of hazardous substances (Moreno-González et al. 2013). Concentrations of pesticides found in estuarine waters can vary noticeably depending upon the sampling site and substance, with most works reporting levels within ng L −1 to µg L −1 range (Topaz et al. 2020;Caracciolo et al. 2023;Li et al. 2023b). In Brazil, levels usually found are within the ng L −1 range (de Souza et al. 2016;Gama et al. 2017;Viana et al. 2020;Abreu et al. 2021a;Souza et al. 2022;Miranda et al. 2022). ...
Pesticide contamination remains a significant environmental concern globally, with important implications for aquatic ecosystems. Despite being one of the world’s largest pesticide consumers, monitoring and assessment of pesticide pollution are limited in Brazil, especially in sensitive regions like the Amazon. In this study, the occurrence and environmental risks of 8 pesticides of different classes, namely alachlor, atrazine, chlorfenvinphos, isoproturon, irgarol, simazine, diuron, and its transformation product DCPMU (1-(3,4-dichlorophenyl)-3-methyl urea) were analysed in surface water of the São Marcos Estuarine Complex (SMEC) in two consecutive years. The quantification of the target compounds was performed using ultra-high-performance liquid chromatography–mass spectrometry (UHPLC-MS). Suspected and untargeted screening analyses with ultra-high-performance liquid chromatography–high resolution mass spectrometry (UHPLC-HRMS) was also conducted to identify transformation products (TPs) and additional pesticides in water samples. All target pesticides, except for alachlor, were found in at least one sampling campaign. The antifouling biocides irgarol and diuron were ubiquitous in 2018 and 2019, with detection frequencies varying between 81 and 100% and maximum concentrations of 13.6 ng L⁻¹ and 17.1 ng L⁻¹, respectively. In 2019, the detection frequencies of the target pesticides were considerably higher than in 2018, with atrazine, isoproturon, and DCPMU being found in 100% of the samples. In 2019, chlorfenvinphos and isoproturon were the pesticides with the highest levels, reaching 48.6 ng L⁻¹ and 44.6 ng L⁻¹, respectively. The UHPLC-HRMS analysis showed the presence of the pesticides DEET (N,N-diethyl-meta-toluamide), octhilinone (2-Octyl-4-isothiazolin-3-one), and cyprodinil (4-cyclopropyl-6-methyl-N-phenylpyrimidin-2-amine) in water samples. Additionally, the TPs 2-hydroxy-atrazine, didemethylisoproturon (1-(4-isopropylphenyl)urea) and M1 (2-methylthio-4-tert-butylamino-6-amino-s-triazine) were found. The environmental risk assessment showed that irgarol was the primary contributor to the global risk quotient in the SMEC region. Similarly, chlorfenvinphos also showed a high risk to the local aquatic biota, especially in 2019. This research not only highlights the urgent need for improved pesticide monitoring in Brazil but also establishes a baseline for future studies and environmental management efforts in SMEC. We emphasize the importance of prioritising pollutants and implementing effective mitigation strategies to protect the fragile aquatic ecosystems of the Brazilian Amazon.
Graphical abstract
... Climate-driven increases in the frequency and intensity of rainfall events (Milly et al., 2002;Wasko et al., 2021) may exacerbate land-use impacts in estuarine systems (Grilo et al., 2011). Stochastic periods of rainfall and associated flooding can transport acute pulses of contaminants, such as pesticides, into catchments (Kuivila & Foe, 1995;Topaz et al., 2020) and cause pronounced changes to the physio-chemistry of estuaries (reviewed by Wetz & Yoskowitz, 2013). Further, estuarine sediments, which serve as a major repository for metals and hydrophobic contaminants, can also be remobilised by increased flows during flooding (Crawford et al., 2022;Zoumis et al., 2001). ...
Contaminants are transported into estuaries during rainfall events, impacting the physiology of harvested species, and thereby threatening fisheries sustainability. Decapods are among the most economically important groups harvested from estuaries, but are at high risk of contaminant exposure. We conducted a systematic review and meta-analysis evaluating the physiological responses of harvested estuarine decapods to contaminants and flooding. A total of 138 research articles were identified, with global research efforts corresponding to the geographic distribution of crustacean harvesting. From these studies, 305 acute toxicity values for metals, polycyclic aromatic hydrocarbons (PAHs) and pesticide chemical classes were extracted and 341 sublethal effect sizes (log-response ratios; LnRRs) calculated using 91 physiological measures across seven response categories. At sublethal environmentally relevant concentrations, exposure to various metals, pesticide chemical classes and PAHs consistently elicited negative effects on decapod physiology (LnRR range: −0.67 to −0.07). Key physiological processes impacted by contaminant exposure included nutritional condition, osmoregulation, oxidative stress defences, acetylcholinesterase activity, metabolism and growth (LnRR range: −0.73 to −0.10), with a general trend for greater effects later in ontogeny. With new agricultural and industrial chemicals continually being marketed, our meta-analysis highlights the need for regulatory testing on harvested species prior to registration for use in catchment areas. Under future climatic variability, harvested estuarine decapods may be increasingly exposed to contaminants, with implications for fisheries and global food security.
... China is a large agricultural country, and its pesticide usage was the highest in the world from 2000 to 2019 according to a survey by the FAO. However, approximately 1% of pesticides reach target pests, and the remainder end up in the soil, water, and air, ultimately entering our food chain and affecting nontarget species, including humans, animals, and plants [2,3]. Chiaia-Hernandez et al. investigated 80 polar pesticides and >90 metabolites in archived topsoil samples from the Swiss Soil Monitoring Network (NABO) from 1995 to 2008, and the application patterns of the pesticides are known. ...
Pesticide residues in soil, especially multiple herbicide residues, cause a series of adverse effects on soil properties and microorganisms. In this work, the degradation of three herbicides and the effect on bacterial communities under combined pollution was investigated. The experimental results showed that the half-lives of acetochlor and prometryn significantly altered under combined exposure (5.02–11.17 d) as compared with those of individual exposure (4.70–6.87 d) in soil, suggesting that there was an antagonistic effect between the degradation of acetochlor and prometryn in soil. No remarkable variation in the degradation rate of atrazine with half-lives of 6.21–6.85 d was observed in different treatments, indicating that the degradation of atrazine was stable. 16S rRNA high-throughput sequencing results showed that the antagonistic effect of acetochlor and prometryn on the degradation rate under combined pollution was related to variation of the Sphingomonas and Nocardioide. Furthermore, the potential metabolic pathways of the three herbicides in soil were proposed and a new metabolite of acetochlor was preliminarily identified. The results of this work provide a guideline for the risk evaluation of combined pollution of the three herbicides with respect to their ecological effects in soil.
... Although they hold similar traits to larger estuaries, such as water stratification and prolonged water residence, their response to hydrological changes is rapid, 9 and they are highly susceptible to anthropogenic stress. 6,7 The constantly changing hydrology creates highly dynamic gradients which may disrupt classical aquatic processes controlling the fate of pollutants, such as sorption−desorption and other transport mechanism. 24,30,36 This study aimed to monitor PFAS in three microestuaries, representing varied hydrological regimes, and report their occurrence, distribution, and risk to the ecosystem, using both estuarine water and sediment data. ...
Microestuaries have a crucial role in supporting biodiversity and human life quality in heavily populated areas. They are also the last barrier controlling fluxes of pollutants from the land to sea. Here, we report the occurrence and distribution of per-and polyfluoroalkyl substances (PFAS) during the dry season in three microestuaries. The total PFAS concentration (n = 12) at the studied estuaries was very high from a global perspective with maximum and median concentrations of 17.4 and 3.4 μg L −1 , respectively. These concentrations significantly exceed the recommended benchmarks for recreational activity. Our analysis reveals that a major fraction of PFAS originated from wastewater effluents, whereas point source pollution dominated when the estuary met an industrial zone containing refinery facilities. In the case of limited dilution by natural riverine water, we suggest using carbamazepine as a steady indicator for the identification of PFAS originating from wastewater. Although the three studied microestuaries exhibit similar characteristics (morphology, precipitation, watershed size, water volume, etc.), changes in water input and connectivity to the sea, along with local anthropogenic activity, dramatically alter the occurrence, concentrations, and distribution of PFAS. This study suggests that microestuaries are subjected to high ecological risk from PFAS pollution due to intensive anthropogenic activity.
... Prolonged exposure to pesticides can lead to population declines, ecological imbalances and endocrine and metabolic disruption in adult fish (Oncorhynchus tshawytscha and Leptocottus armatus) (Meador et al., 2016). As the study in the eastern Mediterranean micro-estuary (Alexander stream) by Topaz et al. (2020), pesticides showed chronic stress on estuarine crustaceans, algae and macrophytes, and insects when exposed to excess insecticides like Imidacloprid at 1.4 μg L − 1 and herbicides like Diuron at 55 μg L − 1 concentrations; particularly, diuron presents significant risks throughout the year for benthic invertebrates, insects, and even fish. ...
Emerging contaminants (ECs) are becoming more prevalent in estuaries and constitute a danger to both human health and ecosystems. These pollutants can infiltrate the ecosystem and spread throughout the food chain. Because of the diversified sources and extensive human activities, estuaries are particularly susceptible to increased pollution levels. A thorough review on recent ECs (platinum group elements, pharmaceuticals and personal care products, pesticides, siloxanes, liquid crystal monomers, cationic surfactant, antibiotic resistance genes, and microplastics) in estuaries, including their incidence, detection levels, and toxic effects, was performed. The inclusion of studies from different regions highlights the global nature of this issue, with each location having its unique set of contaminants. The diverse range of contaminants detected in estuary samples worldwide underscores the intricacy of ECs. A significant drawback is the scarcity of research on the toxic mechanisms of ECs on estuarine organisms, the prospect of unidentified ECs, warrant research scopes.
... Qualitative as well as quantitative ecological risk assessments no longer involve single or individual chemical pollutants (O'Brien and Keough, 2014; Schuijt et al., 2021). Hence, the need to assess risks due to amalgamation of chemicals have become obvious, since micro-organisms are exposed to mixtures of chemical pollutants in natural environments rather than individual compounds, especially in aquatic ecosystems (Aronzon, Peluso and Coll, 2020;Kovalakova, et al., 2020;Topaz et al., 2020). Heavy metals and organic pollutants are two of the major kinds of toxic pollutants found in aquatic ecosystem (Shi et al., 2021: Zhang et al., 2021. ...
The influence of mixtures of metals and pesticide on the activity of algal hydrolytic enzyme alkaline phosphatase was investigated. Toxicity of unary and ternary combinations of Copper (Cu2+), Zinc (Zn2+), Lead (Pb2+), Chromium (Cr2+), Cadmium (Cd2+) ions and 2,4-dichlorophenoxyacetic acid (2,4-D) was assessed via inhibition of phosphatase enzyme activity of Chlorella vulgaris. The effects of the amalgamated ternary mixtures were studied in their fixed percentage ratio of 20:40:40 and 40:30:30. Results obtained showed that all the unary heavy metal ions were toxic to algal phosphatase activity, with a concentration dependent inhibition of alkaline phosphatase activity. The analysis of eco-toxicity concentration (EC50) of toxicant ternary mixtures of metals/ pesticides mixtures in 20:40:40 ratios show that the ternary mixtures 2,4-D/Pb2+/Cd2+and 2,4-D/Zn2+/Cd2+ were more toxic, followed by 2,4-D/Cu2+/Cr2+, 2,4-D/Pb2+/Zn2+, 2,4-D/Cu2+/Zn2+ and 2,4-D/Cu2+/Cd2+. Whereas among the 40:30:30 mixture ratios 2,4-D/Pb2+/Cd2+ and 2,4-D/Zn2+/Cd2+ were most toxic. The decline in the trend of their toxicity strength was followed by 2,4-D/Cu2+/Cr2+, 2,4-D/Cu2+/Zn2+, 2,4-D/Cu2+/Cd2+, 2,4-D/Cu2+/Pb2+ and 2,4-D/Pb2+/Zn2+. In addition, the least toxic amongst them were the 2,4-D/Pb2+/Cr2+, 2,4-D/Zn2+/Cr2+ and 2,4-D/Cr2+/Cd2+ ternary mixtures. Toxicity index analysis of the mixture interaction effect showed that the mixtures of heavy metals with 2,4, D were mostly antagonistic with toxic index (TI) >>1, However, exceptions were the 2,4-D/Pb2+/Cd2+ and 2,4-D/Pb2+/Cd2+mixture which were additive and synergistic with TI=1 and TI<1 respectively. From the foregoing study, the toxicity of the mixtures exhibited largely sigmoidal relationship, increased composition of heavy metal in the mixture resulted in a potentiation of 2,4-D toxicity. These results indicate that mixtures of heavy metals with largely non-toxic 2,4-D may pose ecological risk to freshwater microalgae Chlorella vulgaris, presenting antagonistic, additive and synergistic toxicity interactions based on their relative occurrence in the mixture.
... Most pesticides of traditional formulations were lost in the environment due to spraying drift, rainwater washing, poor wettability, poor adhesion, and light decomposition during the spraying process, and less than 0.1% of pesticides were used effectively [7][8][9]. Such high pesticide losses not only increase farmers' planting costs, but also pose a great threat to non-target organisms, groundwater and ecological security [10,11]. Therefore, a new pesticide formulation is urgently needed to be developed to reduce the massive losses of traditional pesticide formulations and improve its pesticide utilization. ...
... La contamination des milieux aquatiques par les pesticides s'étend jusqu'au milieu marin littoral, où de nombreuses substances ont été détectées dans les estuaires (Topaz et al., 2020), les lagunes et les eaux côtières (Munaron et al., 2012). La connaissance de ces niveaux de contamination a bénéficié du développement récent des techniques d'échantillonnage passif de type POCIS : Polar Organic Chemical Integrative Samplers (Belles et al., 2014) (cf. ...
La protection phytosanitaire des vignobles soulève de nombreuses questions intéressant les viticulteurs. Quels maladies et ravageurs attaquent les vignes dans les différents pays producteurs ? Quelles pratiques en matière de conduite des vignobles permettent d’assurer la protection phytosanitaire ? Quelles sont les conséquences de l’usage des pesticides organiques et inorganiques en termes de risques environnementaux sur les écosystèmes terrestres et aquatiques ? Quelles sont les réactions des espèces biologiques aux impacts des pesticides ?
C’est pour répondre au mieux à toutes ces questions que des chercheurs issus de diverses disciplines (agronomes, agroécologues, agroéconomistes, chimistes de l’environnement, hydrobiologistes, écotoxicologues) se sont associés pour apporter des explications scientifiques, étayées par
leurs expériences sur un site d’étude commun.
Ces auteurs explorent également les stratégies d’évolution des systèmes viticoles pour diminuer drastiquement la pression phytosanitaire actuelle des pesticides sur les écosystèmes et le biote. Ils examinent enfin l’action des politiques publiques d’accompagnement de ces stratégies. Chaque chapitre est accompagné du témoignage d’un acteur socioprofessionnel, ou expert scientifique, afin d’établir une relation étroite entre les besoins sur le terrain et les recherches conduites.
Cet ouvrage s’adresse principalement aux gestionnaires de services agricoles et environnementaux, aux enseignants et étudiants, aux professionnels de terrain : viticulteurs et conseillers, techniciens de rivière… mais aussi à toute personne intéressée par la problématique des pesticides, plus particulièrement en viticulture.
... La contamination des milieux aquatiques par les pesticides s'étend jusqu'au milieu marin littoral, où de nombreuses substances ont été détectées dans les estuaires (Topaz et al., 2020), les lagunes et les eaux côtières (Munaron et al., 2012). La connaissance de ces niveaux de contamination a bénéficié du développement récent des techniques d'échantillonnage passif de type POCIS : Polar Organic Chemical Integrative Samplers (Belles et al., 2014) (cf. ...
La vigne est une plante particulièrement sensible à de multiples pathogènes, notamment fongiques, le mildiou et l’oïdium principalement, ainsi qu’à de nombreux ravageurs. De plus, l’exigence de qualité, aussi bien pour les raisins de table que pour ceux de cuve, destinés à l’obtention de vins aux meilleures propriétés organoleptiques, explique la nécessité d’obtenir une protection sanitaire optimale. Cela se traduit par un nombre important de traitements chimiques, quel que soit le mode de production, conventionnel ou biologique.
Afin de mieux comprendre ces usages de la protection phytosanitaire en vigne, les critères de choix décisionnels des viticulteurs pour mener à bien cette protection, les transferts et les impacts des produits phytosanitaires sur les milieux
connexes et les solutions alternatives dont l’application de base des concepts d’agroécologie par les viticulteurs, nous avons conduit pendant cinq ans un projet de recherche pluridisciplinaire, appelé PhytoCOTE, dans un secteur particulier du Bordelais, en continuum avec l’estuaire de la Gironde. Ce projet a été financé essentiellement par des fonds de l’Agence nationale de la recherche via le laboratoire d’excellence LabEx COTE de l’Université de Bordeaux et par le Conseil régional de la Nouvelle-Aquitaine. Il a généré des travaux de recherche dans une démarche originale d’intégration des différents concepts et processus relatifs à l’usage des pesticides en viticulture. Il a suscité de multiples approches scientifiques pluridisciplinaires (agronomie, agroécologie, chimie environnementale, hydrobiologie, écologie, écotoxicologie, socio-économie).
Ce projet de recherche mené par des équipes de l’Université de Bordeaux, d’INRAE, du CNRS, de l’Ifremer, en relation étroite avec les acteurs socioprofessionnels locaux du secteur viticole et du domaine environnemental, constitue ainsi la genèse de cet ouvrage, élargi à la viticulture dans les pays producteurs sur les
différents continents. Les expérimentations présentées ici ont été produites sur le terrain d’étude de PhytoCOTE afin que les lecteurs ciblés par l’ouvrage, principalement les gestionnaires agricoles et environnementaux, les professionnels de la filière viticole, ou encore les enseignants et les étudiants en écoles agronomiques et agricoles, puissent trouver des références concrètes en illustration aux approches scientifiques.
Dans chaque chapitre figure le témoignage d’un acteur socio-économique ou expert scientifique exprimant l’intérêt des méthodes et des résultats acquis par rapport à la problématique concrète des gestionnaires et des praticiens.
Ce chapitre 7 du livre "Pesticides en viticulture. Usages, impacts et transition agroécologique" présente des stratégies d’évolution des systèmes viticoles et des scénarios prospectifs pour une réduction des pesticides dans le cadre de la transition
agroécologique. L’action des politiques publiques dans les pays producteurs du monde en vue de réduire fortement la pression exercée par les produits phyto�pharmaceutiques sur les milieux est d’abord évoquée. Dans ce chapitre sont rap�pelés les labels et différentes certifications adoptés pour accompagner les mesures
pratiques nécessaires. L’agroécologie est présentée comme un nouveau mode de
raisonnement en vue de l’adaptation des systèmes de production et d’application
de nouvelles pratiques de conduite de la vigne. Des scénarios prospectifs inno�vants en agroécologie, bâtis sur la zone d’étude du projet PhytoCOTE, montrent
des performances socio-économiques et environnementales supérieures à tous les
systèmes étudiés sur le terrain. D’autres voies complémentaires sont évoquées
dont celle de la génétique, le développement conséquent des méthodes de bio�contrôle, les outils de précision et la robotique pour un désherbage mécanique,
l’évolution des équipements de pulvérisation. Enfin de multiples freins d’ordre
économique, technique, psychologique et réglementaire existent et sont analysés.
Le témoignage d’un viticulteur devenu expert en agroécologie présente avec objectivité les critères de choix de ses orientations, mais aussi les difficultés réelles et ses
préoccupations pour l’avenir, eu égard notamment aux futures contraintes dérivant du changement climatique pour assurer une bonne protection sanitaire des vignobles.
... La contamination des milieux aquatiques par les pesticides s'étend jusqu'au milieu marin littoral, où de nombreuses substances ont été détectées dans les estuaires (Topaz et al., 2020), les lagunes et les eaux côtières (Munaron et al., 2012). La connaissance de ces niveaux de contamination a bénéficié du développement récent des techniques d'échantillonnage passif de type POCIS : Polar Organic Chemical Integrative Samplers (Belles et al., 2014) (cf. ...
La vigne est une plante particulièrement sensible à de multiples pathogènes, notamment fongiques, le mildiou et l’oïdium principalement, ainsi qu’à de nombreux ravageurs. De plus, l’exigence de qualité, aussi bien pour les raisins de table que pour ceux de cuve, destinés à l’obtention de vins aux meilleures propriétés organoleptiques, explique la nécessité d’obtenir une protection sanitaire optimale. Cela se traduit par un nombre important de traitements chimiques, quel que soit le mode de production, conventionnel ou biologique.
Afin de mieux comprendre ces usages de la protection phytosanitaire en vigne, les critères de choix décisionnels des viticulteurs pour mener à bien cette protection, les transferts et les impacts des produits phytosanitaires sur les milieux
connexes et les solutions alternatives dont l’application de base des concepts d’agroécologie par les viticulteurs, nous avons conduit pendant cinq ans un projet de recherche pluridisciplinaire, appelé PhytoCOTE, dans un secteur particulier du Bordelais, en continuum avec l’estuaire de la Gironde. Ce projet a été financé essentiellement par des fonds de l’Agence nationale de la recherche via le laboratoire d’excellence LabEx COTE de l’Université de Bordeaux et par le Conseil régional de la Nouvelle-Aquitaine. Il a généré des travaux de recherche dans une démarche originale d’intégration des différents concepts et processus relatifs à l’usage des pesticides en viticulture. Il a suscité de multiples approches scientifiques pluridisciplinaires (agronomie, agroécologie, chimie environnementale, hydrobiologie, écologie, écotoxicologie, socio-économie).
Ce projet de recherche mené par des équipes de l’Université de Bordeaux, d’INRAE, du CNRS, de l’Ifremer, en relation étroite avec les acteurs socioprofessionnels locaux du secteur viticole et du domaine environnemental, constitue ainsi la genèse de cet ouvrage, élargi à la viticulture dans les pays producteurs sur les
différents continents. Les expérimentations présentées ici ont été produites sur le terrain d’étude de PhytoCOTE afin que les lecteurs ciblés par l’ouvrage, principalement les gestionnaires agricoles et environnementaux, les professionnels de la filière viticole, ou encore les enseignants et les étudiants en écoles agronomiques et agricoles, puissent trouver des références concrètes en illustration aux approches scientifiques.
Dans chaque chapitre figure le témoignage d’un acteur socio-économique ou expert scientifique exprimant l’intérêt des méthodes et des résultats acquis par rapport à la problématique concrète des gestionnaires et des praticiens.
Ce chapitre 1 est consacré à la présentation des divers pathogènes de la vigne, aux pratiques viticoles de conduite des vignobles, y compris hors de l’Hexagone, aux usages de la protection phytosanitaire et aux risques agroenvironnementaux
pour les écosystèmes. Certains cépages et leur connexion avec les porte-greffes renforcent ou diminuent leur résistance intrinsèque par rapport aux maladies.
De même, le comportement de la vigne face aux agressions des pathogènes est variable selon les caractéristiques des différentes régions pédoclimatiques. Les modes de production et les systèmes de conduite induisent également des comportements différenciés des viticulteurs, notamment face à l’aversion envers les risques phytosanitaires et leurs conséquences sur la perte qualitative et quantitative de récolte. Les risques agroenvironnementaux de contamination des sols, des eaux, de l’air lors des traitements sont élevés et d’importants travaux de recherche sur les agroéquipements sont menés pour trouver des solutions liées à la suppression des herbicides, à la dérive atmosphérique lors des traitements, aux pertes sur le
sol, tout en optimisant la protection phytosanitaire.
Le témoin de ce chapitre, viticulteur en mode agrobiologique présente les raisons initiales du choix de son mode de production, alors peu répandu dans la région et au-delà, dès la reprise de l’exploitation familiale.
... The current study, provided insights for risk dynamic with various pollutants during flooding event, which could be an important reference for river management. Because both dilution and enrichment effects existed during flooding, pollution source tracing based on risk identification and optimization on pollution dynamic with urban river hydrology become essential for river restoration [74,75]. Our study may provide useful information on guiding where measures need to be taken to reduce pollution. ...
Background
Flood events increase the risk of sediment erosion and hence the release of particle-bound pollutants besides other processes that can be observed during such events like transportation, lateral distribution and other. Macropollutants, such as acids, salts, nutrients, and natural organic matter, are usually diluted by flooding, while the effect of floods on micropollutants is still unclear. To fill this gap, Qingshui Stream, a tributary of the Jialing River in the city of Chongqing that suffered 75,000 m³·s⁻¹ flood in August 2020 was selected in the current study to clarify effects of flood-induced pollution transportation. 14 surface water samples and 14 sediment samples were collected to analyze the occurrence of micropollutants (including 21 organochlorine pesticides (OCPs), 34 organophosphorus pesticides (OPPs) and 3 estrogenic compounds) before, during and after the flood. Finally, the environmental risks were evaluated by risk quotient (RQ).
Results
The concentrations of total phosphorus (TP), total nitrogen (TN), chemical oxygen demand (COD) in the surface water decreased from upstream to downstream, and the amounts were diluted by flooding from 0.08 to 0.05 mg·L⁻¹ for TP, from 0.06 to 0.02 mg·L⁻¹ for TN and from 132 to 27 mg·L⁻¹ for COD, respectively. The concentration of estrogenic compound was up to 90 ng·g⁻¹, which was reduced to be lower than the limit of detection during flood. Alpha-endosulfan, delta-BHC, mirex, dichlorvos, phosdrin, thionazine, tetraethyl pyrophosphate, diazinon, methyl parathion, malathion, chlorpyrifos, famphur, and EPN were diluted by flooding, i.e., the concentration of delta-BHC reduced from 6.67 to 0.09 ng·g⁻¹; whereas, pp'-DDD, heptachlor epoxide, o,o,o-triethylphosphorothioate, dimethoate, rabon and fensulfothion were enriched after the flood. The environmental risk was observed to be mainly arise from the presence of OPPs, which increased after flooding. The RQ values of OPPs and OCPs increased after the flood, and the potential environmental risk of OPPs accounted for the majority portion of the risk.
Conclusions
The concentrations of macropollutants in surface water and sediments, and 14 micropollutants in sediments were diluted, while pesticides such as pp′-DDD, heptachlor epoxide, o,o,o-triethylphosphorothioate, dimethoate, rabon and fensulfothion were enriched after the flood. These results suggested management on urban river should focus on potential risk of OPPs. The current study therefore could provide scientific evidence and regulatory reference for urban river ecosystem protection.
... The application of pesticides and the dispersion of these residues is one of the main causes of contamination of freshwater systems and their biota (del Puerto Rodríguez et al., 2014;Topaz et al., 2020;Liess et al., 2021). This is because after spraying (depending on topography, soil type, application management, and climatic conditions) up to 80% of their compounds or their derivatives and metabolites can be released from the soil (Piccolo et al., 1994) and reach superficial water bodies or groundwater, either by drift, leaching or runoff (Hasenbein et al., 2017;Andrade et al., 2021;Milan et al., 2022). ...
Glyphosate [N-(phosphonomethyl) glycine] is currently the most widely used herbicide worldwide. Its application in agricultural and urban areas can lead to the dispersion and arrival to aquatic systems causing environmental deterioration with detrimental effects on the inhabiting biota. This is triggered not only by the herbicide per se but also its metabolite aminomethyl-phosphonic acid (AMPA), which can be highly toxic to many aquatic organisms. Water fleas are some of the key components in aquatic food webs, being one of the most sensitive groups to pollutants. Although being often used in standardized toxicity tests, they are comparatively less studied in relation to glyphosate exposition. Here we examine the current scientific literature regarding the acute and sublethal toxicity of glyphosate in the Cladocera taxonomic group, with special comparisons between the active ingredient (A.I) and formulations. Our results document a high variation in the lethal concentrations reported for different cladoceran species, due to the high diversity of products used in the toxicity tests. Most articles accounting for sublethal effects were performed on the standard Daphnia magna species. Reproduction, including decreased fecundity and delayed age of first reproduction, is usually one of the most severely affected individual traits. Although still scarce, studies documenting metabolic and genetic alterations might provide accurate information on the mechanisms of action of the herbicide.
... Numerous ecological risk assessments have been conducted for various individual chemical pollutants [4,5]. However, the need to assess risks for combinations of chemicals has become apparent since organisms are exposed to mixtures of chemical pollutants in natural environments rather than individual compounds, especially in aquatic ecosystems [6][7][8]. ...
Nickel and 2,2’,4,4’-tetrabromodiphenyl ether (BDE-47) are two environmental pollutants commonly and simultaneously present in aquatic systems. Nickel and BDE-47 are individually toxic to various aquatic organisms. However, their toxicity mechanisms are species-dependent, and the toxic effects of combined mixtures of BDE-47 and nickel have not yet been investigated. The present study investigated the toxic effects of combined mixtures of BDE-47 and nickel in the diatom Phaeodactylum tricornutum. BDE-47 and nickel mixtures significantly decreased cell abundance and photosynthetic efficiency, while these cells’ reactive oxygen species (ROS) production significantly increased. The EC50-72 h for BDE-47 and mixtures of BDE-47 and nickel were 16.46 ± 0.93 and 1.35 ± 0.06 mg/L, respectively. Thus, combined mixtures of the two pollutants enhance their toxic effects. Interactions between BDE-47 and nickel were evaluated, revealing synergistic interactions that contributed to toxicity in P. tricornutum. Moreover, transcriptomic analyses revealed photosynthesis, nitrogen metabolism, the biosynthesis of amino acids, the biosynthesis of secondary metabolites, oxoacid metabolism, organic acid metabolism, carboxylic acid metabolism, and oxidation-reduction processes were considerably affected by the mixtures. This study provides evidence for the mechanisms of toxicity from combined BDE-47 and nickel exposure while also improving our understanding of the ecological risks of toxic chemicals on microalgae.
... The persistent demands for food, fiber and fuel to meet a growing population are being challenged by agricultural systems of low resilience characterized by inefficient uses of pesticide and fertilizer, soil degradation, water scarcity, and imbalance among plants, insects and microorganisms. [1][2][3] One of potentially feasible countermeasures to rectify this unsustainable way of agricultural production is the improvement of utilization efficiency of agrochemicals such as pesticide and fertilizer. Specifically, it was reported that nearly four million tons of pesticides are consumed annually for the management of diseases and crop protection, 4 while however, most active ingredients of pesticides are lost through off-target delivery and uncontrolled release. ...
BACKGROUND
Confined by the volatile property, pesticides are overused and lost significantly during and after spraying, weakening the ecological microbalance among different species of lives. Acid‐responsive pesticide is a type of smartly engineered pesticides that contribute to the improvement of utilization efficiency of pesticidal active ingredients in acid‐controlled manner, whilst the implementation of acidic solutions may disturb the balance of microenvironment surrounding targeted plants or cause secondary pollution, underscoring the input of acid in a more precise strategy.
RESULTS
Chitosan was chemically modified with a photoacid generator (2‐nitrobenzaldehyde) serving as a light‐maneuvered acid self‐supplier, based on which a smart pesticide was formulated by the integration of attapulgite and organophosphate insecticide chlorpyrifos. Under the irradiation of UV light (365 nm), the modified chitosan would undergo a photolytic reaction to generate an acid and pristine chitosan, which seized the labile protons and facilitated the release of chlorpyrifos based on its inherent pH‐responsive flexibility. According to the pesticide release performance, the release rate of chlorpyrifos under UV light (27.2 mW/cm²) reached 78%, significantly higher than those under sunlight (22%, 4.2 mW/cm²) and in the dark (20%) within the same time, consistent with the pH reduction to 5.3 under UV light and no obvious pH change for the two other situations, exhibiting an attractive UV light‐controlled, acid‐propelled release behavior.
CONCLUSION
Compared to direct acid spray approach, the proposed in situ photo‐induced generation of acid locally on the spots of applied pesticide circumvents the problem of acid contamination to nontargets, demonstrating higher efficiency and biocompatibility for the controlled delivery of acid‐responsive pesticides and pest management. © 2022 Society of Chemical Industry.
By 2030, the global deficit in freshwater resources is projected to reach 40%, in direct correlation with global population growth. To cope with this increase in demand, the Sustainable Development Goals outlined by the United Nations, specifically goal No. 6 of the 2030 agenda, have identified wastewater as a new resource. Indeed, the reuse of wastewater offers three primary advantages: (i) Reused wastewater can serve as an alternative to water from natural reserves, particularly in sensitive geographical areas experiencing water stress. (ii) Wastewater reuse limits the discharge of treated water into the natural environment, which is often a source of pollution, thus helping preserve ecosystems. (iii) Wastewater reuse also facilitates the extraction of valuable compounds, such as fertilisers and precious metals, along with energy generation. This review focuses on various uses of water and the global reuse of treated wastewater from wastewater treatment plants (WWTPs). The focus then shifts to pesticides, exploring the origins of these emerging contaminants and their impacts on aquatic environments. An in-depth analysis of diuron follows, examining its origin, toxicity and regulation and the performance of existing advanced treatments to produce safe water from WWTP effluents.
The improper management of wastewater has become a pressing global environmental issue, demanding immediate attention from the scientific community. A significant concern arises from the increasing presence of “emerging contaminants (ECs),” synthetic compounds detected in minute concentrations across diverse environmental matrices. Recent reports emphasize the prevalence of ECs in wastewater due to unregulated discharges of pharmaceuticals, drugs, endocrine disruptors, pesticides, and various pollutants. The widespread distribution and impact of ECs underscore the necessity for effective removal strategies. This review aims to provide a comprehensive understanding of sustainable wastewater treatment techniques, evaluating their effectiveness and long-term viability. Employing bibliometric analyses on 2785 research papers published between 2016 and 2023 from databases like Scopus, Web of Science, ScienceDirect, PubMed, and Google Scholar, the study reveals Asia, Europe, and North America as major contributors to global EC prevalence. The paper thoroughly assesses experimental conditions and performance of various treatment methods, focusing on phase-changing techniques like membrane processes, adsorption onto solid substrates, advanced oxidation, and biological treatments for removing 55 + different ECs. Among the notable approaches, hybrid constructed wetlands emerge as a sustainable solution, demonstrating enhanced effectiveness. The review also addresses practical challenges, including cost-effectiveness and scalability, while exploring the social and economic repercussions of ECs and their treatment. By consolidating insights from diverse sources, this paper serves as valuable resources for researchers aiming to mitigate the adverse effects of ECs on the environment and human health.
Abstracts
Diuron and Irgarol are common antifouling biocides used in paints to prevent the attachment and growth of fouling organisms on ship hulls and other submerged structures. Concerns about their toxicity to non-target aquatic organisms have led to various restrictions on their use in antifouling paints worldwide. Previous studies have shown the widespread presence of these substances in port areas along the Brazilian coast, with a concentration primarily in the southern part of the country. In this study, we conducted six sampling campaigns over the course of 1 year to assess the presence and associated risks of Diuron and Irgarol in water collected from areas under the influence of the Maranhão Port Complex in the Brazilian Northeast. Our results revealed the absence of Irgarol in the study area, irrespective of the sampling season and site. In contrast, the mean concentrations of Diuron varied between 2.0 ng L⁻¹ and 34.1 ng L⁻¹ and were detected at least once at each sampling site. We conducted a risk assessment of Diuron levels in this area using the risk quotient (RQ) method. Our findings indicated that Diuron levels at all sampling sites during at least one campaign yielded an RQ greater than 1, with a maximum of 22.7, classifying the risk as “high” based on the proposed risk classification. This study underscores the continued concern regarding the presence of antifouling biocides in significant ports and marinas in Brazilian ports, despite international bans.
Graphical Abstract
Hexapods in the Mediterranean Basin are very diverse in terms of species and biological traits, and have been used in both fundamental and applied research. The chapter covers different aspects of the biology and ecology of Hexapods, with special emphasis on those subjects that are relevant in the Mediterranean context. Moreover, it includes a taxonomic key for Entognatha (springtails) at species level and Insecta at order level. The biology and ecology of Hexapods is separated into two different sections: aquatic or semiaquatic springtails and aquatic insects. The second section includes the topics like origin of endemicity, singular aquatic habitats, biological traits, dispersal strategies, metacommunities dynamics, their role in food webs, their response to disturbances, their use in biological assessment of water quality, and known alien aquatic Hexapods. Conservation and management of aquatic Hexapods in the Mediterranean Basin represent a challenge because of their high biodiversity, with adapted species to the hydrological characteristics imposed by the Mediterranean climate, and the fact that aquatic habitats are under intense human pressures.
The Alexander micro-estuary, located at the eastern edge of the Mediterranean Sea, is a typical example of small water bodies that suffer from a combination of urban and agricultural pollution, and overuse of its natural water sources. It is∼6.5 km long, with maximum depth of 3 m and maximum width of 45 m. To evaluate the anthropogenic stress on the system and its ability to mitigate pollution, water samples were collected within the framework of Ruppin's Estuarine and Coastal Observatory [1]. Water samples were collected from the estuary head, which drains about 510 km2, and at a point 300 m upstream from the estuary mouth before water flows into the Mediterranean Sea. A total of 236 stormwater and 44 base-flow water samples between December 2016 and December 2018. Stormwater samples were collected every 0.25 - 4 h along the entire course of the flow events using an automated samplers (Sigma 900, Hach Company, Loveland CO, USA; and ISCO 3700 Full-Size Portable Sampler, Teledyne, Lincoln, NE, USA). Base-flow samples were taken once a month using a horizontal grab sampler (5 L, model 110B, OceanTest Equipment, Fort Lauderdale, FL, USA). All samples were filtered using 90mmGF/F filters (nominal pore size of 0.7 µm, MGF, Sartorius, Göttingen, Germany) and immediately frozen (-20°C) before chemical analysis. Chemical analysis was performed using liquid chromatography with high-resolution mass spectrometry (LC-HRMS) analysis using a QExactive Plus hybrid FT mass spectrometer coupled with a Dionex Ultimate 3000 RS UPLC (Thermo Fisher Scientific, Waltham, MA, USA). The targeted analysis, which included 15 fungicides, 25 herbicides, 18 Insecticides, and 19 pharmaceuticals, concluded with a total of 21,142 entries. All entries are organized in a worksheet, along with location, date, flood section duration, discharge rate, and the total water volume discharged during the relevant period. The provided data offers an opportunity to explore the sources, transport, and impact of a large mixture of organic pollutants in a confined aquatic system located in an urbanized coastal environment.
Bacillus thuringiensis is the leading microbial-based biopesticide, thanks to its parasporal crystal proteins or δ-endotoxins, which are toxic to insect larvae upon ingestion. Once in the insect larvae midgut, the crystal is solubilized by the alkaline pH and the δ-endotoxins activated by proteolytic cleavage. Thanks to its high efficiency as a biopesticide, several efforts have been made to enhance its growth and δ-endotoxins production, in various types of culture media. In this study, a culture medium based on wheat bran (WB), the by-product of cereal grain milling, was used to grow Bacillus thuringiensis and produce δ-endotoxins. Using the response surface methodology (RSM), the effects of three variables were evaluated: WB particles granulometry, their concentration, and their agitation in a 48-h shake-flask culture at 30 °C. Three response parameters were targeted: δ-endotoxins production, final culture pH, and dry-matter consumption. According to the RSM results, the optimum would be at 3.7 g WB/50 mL, with a granulometry above 680 μm and agitation between 170 and 270 rpm. This study is key to developing natural and cheap culture media that can be used at an industrial level for Bacillus thuringiensis-based biopesticides.
Pollutant discharge causing the deterioration of the watershed environment has seriously threatened human health and ecosystem function. The importance of improving the risk warning system is becoming more and more prominent. Traditional chemical risk assessment methods focused on toxicity and the exposure of pollutants without considering the impact of persistent pollutants in different environmental media. In this study, a new approach was proposed to reflect multi-dimensional evaluation with a synthetic risk factor (SRF) of pollutants. The integrating parameters of SRF include toxicity endpoint values, environmental exposure level, persistent properties, and compartment features. Selected pesticides, perfluorinated compounds, organophosphate esters and endocrine disruptors were analyzed by the proposed and traditional methods. The results showed a higher risk outcome using SRF analysis for PFOS, imazalil, testosterone, androstenedione and bisphenol A, which were different from those obtained by the traditional method, which were consistent with existing risk management. The study demonstrated that the SRF method improved the risk assessment of various pollutants in different environmental media in a more robust fashion, and also provided a more accurate decision basis for ecological environment protection.
Cases of mass fish death, mostly flat head mullet (Mugil cephalus) were observed multiple times in the Israeli micro-estuaries. A fish kill event that took place in a short span of time in multiple micro-estuaries during the spring of 2021 is used in this research as a test case to identify the cause of these events. In the past, lack of oxygen, morbidity induced by pathogens and toxicity of organic and inorganic pollutants were tested by experts as causes for the mass fish kills with no conclusive results. Yet, some of the experts suggested ammonia toxicity as a possible cause of fish kills. Ammonia is release during organic matter decomposition and is abundant in the Israeli coastal streams who are frequently subjected to effluents. The dissolved ammonia is found at acidity-controlled equilibrium between two forms, the ammonium ion (NH4+) and the none charged ammonia (NH3). High concentrations of the non-ionized form, damage the membranes of nerve cells, and can lead to damage to the central nervous system and even death. In the present study, the concentration of the non-ionized (toxic) form was calculated based on measurements of the general ammonia concentration (sum of the two forms), temperature, and salinity in the Alexander micro-estuary during the years 2021-2014. The calculation of the concentration of the none ionized form was conducted based on typical acidity values in the Israeli micro-estuaries. The calculated concentration was higher than the acute toxicity threshold (LC50 48h) during 25% of the time in 8.5pH and does not reach the toxic threshold in 7.5pH. The concentration of total ammonia and of the none ionized form where higher during spring than during other seasons, which coincides with observations of mass kill. Our findings indicate that ammonia, possibly in conjunction with other stress factors, might be a significant contributor to mass fish kill events. This work and others ilucidate the damage inflicted to the environment as a result of prolonged discharge of effluents.
Micro-estuaries are small ubiquitous transitional water bodies that are often located in semi-arid zones. Unlike the vastly studied large estuaries, micro-estuaries lack the ability to dilute and contain pollution from point and non-point sources due to low natural water discharges. Therefore, these diverse ecological systems are susceptible to pollutant loads due to prolonged water residence time and complex geochemical dynamics. Although this elevated anthropogenic stress limits their potential to provide ecological and recreational services, micro-estuaries have some traits similar to those found in wetlands, which provide a natural potential to retain and mitigate organic pollutants. A two consecutive years study conducted at the Alexander micro-estuary tracked the influx and outflux of a large organic pollutant mixture during base-flow and flood events. During the research period, 165 kg of active ingredients entered the micro-estuary and 160 kg flowed out to the Mediterranean Sea, suggesting negligible net attenuation. However, this broad picture conceals inner shifts in pollutant mixture loads, which contained 46 pesticides and 19 pharmaceuticals. Only a handful of pollutants were actually balanced, whereas most compounds were either removed or added to the flow, with no observed correlation to chemical properties. A prominent observation was the load increase along the flow for some pollutants during base-flow conditions. This trend, which was correlated with salinity elevation and was verified in lab experiments, suggests that seawater intrusion to the bottom of the estuary may increase desorption rates of pollutants from the estuary bed, creating an estuarine desorption magnification effect. The combination of strong anthropogenic stress with increased desorption rates severely limits the estuary's potential to mitigate pollutants, frequently transforming it into a pollution source rather than a sink.
Micro-estuarine ecosystems have a surface area < 1 km2 and are abundant in Mediterranean regions. As a result of their small size, these systems are particularly vulnerable to effects of chemical pollution. Due to fluctuating flow conditions of base-flow dominated by treated wastewater effluents and flood events transporting rural and urban non-point-source pollution, micro-estuaries are under a dynamic risk regime, consequently, struggling to provide ecological services. This two-year study explored the occurrence and risks of pharmaceutical contamination in the Alexander micro-estuary in Israel. Pharmaceuticals were detected in all samples (n=280) at as high as 18 µg L-1 in flood events and 14 µg L-1 in base-flow. Pharmaceutical mixtures composition was affected by flow conditions with carbamazepine dominating base-flow and caffeine dominating flood events. Median annual risk quotients for fish, crustaceans and algae were 19.6, 5.2, and 4.5, indicating that pharmaceuticals pose high risk to the ecosystem. Ibuprofen, carbamazepine and caffeine were contribute most to the risk quotients. The current work highlights that micro-estuary ecosystems, like the Alexander estuary, are continuously exposed to pharmaceuticals and most likely to other pollutants, placing these ecologically important systems under an elevated risk, in comparison to the more frequently studied large estuarine systems.
Ruppin's Estuarine and Coastal Observatory (RECO) is a Long-Term Ecological Research station positioned on the East Mediterranean shoreline between Tel-Aviv and Haifa, Israel. We present a comprehensive online database and an accompanying website that provides direct access to the physical, chemical, and biological characteristics of the local coastal marine ecosystem and the Alexander micro estuary. It includes three databases that are updated continuously since 2014: a) In situ stationary sensors data (10 min intervals) of surface and bottom temperature, salinity, oxygen and water level measured at three stations along the estuary. b) Monthly profiles and discrete biogeochemical samples (surface and bottom water) of multiple parameters at four stations located at the inland part of the estuary. Measured parameters include concentrations of chlorophyll-a, microalgae and bacteria (counted with a flow cytometer), Nitrate, Nitrite, Ammonium, Phosphate, total N, total P, particulate organic matter (POM), total suspended solids (TSS), biochemical oxygen demand (BOD), as well as Secchi depth in each station c) Bi-weekly profiles, chlorophyll-a concentrations and cell counts at two marine stations adjacent to the estuary, (1, and 7 Km from the estuary mouth, at bottom depths of 8 and 48 m). The database also includes historical data for the Taninim micro-estuary (2014–2016). The RECO observatory provides a unique data set documenting the interaction of highly eutrophicated estuarine water with the ultra-oligotrophic seawater of the Eastern Mediterranean. This combination results in sharp gradients of salinity, temperature, dissolved oxygen, and nutrients over very small scales (centimeters to meters) and therefore offers an important data set for the coastal shelf research community. The data set also provide a long-term baseline of the estuary hydrography and geochemistry with the hope to foster effective science-based management and environmental planning of this and similar systems. Keywords: Micro-estuary, Eutrophication, Marine, Levantine, Coastal
Micro-estuaries in semi-arid areas, despite their small size (shallow depth of a few meters, length of a few kilometers, and a surface area of less than 1 km 2) are important providers of ecosystem services. Despite their high abundance, tendency to suffer from eutrophication and vulnerability to other anthropogenic impacts, such systems are among the least studied water bodies in the world. In low tidal amplitude regions, micro-estuaries often have limited rate of sea-river water exchange, somewhat similar to fjord circulation, caused by a shallow sandbar forming at the coastline. The long-term study, we report here was inspired by the idea that, due to their small size and low discharges regime, relatively small interventions can have large effects on micro-estuaries. We used a stationary array of sensors and detailed monthly water sampling to characterize the Alexander estuary, a typical micro-estuary in the S.E. Mediterranean, and to identify the main stress factors in this aquatic ecosystem. The Alexander micro-estuary is stratified throughout the year with median bottom salinity of 18 PSU. Prolonged periods of hypoxia were identified as the main stress factor. Those were alleviated by breaching of the sandbar at the estuary mouth by sea-waves or stormwater runoff events (mostly during winter) that flush the anoxic bottom water. Analysis of naturally occurring sandbar breaches, and an artificial breach experiment indicate that the current oxygen consumption rate of the Alexander micro-estuary is too high to consider sandbar breaches as a remedy for the anoxia. Nevertheless, it demonstrates and provides the tools to assess the feasibility of small-scale interventions to control micro-estuaries hydrology and biogeochemistry.
Freshwater fungi are a diverse group of organisms and fulfill important functions in the food web dynamics of surface water ecosystems. Ascomycetic and basidiomycetic hyphomycetes play key roles in leaf litter breakdown in rivers and creeks, while parasitic chytrids are an important food source for small invertebrates in lakes. Field studies indicate that fungal communities are affected by fungicides at environmentally relevant concentrations. However, despite their ecological importance, freshwater fungi are currently not specifically addressed in the EU regulatory frameworks with respect to the protection of surface waters. Specifically, the prospective risk assessment of fungicides does not evaluate adverse effects on non-target aquatic fungi. This paper aims to describe important functions of freshwater fungi, provides an overview of adverse effect levels of fungicides on this organism group, and proposes to integrate the fungal community of freshwater ecosystems as an additional trophic level in the current fungicide risk assessment frameworks. Results of a literature review on the effects of fungicides on aquatic fungi revealed that information on the toxicity of fungicides to non-target aquatic fungi is limited. This is, in part, due to the lack of standardized bioassays using aquatic fungi as test species. Although there is an encouraging number of bioassays focusing on the degradation of dead organic material by hyphomycetes, studies on fungicide effects on other important ecological functions, like the control of algal blooms in lentic surface waters by parasitic chytrid fungi, or on mutualistic fungi living in the guts of aquatic arthropods are largely missing. Thus, the further development and standardized of different fungi bioassays is recommended.
Two headwaters located in southwest France were monitored for 3 and 2 years (Auvézère and Aixette watershed, respectively) with two sampling strategies: grab and passive sampling with polar organic chemical integrative sampler (POCIS). These watersheds are rural and characterized by agricultural areas with similar breeding practices, except that the Auvézère watershed contains apple production for agricultural diversification and the downstream portion of the Aixette watershed is in a peri-urban area. The agricultural activities of both are extensive, i.e., with limited supply of fertilizer and pesticides. The sampling strategies used here give specific information: grab samples for higher pesticide content and POCIS for contamination background noise and number of compounds found. Agricultural catchments in small headwater streams are characterized by a background noise of pesticide contamination in the range of 20–70 ng/L, but there may also be transient and high-peak pesticide contamination (2000–3000 ng/L) caused by rain events, poor use of pesticides, and/or the small size of the water body. This study demonstrates that between two specific runoff events, contamination was low; hence the importance of passive sampler use. While the peak pesticide concentrations seen here are a toxicity risk for aquatic life, the pesticide background noise of single compounds do not pose obvious acute nor chronic risks; however, this study did not consider the risk from synergistic “cocktail” effects. Proper tools and sampling strategies may link watershed activities (agricultural, non-agricultural) to pesticides detected in the water, and data from both grab and passive samples can contribute to discussions on environmental effects in headwaters, an area of great importance for biodiversity.
Direct and indirect ecological effects of the widely used insecticide bifenthrin on stream ecosystems are largely unknown. To investigate such effects, a manipulative experiment was conducted in stream mesocosms that were colonized by aquatic insect communities and exposed to bifenthrin-contaminated sediment; implications for natural streams were interpreted through comparison of mesocosm results to a survey of 100 Midwestern streams, USA. In the mesocosm experiment, direct effects of bifenthrin exposure included reduced larval macroinvertebrate abundance, richness, and biomass at concentrations (EC50’s ranged from 197.6 to 233.5 ng bifenthrin/g organic carbon) previously thought safe for aquatic life. Indirect effects included a trophic cascade in which periphyton abundance increased after macroinvertebrate scrapers decreased. Adult emergence dynamics and corresponding terrestrial subsidies were altered at all bifenthrin concentrations tested. Extrapolating these results to the Midwestern stream assessment suggests pervasive ecological effects, with altered emergence dynamics likely in 40% of streams and a trophic cascade in 7% of streams. This study provides new evidence that a common pyrethroid might alter aquatic and terrestrial ecosystem function at the regional scale.
Insecticide use in urban areas results in the detection of these compounds in streams following stormwater runoff at concentrations likely to cause toxicity for stream invertebrates. In this 2013 study, stormwater runoff and streambed sediments were analyzed for 91 pesticides dissolved in water and 118 pesticides on sediment. Detections included 33 pesticides, including insecticides, fungicides, herbicides, degradates, and a synergist. Patterns in pesticide occurrence reveal transport of dissolved and sediment-bound pesticides, including pyrethroids, from upland areas through stormwater outfalls to receiving streams. Nearly all streams contained at least one insecticide at levels exceeding an aquatic-life benchmark, most often for bifenthrin and (or) fipronil. Multiple U.S. EPA benchmark or criterion exceedances occurred in 40 % of urban streams sampled. Bed sediment concentrations of bifenthrin were highly correlated (p < 0.001) with benthic invertebrate assemblages. Non-insects and tolerant invertebrates such as amphipods, flatworms, nematodes, and oligochaetes dominated streams with relatively high concentrations of bifenthrin in bed sediments, whereas insects, sensitive invertebrates, and mayflies were much more abundant at sites with no or low bifenthrin concentrations. The abundance of sensitive invertebrates, % EPT, and select mayfly taxa were strongly negatively correlated with organic-carbon normalized bifenthrin concentrations in streambed sediments. Our findings from western Clackamas County, Oregon (USA), expand upon previous research demonstrating the transport of pesticides from urban landscapes and linking impaired benthic invertebrate assemblages in urban streams with exposure to pyrethroid insecticides.
Electronic supplementary material
The online version of this article (doi:10.1007/s10661-016-5215-5) contains supplementary material, which is available to authorized users.
Cocktail effects and synergistic interactions of chemicals in mixtures are an area of great concern to both the public and regulatory authorities. The main concern is whether some chemicals can enhance the effect of other chemicals, so that they jointly exert a larger effect than predicted. This phenomenon is called synergy. Here we present a review of the scientific literature on three main groups of environmentally relevant chemical toxicants: pesticides, metal ions and antifouling compounds. The aim of the review is to determine 1) the frequency of synergy, 2) the extent of synergy, 3) whether any particular groups or classes of chemicals tend to induce synergy, and 4) which physiological mechanisms might be responsible for this synergy. Synergy is here defined as mixtures with minimum two-fold difference between observed and predicted effect concentrations using Concentration Addition (CA) as a reference model and including both lethal and sub-lethal endpoints. The results showed that synergy occurred in 7%, 3% and 26% of the 194, 21 and 136 binary pesticide, metal and antifoulants mixtures included in the data compilation on frequency. The difference between observed and predicted effect concentrations was rarely more than 10-fold. For pesticides, synergistic mixtures included cholinesterase inhibitors or azole fungicides in 95% of 69 described cases. Both groups of pesticides are known to interfere with metabolic degradation of other xenobiotics. For the four synergistic metal and 47 synergistic antifoulant mixtures the pattern in terms of chemical groups inducing synergy was less clear. Hypotheses in terms of mechanisms governing these interactions are discussed. It was concluded that true synergistic interactions between chemicals are rare and often occur at high concentrations. Addressing the cumulative rather than synergistic effect of co-occurring chemicals, using standard models as CA, is therefore regarded as the most important step in the risk assessment of chemical cocktails.
Mosquito control insecticide use in the coastal zone coincides with the habitat and mariculture operations of commercially and ecologically important shellfish species. Few data are available regarding insecticide toxicity to shellfish early life stages, and potential interactions with abiotic stressors, such as low oxygen and increased CO2 (low pH), are less understood. Toxicity was assessed at 4 and 21 days for larval and juvenile stages of the Eastern oyster, Crassostrea virginica, and the hard clam, Mercenaria mercenaria, using two pyrethroids (resmethrin and permethrin), an organophosphate (naled), and a juvenile growth hormone mimic (methoprene). Acute toxicity (4-day LC50) values ranged from 1.59 to >10 mg/L. Overall, clams were more susceptible to mosquito control insecticides than oysters. Naled was the most toxic compound in oyster larvae, whereas resmethrin was the most toxic compound in clam larvae. Mortality for both species generally increased with chronic insecticide exposure (21-day LC50 values ranged from 0.60 to 9.49 mg/L). Insecticide exposure also caused sublethal effects, including decreased swimming activity after 4 days in larval oysters (4-day EC50 values of 0.60 to 2.33 mg/L) and decreased growth (shell area and weight) in juvenile clams and oysters after 21 days (detected at concentrations ranging from 0.625 to 10 mg/L). Hypoxia, hypercapnia, and a combination of hypoxia and hypercapnia caused mortality in larval clams and increased resmethrin toxicity. These data will benefit both shellfish mariculture operations and environmental resource agencies as they manage the use of mosquito control insecticides near coastal ecosystems.
Mixtures of organophosphate and carbamate pesticides are commonly detected in freshwater habitats that support threatened and endangered species of Pacific salmon (Oncorhynchus sp.). These pesticides inhibit the activity of acetylcholinesterase (AChE) and thus have potential to interfere with behaviors that may be essential for salmon survival. Although the effects of individual anticholin-esterase insecticides on aquatic species have been studied for decades, the neurotoxicity of mixtures is still poorly understood.
We assessed whether chemicals in a mixture act in isolation (resulting in additive AChE inhibition) or whether components interact to produce either antagonistic or synergistic toxicity.
We measured brain AChE inhibition in juvenile coho salmon (Oncorhynchus kisutch) exposed to sublethal concentrations of the organophosphates diazinon, malathion, and chlorpyrifos, as well as the carbamates carbaryl and carbofuran. Concentrations of individual chemicals were normalized to their respective median effective concentrations (EC50) and collectively fit to a nonlinear regression. We used this curve to determine whether toxicologic responses to binary mixtures were additive, antagonistic, or synergistic.
We observed addition and synergism, with a greater degree of synergism at higher exposure concentrations. Several combinations of organophosphates were lethal at concentrations that were sublethal in single-chemical trials.
Single-chemical risk assessments are likely to underestimate the impacts of these insecticides on salmon in river systems where mixtures occur. Moreover, mixtures of pesticides that have been commonly reported in salmon habitats may pose a more important challenge for species recovery than previously anticipated.
Cultivated land is a major source of pesticides, which are transported with the runoff water and eroded soil during rainfall events and pollute riverine and estuarine environments. Common ecotoxicological assessments of riverine systems are mainly based on water sampling and analysis of only the dissolved phase, and address a single pesticide's toxicological impact under laboratory conditions. A clear overview of mixtures of pesticides in the adsorbed and dissolved phases is missing, and therefore the full ecotoxicological impact is not fully addressed. The aim of this study was to characterize and quantify pesticide concentrations in both suspended sediment and dissolved phases, to provide a better understanding of pesticide-load dynamics during storm events in coastal streams in a Mediterranean climate. High-resolution sampling campaigns of seven flood events were conducted during two rainy seasons in Alexander stream, Israel. Samples of suspended sediments were separated from the solution and both media were analyzed separately for 250 pesticides. A total of 63 pesticides were detected; 18 and 16 pesticides were found solely in the suspended sediments and solution, respectively. Significant differences were observed among the pesticide groups: only 7% of herbicide, 20% of fungicide and 42% of insecticide load was transported with the suspended sediments. However, in both dissolved and adsorbed phases, a mix of pesticides was found which were graded from "mobile" to "non-mobile" with varied distribution coefficients. Diuron, and tebuconazole were frequently found in large quantities in both phases. Whereas insecticide and fungicide transport is likely governed by application time and method, the governing factor for herbicide load was the magnitude of the stream discharge. The results show a complex dynamic of pesticide load affected by excessive use of pesticides, which should be taken into consideration when designing projects to monitor riverine and estuarine water quality.
Introduction:
Fish kills are events of strong emotional impact on the population because of the frequent suspicion that they can be the result of serious pollution accidents. As a matter of fact, they are often due to natural occurrences, such as low levels of dissolved oxygen in the water, but in many cases the causes remain unknown. Fish are particularly sensitive to pesticides and pyrethroids are reported to be the most ecotoxicologically active in the aquatic environment. Nevertheless, the reported cases of massive wild fish mortalities due to these toxicants are very few. This paper describes a fish kill episode occurred in the Padua Province (Veneto Region - North Eastern Italy) which involved several fish species and for which it was possible to identify the cause in the presence of pyrethroids in the water.
Case presentation:
When a whitish liquid coming from the rainwater drain of an industrial area was seen to be spilling into a drainage channel, a fish massive mortality was noticed and investigated. The collected water samples showed the presence of relevant concentrations of cypermethrin, permethrin, deltamethrin and tetramethrin. Analyses on the fish tissues revealed the presence of cypermethrin and permethrin at a concentration range of 476-2834μg/kg and 346-2826μg/kg on a lipid basis, respectively.
Discussion:
According to the results of the performed analyses, we can reasonably state that the described episode had been caused by the exposure of biota to high concentrations of pyrethroids. The present case report significantly contributes to the limited literature available on pesticides-related fish kills. Moreover, it highlights the importance of sharing protocols for fish kill management at a national level, as this would help to better define the roles of the different institutions involved and to improve the investigation and the reporting of these events.
Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May–August 2013. In weekly water samples, 94 pesticides and 89 degradates were detected, with a median of 25 compounds detected per sample and 54 detected per site. In a screening-level assessment using aquatic-life benchmarks and the Pesticide Toxicity Index (PTI), potential effects on fish were unlikely in most streams. For invertebrates, potential chronic toxicity was predicted in 53% of streams, punctuated in 12% of streams by acutely toxic exposures. For aquatic plants, acute but likely reversible effects on biomass were predicted in 75% of streams, with potential longer-term effects on plant communities in 9% of streams. Relatively few pesticides in water—atrazine, acetochlor, metolachlor, imidacloprid, fipronil, organophosphate insecticides, and carbendazim—were predicted to be major contributors to potential toxicity. Agricultural streams had the highest potential for effects on plants, especially in May–June, corresponding to high spring-flush herbicide concentrations. Urban streams had higher detection frequencies and concentrations of insecticides and most fungicides than in agricultural streams, and higher potential for invertebrate toxicity, which peaked during July–August. Toxicity-screening predictions for invertebrates were supported by quantile regressions showing significant associations for the Benthic Invertebrate-PTI and imidacloprid concentrations with invertebrate community metrics for MSQA streams, and by mesocosm toxicity testing with imidacloprid showing effects on invertebrate communities at environmentally relevant concentrations. This study documents the most complex pesticide mixtures yet reported in discrete water samples in the U.S. and, using multiple lines of evidence, predicts that pesticides were potentially toxic to nontarget aquatic life in about half of the sampled streams.
Salinity has been reported to influence the water solubility of organic chemicals entering marine ecosystems. However, there is limited data available on salinity impacts for chemicals potentially entering seawater. Impacts on water solubility would correspondingly impact chemical sorption as well as overall bioavailability and exposure estimates used in the regulatory assessment. Pesticides atrazine, fipronil, bifenthrin, cypermethrin, as well as crude oil constituents dibenzothiophene as well as 3 of its alkyl derivatives all have different polarities and were selected as model compounds to demonstrate the impact of salinity on their solubility and partitioning behavior. The n-octanol/water partition coefficient (KOW) was measured in both distilled-deionized water as well as artificial seawater (3.2%). All compounds had diminished solubility and increased KOW values in artificial seawater as compared to distilled-deionized water. A linear correlation curve estimated salinity may increase the log KOW value 2.6% per one log unit increase in distilled water (R2 = 0.97). Salinity appears to generally decrease the water solubility and increase partitioning potential. Environmental fate estimates based upon these parameters indicate elevated chemical sorption to sediment, overall bioavailability, and toxicity in artificial seawater. These dramatic differences suggest that salinity should be taken into account when conducting exposure estimates for marine organisms. This article is protected by copyright. All rights reserved
Despite a changing world in terms of data sharing, availability, and transparency, there are still major resource issues associated with collating datasets that will satisfy the requirements of comprehensive pesticide risk assessments, especially those undertaken at a regional or national scale. In 1996, a long-term project was initiated to begin collating and formatting pesticide data to eventually create a free-to-all repository of data that would provide a comprehensive transparent, harmonized, and managed extensive dataset for all types of pesticide risk assessments. Over the last 20 years, this database has been keeping pace with improving risk assessments, their associated data requirements, and the needs and expectations of database end users. In 2007, the Pesticide Properties DataBase (PPDB) was launched as a free-to-access website. Currently, the PPDB holds data for almost 2300 pesticide active substances and over 700 metabolites. For each substance around 300 parameters are stored, covering human health, environmental quality, and biodiversity risk assessments. With the approach of the twentieth anniversary of the database, this article seeks to elucidate the current data model, data sources, its validation, and quality control processes and describes a number of existing risk assessment applications that depend upon it.
This paper presents the investigation of the influence of salinity variations on the toxicity of sulfapyridine, sulfamethoxazole, sulfadimethoxine and trimethoprim towards the green algae Chlorella vulgaris after exposure times of 48 and 72 h. In freshwater the EC50 values ranged from 0.98 to 123.22 mg L−1 depending on the compound. The obtained results revealed that sulfamethoxazole and sulfapyridine were the most toxic, while trimethoprim was the least toxic pharmaceutical to the selected organism. Deviations between the nominal and real test concentrations were determined via instrumental analysis to support the interpretation of ecotoxicological data. The toxicity effects were also tested in saline water (3, 6 and 9 PSU). The tendency that the toxicity of selected pharmaceuticals decreases with increasing salinity was observed. Higher salinity implies an elevated concentration of inorganic monovalent cations that are capable of binding with countercharges available on algal surfaces (hydroxyl functional groups). Hence it can reduce the permeability of pharmaceuticals through the algal cell walls, which could be the probable reason for the observed effect. Moreover, for the classification of the mode of toxic action, the toxic ratio concept was applied, which indicated that the effects of the investigated drugs towards algae are caused by the specific mode of toxic action.
During the past 50 years, the human population has more than doubled and global agricultural production has similarly risen.
However, the productive arable area has increased by just 10%; thus the increased use of pesticides has been a consequence
of the demands of human population growth, and its impact has reached global significance. Although we often know a pesticide′s
mode of action in the target species, we still largely do not understand the full impact of unintended side effects on wildlife,
particularly at higher levels of biological organization: populations, communities, and ecosystems. In these times of regional
and global species declines, we are challenged with the task of causally linking knowledge about the molecular actions of
pesticides to their possible interference with biological processes, in order to develop reliable predictions about the consequences
of pesticide use, and misuse, in a rapidly changing world.
This study aimed to characterize environmental hazards of pesticides from pineapple production in riparian communities along the Jiménez River watershed. To achieve our objectives riparian ecological quality indices on riparian habitat and macroinvertebrate assemblages were combined with toxicity assays, fish biomarkers, physico-chemical water analysis and pesticide environmental hazards. During two consecutive years and two periods (July and October), three reference and four impacted sites were monitored. The ecological quality of benthic macroinvertebrates and of riparian habitats deteriorated from the reference sites downstream to the polluted reaches along the Jiménez River area affected by pineapple plantations. The toxicity of water to Daphnia magna also increased towards downstream reaches. Biomarkers of fish of the species Poecilia gillii and Bryconamericus scleroparius transplanted across the studied sites evidenced a clear anticholinergic effect towards downstream sites as well as increased levels of lipid peroxidation. Different pesticide residues were frequently detected in water samples collected across the Jiménez River watershed with herbicides (ametryn, bromacil, diuron), organophosphorus insecticides (diazinon and ethoprophos) and triazole fungicides being the greatest reaching levels above 1μgL(-1) in downstream sites. Principal component and environmental hazard analysis of physico-chemical and biological responses established clear relationships among habitat deterioration and the ecological quality of macroinvertebrate communities, high levels of herbicides and poor plant growth, high levels of organophosphorus insecticides in water and anticholinesterase effects on fish, D. magna mortality and deterioration of macroinvertebrate communities. Fungicide and herbicide residue levels were also related with high levels of lipid peroxidation and high activities of glutathione S transferase in fish liver, respectively. These results indicated, thus, that riparian habitat deterioration due to deforestation and land use for agriculture and pesticide contamination are affecting river ecosystems.
The impact of wastewater flow on the channel bed morphology was evaluated in four ephemeral streams in Israel and the Palestinian Territories: Nahal Og, Nahal Kidron, Nahal Qeult and Nahal Hebron. Channel changes before, during and after the halting of wastewater flow were monitored. The wastewater flow causes a shift from a dry ephemeral channel with intermittent floods to a continuous flow pattern similar to that of humid areas. Within a few months, nutrient-rich wastewater flow leads to rapid development of vegetation along channel and bars. The colonization of part of the active channel by vegetation increases flow resistance as well as bank and bed stability, and limits sediment availability from bars and other sediment stores along the channels. In some cases the established vegetation covers the entire channel width and halts the transport of bed material along the channel. During low and medium size flood events, bars remain stable and the vegetation intact. Extreme events destroy the vegetation and activate the bars. The wastewater flow results in the development of new small bars, which are usually destroyed by flood flows. Due to the vegetation establishment, the active channel width decreases by up to 700 per cent. The deposition of fine sediment and organic material changed the sediment texture within the stable bar surface and the whole bed surface texture in Nahal Hebron. The recovery of Nahal Og after the halting of the wastewater flow was relatively fast; within two flood seasons the channel almost returned to pre-wastewater characteristics. The results of the study could be used to indicate what would happen if wastewater flows were introduced along natural desert streams. Also, the results could be used to predict the consequences of vegetation removal as a result of human intervention within the active channel of humid streams. Copyright © 2001 John Wiley & Sons, Ltd.
1 Salt marshes in south-west Spain are being invaded by Spartina densiflora, a South American introduction, although the native S. maritima still dominates many lower marshes. A transplant experiment was used to investigate the means by which physical and chemical factors may determine lower vegetation limits in the tidal frame. Both species were transplanted from a mid-level marsh to lower, unvegetated tidal flats.
2 The survival and growth of transplanted clumps and their constituent tillers were monitored on an elevational gradient. The photosynthetic competence of transplants was assessed by measurements of leaf gas exchange and the fast kinetics of chlorophyll fluorescence. Submergence period, salinity, redox potential and sulphide concentration in the sediment were also examined at the transplant sites.
3 Neither species survived for a year at the lowest transplant point (+ 1.04 m relative to Spanish Hydrographic Zero). At + 1.41 m elevation, S. maritima survived well but all clumps of S. densiflora died. At higher elevations (+ 1.46–1.67 m), clumps of both species had high survival rates. Tiller growth rates in surviving clumps of both species increased with elevation, but that of S. densiflora was more sensitive to low elevation.
4 S. maritima showed no impairment of photosynthetic performance, even at the lowest elevation; its rates of gas exchange were independent of elevation, as were its chlorophyll fluorescence parameters. In contrast, in S. densiflora the rate of CO2 uptake declined and stress to photosystem II (Fv/Fp) increased at lower elevations; both of these photosynthetic measurements were linearly related to sediment redox potential. Stomatal conductance did not vary with elevation.
5 S. maritima has a potentially wide elevational tolerance and an absolute lower limit substantially below that of S. densiflora. The progressively reduced growth and survival of S. densiflora at lower levels appear to result primarily from impairment of photosynthesis when root conditions are hypoxic. This effect is mediated through effects on the photochemical apparatus rather than on stomatal resistance to CO2 uptake.
6 These studies define lower limits to the fundamental niches of the two species in a Mediterranean-type salt marsh and thus provide a basis for future investigations of interactions between them. The correlation between chlorophyll fluorescence and long-term survival of S. densiflora suggests that this short-term measure may be a valuable tool.
Microorganisms contribute significantly to primary production, nutrient cycling, and decomposition in estuarine ecosystems; therefore, detrimental effects of pesticides on microbial species may have subsequent impacts on higher trophic levels. Pesticides may affect estuarine microorganisms via spills, runoff, and drift. Both the structure and the function of microbial communities may be impaired by pesticide toxicity. Pesticides may also be metabolized or bioaccumulated by microorganisms. Mechanisms of toxicity vary, depending on the type of pesticide and the microbial species exposed. Herbicides are generally most toxic to phototrophic microorganisms, exhibiting toxicity by disrupting photosynthesis. Atrazine is the most widely used and most extensively studied herbicide. Toxic effects of organophosphate and organochlorine insecticides on microbial species have also been demonstrated, although their mechanisms of toxicity in such nontarget species remain unclear. There is a great deal of variability in the toxicity of even a single pesticide among microbial species. When attempting to predict the toxicity of pesticides in estuarine ecosystems, effects of pesticide mixtures and interactions with nutrients should be considered. The toxicity of pesticides to aquatic microorganisms, especially bacteria and protozoa, is an area of research requiring further study.
Environmental risks of chemicals are still often assessed substance-by-substance, neglecting mixture effects. This may result in risk underestimations, as the typical exposure is toward multicomponent chemical "cocktails". We use the two well established mixture toxicity concepts (Concentration Addition (CA) and Independent Action (IA)) for providing a tiered outline for environmental hazard and risk assessments of mixtures, focusing on general industrial chemicals and assuming that the "base set" of data (EC50s for algae, crustaceans, fish) is available. As mixture toxicities higher than predicted by CA are rare findings, we suggest applying CA as a precautious first tier, irrespective of the modes/mechanisms of action of the mixture components. In particular, we prove that summing up PEC/PNEC ratios might serve as a justifiable CA-approximation, in order to estimate in a first tier assessment whether there is a potential risk for an exposed ecosystem if only base-set data are available. This makes optimum use of existing single substance assessments as more demanding mixture investigations are requested only if there are first indications of an environmental risk. Finally we suggest to call for mode-of-action driven analyses only if error estimations indicate the possibility for substantial differences between CA- and IA-based assessments.
Biocides and pesticides are used to control unwanted organisms in urban and agricultural areas. After application, they can be lost to surface waters and impair water quality. Several national consumption studies have shown that urban and agricultural use may be in the same range. It is difficult to judge whether this results in similar loadings of surface waters because there is a lack of sound, comparative studies addressing urban and agricultural losses simultaneously. The aim of this study is thus to relate the biocide and pesticide loads found in surface waters to their respective urban and agricultural usage (loss rates). To simultaneously assess the loss rates, we conducted a comprehensive field study in a catchment of mixed land use on the Swiss Plateau. The study area was divided into four sub-catchments with different degrees of urban and agricultural land use. In addition, we studied the only wastewater treatment plant, a combined sewer overflow and a storm sewer within the area. Rain events were sampled at high temporal resolution from March to November, 2007. Information on agricultural applications was gained from local farmers. For urban uses, consumption estimations were conducted based on statistical and product information. Despite substantially lower amounts used, the measured loads of urban biocides were in the same range as the most widely-used agricultural pesticides. The lower usage was compensated by urban loss rates that were up to ten times higher than agricultural ones (0.6 to 15% for urban, 0.4 to 0.9% for agricultural compounds). For most biocides and pesticides, the loads were controlled by rain events. Besides the rain-controlled losses, some urban-used biocides (e.g. diazinon) showed a continuous load independent of rain events and season. This study demonstrates that in catchments with mixed land use, mitigation strategies have to pay sufficient attention to the urban sources.
This study focused on the input of hydrophilic biocides into the aquatic environment and on the efficiency of their removal in conventional wastewater treatment by a mass flux analysis. A fully automated method consisting of on-line solid phase extraction coupled to LC-ESI-MS/MS was developed and validated for the simultaneous trace determination of different biocidal compounds (1,2-benzisothiazoline-3-one (BIT), 3-Iodo-2-propynylbutyl-carbamate (IPBC), irgarol 1051 and 2-N-octyl-4-isothiazolinone (octhilinone, OIT), carbendazim, diazinon, diuron, isoproturon, mecoprop, terbutryn and terbutylazine) and pharmaceuticals (diclofenac and sulfamethoxazole) in wastewater and surface water. In the tertiary effluent, the highest average concentrations were determined for mecoprop (1010 ng/L) which was at comparable levels as the pharmaceuticals diclofenac (690 ng/L) and sulfamethoxazole (140 ng/L) but 1-2 orders of magnitude higher than the other biocidal compounds. Average eliminations for all compounds were usually below 50%. During rain events, increased residual amounts of biocidal contaminants are discharged to receiving surface waters.
The literature on pesticide losses in runoff waters from agricultural fields is reviewed. For the majority of commercial pesticides, total losses are 0.5% or less of the amounts applied, unless severe rainfall conditions occur within 1–2 weeks after application. Exceptions are the organochlorine insecticides, which may lose about 1% regardless of weather pattern because of their long persistence; and soil surface‐applied, wettable‐powder formulations of herbicides, which may lose up to 5%, depending on weather and slope, because of the ease of washoff of the powder.
Pesticides with solubilities of 10 ppm or higher are lost mainly in the water phase of runoff, and erosion control practices will have little effect on such losses. Organochlorine pesticides, paraquat, and arsenical pesticides, however, are important cases of pesticides which are strongly adsorbed by sediments, and erosion control can be important in controlling losses of these compounds.
The behavior and fate of pesticides in streams receiving runoff is generally not known. Information on such factors as time and distance of impact of a given runoff event, ability of local ecosystems to recover from transient pesticide concentrations, and dissipation or concentration processes in aquatic ecosystems will have to be obtained before “edge‐of‐field” pesticide losses can be related to water quality in receiving waters.
Biocides and pesticides are designed to control the occurrence of unwanted organisms. From their point of application, these substances can be mobilized and transported to surface waters posing a threat to the aquatic environment. Historically, agricultural pesticides have received substantially more attention than biocidal compounds from urban use, despite being used in similar quantities. This study aims at improving our understanding of the influence of mixed urban and agricultural land use on the overall concentration dynamics of biocides and pesticides during rain events throughout the year. A comprehensive field study was conducted in a catchment within the Swiss plateau (25 km(2)). Four surface water sampling sites represented varying combinations of urban and agricultural sources. Additionally, the urban drainage system was studied by sampling the only wastewater treatment plant (WWTP) in the catchment, a combined sewer overflow (CSO), and a storm sewer (SS). High temporal resolution sampling was carried out during rain events from March to November 2007. The results, based on more than 600 samples analyzed for 23 substances, revealed distinct and complex concentration patterns for different compounds and sources. Five types of concentration patterns can be distinguished: a) compounds that showed elevated background concentrations throughout the year (e.g. diazinon >50 ng L(-1)), indicating a constant household source; b) compounds that showed elevated concentrations driven by rain events throughout the year (e.g. diuron 100-300 ng L(-1)), indicating a constant urban outdoor source such as facades; c) compounds with seasonal peak concentrations driven by rain events from urban and agricultural areas (e.g. mecoprop 1600 ng L(-1) and atrazine 2500 ng L(-1) respectively); d) compounds that showed unpredictably sharp peaks (e.g. atrazine 10,000 ng L(-1), diazinon 2500 ng L(-1)), which were most probably due to improper handling or even disposal of products; and finally, e) compounds that were used in high amounts but were not detected in surface waters (e.g. isothiazolinones). It can be safely concluded that in catchments of mixed land use, the contributions of biocide and pesticide inputs into surface waters from urban areas are at least as important as those from agricultural areas.
A new hypothesis, the funnel hypothesis, was derived to explain the variation in toxicity of equitoxic multicomponent mixtures of nonspecific toxicants (narcotics). The variation is explained in terms of the volumes associated with solute-solute and solute-solvent interactions. The hypothesis predicts that as the number of components in a mixture increases, the range of deviation from toxic additivity decreases. It also predicts that the toxicity of mixtures measured using biological endpoints that require high toxicant concentrations will deviate more from toxic additivity than endpoints that require low concentrations. Aquatic toxicity data for equitoxic mixtures of narcotic toxicants to a range of aquatic organisms compiled from the literature support the predictions of the funnel hypothesis.
Two agricultural runoff events involving the pesticide azinphos-methyl occurred in July 2002 on the Wilmot River, Prince Edward Island, Canada, resulting in the death of thousands of fish. The fish communities from three sites on this river had been sampled in 2001, permitting comparisons of brook trout (Salvelinus fontinalis) and rainbow trout (Oncorhynchus mykiss) populations before and after the events. Samples taken immediately after the runoff events suggested that brook trout suffered higher mortality than rainbow trout. Young-of-the-year fish were more affected than older age classes for both species. Sampling in 2003, a year after the pesticide runoff events, revealed salmonid communities that were still skewed towards rainbow trout, and a decrease in the 1+ age class density (2002's young of the year) at affected sites. These results suggest a differential effect of the pesticide azinphos-methyl on salmonid species and age classes under natural conditions, and a subsequent change in population and community structure. The possibility of these pesticide runoff events selecting for rainbow trout, an exotic species, is a consideration in management of agriculturally impacted rivers.
Sorption and desorption behaviors of phenanthrene and naphthalene were studied with the whole sediment, humic acid (HA) and humin samples from downstream and upstream sites along the Kishon River, Israel. The 13C nuclear magnetic resonance spectra and the sorption coefficients suggest that sorption occurs to both aromatic and aliphatic moieties of the sedimentary organic matter and that rigid paraffinic domains probably contribute to the sorption non-linearity. The carbon-normalized Freundlich affinity values for the two sorbates were significantly higher for the whole sediment and humin samples from the downstream region of the river than for the upstream sediment samples. On the basis of the measured affinity values, the sorbents can be arranged in the following order: humin>HA>whole sediment. Phenanthrene exhibited the lowest desorption from the whole sediment samples compared with the other sorbents. For naphthalene, the desorption hysteresis obtained with the whole sediment and humin samples were similar: both exhibited a decrease in desorption with decreasing solute concentration. The higher sorption affinities observed for all the organic fractions from the downstream sediment are suggested to be related to the low levels of polar domains and humin content. It is concluded that in bulk sediment samples, the overall contribution of the HA fraction to short-term sorption is of high importance, but the sorption non-linearity is controlled mainly by the humin complexes. The low desorption potential recorded for the whole sediment samples could affect the natural attenuation of the sorbed hydrophobic organic compounds.
Antifouling paints are used to reduce the attachment of living organisms to the submerged surfaces of ships, boats and aquatic structures, usually by the release of a biocide. Two 'booster' biocides in common use are the triazine herbicide Irgarol 1051 (N-2-methylthio-4-tert-butylamino-6-cyclopropylamino-s-triazine), and diuron (1-(3,4-dichlorophenyl)-3,3-dimethylurea), which are designed to inhibit algal photosynthesis. Previous research has been directed at the effects of these compounds in marine and estuarine environments. In 2001 we sampled the main rivers and shallow freshwater lakes (Broads) of East Anglia UK for Irgarol 1051, its metabolite GS26575 (2-methylamino-4-tert-butylamino-6-amino-s-triazine) and diuron in order to establish the baseline environmental concentrations of these compounds in freshwater systems of eastern UK and to investigate their possible effects on aquatic plants. Irgarol 1051, GS26575 and diuron were found in water samples collected from 21 locations. The highest concentrations were found in the Norfolk and Suffolk Broads in May. The rivers Great Ouse, Wissey, Bure and Yare also contained all three compounds, as did the Great Ouse Cut-off Channel. The toxicity of these biocides to three macrophyte species (Apium nodiflorum, Chara vulgaris, and Myriophyllum spicatum) was investigated. Deleterious effects on relative growth rate, the maximum quantum efficiency (Fv/Fm) of photosystem II and, for Apium, root mass production were found. C. vulgaris was generally most sensitive; growth, especially of roots, was strongly affected in A. nodiflorum; growth rate of M. spicatum was sensitive to diuron. No observed effect concentrations (NOEC) were interpolated using standard toxicological analysis. These were compared with measured environmental concentrations (MEC) to determine the ranges of risk quotients (MEC/NOEC). Both Irgarol 1051 and diuron represented significant risks to A. nodiflorum and C. vulgaris in this area.
Methods for the assessment of ecological risks associated with exposure to defined mixtures of toxicants are reviewed and formalized for single-species toxicity. Depending on the modes of action of toxicants in a mixture, these methods apply either the model for concentration additivity (CA) or the model for response additivity (RA). For complex mixtures, the present paper advocates the use of a new, two-step, mixed-model approach as a logical extension of model selection: Mixture toxicity for individual modes of action is evaluated with the CA model, and the toxicities of different modes of action are combined using the RA model. Using comparable mixture toxicity strategies in combination with the concept of species-sensitivity distributions, we develop a method to address and predict the risk for direct effects on the composition of species assemblages and biodiversity. The data needed for modeling can be obtained from existing databases, and lack of data can, in part, be addressed by the use of toxicity patterns in those databases. Both single- and multiple-species methods of mixture risk prediction are useful for risk management, because they allow ranking of polluted sites and affected species as well as identification of the most hazardous contaminants, at least in a comparative way. Validation of the proposed methods is feasible but currently limited because of a lack of appropriate data.
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