Ecological risk assessment of pesticide residues in Taihu Lake wetland, China

Cellular metabolism and health impacts of dichlorvos: Occurrence, detection, prevention, and remedial strategies-A review

Dichlorvos (2,2-Dichlorovinyl dimethyl phosphate, [DDVP]) belongs to the class of organophosphates and is widely used as an insecticide in agriculture farming and post-harvest storage units. Extensive research has been conducted to assess the factors responsible for the presence of DDVP in terrestrial and aquatic ecosystems, as well as the entire food chain. Numerous studies have demonstrated the presence of DDVP metabolites in the food chain and their toxicity to mammals. These studies emphasize that both immediate and chronic exposure to DDVP can disrupt the host's homeostasis, leading to multi-organ damage. Furthermore, as a potent carcinogen, DDVP can harm aquatic systems. Therefore, understanding the contamination of DDVP and its toxicological effects on both plants and mammals is vital for minimizing potential risks and enhancing safety in the future. This review aimed to comprehensively consolidate information about the distribution, ecological effects, and health impacts of DDVP, as well as its metabolism, detection, prevention, and remediation strategies. In summary, this study observes the distribution of DDVP contaminations in vegetables and fruits, resulting in significant toxicity to humans. Although several detection and bioremediation strategies are emerging, the improper application of DDVP and the alarming level of DDVP contamination in foods lead to human toxicity that requires attention.

Distribution Characteristics and Risk Assessment of 57 Pesticides in Farmland Soil and the Surrounding Water

To investigate the effect of pesticide use on surface water, the concentration and distribution characteristics of 57 pesticides and 3 degradation products were analyzed in the farmland soil and surface water in the Xingkai Lake area, including water from paddy fields, drainages and the Xingkai Lake, in Heilongjiang Province, China. Forty-three pesticides and three degradation products were detected in farmland soil. In dry field (corn and soybean field) soil, the main detected pesticides were atrazine and acetochlor with mean concentrations of 26.09 ng·g-1 and 49.08 ng·g-1, respectively. In paddy field soil, oxadiazon, mefenacet and chlorpyrifos were the main detected pesticides with mean concentrations of 14.32 ng·g-1, 78.60 ng·g-1 and 20.03 ng·g-1, respectively. In the surrounding water, including water from paddy fields, drainages and Xingkai Lake, the total concentrations of contaminants detected in the water samples ranged from 71.19 ng·L-1 to 10,145.76 ng·L-1. Of the three sampling periods, the mean concentration of contaminants in the water exhibited its peak during the vegetative period. In the analysis of the drainage water, the primary pesticides detected were atrazine, acetochlor and buprofezin with mean concentrations of 354.83 ng·L-1, 109.09 ng·L-1 and 254.56 ng·L-1, respectively. Atrazine, simetryn, buprofezin and isoprothiolane were the main pesticides detected in Xingkai Lake water, with the mean concentrations of 222.35 ng·L-1, 112.76 ng·L-1, 301.87 ng·L-1 and 138.02 ng·L-1, respectively. The concentrations of contaminants could be correlated with drainage, Da Xingkai Lake and Xiao Xingkai Lake water (ρ > 0.8) suggested that the source of these contaminants in drainage and Xingkai Lake water could be the same. The maximum potentially affected fraction (PAF) values of atrazine, chlorpyrifos and prometryn were higher than 5% in Xingkai Lake water, resulting in high ecological risks.

Spatial distribution, ecological and health risk assessment of organophosphorus pesticides identified in the water of Naseri artificial wetland, Iran

Agricultural development is inevitable to meet the growing need for food. But along with this development, there are unintended and undesirable consequences for human life and the environment that need, found a solution and corrected. One of the most important adverse consequences of agricultural development is the pollution of surface and groundwater resources, which results from various factors such as soil erosion and improper use of different pesticides. This study aimed to conduct an environmental monitoring program in Naseri wetland to determine the concentrations of organophosphorus pesticides (OPP_s) in water samples and also to evaluate the potential risks (ecological and health risk assessment) of these pesticides. The salting-out assisted liquid-liquid extraction method was used to extract pesticides. The residual concentrations of OPP_s evaluated by gas chromatography/mass spectrometry (GC/MS). In this study, the ecological risk of OPP_s calculated for wetland ecosystem, based on the acute risk quotient (RQ_i) formula with maximum (RQ_max), mean (RQ_mean), and mixture (RQ_mix) concentrations of organophosphorus pesticides in the wetland water. Also, to assess the health risk of consuming contaminated fish with organophosphate pesticides, the potential non-carcinogenic and carcinogenic risks were determined by the hazard quotient (Index) (HQ, HI) and incremental lifetime cancer risk (ILCR) indices, respectively. The mean ± SD concentration of OPP_s (Chlorpyrifos, Malathion, Ethion, Dichlorvos, Trifluralin and Diazinon) in samples of wetland water ranged from 0.14 ± 0.08 to 0.35 ± 0.12 and 0.054 ± 0.06 to 0.2 ± 0.1 (μg/L) in summer and autumn, respectively. The mean ± SD of OPP_s in fish varied from 0.68 ± 0.86 to 3.94 ± 2.7 (μg/kg). Overall, the concentrations of pesticides in all water and fish samples were below the maximum residue limit (30 μg/kg) during the study period, according to the Environmental Protection Agency (EPA) and the World Health Organization (WHO). The results of acute risk quotient were in summer (RQ_max = 3.49E-4 to 0.067, RQ_mean = 5.8E-5 to 0.029, RQ_mix = 0.139-0.026, 0.018-3.42E-3) and autumn (RQ_max = 8E-4 to 0.051, RQ_mean = 7.74E-6 to 0.018 RQ_mix = 0.1-0.013, 6E-3- 1.5E-3). The non-carcinogenic and carcinogenic risk indexes due to fish consumption for adults and children were (HQ = 0.026-4.68E-4, HI = 0.041, ILCR = 1.7E-7) and (HQ = 1.85E-3-1.3E-5, HI = 0.041, ILCR = 5.55E-8), respectively. The risk of OPP_s was generally low. But cumulative risk (pesticide mixtures), should not be ignored.

A critical review of effect modeling for ecological risk assessment of plant protection products

A wide diversity of plant protection products (PPP) is used for crop protection leading to the contamination of soil, water, and air, which can have ecotoxicological impacts on living organisms. It is inconceivable to study the effects of each compound on each species from each compartment, experimental studies being time consuming and cost prohibitive, and animal testing having to be avoided. Therefore, numerous models are developed to assess PPP ecotoxicological effects. Our objective was to provide an overview of the modeling approaches enabling the assessment of PPP effects (including biopesticides) on the biota. Six categories of models were inventoried: (Q)SAR, DR and TKTD, population, multi-species, landscape, and mixture models. They were developed for various species (terrestrial and aquatic vertebrates and invertebrates, primary producers, micro-organisms) belonging to diverse environmental compartments, to address different goals (e.g., species sensitivity or PPP bioaccumulation assessment, ecosystem services protection). Among them, mechanistic models are increasingly recognized by EFSA for PPP regulatory risk assessment but, to date, remain not considered in notified guidance documents. The strengths and limits of the reviewed models are discussed together with improvement avenues (multigenerational effects, multiple biotic and abiotic stressors). This review also underlines a lack of model testing by means of field data and of sensitivity and uncertainty analyses. Accurate and robust modeling of PPP effects and other stressors on living organisms, from their application in the field to their functional consequences on the ecosystems at different scales of time and space, would help going toward a more sustainable management of the environment. Graphical Abstract Combination of the keyword lists composing the first bibliographic query. Columns were joined together with the logical operator AND. All keyword lists are available in Supplementary Information at https://doi.org/10.5281/zenodo.5775038 (Larras et al. 2021).

Ecotoxicological and human health risk assessment of selected pesticides in Kurose River, Higashi-Hiroshima City (Japan)

This study conducted an integrated approach combining monitoring and risk assessment of pesticides in Kurose River and its catchment area, Japan. Water samples (n = 168) were collected every month for 1 year (March 2016 to February 2017). Pesticides (cyanazine, simetryn, fenarimol, isoprothiolane, and diazinon) were extracted by Sep-Pack C18 cartridges and analyzed using a reversed-phase HPLC-UV system. The pesticides were also determined in non-target organisms Red algae (Audouinella sp.) and diatoms (Cocconeis placentula) from the river. Based on the residual concentrations, an ecotoxicological risk assessment was conducted using the risk quotient (RQ) index. The human health carcinogenic and non-carcinogenic risk assessments were evaluated using hazard quotients (HQ). Results showed that cyanazine was the most commonly detected (64%), followed by simetryn (58%), and diazinon (57%) in all the sample sites (n = 12). Except for isoprothiolane, the pesticides were highest in spring followed by summer, autumn and winter. Based on extreme values (ex), non-acceptable ecotoxicological risk was obtained for diazinon (RQ_ex  = 21.317), cyanazine (RQ_ex  = 3.129), simetryn (RQ_ex  = 8.577) and fenarimol (RQ_ex  = 10.855), while that of isoprothiolane (RQ_ex  = 0.013) was negligible. Based on the HQ estimates, all the pesticides were below the threshold value of 1, hence pose no significant health risks to humans. PRACTITIONER POINTS: Pesticides affect non-target organisms in rivers and other aquatic systems Pesticides were frequently detected in spring and summer and accumulated in red algae and diatom The detected pesticides posed high ecotoxicological and human health risks.

Changes of Land Use and Land Cover with the Diversity of Fishes, Aquatic Plants, and Bird's Species at Wetland Ecosystem

Bangladesh is rich in wetland biodiversity with aquatic plants, fishes, and birds. Mohanganj Upazila is known as the capital of lower Bangladesh. The present study focuses on the changes of land use and land cover (LULC) with a diversity of species that are being least concerned (LC), vulnerable (VU), and endangered (EN). Over the last two decades, the wetland species of Mohanganj were gradually declined. Our results showed that 19 fish, 4 aquatic plants, and 7 bird species were LC in 2015. Among the fish and aquatic plant species, 6 fish species (Wallago attu, Ompok pabda, Channa punctate, Chitala chitala, Salmostoma phulo, and Corica soborna) and 2 aquatic plant species (Nymphaea nouchali and Nymphaea lotus) were VU during the dry and rainy season of 2017 and 2019, respectively. In the dry season of 2019, 4 fish species (W. attu, O. pabda, C. punctate, and Ch. chitala), 2 aquatic plant species (N. nouchali and N. lotus), and 7 bird species (Anas platyrhynchos, Ardeola grayii, Gyps bengalensis, Alcedo atthis, Phalacrocorax fuscicollis, Porphyrio porphyria, and Larus ridibundus) were EN. Among the species, W. attu, N. nouchaii, G. bengalensis, P. porphyria, and L. ridibundus were extremely endangered categories. Changes in LULC, the establishment of settlements for the increasing population, indiscriminate use of pesticides, environmental pollutions, and climate change are the potential reasons for declining trends of wetland biodiversity. Stern actions on land use policy, expansion of organic agriculture, bioremediation of industrial effluents, and adoption of sustainable environmental policies should be taken by the Government of Bangladesh for immediate conservation of wetland biodiversity.

Identification and Prediction of Wetland Ecological Risk in Key Cities of the Yangtze River Economic Belt: From the Perspective of Land Development

Rapid urbanization aggravates the degradation of wetland function. However, few studies have quantitatively analyzed and predicted the comprehensive impacts of different scenarios and types of human activities on wetland ecosystems from the perspective of land development. Combined with the Habitat Risk Assessment (HRA) model and the Cellular Automata (Ca)-Markov model, this study quantitatively measured the impact intensity and spatial distribution of different types of human activities on the wetland ecosystem in 2015, simulated and predicted the ecological pressure on the wetland in 2030, and identified the ecological risk hotspots of the Yangtze River waterfront along the upper, middle, and lower reaches of the Yangtze River Economic Belt. The results showed that the ecological risk of wetlands in the study area was low in the urban core and high in the suburbs. Construction activities posed a greater risk to wetlands. The intensity of human activities in the ecological protection scenario will be significantly lower than that in the natural development scenario in 2030. The waterfront in the middle and lower reaches of the Yangtze River will face more ecological risks. The results of the study can provide theoretical and technical support for wetland conservation policy formulation and waterfront development in the Yangtze River Economic Belt.

Occurrence and risk evaluation of organophosphorus pesticides in typical water bodies of Beijing, China

AbstractHuman activities, particularly in large cities, can lead to pollution caused by micropollutants such as pesticides in water bodies, which have been recognized as serious threats to the environment and human health. The pollution level of six organophosphorus pesticides, three herbicides, and one bactericide in groundwater and the Wenyu River, and their fates in three sewage treatment plants (STPs) and a hospital were investigated in this study. The concentrations of the ten detected pesticides ranged from not detected (ND) to 323.44 ng L^-1 in different water samples from Beijing; metalaxyl was detected to have the highest concentration (89.58 ng L^-1), and the detection frequencies of atrazine and metalaxyl were 100%. The maximum concentrations of pesticides in the Wenyu River, STPs, and the hospital were 1-2 orders of magnitude higher than those in the groundwater. Good removal efficiencies by the treatment processes were observed for ametryn (100%), while the removal efficiencies for atrazine and omethoate were the lowest in the three STPs (- 9.6% and 12.67%, respectively). Finally, risk quotient (RQ) values of each contaminant were estimated from the maximum values determined for typical urban to assess the ecology and health effects. In the case of environmental toxicity, the highest RQ values (> 1) were obtained for dichlorvos and omethoate. In the case of health toxicity, the RQ values show that the pesticides found in groundwater pose no potential health risks to humans at current concentrations.

Herbicide residues in sediments from Lake St Lucia (iSimangaliso World Heritage Site, South Africa) and its catchment areas: Occurrence and ecological risk assessment

The impact of agricultural pesticides on sensitive aquatic ecosystems is a matter of global concern. Although South Africa is the largest user of pesticides in sub-Saharan Africa, few studies have examined the toxicological threats posed by agricultural runoff, particularly to conservation areas of international importance. This study investigated the occurrence of 11 priority listed herbicides in sediments from Lake St Lucia, located on the east coast of South Africa. While characterised by exceptionally high levels of biodiversity, Lake St Lucia is affected by agricultural runoff primarily via inflow from two major rivers; the Mkhuze and Mfolozi. Sediment samples collected from Lake St Lucia and its two major fluvial inputs reveal widespread herbicide contamination of the aquatic environment. Residues were detected in the vast majority of samples analysed, with Mkhuze (27.3 ± 17 ng g^-1) and Mfolozi (25.6 ± 20 ng g^-1) sediments characterised by similar total herbicide levels, while lower concentrations were typically detected in Lake St Lucia (12.9 ± 12 ng g^-1). Overall, the most prominent residues detected included acetochlor (3.77 ± 1.3 ng g^-1), hexazinone (2.86 ± 1.4 ng g^-1) and metolachlor (10.1 ± 8.7 ng g^-1). Ecological assessment using Risk Quotients (RQs) showed that cumulative values for triazines and anilides/aniline herbicide classes presented low to medium risk for algae and aquatic invertebrate communities. Considering the biological importance of Lake St Lucia as a nursery for aquatic organisms, it is recommended that further research on the aquatic health of the system be undertaken. Additional monitoring and investigation into mitigation strategies is suggested, particularly as agricultural activities surrounding Lake St Lucia are likely to expand in the future.

Sorption-desorption of dimethoate in urban soils and potential environmental impacts

The environmental fate and impact of dimethoate application in the urban environment were assessed in nine selected soils. The pseudo-second-order kinetics model described the kinetics of dimethoate sorption very well in the urban soils exhibiting two distinct phases, an initial partitioning into clay surfaces and soil organic matter, and eventual diffusion into soil micropores. Dimethoate sorption in the urban soils followed the Freundlich model with an R² value of 0.94-0.99, suggesting a multi-layered sorption on the heterogeneous surfaces. Sorption of dimethoate in the soils was influenced by clay, silt, organic matter, carboxyl and alkyl groups, and Al and Fe oxides. The undecomposed or incompletely decomposed organic matter present in the soils greatly reduced the sorption and enhanced desorption. The calculated lower values for Freundlich constant (K_F) indicate the high mobility of dimethoate in the selected soils. Also, the values of groundwater ubiquity score (GUS), leachability index (LIX), hysteresis index (HI), and coefficient of distribution (K_d) for dimethoate in the soils clearly suggest that the insecticide is prone to leaching out significantly from the soil surface to groundwater. Moreover, the surface runoff from impervious places in the urban environment can be considered as a direct source of groundwater contamination, thereby affecting the quality of potable water besides posing a threat to non-target organisms of ecological importance and food safety. Thus, the present novel study suggests that the application of dimethoate in the urban environment having impervious surfaces must be judicious in order to minimize the potential human and ecological health risks.

History traces of HCHs and DDTs by groundwater dating and their behaviours and ecological risk in northeast China

Organochlorine pesticides legacies, such as hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT), remained in sediments or soils due to their difficulty in decomposition, especially in the agricultural areas where pesticides were widely used historically. Different from the little disturbed depositional environment of lake, it was difficult for rivers to explore the timing of DDT and HCH inputs through dating sediment cores as records. Based on groundwater dating, this study ascertained the historic pollution of DDT and HCH in Taizi River basin. HCH and DDT residues in groundwater were consistent with the historical production and usage, which increased from the 1950s to the 1980s and declined from the 1980s to the 1990s. Moreover, the partitioning behaviours of HCHs and DDTs in surface water and suspended particulate matter were discussed. It was revealed that β-HCH and o,p'-DDT were more likely to attach to suspended particulate matter than other isomers. Furthermore, species sensitivity distribution curves were generated using 54 toxicity data records to assess the risk of HCHs and DDTs in water and suspended particulate matter. These results indicated that p,p'-DDT in surface water posed a high risk to 95% of the aquatic life in the long run.

Effects of hydrogeochemical conditions on the distribution of pesticides in the karst river system

Karst aquifer systems are tended to be polluted compared to other types of aquifers because pollutants are able to enter aquifers through developed conduit systems. To identify the effects of hydrogeochemical conditions on the distribution of pesticides in a karst river system in Kaiyang, southwest China, a typical pollution mode combining intermittent infiltration with intrusion was constructed. Twelve aqueous samples were collected along the karst river, and a total of 24 pesticides were detected. The results showed that the pesticide ubiquity and the dominant organophosphate (40%) and organonitrogen pesticides (49%) were both observed. Based on the spatial distribution, the attenuation of pesticides was found in the underground conduit and surface river. The wastewater treatment plant and the rural dump were the two important point sources releasing pesticides. In addition, ten core pesticides were identified by clustering analysis and regional characteristics of three types of pesticides in Songnen Plain, North China Plain, and Southwest karst areas were also summarized. With correlation analysis between pesticides and environmental factors, the significant correlations of pesticides with ammonium ion and dissolved oxygen were found, which indicated that rapid developing urbanization and long-term agricultural practices could remarkably affect the spatial distribution of pesticides. The calculation of ecological risk quotients showed that organophosphate pesticides had the highest risk to invertebrate, followed by organonitrogen pesticides, and finally organochlorine pesticides. Invertebrates were the most vulnerable aquatic organisms. These findings fill a gap in the multiple pesticides' pollution in the karst areas of China. Graphical abstract.

Ecological risk assessment of glyphosate in surface water when it is used to control floating aquatic macrophytes

The present work evaluated the ecological risk of glyphosate by its commercial formulation (Roundup Original®) used to control floating aquatic macrophytes. Exposure analysis and ecological effects were performed from microcosm studies. The risk characterization was performed based on the calculation of the risk quotient. The commercial formulation of glyphosate had high toxicity when it was assessed separately. On the other hand, ecotoxicological evaluation of water samples from microcosms did not present toxicity to any tested organisms, however, glyphosate application is recommended exclusively to water bodies that have the surface completely covered by macrophytes.

Fate of organic micropollutants and their biological effects in a drinking water source treated by a field-scale constructed wetland

The safety of drinking water is directly related to the occurrence and concentrations of numerous organic micropollutants (OMPs) in source water. In this study, an approach integrating in vitro bioassays and chemical analyses was used to assess the purification effects of a field-scale constructed wetland on the fates of OMPs and their relevant toxicities and health risks in both summer and winter. Overall, 45 of 86 OMPs, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs), and phthalates (PAEs), were detected in at least one of the water samples. The constructed wetland significantly decreased the concentrations of most types of OMPs, while showed negative effects on the PAEs and OPPs. Toxicological evaluation of water samples indicated that the cytotoxicity, reactive oxygen species (ROS) level and anti-androgen (Ant-AR) activity were all dramatically decreased after the constructed wetland treatment. PAEs and PAHs were the dominant contributors and accounted for 75.12-97.48% of the predicted Ant-AR potencies, while the total predicted Ant-AR potencies only contributed 3.13-15.97% of the observed Ant-AR potencies in the examined water samples, suggesting more OMPs that pose toxic effects are still undetected. The human health risk assessment demonstrated that noncarcinogenic risks of the water samples were acceptable. However, potential carcinogenic risks that were mainly induced by 2, 6-dinitrotoluene, 2, 4-dinitrotoluene, pentachlorophenol and PAEs cannot be ignored. This study can help to understand the role of constructed wetlands in removing OMPs and biological effects from drinking water sources.

Toxicological and ecotoxicological evaluation of the water quality in a large and eutrophic freshwater lake of China

Effect-based methods (EBMs) are recommended as holistic approach for diagnosis and monitoring of water quality; however, the application of EBMs is still scare in China. In the present study, water quality of the freshwater lake Taihu (China) was investigated by EBMs. Different types of water samples were collected from three bays of the lake during 2015, 2016 and 2017. A battery of seven effect-based bioassays, including both specific and non-specific toxicity assays, was used. The bioassay battery was recently suggested based on joint activities of the EU project SOLUTIONS and the NORMAN network on emerging pollutants and is also under discussion for being implemented into monitoring activities in the context of the European Water Framework Directive (WFD). Adverse effects were observed towards the primary producer, primary consumer and fish, indicating the potential ecotoxicity of water in Taihu Lake. Mutagenic and estrogenic effects were found in the Ames fluctuation assay and ERα CALUX (Chemically Activated Luciferase Gene-eXpression) assay, respectively, highlighting the potential risks on human health. Algal growth inhibition and mutagenic effects can be observed during each of the three years. Acute toxicity towards Daphnia magna and estrogen receptor agonistic effects were found in at least one of the samples collected in 2016 and 2017, but not in 2015. The endpoints for fish toxicity in the Danio rerio fish embryo test included both lethal and additionally several sublethal effects (only for samples from 2017) and were not compared between years. Algal growth inhibition, fish embryo toxicity, mutagenic effect and estrogenicity were observed in each of the three bays, while Daphnia acute toxicity was only found in Zhushan Bay. Taking together, this study provides a big picture on the water quality of Taihu Lake. The battery of effect-based tools is promising to be a routine for water quality monitoring in China.

Assessment of water resource contamination by pesticides in vegetable-producing areas in Burkina Faso

This study proposes a comprehensive approach to investigate water resource contamination by pesticides under the specific climatic and hydrological conditions of the Sudano-Sahelian climate. Samples were collected from traditional wells, boreholes, and a lake in Burkina Faso. A multiresidue analysis was developed for 25 pesticides identified during field surveys. Polar organic chemical integrative samplers (POCIS) were used to confirm trends observed with grab samples. Uptake kinetics of POCIS were assessed by in situ calibration. The proposed use of nonlinear least squares regression proved to be a robust approach for estimating time-weighted average concentration in cases of nonlinear uptake. High sampling rates for triazines in a quasi-stagnant lake were attributed to warm water temperatures (30.8 ± 1.3 °C). The combination of sampling techniques during a 3-year monitoring period allowed for identifying potential interactions between resources, seasonal patterns, and origins of contaminants. Atrazine, azadirachtin, carbofuran, chlorpyrifos, cypermethrin, dieldrin, imidacloprid, and profenofos exceeded 0.1 μg L^-1, indicating a potential risk for the consumers. Ecological risk assessment was performed using the Pesticide Tool Index for fish, cladocerans, and benthic invertebrates. Peak concentrations of cypermethrin and chlorpyrifos were systematically associated with hazard to the studied taxa.

Endocrine disrupting compounds in drinking water supply system and human health risk implication

To date, experimental and epidemiological evidence of endocrine disrupting compounds (EDCs) adversely affecting human and animal populations has been widely debated. Notably, human health risk assessment is required for risk mitigation. The lack of human health risk assessment and management may thus unreliably regulate the quality of water resources and efficiency of treatment processes. Therefore, drinking water supply systems (DWSSs) may be still unwarranted in assuring safe access to potable drinking water. Drinking water supply, such as tap water, is an additional and crucial route of human exposure to the health risks associated with EDCs. A holistic system, incorporating continuous research in DWSS monitoring and management using multi-barrier approach, is proposed as a preventive measure to reduce human exposure to the risks associated with EDCs through drinking water consumption. The occurrence of EDCs in DWSSs and corresponding human health risk implications are analyzed using the Needs, Approaches, Benefits, and Challenges (NABC) method. Therefore, this review may act as a supportive tool in protecting human health and environmental quality from EDCs, which is essential for decision-making regarding environmental monitoring and management purposes. Subsequently, the public could have sustainable access to safer and more reliable drinking water.

Ecogenomics of Zooplankton Community Reveals Ecological Threshold of Ammonia Nitrogen

Communities of zooplankton can be adversely affected by contamination resulting from human activities. Yet understanding the influence of water quality on zooplankton under field-conditions is hindered by traditional labor-intensive approaches that are prone to incomplete or uncertain taxonomic determinations. Here, for the first time, an eco-genomic approach, based on genetic diversity in the mitochondrial cytochrome c oxidase I (COI) region of DNA of zooplankton was used to develop a site-specific, water quality criterion (WQC) for ammonia (NH₃). Ammonia has been recognized as a primary stressor in the catchment of the large, eutrophic Tai Lake, China. Nutrients, especially NH₃ and nitrite (NO₃^-) had more significant effects on structure of the zooplankton community than did other environmental factors. Abundances of rotifers increased along a gradient of increasing concentrations of total ammonia nitrogen (TAN), while abundances of copepods and cladocera decreased. A novel, rapid, species sensitivity distribution (SSD) approach based on operational taxonomic units (OTUs) was established to develop a WQC for NH₃. The WQC based on OTUs was consistent with the WQC based on the traditional morphology taxonomy approach. This genetics-based SSD approach could be a useful tool for monitoring for status and trends in species composition and deriving ecological criteria and an efficient biomonitoring tool to protect local aquatic ecosystems in virtually any aquatic ecosystem.

Ecological risk assessment of ecosystem services in the Taihu Lake Basin of China from 1985 to 2020

There are tremendous theoretical, methodological and policy challenges in evaluating the impact of land-use change on the degradation of ecosystem services (ES) at the regional scale. This study addresses these challenges by developing an interdisciplinary methodology based on the Procedure for Ecological Tiered Assessment of Risk (PETAR). This novel methodology integrates ecological models with a land-use change model. This study quantifies the multi-dimensional degradation risks of ES in the Taihu Lake Basin (TLB) of China from 1985 to 2020. Four key ES related to water purification, water quantity adjustment, carbon sequestration and grain production are selected. The study employs models of Denitrification-Decomposition (DNDC), Soil-Water-Atmosphere-Plant (SWAP), Biome-BGC and Agro-ecological Zoning (AEZ) for assimilations. Land-use changes by 2020 were projected using a geographically weighted multinomial logit-cellular automata (GWML-CA) model. The results show that rapid land-use change has posed a great degradation risk of ES in the region in 1985-2020. Slightly less than two-thirds of the basin experienced degradation of ES over the 1985-2010 period, and about 12% of the basin will continue to experience degradation until 2020. Hot spots with severe deterioration in 2010-2020 are projected to be centered around some small and less developed cities in the region. Regulating accelerated urban sprawl and population growth, reinforcing current environmental programs, and establishing monitoring systems for observing dynamics of regional ES are suggested as practical counter-measures.

Cooperation control strategies for China's cross-region pollution in a lake basin based on green reduction cost

The cross-region water pollution issue has always been the widespread concern around the world. It becomes especially critical for China due to the imbalance relates to environmental costs that have accompanied rapid growth of economy. Though the government makes great efforts to improve it, the potential for water pollution conflict is still great. We consider the problem of determining combined control strategies for China's cross-region lake pollution based on the environmental green costs. The problem is first formulated as a generalized bilevel mathematical program where the upper level consists in each region that reduces environmental green costs including three parts: the reduction cost, pollution permit trade cost and cost of environment damage, while the lower level is represented by pollution permit equilibrium market. Finally, we take an empirical analysis in Taihu lake. The numerical study shows that the minimum costs of both total and regional are obviously superior to the current processing costs, which provides theoretical basis for the price of emission permits.

IMPLICATIONS

Today, China's rapid gross domestic product (GDP) growth has come at a very high cost, as real estate prices have skyrocketed, the wealth gap has widened, and environmental pollution has worsened. China's central government is urged to correct the GDP-oriented performance evaluation system that is used to judge administrative region leaders. The cross-region water pollution issue has become a troubling issue that urgently needs to be resolved in China. This paper will not only actively aid efforts to govern Lake Taihu and other cross-region valleys, but it will also provide a supplement for theoretical research on cross-region pollution issues.

An integrated model for assessing heavy metal exposure risk to migratory birds in wetland ecosystem: A case study in Dongting Lake Wetland, China

Heavy metal contamination is present in wetland ecosystem worldwide, and quantitative risk assessment model is significant. In this study, an exposure model was integrated for assessing heavy metal exposure risk to migratory birds in Dongting Lake Wetland (DTW). The concentrations of Cr, Cu, Pb, Cd, Hg and As in water, plant, soil and fish were investigated from 9 migratory bird habitats. The results showed that exposure doses from drinking water pathways were very low. There was a sensitive area that Cd and As exposure doses exceeded the most conservative tolerable daily intake, which is located at the estuary of Xiang River. In general, Dunlin had a greater risk than Eurasian Spoonbill. Hg, Pb and Cr were likely to have adverse effect on carnivorous migrants in DTW, while Cu and Cd were considered to be relatively safe. Almost all heavy metals were at no risk for Lesser White-fronted Goose in DTW.

Occurrence and ecological risks from fipronil in aquatic environments located within residential landscapes

This study investigated the occurrence of fipronil and its metabolites in aquatic environments in residentially-developed landscapes, including five canals and three retention ponds. Fipronil was detected at four of the sites, with concentrations of 0.5-207.3 ng L(-1). Fipronil sulfone and fipronil sulfide were detected at three sampling sites, with concentrations ranging from 0.46 to 57.75 and 0.40-26.92 ng L(-1), respectively. Multiple risk assessment methods were performed to characterize potential ecological risks, including deterministic screening and probabilistic risk assessment techniques. The deterministic method indicated no risk to certain biotic groups (i.e. aquatic plants, fish, molluscs, and algae-moss-fungi), but did indicate risks to larval insects and crustaceans. Results from the probabilistic risk assessment indicated significant ecological risks (acute and chronic) ranging from 0.75 to 58.9% and 3.9-35.0% when organisms were exposed to the maximum and median concentrations detected, respectively. The potentially affected fraction of species (PAF) likely to be acutely impacted ranged from 4.6 to 8.1% (fipronil), 0.2-1.6% (fipronil sulfone), and 1.9-3.1% (fipronil sulfide) in the ponds with frequent detectable concentrations. The PAF likely to be impacted at chronic toxicity levels ranged from 16.5 to 23.8% for fipronil. Joint probability curve analysis indicated that concentrations exceeded the LC50 of the most sensitive 5% of species 8.5-18.8% of the time at two of the sites with the most frequent detections. Using the more conservative NOEC/LOEC values, there was a 75-78% probability that concentrations were high enough to negatively affect the most sensitive 5% of species at the same two sites, indicating significant risks for chronic toxicity. JPCs indicated a ≤2.6% probability of fipronil sulfone exceeding the LC50 concentrations for the most sensitive 5% of species at the same two sites; and a 4.3-6.8% probability of fipronil sulfide exceeding the LC50 concentrations at the same sites. Results indicate that fipronil and its sulfone and sulfide degradation products may present significant risks to aquatic organisms in some residentially-developed areas.

Risk assessment of pesticides detected in surface water of the Alqueva reservoir (Guadiana basin, southern of Portugal)

The purpose of this study was to evaluate the potential impact of the pesticides detected in the Alqueva reservoir (Guadiana Basin, South Iberian Peninsula) on the aquatic organisms belonging to this ecosystem. For this purpose, the occurrence and risk assessment of 25 pesticides and of a number of their degradation products were determined in the Alqueva surface waters. The areas (sampling stations) most polluted by pesticides were Sra. Ajuda, Lucefecit and Álamos in the northern and in the middle portions of the reservoir, respectively. The aquatic risk assessment revealed that from the various compounds analysed terbuthylazine, chlorfenvinphos and diazinon presented non-acceptable risk when maximum concentrations were used as the measured environmental concentrations (MEC). The locations that had more samples with risk quotients higher than 1 (high risk) were Sra. Ajuda followed by Lucefécit. The use of risk assessment allowed us to conclude that, despite that the pesticides' concentrations in the water column fulfil the European environmental quality standards, a number of the compounds show a high ecotoxicological risk for the aquatic organisms in the Alqueva ecosystem. The results thereby demonstrate that to have an efficient risk management process, the regulatory authorities of each country must consider an integrative chemical and ecotoxicological approach.

Identification of thyroid receptor ant/agonists in water sources using mass balance analysis and monte carlo simulation

Some synthetic chemicals, which have been shown to disrupt thyroid hormone (TH) function, have been detected in surface waters and people have the potential to be exposed through water-drinking. Here, the presence of thyroid-active chemicals and their toxic potential in drinking water sources in Yangtze River Delta were investigated by use of instrumental analysis combined with cell-based reporter gene assay. A novel approach was developed to use Monte Carlo simulation, for evaluation of the potential risks of measured concentrations of TH agonists and antagonists and to determine the major contributors to observed thyroid receptor (TR) antagonist potency. None of the extracts exhibited TR agonist potency, while 12 of 14 water samples exhibited TR antagonistic potency. The most probable observed antagonist equivalents ranged from 1.4 to 5.6 µg di-n-butyl phthalate (DNBP)/L, which posed potential risk in water sources. Based on Monte Carlo simulation related mass balance analysis, DNBP accounted for 64.4% for the entire observed antagonist toxic unit in water sources, while diisobutyl phthalate (DIBP), di-n-octyl phthalate (DNOP) and di-2-ethylhexyl phthalate (DEHP) also contributed. The most probable observed equivalent and most probable relative potency (REP) derived from Monte Carlo simulation is useful for potency comparison and responsible chemicals screening.

Occurrence and potential causes of androgenic activities in source and drinking water in China

The increased incidences of disorders of male reproductive tract as well as testicular and prostate cancers have been attributed to androgenic pollutants in the environment. Drinking water is one pathway of exposure through which humans can be exposed. In this study, both potencies of androgen receptor (AR) agonists and antagonists were determined in organic extracts of raw source water as well as finished water from waterworks, tap water, boiled water, and poured boiled water in eastern China. Ten of 13 samples of source water exhibited detectable AR antagonistic potencies with AR antagonist equivalents (Ant-AR-EQs) ranging from <15.3 (detection limit) to 140 μg flutamide/L. However, no AR agonistic activity was detected in any source water. All finished water from waterworks, tap water, boiled water, and poured boiled water exhibited neither AR agonistic nor antagonistic activity. Although potential risks are posed by source water, water treatment processes effectively removed AR antagonists. Boiling and pouring of water further removed these pollutants. Phthalate esters (PAEs) including diisobutyl phthalate (DIBP) and dibutyl phthalate (DBP) were identified as major contributors to AR antagonistic potencies in source waters. Metabolites of PAEs exhibited no AR antagonistic activity and did not increase potencies of PAEs when they coexist.

Levels, distribution, and risk assessment of organochlorines in surficial sediments of the Red Sea coast, Egypt

The analyses of environmentally persistent pollutants like polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) isomers, and dichlorodiphenyltrichloroethane (DDT) and its metabolites in surficial sediment samples collected from 17 locations along with the coast of the Red Sea in Egypt were carried out using gas chromatography-mass spectrometry. Several potential organic contaminants from agricultural (e.g., DDT and its breakdown products, lindane, endrin, dieldrin, and endosulfan) and industrial (PCBs) sources were measured. The levels of 20 organochlorine pesticides (OCPs) and ten PCB congeners in sediment collected from 17 stations along ~1,200 km were investigated. Concentrations of PCBs, HCHs, DDTs, and cyclodienes ranged from 0.40 to 6.17, 0.01 to 0.09, n.d. to 0.46, and 0.08 to 0.90 ppb dry weight. Two statistical programs were applied on the data (principal component analysis, PCA, and cluster analysis, CA), and it was concluded that it is impossible to predict the distribution patterns of the OCPs in a contaminated area. Risk assessment of the organochlorines contaminated in the sediments of the studied area was investigated.

Effects of landuse and precipitation on pesticides and water quality in playa lakes of the southern high plains

The 25000 playa wetlands within the Southern High Plains (SHP) of the United States of America (USA) are the dominant hydrogeomorphic feature in the region, providing habitat for numerous plants and wildlife. The SHP are among the most intensively cultivated regions; there are concerns over the degradation and/or loss of playa wetland habitat. We examined water quality in playa wetlands surrounded by both grassland and agriculture and measured water concentrations of pesticides used on cotton (acephate, trifluralin, malathion, pendimethalin, tribufos, bifenthrin, λ-cyhalothrin, acetamiprid, and thiamethoxam), the dominant crop in the SHP. Pesticides used on cotton were detected in water samples collected from all playas. Precipitation events and the amount of cultivation were related to pesticide concentrations in sediment and water. Our results show that pesticide concentrations were related in some circumstances to time, precipitation, and tilled-index for some but not all pesticides. We further compared measured pesticide concentrations in playas to toxicity benchmarks used by the US EPA in pesticide ecological risk assessments to obtain some insight into the potential for ecological effects. For all pesticides in water, the maximum measured concentrations exceeded at least one toxicity benchmark, while median concentrations did not exceed any benchmarks. This analysis indicates that there is a potential for adverse effects of pesticides to aquatic organisms.

In vitro assessment of thyroid hormone disrupting activities in drinking water sources along the Yangtze River

The thyroid hormone disrupting activities of drinking water sources from the lower reaches of Yangtze River were examined using a reporter gene assay based on African green monkey kidney fibroblast (CV-1) cells. None of the eleven tested samples showed thyroid receptor (TR) agonist activity. Nine water samples exhibited TR antagonist activities with the equivalents referring to Di-n-butyl phthalate (DNBP) (TR antagonist activity equivalents, ATR-EQ(50)s) ranging from 6.92 × 10(1) to 2.85 × 10(2) μg DNBP/L. The ATR-EQ(50)s and TR antagonist equivalent ranges (ATR-EQ(30-80) ranges) for TR antagonist activities indicated that the water sample from site WX-8 posed the greatest health risks. The ATR-EQ(80)s of the water samples ranging from 1.56 × 10(3) to 6.14 × 10(3) μg DNBP/L were higher than the NOEC of DNBP. The results from instrumental analysis showed that DNBP might be responsible for the TR antagonist activities in these water samples. Water sources along Yangtze River had thyroid hormone disrupting potential.

Identification of trace organic pollutants in drinking water and the associated human health risks in Jiangsu Province, China

Organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), dibutyl phthalate (DNBP) and di-2-ethylhexyl phthalate (DEHP) were all detectable in surface water in Jiangsu Province, China. Concentrations of OCPs ranged from 5.13 to 8.15 ng/L. PAHs were found ranging from 14.7 to 24.5 ng/L. Concentrations of DNBP and DEHP ranged from 16 to 5,857.5 ng/L and 556 to 15,670.7 ng/L, respectively. Greater than 70 % of chemicals were removed in water treatment processes. The carcinogenic risks posed by trace organic pollutants through tap water ingestion were lower than 10(-6), and the noncarcinogenic risks were less than 10(-5).

Identification of trace organic pollutants in freshwater sources in Eastern China and estimation of their associated human health risks

Concentrations of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in ten water samples (four pairs of tap water with source water and two additional tap water) were analyzed and a US EPA algorithm was used to estimate their associated human health risks. Organochlorine pesticides were found in most samples analyzed. Concentrations of total PAHs ranged from 4.8 to 84.4 and 0.7 to 53.8 ng/l, for source and tap water, respectively. Carcinogenic and noncarcinogenic risk assessments were employed for various trace organic pollutants in the tap water. The results indicated that carcinogenic risk for male and female lifetime of tap water from XuZh (XZ) city was higher than the others. XZ located in the northern part of Jiangsu province, which takes ground water as the water source. Children were more vulnerable to the carcinogenic chemicals than adults. Carcinogenic risks for male children (0-14 years old) in XZ were the highest, reaching 3.68 × 10(-6). Contribution analysis showed that dibenz[a,h]anthracene contributed most to the carcinogenic risk in XZ city, and α-HCH, β-HCH and γ-HCH posed the most carcinogenic risk in tap water from GoHu (GH) in Eastern Taihu Lake. Additionally, noncarcinogenic risks posed by the detected chemicals to local people were negligible. Risk alleviation strategies should be adopted, taking into account the results of these health risk assessments.