A pesticide monitoring survey in rivers and lakes of northern Greece and its human and ecotoxicological risk assessment

Pretilachlor Releasable Polyurea Microcapsules Suspension Optimization and Its Paddy Field Weeding Investigation

In this study, pretilachlor was encapsulated into polyurea microcapsules prepared by water-initiated polymerization of polyaryl polymethylene isocyanate and eventually made into pretilachlor microcapsules suspension (PMS). We used response surface methodology (RSM) combined with the Box–Behnken design (BBD) model to optimize the formulation of PMS. The encapsulation efficiency (EE) of PMS was investigated with respect to three independent variables including wall material dosage (X₁), emulsifier dosage (X₂), and polymerization stirring speed (X₃). The results showed that the regression equation model had a satisfactory accuracy in predicting the EE of PMS. To achieve an optimal condition for PMS preparation, the dose of wall material was set to 5%, the dose of emulsifier was set to 3.5% and the polymerization stirring speed was set to 200 rpm. The EE of PMS was up to 95.68% under the optimized condition, and the spherical shape with smooth surface morphology was observed. PMS was also proven to have delayed release capability and in vivo herbicidal activity against barnyard grass [Echinochloa crusgalli (L.) Beauv.] with an LC₅₀ value of 274 mg/L. Furthermore, PMS had efficient weed management compared to commercially available 30% pretilachlor emulsifier (PE), showing a promising potential application for weeding paddy fields.

Risk Assessment of Pesticide Mixtures in Australian Rivers Discharging to the Great Barrier Reef

Rivers discharging to the Great Barrier Reef carry complex pesticide mixtures. Here we present a first comprehensive ecotoxicological risk assessment using species sensitivity distributions (SSDs), explore how risk changes with time and land use, and identify the drivers of mixture risks. The analyzed data set comprises 50 different pesticides and pesticide metabolites that were analyzed in 3741 samples from 18 river and creek catchments between 2011 and 2016. Pesticide mixtures were present in 82% of the samples, with a maximum of 23 pesticides and a median of five compounds per sample. Chemical-analytical techniques were insufficiently sensitive for at least seven pesticides (metsulfuron-methyl, terbutryn, imidacloprid, clothianidin, ametryn, prometryn, and thiamethoxam). The classical mixture concepts of concentration addition and independent action were applied to the pesticide SSDs, focusing on environmental threshold values protective for 95% of the species. Both concepts produced almost identical risk estimates. Mixture risk was therefore finally assessed using concentration addition, as the sum of the individual risk quotients. The sum of risk quotients ranges between 0.05 and 122 with a median of 0.66. An ecotoxicological risk (i.e., a sum of individual risk quotients exceeding 1) was indicated in 38.5% of the samples. Sixteen compounds accounted for 99% of the risk, with diuron, imidacloprid, atrazine, metolachlor, and hexazinone being the most important risk drivers. Analysis of land-use patterns in catchment areas showed an association between sugar cane farming and elevated risk levels, driven by the presence of diuron.

Occurrences of microorganic pollutants in the Kumho River by a comprehensive target analysis using LC-Q/TOF-MS with sequential window acquisition of all theoretical fragment ion spectra (SWATH)

In this study, simultaneous identification and semi-quantification of hundreds of micropollutant compounds, including pharmaceutical and personal care products (PPCPs) and pesticides were performed in river and effluent samples from the Kumho River Basin using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) with sequential window acquisition of all theoretical fragment ion spectra (SWATH). In total, 85 compounds (29 pesticides and 56 PPCPs) were identified. The highest proportions of PPCP residues were detected in the downstream area of the Kumho River, close to the central city. On the other hand, the highest proportions of pesticide residues were observed upstream, near agricultural land and golf courses. Additionally, the highly exposable chemicals were prioritized using a scoring and ranking system based on their concentration and detection frequency. Thus, 20 compounds (7 pesticides and 13 PPCPs) with scores of 200 or higher were defined as highly exposable compounds in Kumho River basin.

Endocrine Disruptors in Water and Their Effects on the Reproductive System

Anthropogenic contaminants in water can impose risks to reproductive health. Most of these compounds are known to be endocrine disrupting chemicals (EDCs). EDCs can impact the endocrine system and subsequently impair the development and fertility of non-human animals and humans. The source of chemical contamination in water is diverse, originating from byproducts formed during water disinfection processes, release from industry and livestock activity, or therapeutic drugs released into sewage. This review discusses the occurrence of EDCs in water such as disinfection byproducts, fluorinated compounds, bisphenol A, phthalates, pesticides, and estrogens, and it outlines their adverse reproductive effects in non-human animals and humans.

Thermodynamics and Kinetics of Pretilachlor Adsorption on Organobentonites for Controlled Release

Thermodynamics and kinetics of pretilachlor adsorption on organobentonites modified with hexadecyltrimethyl ammonium chloride were investigated to reveal the structural effects of organobentonites on the interaction with pretilachlor and the diffusion of the herbicide and were related to the controlled release from organobentonites. The adsorption of pretilachlor was entropically driven by hydrophobic interaction. The entropy change dropped with increasing surfactant loading from 0.4 to 1.50 times the cation exchange capacity (CEC) of the bentonite used, corresponding to a decrease in the degree of freedom of pretilachlor molecules due to the enhanced order of surfactant in the interlayer. The kinetics of pretilachlor adsorption was well fitted to the pseudo-second-order model and related to the structural features of organobentonites. The enhanced packing density of the surfactant in the interlayer generally resulted in a reduction of the rate constant of the pretilachlor adsorption onto organobentonites. However, the stepwise increase in the basal spacing due to the surfactant arrangement transition, from lateral-monolayer to lateral-bilayer at a loading level of more than 0.8 × CEC, benefited the diffusion of pretilachlor and diminished the influence of the increase in surfactant packing density. The release of pretilachlor from organobentonites was predominated by Fickian diffusion, which could be understood from the adsorption thermodynamics and kinetics. The time taken for the release of 50% of active ingredient was 16-23 times that for the control formulation and exhibited a linear increase with the relative value of the equilibrium constant to the rate constant of pretilachlor adsorption.

Chlorpyrifos levels within permitted limits induce nuclear abnormalities and DNA damage in the erythrocytes of the common carp

The organophosphate pesticide chlorpyrifos (CPF) is defined as a priority pollutant in surface freshwaters according to Directive 2013/39/EU of the European Parliament. The focus of this study was to assess the potential cytotoxic and genotoxic effects of permissible CPF levels on juvenile forms of the common carp. We found that low-level CPF exposure did not induce elevated levels of micronuclei, but significantly increased the frequency of total nuclear abnormalities (NAs) proportional to dose and time; notched, blebbed, lobed and eight-shaped nuclei, nuclear buds, nuclear bridges and binucleated cells were all detected. Decreased frequencies of polychromatic erythrocytes (PCEs) and DNA damage detected by comet assay were also observed, confirming the cytotoxic and genotoxic effects of CPF. Altogether, these data (1) demonstrate that CPF is toxic even at permissible levels, possessing considerable genotoxic and cytotoxic potential in peripheral erythrocytes of exposed fish and (2) validate the assessment of NAs, PCEs and comet assay performance as sensitive biomarkers for the early detection of CPF pollution. These findings can be applied to guide environmental risk assessment and biomonitoring programs.

QSPR studies on water solubility, octanol-water partition coefficient and vapour pressure of pesticides

The assessment of the environmental fate and (eco)toxicological effects of pesticide compounds is of crucial importance. The present review is focused on Quantitative Structure-Property Relationships (QSPR) applications on three environmentally relevant physicochemical properties of pesticides, which can be used for assessing their environmental partition and transport, as well as exposure potential namely water solubility, octanol-water partition coefficient and vapour pressure. This article revises various interesting QSPR applications with special emphasis on studies developed during the 2009-2019 period.

An integrated strategy for rapid on-site screening and determination of prometryn residues in herbs

We produced a prometryn-specific monoclonal antibody and propose a strategy for convenient on-site detection of prometryn residues in herbs for the first time. This strategy has perfect applicability in a complex herbal medicine matrix. The strategy combines a semiquantitative immunochromatographic strip assay with a heterologous indirect competitive ELISA. When there was no matrix interference, the ELISA had a half-maximal inhibitory concentration of 2.6 ng·mL^-1 and a limit of detection of 0.2 ng·mL^-1. The immunochromatographic strip assay can be completed within 5 min with a visual limit of detection of 1 ng·mL^-1. Although the sample matrix had different effects on the sensitivity of the antibody, excellent repeatability and accuracy were achieved. The method was successfully applied for the screening and determination of prometryn residue in multiple complex herb samples for the first time, and the results were in good agreement with those obtained by liquid chromatography-tandem mass spectrometry. The proposed strategy is rapid, of high-throughput, and of low cost, and may be a promising choice for on-site detection of prometryn in different kinds of herbs. Graphical abstract.

Basin-scale monitoring and risk assessment of emerging contaminants in South American Atlantic coastal lagoons

Emerging contaminants (ECs) such as pharmaceuticals, personal care products, drugs of abuse and polar pesticides are under particular attention due to their high consumption, frequent detection in the environment and reported ecotoxicological risk. This study investigates the occurrence and distribution of multiclass of ECs in surface waters at basin scale of two Atlantic coastal lagoons of Uruguay, South America. For this purpose, a target screening approach covering up to 362 compounds was employed using nanoflow liquid chromatography - high resolution mass spectrometry (nanoLC/HRMS). 56 compounds were identified including five banned pesticides in the European Union: atrazine, carbendazim, chlorpyrifos ethyl, diazinon, and ethion. Pharmaceuticals, hormones and drugs of abuse showed maximum detection frequencies and concentrations downstream cities. The highest occurrence of pesticides was found in lagoons and streams with neighboring agricultural activity. ECs were also found in coastal sea. Environmental risk assessment revealed that the hormones 17α-ethinylestradiol and 17-β-estradiol showed the highest risk to aquatic organisms in these basins. This study represents the first basin- scale monitoring of ECs in superficial waters encompassing streams, lagoons, and coastal seas in Uruguay, South America.

Risk assessment of organochlorine pesticides in drinking water source of the Yangtze River

Organochlorine pesticides have been banned for many years, but the residual trace amount of organochlorine in water may still pose ecotoxicological risk. Meanwhile, the potential risk of organochlorine pesticides released from sediments, especially into drinking water sources, is receiving increasing attention. The present study assessed the pollution and potential risk of drinking water sources along the midstream and downstream Yangtze River. Residues of organochlorine pesticides (OCPs) in water, suspended particle matter (SPM), and sediment were evaluated with isotope dilution HRGC/HRMS. The results indicated that OCPs in water, SPM, and sediment ranged in 0.52-92.97 ng/L, 0.10-4.10 ng/L, and 0.038-11.36 ng/g, respectively. The predominant OCPs in water, SPM, and sediment were β-HCH, p,p'-DDE and PeCB. At site Y1, 8, 13, 18, β-HCH has a higher proportion in sediment samples, while, α-HCH has a higher proportion in SPM samples. The industrial use of HCHs in the history was the main HCHs source for most water and sediment samples, which indicated an absence of fresh inputs of industrial HCHs. Meanwhile, the abundance of p,p'-DDE in water, sediment and SPM samples could be attributed to long-term aerobic degradation of DDTs. The values of ffsw of HCHs, DDTs and PeCB indicate the transfer from water to sediment. Risk assessment showed that HCHs and DDTs posed low ecotoxicological risk to the Yangtze River.

Nuclear receptor AHR-mediated xenobiotic detoxification pathway involves in atrazine-induced nephrotoxicity in quail (Coturnix C. coturnix)

Atrazine (ATR), one of the most widely used pesticides in agricultural production, are gradually concerned due to potential ecosystem and health risks. Further, the induction of ATR nephrotoxicity and detoxification response is still unknown. To evaluate ATR-induced nephrotoxicity, quails were treated with 0, 50, 250 or 500 mg/kg ATR by gavage administration for 45 days. Histopathology indicated that ATR exposure caused renal tubular epithelial cell swelling and endoplasmic reticulum degeneration, suggesting that ATR exposure causes renal impairment even renal diseases. Notably, ATR interfered cytochrome P450 system (CYP450s) homeostasis by enhancing contents or activities of CYP450s (total CYP450, Cyt b5, AH, APND, NCR and ERND) and the expression of CYP450 isoforms (CYP1A, CYP1B, CYP2C and CYP3A). ATR triggered phase II detoxifying reaction, reflected by the elevated GSH level, GST activity and the up-regulation of GST isoforms (GSTa, GSTa3 and GSTt1) and GSH synthetase (GCLC). Moreover, ABC transporters were activated to expel ATR from the body by increasing expression of MRP1 and P-GP gene. Accompanying these alterations, the nuclear receptors (AHR, CAR and PXR) were activated by ATR in a dose-dependent manner. Analysis results of present study demonstrated that the induction of phase II detoxifying enzyme system and ABC transporters could be modulated by nuclear receptors response and CYP450s disturbance in low-dose ATR-treated quail. In conclusion, all data suggested that nuclear receptors AHR-mediated detoxification pathway was involved in ATR-induced nephrotoxicity. These results provided new evidence about the nephrotoxic effects of ATR on the response of biotransformation and detoxification system.

First report on probabilistic risk assessment of pesticide residues in a riverine ecosystem in South-South Nigeria

The present study evaluated the ecological and human health risk associated with concentrations of legacy organochlorine pesticide residues in Ikpoba River, a major River in the heart of Benin City, a Nigerian urban town located in Edo State. Standard methods were used to collect, extract and analyze samples, while risk assessment was carried out using standard models and indices. Results showed varying pesticide concentrations in both sediment and water samples with α-HCH (0.24 ± 0.11 μg L^-l), predominant in water, whereas dieldrin (0.99 ± 0.33 μg kg^-l) was the highest concentration in sediment. Compared to the Sediment Quality Guidelines (SQGs), this study concentrations of pesticides in sediments were below the values of effect range medium, effect range low, probable effect level and threshold effects level, suggesting low environmental hazard to benthic organisms. However, on exposure to contaminated sediments, probabilistic ecological risk assessment using Monte Carlo techniques showed potential risk to algae, daphnid and fish. Human health risk estimates using dermal and ingestion exposure deterministic and probabilistic routes revealed a potential risk to adults and children exposed to contaminated water and sediment. Estimates for detected pesticides exceeded the threshold level, indicating potential cancer effects for both children and adults who rely on the resources of the river. This study highlights the need for concerted efforts to curb the threat of pesticides and other contaminants in the aquatic environment by all relevant stakeholders in Nigeria and Africa as a whole.

Prospecting Plant Growth-Promoting Bacteria Isolated from the Rhizosphere of Sugarcane Under Drought Stress

In the rhizosphere, the soil bacteria and the plants are closely related, with the plant-associated microbiota playing an important role in promoting plant growth under both normal and stress conditions. In this study, the cultivable bacteria in the sugarcane rhizosphere under different levels of drought stress were characterized and screened for plant growth activities. The results suggested that the microbial community associated with the sugarcane rhizosphere was strongly affected by drought, but some important genera of bacteria such as Arthrobacter, Pseudomonas, Microbacterium, and Bacillus remained present during the entire experiment, indicating the adaptability of these organisms and their importance in the rhizosphere community. Many isolates exhibited positive results for one or more plant growth activity, and they were also capable of growing under simulated drought stress, suggesting that the microorganisms isolated from the sugarcane rhizosphere could be explored for uses such as biofertilizers or biocontrol agents in agriculture.

Ecological risk assessment of agricultural pesticides in the highly productive Ndop flood plain in Cameroon using the PRIMET model

Flood plains can make a significant contribution to food security due to their rich agricultural and aquaculture potentials but the misuse of pesticides in these ecosystems may seriously threaten their sustainability. We have assessed the risk of commonly used pesticides by rice and vegetable farmers on two major streams in the Ndop flood plain in Cameroon using the PRIMET model. Thirty pesticide formulations were identified containing 17 active ingredients belonging to fungicides (7), herbicides (3), and insecticides (7). Out of these, five posed acute and/or chronic risks to the streams. Chlorpyriphos-ethyl (ETR = 655), chlorothalonil (ETR = 250), and cypermethrin (ETR = 190) posed a definite acute risk to both streams. These pesticides also posed possible chronic risks with cypermethrin also posing a definite chronic risk (ETR = 1658) to fish in one of the streams. Mancozeb (ETR = 2.2) and λ-cyhalothrin (ETR = 2.8) posed a possible acute risk to both streams. It was interesting to note that most pesticides, including some of those that posed a risk, were applied at lower doses than their respective recommended doses. Differences in ETRs were also observed in the two streams with higher values occurring in the stream having a lower concentration of suspended solids. The higher velocity of the Ngwala-Mesaw stream did not affect the acute risk posed by pesticides. Pesticide toxicity was an important determinant in the risk posed and we recommend that appropriate mitigation measures be put in place to reduce the risk of these pesticides such as the implementation of an appropriate buffer zone between the edge of field and water body.

The environmental condition of an estuarine ecosystem disturbed by pesticides

Knowledge regarding the concentration levels resulting from the use of agricultural pesticides may indicate the nature of the controls necessary to reduce environmental and human health risks to an acceptable level. Therefore, the main goal of the present work was to assess the spatial and temporal occurrence of 35 pesticides in the River Sado estuary (Portugal) in 2017 and evaluate its environmental condition, as data for estuarine ecosystems is scarce. Since pesticides are very susceptible to matrix effects promoted by environmental samples, to attain the main goal, we developed a fast and almost solvent-free environmentally friendly method with a good performance for both estuarine surface water and sediment samples. Quantified residues were determined mostly during summer, in line with the pesticide application period. Five herbicides (alachlor, bentazon, metobromuron, metribuzin and triclopyr) were measured in the water before and after the production season, suggesting a long-term aquatic exposure. Sediment samples were less contaminated, since a lower number of quantified pesticides were found in the study area, in lower frequencies and lower concentrations. No potential high adverse effects of the use of agricultural pesticides were expected on the aquatic organisms of the Sado estuary, even considering the potential combination effect of pesticide mixtures.

Long-term Data from the Swedish National Environmental Monitoring Program of Pesticides in Surface Waters

Environmental monitoring is essential for assessing the impact of human activities on the environment. Monitoring data are used to ascertain that environmental standards are met, to inform policy making, to determine trends, and to provide parameterization data for prediction models. The design of monitoring programs depends on what is being monitored, for what purpose, and available resources. Here we describe the strategy and design of the Swedish environmental monitoring program for chemical pesticides in surface waters and provide data generated within this program since 2002 (). We include examples of how the data can be used for toxicity assessments, trend analyses, and comparison between sampling strategies. Our goal is to increase awareness of this dataset and provide detailed information about the data so that it may be incorporated into meta-analytical research, comparison studies, model validation, and other scientific efforts.

Screening of pesticides and veterinary drugs in small streams in the European Union by liquid chromatography high resolution mass spectrometry

Water samples from 29 small waterways located in 10 different countries in the European Union were screened for the presence of a large number of pesticides (275) and veterinary drugs (101). Solid phase extraction was combined with liquid chromatography coupled to Orbitrap high resolution tandem mass spectrometry to quantify the levels of pesticides in the samples and to detect the presence of veterinary drugs. All the sampled European rivers and canals included in this investigation were contaminated with mixtures of pesticides and, in most of the cases, with several veterinary drugs at the time of sampling, without a clear national or regional pattern. In total, 103 different pesticides, 24 of them banned in the EU, and 21 veterinary drugs were found in the analysed samples. Herbicides were the main contributor to the total amount of pesticides found in the samples, with terbuthylazine present in all the samples. The maximum individual concentration recorded was of dimethenamid at 59.85 μg L^-1. The maximum combined pesticide concentration was found in a sample from the Wulfdambeek canal, Belgium, with 94.02 μg L^-1 comprised of a mixture of 70 different pesticides. European regulatory standards defining acceptable concentration levels were exceeded for at least one pesticide in 13 of the 29 samples analysed, with the neonicotinoid insecticides imidacloprid and clothianidin most frequently present above such limits. The majority of the veterinary drugs detected were antimicrobials, most being antibiotics. The β-lactam antibiotic dicloxacillin was present in two thirds of the analysed samples. The application of this consistent research approach across Europe allowed the identification of a significant threat to the aquatic environment associated with pesticide contamination, and in some cases veterinary drugs, at the time of sampling in the water bodies tested.

Temporal trends in organophosphorus pesticides use and concentrations in river water in Japan, and risk assessment

We reviewed organophosphorus pesticide use in Japan between 1982 and 2016 using data from the National Institute of Environmental Studies. Organophosphorus pesticide concentrations in river water throughout Japan were taken from the literature, and risk assessments were performed for some organophosphorus pesticides based on risk quotients and hazard quotients. Assessments were performed for 20 common pesticides, including insecticides, fungicides, and herbicides. The amounts used decreased in the order: insecticides > herbicides > fungicides. Organophosphorus insecticide and fungicide use have decreased over the last four decades, but organophosphorus herbicide use has increased. During this period, annual organophosphorus pesticide use was the highest for chlorpyrifos (105,263 tons/year) and the lowest for glyphosate-sodium (8 tons/year). The ecotoxicological risk assessment indicated that diazinon and fenitrothion posed strong risks to the Japanese aquatic environment, and chlorpyrifos and malathion have moderate risks. None of the pesticides that were assessed posed significant risks to humans. Continued use of organophosphorus pesticides in Japan may cause strong risks to aquatic environments. These risks should be reassessed periodically.

Emerging contaminants in sediment core from the Iron Gate I Reservoir on the Danube River

The Iron Gate I Reservoir is the largest impoundment on the Danube River. It retains >50% of the incoming total suspended solids load and the associated organic contaminants. In the sediment core of the Iron Gate I Reservoir we report the presence and fate of four classes of emerging contaminants (pharmaceuticals, pesticides, steroids and perfluorinated compounds), predominantly not covered by the EU monitoring programs, but considered as future candidates. Based on contaminant's partitioning behavior in the water/sediment system and the suspected ecotoxicological potential asserted from the literature data, the risk of recorded concentrations for sediment-dwelling organisms was discussed. The high anticipated risk was associated with antibiotics sulfamethoxazole and erythromycin, and pesticides linuron and carbendazim (banned in the EU, but still approved for use in the investigated area) and malathion. This indicated the need for better control of release of these compounds into the river, and implied their inclusion in future regular monitoring. Higher concentrations of pharmaceuticals and most pesticides and sterols were recorded in the fragment of allochthonous coarser sediment, assumed to have entered the reservoir during a high discharge event. Only one perfluorinated compound was recorded in the upper part of the sediment core. The vertical concentration profiles of pesticides propazine and malathion indicated their uniform source, most likely atmospheric transport and deposition of particles deriving from agricultural land.

Assessment and management of pesticide pollution at a river basin level part I: Aquatic ecotoxicological quality indices

During the last decade numerous monitoring programs have been conducted in order to assess pesticide pollution in catchments. This effort has led to the production of large, complex data sets of environmental results making the task of evaluation of the aquatic chemical status more difficult. Furthermore, the evaluation of the chemical status of the water ecosystems is one of the main aspects which should be considered in a River Basin Management Plan. In this study, two indices were developed in order to assess the combined pesticide ecotoxicity to aquatic non-target organisms, the Aquatic Quality Index of Short term Toxicity of Pesticides (AQI ShToxP) and the Aquatic Quality Index of Long term Toxicity of Pesticides (AQI LToxP). These indices were applied to the environmental results obtained from an intensive monitoring study of 302 pesticides in 102 stationary sampling stations located on the surface aquatic network of the Pinios River Basin, in Greece, in 2011 and 2012. The evaluation of the surface water quality was achieved by taking into consideration the frequency and the intensity of exposure of the aquatic organisms to pesticides above the respective ecotoxicological quality objectives such as the acute or chronic term predicted no-effect concentrations derived from risk assessment. Seventy-five pesticides, that have been previously identified as the River Basin Specific Pollutants of Pinios by an environmental and human risk hierarchy exercise, were assessed. It appears, from the implementation of the two indices, that the detected pesticides in the surface aquatic ecosystem of the Pinios River Basin exert significant pressure on the aquatic non-target organisms especially at the chronic effect level. The developed AQI ShToxP and AQI LToxP indices, as well as the proposed quality classification system could be valuable communication and interpretation tools for River Basin Management Plans that can contribute in the restoration of environmental health.

Environmental monitoring and risk assessment of pesticide residues in surface waters of the Louros River (N.W. Greece)

Estuarine environments are being constantly stressed by new sources of pollution (e.g. pesticides) derived from activities of industry and intensive agriculture. The present study aims at quantify pesticides of three different categories (fungicides, herbicides and insecticides) in the Louros River (Epirus region, North-Western Greece). A monitoring study of 34 compounds was carried out in surface river waters from June 2011 until May 2012. Seven water sampling stations were established and 35 water samples were collected. A solid-phase extraction (SPE) method coupled with gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), depending on the compound, was developed and validated. During the monitoring study 25 pesticides were detected (13 herbicides, 9 insecticides, 3 fungicides). The most commonly encountered pesticides were quizalofop-ethyl, trifluralin and pendimethaline. Tebufenpyrad was found in all sampling stations and seasons, with the highest concentrations of 0.330 μg/L at Tsopeli Lagoon exceeding the rather low concentrations reported nationwide. Regarding the environmental risk due to the presence of target compounds in surface waters, this was estimated by calculating risk quotients (RQs) for different aquatic organisms (algae, zooplankton and fish). The results denoted a possible threat for the aquatic environment, rendering in this way the RQ method as a useful screening tool. In any case, further extensive study is needed for acetochlor, pirimiphos-methyl, endosulfan-a and azinphos-ethyl in order to better correlate their occurrence and potential toxic effects in aquatic life and humans.

Evaluating polar pesticide pollution with a combined approach: a survey of agricultural practices and POCIS passive samplers in a Tunisian lagoon watershed

A study of pesticides in the Bizerte lagoon watershed on the Mediterranean coast of Tunisia showed that herbicides and fungicides are the most commonly used compounds. A survey was made of selected farmers. Pesticide contamination was monitored in the water column and sediments at four selected sampling sites (lagoon (A) and in three oueds-Chegui (B), Garaa (C), and Tinja (D)). Polar organic chemical integrative samplers (POCIS) were used to assess pesticide contamination. Thirty-two pesticides were investigated; the total concentration of active ingredients ranged from 35.9 ng L^-1 in Tinja oued to 1246 ng L^-1 in Chegui oued. In the lagoon, the total concentration of pesticides was 67.7 ng L^-1. In the sediments, the highest concentration was measured in Chegui oued in the spring (31 ng g^-1 dw). The main compounds found in the analyzed sediments were prosulfocarb and tebuconazole molecules.

Ecological risk assessment of pesticide mixtures in the alluvial aquifers of central Italy: Toward more realistic scenarios for risk mitigation

In this study we used the data of an extensive pesticide monitoring survey that took place in 11 alluvial aquifers of central Italy from 2010 to 2015 to explore 4 different scenarios of risk. The Scenarios 1 and 2 were used to depict the risk of failing to meet the good groundwater chemical status as defined by the Water Framework Directive. The Scenarios 3 and 4 were used to assess for the first time the ecological risk in groundwater bodies, defined as the likelihood of hazard to the groundwater communities stably residing in the 11 alluvial aquifers that may be affected by pesticide contamination. The ecological risk was assessed through a new procedure called GERAp (Groundwater Ecological Risk Assessment due to pesticides). The main results of this study highlighted that: 1) the Scenario 1 provided information of little use for risk managers; 2) more realistic information was provided by using the highest concentrations measured in the six-year monitoring period and considering the ecological risk in a combined scenario (Scenarios 2 and 4); 3) the achievement of the good chemical status by 2027 in 3 aquifers will be likely much more difficult than in the others because the ecosystem services, such as pesticide biodegradation, are likely less efficient in the 3 groundwater bodies; 4) some pesticides that were banned in Europe in 2009 should be kept monitored in the next surveys because they showed a persistent occurrence in the 11 aquifers; 5) DDT forms, Dieldrin and Heptachlor are expected to damage groundwater communities at concentrations that are lower than the present legal limits.

The use of a disability-adjusted life-year (DALY) metric to measure human health damage resulting from pesticide maximum legal exposures

Most agencies around the world have developed a separate regulation frameworks for pesticides with different modes of action, likely because of the lack of a uniform quantification for health damage, which may underestimate pesticides' impact on human health and disease burden. In this study, the disability-adjusted life-year, a uniform metric used to express the human health impact and damage, was used to measure theoretical health damage resulting from maximum exposure as permitted by law to the most widely used pesticides. The total human risk characterization factors computed from chlorpyrifos and diazinon standard values through main exposure routes are generally larger than that of other widely used pesticides, and most factors of chlorpyrifos exceed the upper bounds of health risk. In addition, the damages to human health quantified from soil legal exposure to these widely used pesticides are much lower than that from exposure to drinking water or foods, which could help derive exposure allocation factors for different exposure routes. A total of 412 (28.3% of the total) computed total risk characterization factors of the 13 pesticides exceed the upper bound of tolerable risk uncertainty. Some nations, such as those in Europe, have adopted uniform and strict pesticide standard values as well as some computed risk characterization factors presented in the consensus data cluster. In addition, the results of an analysis on the geographical distribution of health risk characterization factors indicated that European nations have provided more conservative pesticide standard values in general. It is hoped that regulatory agencies can apply this uniform metric to compare and formulate legal limits for pesticides that have different modes of action.

Trace organic chemical pollutants from the lake waters of San Pablo City, Philippines by targeted and non-targeted analysis

More than half of the freshwater lakes in the Philippines are small with surface areas of <2 km². The dynamics in these lakes are different from those in the bigger lakes. This study was conducted to determine the organic pollutants and their sources in three of the seven lakes of San Pablo City in Laguna, Philippines: lakes Palakpakin, Sampaloc, and Pandin. Gas Chromatography-Mass Spectrometry (GC-MS) and Liquid Chromatography - Tandem Mass Spectrometry (LC-MS/MS) were used in the targeted and non-targeted analysis of the lake water samples. The three lakes are all volcanic crater lakes but are exposed to different anthropogenic activities, which includes domestic activities, livelihood (farming and aquaculture) and eco-tourism. Due to the presence of rice fields and fruit plantations, chlorpyrifos was detected in the three lakes while other pesticides like cypermethrin, picolinafen and quinoxyfen were additionally found in Lake Sampaloc, which is the biggest of the three lakes and located within the urbanized section of the city. Traces of different surfactants (linear alkylbenzene sulfonates, secondary alkyl sulfonates, alkyl sulfates, alkyl ether sulfates), biocide benzalkonium chloride, insect repellent diethyltoluamide, antibiotics (sulfadiazine and sulfamethoxazole), hypertension drug telmisartan, phosphate-based fire retardants, and artificial sweeteners (acesulfame, cyclamate, saccharin and sucralose) were detected in lakes Sampaloc and Palakpakin. The same surfactants, artificial sweeteners, insect repellant and phosphate-based fire retardants were also found in Lake Pandin, which is mainly used for eco-tourism activities like swimming and boating. The results of this study suggest that the organic pollutants present in the small lakes can be linked to the various human activities in the immediate lake environment. Because small lakes are more prone to environmental stresses, human activities in the said lakes must be regulated to ensure sustainable development.

Pesticide monitoring and ecotoxicological risk assessment in surface water bodies and sediments of a tropical agro-ecosystem

A pesticide monitoring study including 80 and 60 active ingredients (in surface waters and sediments, respectively) was carried out in a river basin in Costa Rica during 2007-2012. A special emphasis was given on the exceptional ecological conditions of the tropical agro-ecosystem and the pesticide application strategies in order to establish a reliable monitoring network. A total of 135 water samples and 129 sediment samples were collected and analyzed. Long-term aquatic ecotoxicological risk assessment based on risk quotient in three trophic levels was conducted. Short-term risk assessment was used to calculate the toxic unit and prioritization of sampling sites was conducted by the sum of toxic units in both aquatic and sediment compartments. Dimethoate (61.2 μg/L), propanil (30.6 μg/L), diuron (22.8 μg/L) and terbutryn (4.8 μg/L) were detected at the highest concentrations in water samples. Carbendazim and endosulfan were the most frequently detected pesticides in water and sediment samples, respectively. Triazophos (491 μg/kg), cypermethrin (71.5 μg/kg), permethrin (47.8 μg/kg), terbutryn (38.7 μg/kg), chlorpyrifos (18.2 μg/kg) and diuron (11.75 μg/kg) were detected at the highest concentrations in sediment samples. The pesticides carbendazim, diuron, endosulfan, epoxyconazole, propanil, triazophos and terbutryn showed non-acceptable risk even when a conservative scenario was considered. Sum TU_site higher than 1 was found for one and two sampling sites in water and sediment compartments, respectively, suggesting high acute toxicity for the ecosystem.

MAIN FINDING OF THE WORK

Exceptional ecological conditions of the tropical agro-ecosystem affect the fate of pesticides in water and sediment environment differently than the temperate one.

GC-MS/MS determination and ecological risk assessment of pesticides in aquatic system: A case study in Hooghly River basin in West Bengal, India

A liquid-liquid extraction (LLE) for water and modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for sediment combined with gas chromatography-tandem mass spectrometry (GC-MS/MS) detection in multiple reaction monitoring (MRM) mode was standardized for determination of 31 pesticides. Performance characteristics for the selected pesticides were acceptable according to European Commission's (EC) guidelines for method validation (recovery 70-120%, RSD <20% and R² value ≥ 0.99). River, pond and tubewell water and river sediment samples (64 nos.) were collected from Hooghly River basin in West Bengal, India during 2014-2016. About 42% of the samples showed the presence of 19 pesticides with the highest loading of total pesticides (T-pesticides) in river water (3.01 ng mL^-1) followed by sediment (1.25 ng g^-1), pond (0.40 ng mL^-1) and tubewell (0.02 ng mL^-1) water. The non-agricultural OC (organochlorine) insecticides were detected in all river water and sediment samples mainly due to HCHs (hexachlorocyclohexane) from old source and fresh use of DDTs (dichlorodiphenyltrichloroethane) in local areas. No OC insecticides were detected in pond and tubewell water. Maximum residues of some recommended pesticides in agriculture were obtained in pond water. Most of the river water samples (93.7%) were in excess of EC limit (0.50 ng mL^-1) of T-pesticides for drinking followed by pond water samples (56.2%). Tubewell water samples were free from T-pesticide threat but exceeded the EC limit (0.10 ng mL^-1) for single pesticide in case of chlorpyrifos only. Ecological risk on aquatic animals was observed for OCs in river and chlorpyrifos in pond aquatic ecosystem.

Distribution and risk assessment of banned and other current-use pesticides in surface and groundwaters consumed in an agricultural catchment dominated by cocoa crops in the Ankobra Basin, Ghana

The existence of pesticides, such as organochlorine pesticides, parathion-ethyl, methamidophos which is banned globally and some current-use non-banned pesticides of organophosphorus and synthetic pyrethroids in freshwater sources is an ecological and public health concern in many countries, including Ghana. Prompted by this concern, the exposure levels and risk assessment of these pesticides to humans and non-target organisms via groundwater and surface water sources in an agricultural catchment dominated by cocoa crops in the Ankobra Basin, Ghana, were investigated. The individual concentrations of the banned pesticides in the surface water and groundwater samples varied from < LOD to 0.110 μg/L and < LOD to 0.055 μg/L, respectively, while the concentrations of the non-banned pesticides ranged from < LOD to 0.925 μg/L and < LOD to 2 μg/L, respectively. The mean concentrations of chlorpyrifos, cypermethrin, p,p'-DDT and pirimiphos-methyl in some water sources exceeded the EU limit of 0.1 μg/L. Some surface water sources were more contaminated with DDTs, endrin, dieldrin, methoxychlor, chlorpyrifos, and HCH isomers than were freshwater sources in river basins in some countries of the world. Chlorpyrifos, p,p'-DDT and methoxychlor were ubiquitous in both water sources. The hydrochemical and compositional profiles of the pesticides indicate that water-exchange and secondary porosities in the bedrock likely contributed to the occurrence of the pesticides in the water sources. The pesticides were of low risk to humans that consume the water, but considering the US EPA safe limit for carcinogenic effects of 10^-6, the high levels of DDTs, β-HCH, and dieldrin in some of the surface water and groundwater sources may cause cancer in children or infants. The toxicity of pesticide mixtures to surface water non-target organisms decreased in the order of fish > Daphnia magna > algae. The pesticides in the water sources were anthropogenic in origin and recently used. DDT and HCH in the water were of technical-grade origin.

Removal of prometryn from hydroponic media using marsh pennywort (Hydrocotyle vulgaris L.)

The aquatic plant Hydrocotyle vulgaris was evaluated for its efficacy in removing prometryn from nutrient solution. Under optimized experimental conditions, up to 94.0% of the initial prometryn was removed from the hydroponic culture medium by H. vulgaris in 30 days. The concentration of prometryn decreased from the initial level of 0.55 ± 0.013 mg/L to 0.036 ± 0.001 mg/L at the end of the experimental period. The removal kinetics followed first-order kinetic equation (Ct = 0.4569e^-0.09t). Half-life (t_1/2) of prometryn was greatly shortened from 27.16 days (without plant) to 5.58 days (with H. vulgaris). Approximately 22% of the initial prometryn residue was found in H. vulgaris tissue, while 11.7% was degraded by the plant in 30 days. The metabolites of prometryn detected were 2,4-diamino-1,3,5-triazine (in the hydroponic culture medium) and 2,4,6-trihydroxy-1,3,5-triazine (in plant tissue) after 30 days. The results indicate that H. vulgaris can be used for phytoextraction of prometryn and could potentially be effective in removing other s-trazine pesticides from contaminated aquatic ecosystems.

Occurrence, impact variables and potential risk of PPCPs and pesticides in a drinking water reservoir and related drinking water treatment plants in the Yangtze Estuary

PPCPs and pesticides have been documented throughout the world over the years, yet relatively little is known about the factors affecting their spatial distribution and temporal change in order to know their potential risk to the ecosystem or human health in the future. In our study, 5 PPCPs and 9 pesticides were selected to study their occurrence, impact variables and potential risk in a drinking water reservoir in Yangtze Estuary and related drinking water treatment plants (DWTPs) in China. The detection results showed the presence of PPCPs and pesticides reflected in a large part of croplands and urban and built-up land in the adjacent basin. The discrepancy of concentration among the different PPCPs and pesticides was mainly decided by their application amount or daily usage. Then, the major factors regulating the occurrence of these contaminants in the surface water were found as the living expenditure attributed to food and medicine based on a correlation analysis. Also, the PPCPs were found to negatively correlate to the effectiveness of sewage management. The detection of the PPCPs and pesticides in DWTPs indicated that, except for atrazine and simazine, the removal percentages were increased significantly in advanced DWTPs. Moreover, risk assessment estimated by a Risk Quotient and Hazard Quotient showed that while caffeine, bisphenol A, estrone and simazine were at a high-risk level in the reservoir water, all of the contaminants detected posed no risk to human health through drinking water. It's possible that atrazine could pose a high risk to the ecosystem while simazine could pose a risk to human health in the future considering the increasing expenditure attributed to food.

Pesticides in the rivers and streams of two river basins in northern Greece

The pollution caused by pesticides, and their ecotoxicological implications were investigated in water samples from the Strymonas and Nestos river basins (Northern Greece). Chlorpyrifos was the most frequently detected pesticide in both basins (42 and 37% in the Strymonas and Nestos basins, respectively), followed by fluometuron and terbuthylazine (25 and 12%, Strymonas), and bentazone and boscalid (24 and 10%, Nestos). The Annual Average and the Maximum Allowable Concentration of Environmental Quality Standards set in European Union Directives were exceeded in several cases by alphamethrin and chlorpyrifos. Risk Quotient assessment revealed significant ecological risk towards the aquatic organisms in over 20% of the water samples. Insecticides (mostly pyrethroids and organophosphosphates) contributed more in the ecotoxicological risk than herbicides and fungicides. The three main rivers in the current study (Strymonas, Aggitis, Nestos) exhibited similar sum of RQs indicating that aquatic life in all three of them was at the same risk level. However, the sums of RQs were higher in the various streams monitored than the three rivers.

Application of a health risk assessment model for cattle exposed to pesticides in contaminated drinking waters: A study case from the Pampas region, Argentina

Using the USEPA methodology we estimated the probabilistic chronic risks for calves and adult cows due to pesticide exposure through oral intake of contaminated surface and ground waters in Tres Arroyos County (Argentina). Because published data on pesticide toxicity endpoints for cows are scarce, we used threshold levels based on interspecies extrapolation methods. The studied waters showed acceptable quality for cattle production since none of the pesticides were present at high-enough concentrations to potentially affect cow health. Moreover, ground waters had better quality than surface waters, with dieldrin and deltamethrin being the pesticides associated with the highest risk values in the former and the latter water compartments, respectively. Our study presents a novel use of the USEPA risk methodology proving it is useful for water quality evaluation in terms of pesticide toxicity for cattle production. This approach represents an alternative tool for water quality management in the absence of specific cattle pesticide regulatory limits.

A review on environmental monitoring of water organic pollutants identified by EU guidelines

The contamination of fresh water is a global concern. The huge impact of natural and anthropogenic organic substances that are constantly released into the environment, demands a better knowledge of the chemical status of Earth's surface water. Water quality monitoring studies have been performed targeting different substances and/or classes of substances, in different regions of the world, using different types of sampling strategies and campaigns. This review article aims to gather the available dispersed information regarding the occurrence of priority substances (PSs) and contaminants of emerging concern (CECs) that must be monitored in Europe in surface water, according to the European Union Directive 2013/39/EU and the Watch List of Decision 2015/495/EU, respectively. Other specific organic pollutants not considered in these EU documents as substances of high concern, but with reported elevated frequency of detection at high concentrations, are also discussed. The search comprised worldwide publications from 2012, considering at least one of the following criteria: 4 sampling campaigns per year, wet and dry seasons, temporal and/or spatial monitoring of surface (river, estuarine, lake and/or coastal waters) and ground waters. The highest concentrations were found for: (i) the PSs atrazine, alachlor, trifluralin, heptachlor, hexachlorocyclohexane, polycyclic aromatic hydrocarbons and di(2-ethylhexyl)phthalate; (ii) the CECs azithromycin, clarithromycin, erythromycin, diclofenac, 17α-ethinylestradiol, imidacloprid and 2-ethylhexyl 4-methoxycinnamate; and (iii) other unregulated organic compounds (caffeine, naproxen, metolachlor, estriol, dimethoate, terbuthylazine, acetaminophen, ibuprofen, trimethoprim, ciprofloxacin, ketoprofen, atenolol, Bisphenol A, metoprolol, carbofuran, malathion, sulfamethoxazole, carbamazepine and ofloxacin). Most frequent substances as well as those found at highest concentrations in different seasons and regions, together with available risk assessment data, may be useful to identify possible future PS candidates.

Pyrethroid pesticide residues in the global environment: An overview

Pyrethroids are synthetic organic insecticides with low mammalian toxicity that are widely used in both rural and urban areas worldwide. After entering the natural environment, pyrethroids circulate among the three phases of solid, liquid, and gas and enter organisms through food chains, resulting in substantial health risks. This review summarized the available studies on pyrethroid residues since 1986 in different media at the global scale and indicated that pyrethroids have been widely detected in a range of environments (including soils, water, sediments, and indoors) and in organisms. The concentrations and detection rates of agricultural pyrethroids, which always contain α-cyanogroup (α-CN), such as cypermethrin and fenvalerate, decline in the order of crops > sediments > soils > water. Urban pyrethroids (not contain α-CN), such as permethrin, have been detected at high levels in the indoor environment, and 3-phenoxybenzoic acid, a common pyrethroid metabolite in human urine, is frequently detected in the human body. Pyrethroid pesticides accumulate in sediments, which are a source of pyrethroid residues in aquatic products.

In vitro effects of endosulfan-based insecticides on mammalian sperm

Endosulfan is an organochloride insecticide extensively used in several countries to protect crops from pests. As several studies indicate that endosulfan can affect human and animal development, the aim of this study was to analyse whether sperm parameters and the process of chromatin decondensation could be altered by endosulfan in mice sperm. Spermatozoa from cauda epididymis were obtained from mature male mice and incubated in the presence of two commercial formulations (CFs) of endosulfan (Master® and Zebra Ciagro®) or the active ingredient (AI) alone. A significant decrease in the percentage motility and viability of spermatozoa with respect to controls was found. In vitro decondensation was performed in the presence of glutathione and heparin. Spermatozoa incubated with the AI, endosulfan Master® and endosulfan Zebra Ciagro® showed an increase in chromatin decondensation. In addition, the TUNEL assay showed that DNA fragmentation was significantly higher when sperm were incubated with either one of the CFs when compared to the AI or controls. The ultrastructure analysis of sperm cells showed evident changes in the structure of the plasma and acrosome membranes of sperm incubated with endosulfan AI or the CFs. These results suggest that endosulfan can affect sperm integrity and in vitro chromatin decondensation as well as DNA fragmentation.

Occurrence and distribution of trifluralin, ethalfluralin, and pendimethalin in soils used for long-term intensive cotton cultivation in central Greece

In the present study, a soil monitoring program was undertaken in Greek cotton cultivated areas in 2012. Twenty-seven soil samples were collected from the entire Thessaly plain in early summer of 2012, corresponding to approximately three months (current use of pendimethalin), up to one year (for the banned ethalfluralin), and three years (for the also banned trifluralin), after the last dinitroaniline application. Low but not negligible levels of dinitroanilines were detected, ranging from 0.01 to 0.21 μg g^-1 d.w. for trifluralin and 0.01-0.048 μg g^-1 d.w. for pendimethalin, respectively. Trifluralin was the herbicide most frequently detected (44.4%). The high historic application of trifluralin and its high persistence and accumulation potential is in line with the abundance of the detected residues. The present data indicate that soil samples contain extractable residues of banned trifluralin, but based on the comparison of the theoretical PECplateau for trifluralin (0.277 µg g^-1) and the maximum Measured Environmental Concentration, it was concluded that the detected residues should be attributed to previous years' application. The latter suggested the need for continual monitoring of the dinitroaniline family of pesticides, including the banned substances, aiming thus to an improved environmental profile for agricultural areas.

Malondialdehyde concentrations in the intestine and gills of Vardar chub (Squalius vardarensis Karaman) as indicator of lipid peroxidation

A lipid peroxidation product, malondialdehyde (MDA), was studied in Vardar chub (Squalius vardarensis Karaman) as an indicator of oxidative stress, using native fish from three rivers in northern Macedonia: the mining-impacted Zletovska and Kriva rivers and the agriculturally impacted Bregalnica River. MDA concentrations were measured in the intestine in the spring and autumn of 2012 and in the gills in autumn. The aims of the study were to establish the type of contamination which provokes a more pronounced MDA increase, as well as the organ which more reliably reflects the occurrence of oxidative stress. MDA levels in the intestine in spring amounted to 3.29-155.8 nmol g^-1 and in autumn to 4.85-111.1 nmol g^-1, whereas MDA concentrations in the gills in autumn were 7.69-147.5 nmol g^-1. Stronger influence of organic contamination on development of oxidative stress was observed in both organs, as seen from higher median MDA concentrations in autumn in fish from the highly pesticide-contaminated Bregalnica River (gills 78.4 nmol g^-1; intestine 23.5 nmol g^-1) compared to the highly metal-contaminated Zletovska River (gills 15.9 nmol g^-1; intestine 17.4 nmol g^-1). The response of the gills to contamination was twice stronger than that of the intestine. The majority of fish from the pesticide-polluted river had increased MDA in the gills, in contrast to only sporadically increased MDA in the intestine. Our results indicated that development of oxidative stress strongly depends on the selected fish organ and that the gills seem to be a better choice for monitoring oxidative stress than the intestine, due to their continuous and direct exposure to polluted river water.

Binding affinity and adhesion force of organophosphate hydrolase enzyme with soil particles related to the isoelectric point of the enzyme

The binding affinity of organophosphate hydrolase enzyme (OphB) with soil particles in relation to the isoelectric point (pI) was studied. Immobilization of OphB with soil particles was observed by confocal microscopy, Fourier transform infrared spectroscopy (FT-IR), and Atomic force microscopy (AFM). The calculated pI of OphB enzyme was increased from 8.69 to 8.89, 9.04 and 9.16 by the single, double and triple mutant of OphB enzyme, respectively through the replacement of negatively charged aspartate with positively charged histidine. Practically, the binding affinity was increased to 5.30%, 11.50%, and 16.80% for single, double and triple mutants, respectively. In contrast, enzyme activity of OphB did not change by the mutation of the enzyme. On the other hand, adhesion forces were gradually increased for wild type OphB enzyme (90 pN) to 96, 100 and 104 pN for single, double and triple mutants of OphB enzyme, respectively. There was an increasing trend of binding affinity and adhesion force by the increase of isoelectric point (pI) of OphB enzyme.

High frequency monitoring of pesticides in runoff water to improve understanding of their transport and environmental impacts

Rainfall-induced peaks in pesticide concentrations can occur rapidly. Low frequency sampling may therefore largely underestimate maximum pesticide concentrations and fluxes. Detailed storm-based sampling of pesticide concentrations in runoff water to better predict pesticide sources, transport pathways and toxicity within the headwater catchments is lacking. High frequency monitoring (2min) of seven pesticides (Dimetomorph, Fluopicolide, Glyphosate, Iprovalicarb, Tebuconazole, Tetraconazole and Triadimenol) and one degradation product (AMPA) were assessed for 20 runoff events from 2009 to 2012 at the outlet of a vineyard catchment in the Layon catchment in France. The maximum pesticide concentrations were 387μgL^-1. Samples from all of the runoff events exceeded the legal limit of 0.1μgL^-1 for at least one pesticide (European directive 2013/39/EC). High resolution sampling used to detect the peak pesticide levels revealed that Toxic Units (TU) for algae, invertebrates and fish often exceeded the European Uniform principles (25%). The point and average (time or discharge-weighted) concentrations indicated up to a 30- or 4-fold underestimation of the TU obtained when measuring the maximum concentrations, respectively. This highlights the important role of sampling methods for assessing peak exposure. High resolution sampling combined with concentration-discharge hysteresis analyses revealed that clockwise responses were predominant (52%), indicating that Hortonian runoff is the prevailing surface runoff trigger mechanism in the study catchment. The hysteresis patterns for suspended solids and pesticides were highly dynamic and storm- and chemical-dependent. Intense rainfall events induced stronger C-Q hysteresis (magnitude). This study provides new insights into the complexity of pesticide dynamics in runoff water and highlights the ability of hysteresis analysis to improve understanding of pesticide supply and transport.

Distribution, characterization, and human health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in Ovia River, Southern Nigeria

The levels and distribution of polycyclic aromatic hydrocarbons (PAHs) in surface water, sediment, and fish (Clarias gariepinus) samples from Ovia River, Southern Nigeria, were evaluated, to assess the contamination profile, dietary intake, and human health risks associated with exposure. Results showed that naphthalene, acenaphthylene, and fluoranthene were the most dominant contaminant in water, sediment, and fish, respectively, with mean concentrations (μg/L) of 3.08, 45.4, and 90.7. Spatial distribution showed high occurrence of PAHs in Ekenwan, the downstream station, for all the matrices. Source identification using multivariate analysis revealed mixed patterns of pyrogenic and petrogenic origins. Estimated daily intake (EDI) of PAHs through fish consumption ranged from 2.18 × 10^-7 to 5.23 × 10^-5 mg/kg/day; values were however lower than the reference dose (RfD) indicating low risk. Estimated values for hazard quotients (HQs) and hazard index (HI) for both non-carcinogenic and carcinogenic risks were below 1 indicating low risk through dietary and non-dietary exposure to water, sediment, and fish from Ovia River. However, estimated HI values for direct ingestion of sediment were above 1, indicating the possibility of non-carcinogenic health risk from exposure. Carcinogenic risk indices also indicated low risk from fish consumption. In spite of the assessed low risk from exposure, continuous monitoring of PAH levels in this water body is imperative to prevent future human health effects.

Herbicide micropollutants in surface, ground and drinking waters within and near the area of Zagreb, Croatia

The frequency and mass concentrations of 13 herbicide micropollutants (triazines, phenylureas, chloroacetanilides and trifluralin) were investigated during 2014 in surface, ground and drinking waters in the area of the city of Zagreb and its suburbs. Herbicide compounds were accumulated from water by solid-phase extraction using either octadecylsilica or styrene-divinylbenzene sorbent cartridges and analysed either by high-performance liquid chromatography with UV-diode array detector or gas chromatography with mass spectrometric detection. Atrazine was the most frequently detected herbicide in drinking (84 % of samples) and ground (61 % of samples) waters in mass concentrations of 5 to 68 ng L^-1. It was followed by metolachlor and terbuthylazine, the former being detected in 54 % of drinking (up to 15 ng L^-1) and 23 % of ground (up to 100 ng L^-1) waters, and the latter in 45 % of drinking (up to 20 ng L^-1) and 26 % of ground (up to 25 ng L^-1) water samples. Acetochlor was the fourth most abundant herbicide in drinking waters, detected in 32 % of samples. Its mass concentrations of 107 to 117 ng L^-1 in three tap water samples were the highest of all herbicides measured in the drinking waters. The most frequently (62 % of samples) and highly (up to 887 ng L^-1) detected herbicide in surface waters was metolachlor, followed by terbuthylazine detected in 49 % of samples in mass concentrations of up to 690 ng L^-1, and atrazine detected in 30 % of samples in mass concentrations of up to 18 ng L^-1. The seasonal variations in herbicide concentrations in surface waters were observed for terbuthylazine, metolachlor, acetochlor, chlortoluron and isoproturon with the highest concentrations measured from April to August.

Determination of the priority substances regulated by 2000/60/EC and 2008/105/EC Directives in the surface waters supplying water treatment plants of Athens, Greece

An investigation into the occurrence of priority substances regulated by 2000/60/EC Water Framework Directive and 2008/105/EC Directive was conducted for a period of one year in the surface water sources supplying the water treatment plants (WTPs) of Athens and in the raw water of WTPs. Samples from four reservoirs and four water treatment plants of Athens were taken seasonally. The substances are divided into seven specific groups, including eight volatile organic compounds (VOCs), diethylhexylphthalate, four organochlorine pesticides (OCPs), three organophosphorus/organonitrogen pesticides (OPPs/ONPs), four triazines and phenylurea herbicides, pentachlorophenol, and four metals. The aforementioned substances belong to different chemical categories, and different analytical methods were performed for their determination. The results showed that the surface waters that feed the WTPs of Athens are not burdened with significant levels of toxic substances identified as European Union (EU) priority substances. Atrazine, hexachlorocyclohexane, endosulfan, trifluralin, anthracene and 4-nonylphenol were occasionally observed at very low concentrations. Their presence in a limited number of cases could be attributed to waste disposal, agricultural activities, and to a limited industrial activity in the area nearby the water bodies.

Evaluation of residue risk and toxicity of different treatments with diazinon insecticide applied to mushroom crops

This work describes the phytotoxic effect of different doses of diazinon and different application times on Agaricus bisporus mycelium, and determines the residue levels in mushrooms from the first three flushes. Mushroom cultivation is a widespread commercial activity throughout the world. The application of insecticide diazinon to the compost or casing layer is a common practice to control two mushroom pests, the phorid Megaselia halterata and the sciarid Lycoriella auripila. Application to the compost does not result in any appreciable fall in yield or quality, and does not delay the harvest time. In contrast, application to the casing led to a slight fall (6.2%) in production and a smaller number of mushrooms although they are larger in size. Residue levels of more than 0.01 ppm are detected in many of the samples analyzed, and raising the question whether the product should continue to be used in mushroom cultivation in the conditions in which it is currently applied.