Pesticide monitoring in the basin of Llobregat River (Catalonia, Spain) and comparison with historical data

Widespread pesticide pollution in two English river catchments of contrasting land-use: from sediments to fish

Water, sediments, fish and invertebrates were collected along two English rivers (R. Tone, Sommerset and R. Wensum, Norfolk) and analysed for 52 pesticides to assess source to sea spatial distribution and track bioaccumulation within wildlife. Chemical risk assessments, using Toxic Units, Risk Quotients, and Microtox® solid phase tests were applied to understand threats to river health. Widespread pesticide pollution was detected in the water and sediments of both rivers, often forming complex mixtures containing numerous pesticides. Hydrophobic pesticides, such as Fipronil and Propiconazole, were also observed widely bioaccumulating in fish. The veterinary pesticide Fipronil was measured in the highest concentrations, up to 87.7 ng/g in fish muscle and 322 ng/g in invertebrates. Of particular concern were neonicotinoids in water, which frequently exceeded environmental quality standards (detected ranges: Imidacloprid <1.2-97.1 ng/L; Clothianidin <28.7-63.4 ng/L) and presented a significant risk to aquatic invertebrates and overall river health. Chronic sub-lethal risks to fish resulting from pesticide exposure were also identified. In sediments, Fipronil regularly exceeded likely-effect benchmarks by up to 256 % (0-0.355 ng/g OC; 0-12.6 ng/g). The findings highlight the potentially negative impact of pesticide pollution on river health in England, and emphasise the need for stricter regulation of the most high-risk pesticides, particularly those used in veterinary care.

Unraveling the complexity of organophosphorus pesticides: Ecological risks, biochemical pathways and the promise of machine learning

Organophosphorus pesticides (OPPs) are widely used in agriculture but pose significant ecological and human health risks due to their persistence and toxicity in the environment. While microbial degradation offers a promising solution, gaps remain in understanding the enzymatic mechanisms, degradation pathways, and ecological impacts of OPP transformation products. This review aims to bridge these gaps by integrating traditional microbial degradation research with emerging machine learning (ML) technologies. We hypothesize that ML can enhance OPP degradation studies by improving the efficiency of enzyme discovery, pathway prediction, and ecological risk assessment. Through a comprehensive analysis of microbial degradation mechanisms, environmental factors, and ML applications, we propose a novel framework that combines biochemical insights with data-driven approaches. Our review highlights the potential of ML to optimize microbial strain screening, predict degradation pathways, and identify key active sites, offering innovative strategies for sustainable pesticide management. By integrating traditional research with cutting-edge ML technologies, this work contributes to the journal's scope by promoting eco-friendly solutions for environmental protection and pesticide pollution control.

Chronic chlorpyrifos exposure induces oxidative stress, neurological damage, and hepatopancreas enrichment in Chinese mitten crab (Eriocheir sinensis)

The toxic effects of long-term exposure to low doses of chlorpyrifos (CPF) on Eriocheir sinensis were evaluated using acute toxicity tests, transcriptome analyses, and metabolome profiling. Four groups (three replicates per group, 60 crabs)-control (no CPF exposure), high exposure (0.12 mg/L CPF), medium exposure (0.036 mg/L), and low exposure (0.012 mg/L)-were subjected to CPF for 21 days. Tissue damage, antioxidant enzyme activity, transcriptional changes, and metabolic alterations in E. sinensis were analyzed. The results demonstrated that CPF disrupted the regulatory networks of transcription and metabolism in crabs under the experimental concentration conditions, with the severity of effects increasing as the duration of exposure lengthened despite the crabs' efforts to activate key defense mechanisms, such as upregulation of cholinesterase 1-like gene expression, to counteract organophosphorus toxicity and adapt to CPF presence in their environment. Even at low concentrations (0.012 mg/L), neurobehavioral development and the antioxidant kinase system in crabs were impaired, leading to hepatopancreatic tissue lesions that negatively affect their growth and survival rates. Additionally, E. sinensis accumulates significant levels of CPF, which may pose food safety concerns when humans consume them. Therefore, ensuring the rational use of CPF requires maintaining appropriate water concentrations to minimize direct harm to aquatic organisms and indirect impacts on food safety associated with this pesticide.

Benzimidazole Fungicide Carbendazim Induces Gut Inflammation through the TLR5/NF-κB Pathway in Grass Carp

Fungicides have been increasingly used across various sectors, including agriculture and textiles. The biocidal properties of fungicides may negatively impact the stability of intestinal microbiota, thereby posing a threat to intestinal health. In this study, we investigated the mechanisms of intestinal damage and functional abnormalities in grass carp following a 42-day exposure to the widely used fungicide carbendazim at environmentally relevant concentrations (0.2 to 20 μg/L). Histopathological observations, mRNA and protein expression analyses, biochemical analysis, quantification of short-chain fatty acids (SCFAs), cytokines, lipopolysaccharide (LPS), and 16S ribosomal ribonucleic acid (rRNA), as well as internal transcribed spacer (ITS) sequencing, were performed. At environmentally relevant concentrations, carbendazim strongly induced intestinal inflammation, leading to increased transcriptional and translational levels of genes involved in the toll-like receptor five (TLR5)/nuclear factor kappa B (NF-κB) pathway, including TLR5, NF-κB, interleukin-1 beta (IL-1β), and tumor necrosis factor-alpha (TNFα). Additionally, carbendazim damaged intestinal barriers and reduced the expression of tight junction proteins (e.g., occludin and zonula occludens-1/2), goblet cells, and immunoglobulin M levels, while also disrupting the gut microbiome, leading to intestinal metabolic disorders, particularly decreases in SCFAs and increases in LPS. Treatment with the TLR5 antagonist TH1020 mitigated intestinal inflammation caused by carbendazim, subsequently improving mechanical barrier function. Overall, our findings provide new insights into the toxicological mechanisms underlying intestinal damage caused by carbendazim in grass carp, indicating that carbendazim poses a significant threat to nontarget organisms. Given its widespread detection in the environment, these results underscore the substantial ecological risks to the gut health of fish living in carbendazim-contaminated water bodies.

Prediction of Potential Risk for Ten Azole and Benzimidazole Fungicides with the Aryl Hydrocarbon Receptor Agonistic Activity to Aquatic Ecosystems

Azole and benzimidazole fungicides are widely used agrochemicals to prevent and treat fungal growth and are frequently detected in aquatic environments. Here, we aimed to assess the aquatic ecological risks of ten currently used azole and benzimidazole fungicides, which with the aryl hydrocarbon receptor (AhR) agonistic activity, and their transformation products (TPs). We obtained over 400 types of aerobic TPs for ten fungicides. Some fungicides and their TPs (approximately 26.7%) exhibited the potential AhR agonistic activity and toxicity to different aquatic species. Meanwhile, some compounds with the chlorine element and benzene ring structure exhibited environmental persistence and mobile ability. Several of them were frequently detected in aquatic environments, posing potential risks to aquatic ecosystems. These harmful fungicides and their TPs should be given attention. This study provides important insight into the aquatic ecological risks caused by azole and benzimidazole fungicides, which can provide theoretical guidance for their pollution control.

Pesticide residues in European sediments: A significant concern for the aquatic systems?

The presence of pesticide residues in waterbed sediments poses a significant concern for aquatic ecosystems' health. This study examined pesticide contamination in sediments of 38 water bodies, embedded in agricultural-dominated regions, across eight European countries. Three indicators were targeted: occurrence, type, and concentrations of multiple pesticide residues in sediments. 196 pesticide residues (including degradation products) were tested in the sediment samples. The analytical results showed that only one sample was 'pesticide-free', three samples contained a single pesticide residue, and the remaining 34 samples contained mixtures of residues. Overall, 99 different residues were found in the sediments, with a maximum of 48 in a single sample. Twenty-seven out of the 99 detected residues were not approved for agricultural use at the time of sampling. The numbers of detected residues and pesticide levels varied among countries. AMPA, glyphosate and DDTs were the most common residues in sediment samples with frequencies of 76, 61, and 52%, respectively. The sediments from the Czech Republic had the highest pesticide concentrations, with total pesticide concentrations ranging between 600 and 1200 μg kg-1. The lowest total pesticide concentrations were found in Slovenia, Switzerland, Croatia, and Denmark, ranging between 80 and 120 μg kg-1. Sediments presented a mix of non-persistent and persistent compounds. Twelve of the detected pesticides are very persistent/stable in sediments, raising concerns about the long-term impacts of pesticides. Our study on the distribution of pesticide residues in European sediments provides valuable insights into the extent of pesticide contamination and possible risks of pesticides to water bodies' health. It also underlines the need for monitoring, research, and policy efforts to mitigate the impacts of pesticides, and to evaluate potential risks of re-use of dredged sediments.

Occurrence of emerging contaminants in three river basins impacted by wastewater treatment plant effluents: Spatio-seasonal patterns and environmental risk assessment

The concern on the fate and distribution of contaminants of emerging concern (CECs) is a burning topic due to their widespread occurrence and potential harmful effects. Particularly, antibiotics have received great attention due to their implications in antimicrobial resistance occurrence. The impact of wastewater treatment plants (WWTP) is remarkable, being one of the main pathways for the introduction of CECs into aquatic systems. The combination of novel analytical methodologies and risk assessment strategies is a promising tool to find out environmentally relevant compounds posing major concerns in freshwater ecosystems impacted by those wastewater effluents. Within this context, a multi-target approach was applied in three Spanish river basins affected by different WWTP treated effluents for spatio-temporal monitoring of their chemical status. Solid phase extraction followed by ultra-high-performance liquid chromatography were used for the quantification of a large panel of compounds (n = 270), including pharmaceuticals and other consumer products, pesticides and industrial chemicals. To this end, water samples were collected in four sampling campaigns at three locations in each basin: (i) upstream from the WWTPs; (ii) WWTP effluent discharge points (effluent outfall); and (iii) downstream from the WWTPs (500 m downriver from the effluent outfall). Likewise, 24-h composite effluent samples from each of the WWTPs were provided in all sampling periods. First the occurrence and distribution of these compounds were assessed. Diverse seasonal trends were observed depending on the group of emerging compounds, though COVID-19 outbreak affected variations of certain pharmaceuticals. Detection frequencies and concentrations in effluents generally exceeded those in river samples and concentrations measured upstream WWTPs were generally low or non-quantifiable. Finally, risks associated with maximum contamination levels were evaluated using two different approaches to account for antibiotic resistance selection as well. From all studied compounds, 89 evidenced environmental risk on at least one occasion in this study.

Understanding the carbendazim adsorption from water using biochar derived from apple pomace and industrial wastewater sludge: experimental and DFT approaches

Biochars derived from apple pomace (AP-BC) and industrial wastewater sludge (IS-BC) were used to investigate adsorption performance and mechanism for removing carbendazim from water and compare its performance with commercial biochar (commercial BC). The results showed that the adsorption capacity of AP-BC and IS-BC were 76 mg g-1 and 82 mg g-1 respectively that was comparable with the commercial BC (80 mg g-1). The adsorption kinetics and isotherms were best described by the Pseudo-second-order and Langmuir models. Thermodynamic analysis suggested that higher temperatures can enhance the mobility of molecules, increased mobility facilitates more frequent and stronger interactions between the adsorbate molecules and the surface of the adsorbent material, leading to greater adsorption capacity. Density functional theory (DFT) calculations confirmed carbendazim's weak electrophilic nature, supporting the primary physisorption mechanism. Even after five cycles of recycling, both biochars maintained a consistent carbendazim removal efficiency of around 82%, highlighting their high reusability. In this study, the examination of waste-derived biochar's economic feasibility revealed that using biochars derived from waste biomass for large-scale wastewater treatment applications is an economically viable choice.

Preliminary insights on the development of a continuous-flow solar system for the photocatalytic degradation of contaminants of emerging concern in water

The ubiquity and impact of pharmaceuticals and pesticides, as well as their residues in environmental compartments, particularly in water, have raised human and environmental health concerns. This emphasizes the need of developing sustainable methods for their removal. Solar-driven photocatalytic degradation has emerged as a promising approach for the chemical decontamination of water, sparking intensive scientific research in this field. Advancements in photocatalytic materials have driven the need for solar reactors that efficiently integrate photocatalysts for real-world water treatment. This study reports preliminary results from the development and evaluation of a solar system for TiO2-based photocatalytic degradation of intermittently flowing water contaminated with doxycycline (DXC), sulfamethoxazole (SMX), dexamethasone (DXM), and carbendazim (CBZ). The system consisted of a Fresnel-type UV solar concentrator that focused on the opening and focal point of a parabolic trough concentrator, within which tubular quartz glass reactors were fixed. Concentric springs coated with TiO2, arranged one inside the other, were fixed inside the quartz reactors. The reactors are connected to a raw water tank at the inlet and a check valve at the outlet. Rotating wheels at the collector base enable solar tracking in two axes. The substances (SMX, DXC, and CBZ) were dissolved in dechlorinated tap water at a concentration of 1.0 mg/L, except DXM (0.8 mg/L). The water underwent sequential batch (~ 3 L each, without recirculation) processing with retention times of 15, 30, 60, 90, and 120 min. After 15 min, the degradation rates were as follows: DXC 87%, SMX 35.5%, DXM 32%, and CBZ 31.8%. The system processed 101 L of water daily, simultaneously removing 870, 355, 256, and 318 µg/L of DXC, SMX, DXM, and CBZ, respectively, showcasing its potential for real-world chemical water decontamination application. Further enhancements that enable continuous-flow operation and integrate highly effective adsorbents and photocatalytic materials can significantly enhance system performance.

Occurrence, ecological risk, and advanced removal methods of herbicides in waters: a timely review

Coastal pollution caused by the importation of agricultural herbicides is one of the main environmental problems that directly affect the coastal primary productivity and even the safety of human seafood. It is urgent to evaluate the ecological risk objectively and explore feasible removal strategies. However, existing studies focus on the runoff distribution and risk assessment of specific herbicides in specific areas, and compared with soil environment, there are few studies on remediation methods for water environment. Therefore, we systematically reviewed the current situation of herbicide pollution in global coastal waters and the dose-response relationships of various herbicides on phytoplankton and higher trophic organisms from the perspective of ecological risks. In addition, we believe that compared with the traditional single physical and chemical remediation methods, biological remediation and its combined technology are the most promising methods for herbicide pollution remediation currently. Therefore, we focus on the application prospects, challenges, and management strategies of new bioremediation systems related to biology, such as constructed wetlands, membrane bioreactor processes, and microbial co-metabolism, in order to provide more advanced methods for reducing herbicide pollution in the water environment.

First surveillance of pesticides in soils of the perimeter of Tadla, a Moroccan sugar beet intensive area

With the long-term application of pesticides on sugar beet farms in the irrigated perimeter of Tadla in Morocco for over 50 years, pesticide monitoring is necessary to assess soil health. The objective of our study was to monitor multiple pesticide residues in topsoil samples collected from post-harvest sugar beet fields and verify their migration to deep soil layers. Topsoil and deep soil samples were collected from arbitrarily selected sugar beet fields in the IPT. In this study, a target-screening method was applied. All target pesticides were detected in soil samples, with tefluthrin being the most frequently detected pesticide. The residue with the highest concentration in soil samples was DDE. All the soil samples contained a mixture of pesticide residues, with a maximum of 13 residues per sample. The total pesticide content decreased toward more profound layers of soil, except in one field where it reached a concentration of 348 µg/kg at the deeper soil layer. For pesticides detected at the three soil depths, only tefluthrin concentration increased in the deep soil layer. The results provide comprehensive and precise information on the pesticide residue status in sugar beet soils warning against the multiple risks that this contamination can cause. This study indicates the need of regular monitoring of pesticides over a large area of the perimeter to enable decision-makers to pronounce the impacts of the extension and intensification of sugar beet cultivation at the irrigated perimeter of Tadla.

Multigenerational effects of the insecticide Pyriproxyfen and recovery in Daphnia magna

In the present study, an ecotoxicological approach to the evaluation of the insecticide Pyriproxifen in the crustacean Daphnia magna was done. Acute toxicity tests (48 h), feeding behavior test (5 h) and chronic toxicity test (21 days) were carried out on a parental daphnid generation (F0). Pyriproxifen D. magna EC50 value in our experimental conditions was 336.47 μg/L. Based on this result, sublethal test concentrations were selected for the feeding study and the F0 chronic experiment. Filtration and ingestion rates of D. magna exposed animals did not show any significant difference respect to control daphnids. However, daphnids from the parental F0 generation when exposed to the insecticide during 21 days showed a decreased in all the reproductive parameters tested (mean total neonates per female, mean brood size, time to first brood, and mean number of broods per female) as well as in the population statistic growth rate (r), although survival was not affected. On the other hand, offspring from F0 females exposed to the highest Pyriproxifen concentration (14.02 μg/L) were separated in two F1 generation experiments. One group was transferred during 21 days to a medium free of toxicant (F1 generation-TC group) while the other group was exposed during 21 days to the same insecticide concentration as their mothers (14.02 μg/L) (F1 generation-TT group). Results from both experiments determined a decreased in most of the reproductive parameters which was higher in the F1-TT group, although some of them were recovered in the F1-TC group. On the other hand, the morphological analysis of the daphnids showed that the coloration pattern was altered in the daphnids exposed to the insecticide, together with a significant size decreased, and neonates from F0 progeny with the same morphological abnormality. Finally, we determined that the insecticide caused the appearance of males among the offspring generated by the F0.

The diabetogenic effects of pesticides: Evidence based on epidemiological and toxicological studies

While the use of pesticides has improved grain productivity and controlled vector-borne diseases, the widespread use of pesticides has resulted in ubiquitous environmental residues that pose health risks to humans. A number of studies have linked pesticide exposure to diabetes and glucose dyshomeostasis. This article reviews the occurrence of pesticides in the environment and human exposure, the associations between pesticide exposures and diabetes based on epidemiological investigations, as well as the diabetogenic effects of pesticides based on the data from in vivo and in vitro studies. The potential mechanisms by which pesticides disrupt glucose homeostasis include induction of lipotoxicity, oxidative stress, inflammation, acetylcholine accumulation, and gut microbiota dysbiosis. The gaps between laboratory toxicology research and epidemiological studies lead to an urgent research need on the diabetogenic effects of herbicides and current-use insecticides, low-dose pesticide exposure research, the diabetogenic effects of pesticides in children, and assessment of toxicity and risks of combined exposure to multiple pesticides with other chemicals.

Multicompartmental monitoring of legacy and currently used pesticides in a subtropical lake used as a drinking water source (Laguna del Cisne, Uruguay)

A pilot annual monitoring survey (April 2018-March 2019) was conducted to investigate the presence of pesticides in superficial water and fish in Laguna del Cisne, one of the most critical drinking water sources in Uruguay. A total of 25 pesticide residues were detected in superficial water (89.3 % of the samples). Pesticide's temporal distribution was associated with crops and livestock practices, with higher occurrences in spring and summer than in autumn and winter. The most frequent compounds in superficial water were the insecticide chlorantraniliprole, and the herbicides glyphosate (including its metabolite AMPA) and metolachlor. The levels of Organochlorine pesticide, p,p'-DDT, was in some cases two order of magnitude above the international water quality guidelines for Ambient Water Criteria. In fishes, eight different pesticides were detected, at concentrations from 1000 to 453,000 ng·kg^-1. The most frequent pesticides found were propiconazole, chlorpyrifos, and p,p'-DDE. The widespread occurrence of pesticides in fish suggests potential exposure effects on fish populations and the aquatic ecosystem. The sampling approach of this work allowed monitoring the continuous concentrations of several pesticides in surface waters and fishes to establish the influence from past and current agriculture practices in Laguna del Cisne basin. For safety measures, continuous monitoring programs must be performed in this system to prevent toxicity impacts on aquatic organisms and human health.

Chemical monitoring and risk assessment of 56 pesticides in the Ave River and adjoining Atlantic coastline (Iberian Peninsula, Portugal)

The Ave basin (North Atlantic Ocean Ecoregion) is highly disturbed by anthropogenic activities. The amounts and distribution patterns of 56 priority pesticides (fungicides, herbicides, and insecticides) dissolved in the aqueous phase (DAP) and suspended particle matter (SPM) were evaluated seasonally along the river, estuary and coastline. Over 83 % of the GC-MS/MS-identified pesticides were quantified in DAP and 91 % in SPM. Pesticides' average annual amounts were ≅316 ng/L and 1.3 μg/g (fungicides), ≅272 ng/L and 2.2 μg/g (herbicides) and ≅1344 ng/L and 6.6 μg/g (insecticides). Invertebrates were the most vulnerable trophic level in the theoretical assessment of pesticide mixture hazards. This hypothesis was strengthened by acute in vivo assays using Artemia salina and Daphnia magna. These data, and the fact that 38 % of pesticides showed concentrations above the maximum established by the European legislation, plus the high concentrations of nitrates, nitrites, ammonia and phosphates, request further depollution actions in this region.

Single and mixed exposure to distinct groups of pesticides suggests endocrine disrupting properties of imidacloprid in zebrafish embryos

Due to their selective toxicity to insects, nicotinoid compounds have been widely used to control pests in crops and livestock around the world. However, despite the advantages presented, much has been discussed about their harmful effects on exposed organisms, either directly or indirectly, with regards to endocrine disruption. This study aimed to evaluate the lethal and sublethal effects of imidacloprid (IMD) and abamectin (ABA) formulations, separately and combined, on zebrafish (Danio rerio) embryos at different developmental stages. For this, Fish Embryo Toxicity (FET) tests were carried out, exposing two hours post-fertilization (hpf) zebrafish to 96 hours of treatments with five different concentrations of abamectin (0.5-11.7 mg L^-1), imidacloprid (0.0001-1.0 mg L^-1), and imidacloprid/abamectin mixtures (LC₅₀/2 - LC₅₀/1000). The results showed that IMD and ABA caused toxic effects in zebrafish embryos. Significant effects were observed regarding egg coagulation, pericardial edema, and lack of larvae hatching. However, unlike ABA, the IMD dose-response curve for mortality had a bell curve display, where medium doses caused more mortality than higher and lower doses. These data demonstrate the toxic influence of sublethal IMD and ABA concentrations on zebrafish, suggesting that these compounds should be listed for river and reservoir water-quality monitoring.

Occurrence, spatiotemporal dynamics, and ecological risk of fungicides in a reservoir-regulated basin

As an indispensable type of pesticide, fungicides have been somewhat neglected compared to insecticides and herbicides. Heavy fungicide application in agricultural regions may generate downstream ecological concerns via in-stream transport, and the reservoir complicates the process. Monitoring fungicide exposure and exploring reservoir effect on fungicide transport is the key to develop the downstream strategies of agricultural diffusion pollution control. Here, we investigated the exposure, spatiotemporal dynamics, and ecological risk of fungicides in a reservoir-regulated agricultural basin, located in the middle of the Yangtze River Basin, China. Seven fungicides were preliminarily identified and exhibited high detection frequencies (>85 %) in subsequent quantification of water samples from three sampling activities. The total concentration of fungicides ranged from 2.47 to 560.29 ng/L, 28.35 to 274.69 ng/L, and 13.61 to 146.968 ng/L in April, September, and November, respectively. Overall, the contamination levels of fungicides were in the ascending order of April < November < September. The spatial distribution of fungicides was closely associated with the dense of cultivated land, supporting its agricultural source. Furthermore, the reservoir plays a retention role in fungicides, alleviating ecological pressure downstream during the water storage period. Yet, due to the alternation of "source" and "sink" function of the reservoir, the contribution of Zijiang River to the fungicide load in the Yangtze River Basin still needs further attention. Although there is no acute risk posed by fungicides, even in the high-exposure scenario, the chronic ecological risk could not be ignored. Agricultural intensive regions, coupled with the reservoir, provide rather substantial chronic ecological concerns. Carbendazim has been designated as a priority pollutant that contributes significantly to cumulative chronic risk. Thus, we emphasize strengthening the supervision of fungicides in surface water and rationally restricting the use of carbendazim in agricultural operations.

Gene expression study alerted to possible impairment in Daphnia magna individuals as a consequence of exposure to sublethal concentrations of prochloraz

In the present study, Daphnia magna individuals were exposed for 21 days to 87, 130, 170, 230 and 380 μg/L of prochloraz. The expression of genes related to lipid metabolism (fabd), oxidative stress (cat and gst), heat shock proteins synthesis (hsp70 and hsp90), haemoglobin synthesis (hgb1 and hgb2), metallothioneins synthesis (mt-a, mt-b and mt-c), and vitellogenin synthesis (vgt1 y vgt2) were analyzed. Results showed that some gene expression in D. magna was altered as a consequence of the individual exposure to the fungicide. The genes fabd, vtg1 and vtg2, cat and gst resulted unaltered by the exposure of the daphnids to different fungicide concentrations. However, daphnid exposure to 380 μg/L of prochloraz resulted in an overexpression (p < 0.05) of hsp70 gene which indicated an alteration of the normal protein synthesis and its integrity maintenance. On the other hand, mt-b gene resulted significantly underexpressed (p < 0.05) in daphnids exposed to the lowest fungicide concentrations (87, 130 and 170 μg/L, respectively). In addition, hgb1 and hgb2 genes which are related with the haemoglobin synthesis weresignificantly overexpressed (p < 0.05). Results showed that hgb1 gene was overexpressed almost 100 times more in daphnids exposed for 21 days to 170, 230 and 380 μg/L than control values. However, many authors advocate for an association of these gene expression changes with the presence of contaminants in the medium, in fact they could be used as a good indicator of early contamination at low concentrations of toxicants.

The prochloraz chronic exposure to Daphnia magna derived in biochemical alterations of F0 generation daphnids and malformed F1 progeny

In the present study, D. magna individuals were exposed to several sublethal prochloraz concentrations (87, 130, 170, 230 and 380 μg/L) for 21 days according to; the previous acute toxicity results. The fungicide effects on reproduction, survival, individual size, and growth population rate were evaluated after an exposure of 21 days, and no changes were observed compared to the control group. On the other hand, F1 generation neonates were collected and their external morphology evaluated; to estimate if the fungicide concentrations used induced effects during oogenesis and; embryogenesis processes. Neonates from parents which were previously exposed to 170 μg/L and higher concentrations were malformed since 16-d of exposure onward. All animals presented the same malformation: asymmetrical shell morphology and separated valves that did not cover the complete animal body regardless of the; concentration. The biochemical parameters tested in the broodstock were cholesterol, triglycerides, glucose and LDH activity. At the end of the chronic exposure experiment, cholesterol and triglycerides remained unaltered while glucose and the LDH enzyme levels increased significantly. The results of the present work showed a direct effect of; prochloraz on D. magna individual growth, along with mobilization of some; biochemical intermediate metabolism. A daphnid stress response as a result of the fungicide presence in the medium could be an explanation for the metabolic disorders. On the other hand, the F1 malformed neonates found in the present study suggested an effect of prochloraz among different daphnid generations and more studies would be necessary in this field.

Review: Presence, distribution and current pesticides used in Spanish agricultural practices

To guarantee an adequate food supply for the world's growing population, intensive agriculture is necessary to ensure efficient food production. The use of pesticides helps maintain maximum productivity in intensive agriculture by minimizing crop losses due to pests. However, pesticide contamination of surface waters constitutes a major problem as they are resistant to degradation and soluble enough to be transported in water. In recent years, all groups of pesticides defined by the World Health Organization have increased their use and, therefore, their prevalence in the different environmental compartments that can have harmful effects. Despite this effort, there is no rigorous monitoring program that quantifies and controls the toxic effects of each pesticide. However, multiple scientific studies have been published by specialized research groups in which this information is disseminated. Therefore, any attempt to systematize this information is relevant. This review offers a current overview of the presence and distribution of the most widely-used pesticides (insecticides, herbicides, and fungicides) by crop type and an evaluation of the relationships between their uses and environmental implications in Spain. The data demonstrated that there are correlations between the presence of specific pesticides used in the main crops and their presence in the environmental compartments. We have found preliminary data pointing to existing associations between specific pesticides used in the main crops and their presence in environmental compartments within different geographical areas of Spain; this should be the subject of further investigation.

Occupational and residential exposures to organophosphate and pyrethroid pesticides in a rural setting

Organophosphate (OP) and pyrethroid pesticides (PYR) are extensively used in agriculture, resulting in higher exposures among farmworkers. The present study reports the occurrence of 8 urinary OP and PYR metabolites in a sample of farmworkers and residents from Sucs (n = 87), a rural township in North West Catalonia (Spain). The aim of the present study was to examine differences in urinary pesticide metabolite concentrations between occupationally-exposed (farmworkers; n = 45) and environmentally-exposed subjects (n = 42) and to assess the relationship between pesticide's exposures and occupational activities in a real-case scenario. Six OP and two PYR metabolites have been investigated, urine samples were extracted using SPE extraction and analyzed by UPLC-MS/MS. Three OP metabolites were commonly detectable in urine, namely TCPY (metabolite of chlorpyrifos), PNP (parathion) and DEAMPY (pirimiphos). Regarding pyrethroids, the two analyzed metabolites, 3-PBA and 4F-3-PBA, were detected in a high proportion of urine samples. Differences in concentrations between both groups were statistically significant for TCPY and 4F-3-PBA (Mann-Whitney U Test for independent groups, p < 0.05). In the case of TCPY, the concentrations were higher among the farmworkers, which is consistent with their occupational activity. The small differences found in DEAMPY, PNP, 3-PBA or even the significant higher concentrations of 4F-3-PBA among rural population suggest a general exposure to these compounds, even in those who do not carry an occupational activity. Specific personal protective equipment (PPE) among farmworkers, such as the use of gloves and mask during mixing, showed a decrease in the exposure levels, although the differences were not statistically significant. However, a positive association was found between the use of a cap during mixing (for PNP and 3-PBA) and during application (only for 3-PBA). However, this piece of cloth is mainly used for sun protection, and when not cleaned after the handling of pesticides, it might represent a continuous source of exposure through dermal contact. Farmworkers using tractors with cabin had statistically significant lower concentrations of DEAMPY than those using a tractor without cabin. The previous results suggest that occupational protections should be encouraged among farmworkers and other potential workers handling with pesticides.

Carbendazim toxicity in different cell lines and mammalian tissues

The extensive production and use of harmful pesticides in agriculture to improve crop yield has raised concerns about their potential threat to living components of the environment. Pesticides cause serious environmental and health problems both to humans and animals. Carbendazim (CBZ) is a broad spectrum fungicide that is used to control or effectively kill pathogenic microorganisms. CBZ is a significant contaminant found in food, soil and water. It exerts immediate and delayed harmful effects on humans, invertebrates, aquatic animals and soil microbes when used extensively and repeatedly. CBZ is a teratogenic, mutagenic and aneugenic agent that imparts its toxicity by enhancing generation of reactive oxygen species generation. It elevates the oxidation of thiols, proteins and lipids and decreases the activities of antioxidant enzymes. CBZ is cytotoxic causing hematological abnormalities, mitotic spindle deformity, inhibits mitosis and alters cell cycle events which lead to apoptosis. CBZ is known to cause endocrine-disruption, embryo toxicity, infertility, hepatic dysfunction and has been reported to be one of the leading causes of neurodegenerative disorders. CBZ is dangerous to human health, the most common side effects upon chronic exposure are thyroid gland dysfunction and oxidative hepato-nephrotoxicity. In mammals, CBZ has been shown to disrupt the antioxidant defense system. In this review, CBZ-induced toxicity in different cells, tissues and organisms, under in vitro and in vivo conditions, has been systematically discussed.

Organophosphate pesticides in South African eutrophic estuaries: Spatial distribution, seasonal variation, and ecological risk assessment

The seasonal variation, spatial distribution, and ecological risks of thirteen organophosphate pesticides (OPPs) were studied in the Sundays and Swartkops estuaries in South Africa. Ten pesticides were detected in surface water samples from both estuaries, while all OPPs were detected in sediments. The highest concentration of OPPs (18.8 μg pyrazophos L^-1) was detected in surface water samples from Swartkops Estuary, while 48.7 μg phosalone kg^-1 dw was the highest in sediments collected from Sundays Estuary. There was no clear seasonal pattern in OPPs occurrence in surface water from both systems. However, their occurrence in sediments was in the following order: winter > autumn > summer > spring, perhaps indicating major pesticide input in the winter seasons. Results from ecological risk assessment showed that pyraclofos and chlorpyrifos (CHL) in surface water from both systems are respectively likely to cause high acute and chronic toxicity to fish (risk quotient - RQ > 1). For sediments of both estuaries, the highest acute and chronic RQs for fish were calculated for isazophos and CHL respectively. The majority of the detected OPPs in sediments posed potential high risks to Daphnia magna from both systems. These results suggest that these aquatic organisms (fish, and Daphnia), if present in the studied estuaries, can develop certain forms of abnormalities due to OPP exposure. To this end, proper measures should be taken to reduce OPP input into the estuarine systems.

Occurrence, Distribution, and Risk Assessment of Organophosphorus Pesticides in the Aquatic Environment of the Sele River Estuary, Southern Italy

The intensive use of organophosphorus pesticides (OPPs) causes concern among authorities in different countries, as many of them, remaining unchanged for a long time, pose a threat to environmental sustainability. This study assessed the spatio-temporal trends of nine OPPs in the water dissolved phase (WDP), suspended particulate matter (SPM), and sediment samples from the Sele River estuary, Southern Italy. Samples were collected in 10 sampling sites during four seasons. The highest levels were found at the mouth (mean value 28.25 ng L⁻¹ as WDP + SPM) and then decreased moving southwards to the Mediterranean Sea. Moreover, highest concentrations were detected in the warm season (July) with a mean value of 27.52 ng L⁻¹. The load contribution to the Mediterranean Sea was evaluated in about 61.5 kg year⁻¹, showing that the river was an important source of OPPs through discharge into the sea. The risk assessment revealed that no high-risk indices for the general-case scenario were observed, but for the worst-case scenario, potential risks were associated with chlorpyrifos, pyrimifos-methyl, and parathion, suggesting that OPP contamination should not be neglected. This study makes up the first record of OPPs in the surface waters of the Sele River and provides helpful data as a starting point for future studies.

Degradation of carbendazim in aqueous solution by different settings of photochemical and electrochemical oxidation processes

The present study analyzed the performance of photochemical and electrochemical techniques in the degradation and mineralization of the pesticide carbendazim (CBZ). Direct photolysis (DP), heterogeneous photocatalysis (HP), photoelectrocatalysis (PEC), and electrochemical oxidation (EO) were tested, and the influence of UV radiation, current density (j), and supporting electrolyte concentration were evaluated. The results suggest that CBZ is only degraded by DP when UV-C_254nm is used. For HP, the CBZ degradation was observed both when UV-A_365nm or UV-C_254nm were used, which is related to the reactive oxygen species (ROS) formed by the photocatalytic activity (photon-ROS). Neither DP nor HP were able to mineralize CBZ, demonstrating its resistance to photomediated processes. For EO, regardless of the j, there were higher CBZ degradation and mineralization than those observed when using DP and HP. The increase in the supporting electrolyte concentration (Na₂SO₄) did not affect the levels of degradation and mineralization of CBZ. Concerning the PEC, a CBZ mineralization of 52.2% was accomplished. These findings demonstrate that the EO is the main pathway for CBZ mineralization, suggesting an additional effect of the electro-ROS on the photon-ROS and UV-C_254nm. The values of mineralization, kinetics, and half-life show that PEC UV-C_254nm with a j of 15 mA cm^-2 was the best setting for the degradation and mineralization of CBZ. However, when the values of specific energy consumption were considered for industrial applications, the use of EO with a j of 3 mA cm^-2 and 4 g L^-1 of Na₂SO₂ becomes more attractive. The assessment of by-products formed after this best cost-efficient treatment setting revealed the presence of aromatic and aliphatic compounds from CBZ degradation. Acute phytotoxicity results showed that the presence of sodium sulfate can be a representative factor regarding the toxicity of samples treated in electrochemical systems.

Removal efficiency for emerging contaminants in a WWTP from Madrid (Spain) after secondary and tertiary treatment and environmental impact on the Manzanares River

The effluents from wastewater treatment plants (WWTPs) can be an important contamination source for receiving waters. In this work, a comprehensive study on the impact of a WWTP from Madrid on the aquatic environment has been performed, including a wide number of pharmaceuticals and pesticides, among them those included in the European Watch List. 24-h composite samples of influent (IWW) and effluent wastewater after secondary (EWW2) and after secondary + tertiary treatment (EWW3) were monitored along two campaigns. Average weekly concentrations in IWW and EWW2 and EWW3 allowed estimating the removal efficiency of the WWTP for pharmaceutical active substances (PhACs). In addition, the impact of EWW3 on the water quality of the Manzanares River was assessed, in terms of PhAC and pesticide concentrations, through analysis of the river water collected upstream and downstream of the discharge point. After a preliminary risk assessment, a detailed evaluation of the impact on the aquatic environment, including a toxicological study and screening of pharmaceutical metabolites, was made for the seven most relevant PhACs: sulfamethoxazole, azithromycin and clarithromycin (antibiotics), metoprolol (antihypertensive), diclofenac (anti-inflammatory/analgesic), irbesartan (antihypertensive), and the antidepressant venlafaxine. Among selected PhACs, irbesartan, clarithromycin and venlafaxine presented moderate or high risk in the river water downstream of the discharge. Albeit no acute toxicity was detected, more detailed studies should be carried out for these substances, including additional toxicological studies, to set up potential sublethal and chronic effects on aquatic organisms.

A global systematic review of the concentrations of Malathion in water matrices: Meta-analysis, and probabilistic risk assessment

Pesticide applications and the proximity of land use to water matrices have resulted in discharges of pollutants including Malathion -one of the most widely used organophosphorus pesticides- to water resources such as marine, freshwater, and under groundwater. Exposure to malathion through consumption of contaminated water may cause deleterious health effects on consumers. Determining the amount of pesticides used on farms can play an important role in preventing potential toxicity and pollution of nearby aquatic ecosystems. Therefore, this systematic review and meta-analysis is focused on evaluating the concentrations of Malathion in water resources while considering probabilistic health risk assessment. The international databases of Scopus, Embase, and PubMed were investigated to evaluate the related articles from January 01, 1968 to March 25, 2021. Thirty-four articles containing 206 samples from 15 countries were included. A meta-analysis of carcinogenic and non-carcinogenic risk assessments for Malathion was also performed. To determine uncertainty intervals, a Monte-Carlo simulation was conducted. The results of the meta-analysis showed that the rankings of Malathion pollution (from the most to the least) were: drinking water > surface waters > groundwaters. Moreover, the results of the risk assessments confirm that there is no non-carcinogenic risk for any of the study areas. The carcinogenic risk assessment was within the limit for the countries under this study, except for Ethiopia that was slightly over the limit as well as Iran, and Mexico had high carcinogenic risk.

Seasonal variation of pesticides in surface water and drinking water wells in the annual cycle in western Poland, and potential health risk assessment

Drinking water wells on a riverbank filtration sites are exposed to contamination from farmlands (like pesticides) that had migrated from the contaminated river. In this study, pesticide contamination of the Warta River and riverbank filtration water at the Mosina-Krajkowo well field (Poland) were examined during the annual cycle. Among the 164 pesticides analysed, 25 were identified. The highest concentrations occurred in the river water and decreased along the flow path from the river to wells. Only the most persistent substances were detected at the farthest points. During the study, seasonal changes in pesticide concentrations and differences in the types of occurring substances were observed. Most substances and the highest concentrations were detected in May 2018, while the lowest number and the lowest concentrations were detected in February 2018. Spring is the period of increased exposure of water to pollution, which is correlated with increased pesticides use and increased rainfall. Seven toxic and persistent pesticides were found with the highest concentrations in water: isoproturon, nicosulfuron, imidacloprid, terbuthylazine, chlorotoluron, S-metalachlor, and prometryn. Pesticides are widely used in the study area; therefore, a potential health risk assessment was performed. The hazard quotient (HQ) values did not exceed one, which indicated a less significant health risk.

Occurrence and spatial-temporal distribution of atrazine and its metabolites in the aquatic environment of the Volturno River estuary, southern Italy

The present study assesses the spatial distribution and temporal trends of the water dissolved phase (WDP), suspended particulate matter (SPM) and sediment partitioning of atrazine (ATR) and its metabolites in the Volturno River estuary. The load contribution of ATR and its metabolites in this river to the Central Mediterranean Sea was estimated. Samples were collected in 10 sampling sites during the four seasons. The total concentrations of ATR and DPs detected ranged from 18.1 to 105.5 ng L^-1 in WDP, from 4.5 to 63.2 ng L^-1 in SPM, and from 4.6 to 18.6 ng g^-1 in sediment samples, indicating high levels of these pollutants. Structural equation model and the ratio study indicated that the relationship between sediment and WDP pollutants occurred through the SPM. The pollutants load at the Volturno River in its mouth was evaluated in about 30.4 kg year^-1, showing that this river is an important source of these analytes through discharge into Central Mediterranean Sea. Principal component analysis indicated that ATR and its metabolites pollution moves from Volturno River mouth southward and increased in the rainy season. The desethylatrazine-to-atrazine ratio was higher than 0.5 for all samples analyzed, indicating an historical discharge and a long residence time of ATR in sediment about two decades after its ban, and classifying ATR as a nonpoint source contaminant. This study makes up the first record of ATR and its metabolites in superficial water of Southern Italy and provides helpful data as starting point for future studies.

Occurrence, human health, and ecotoxicological risk assessment of pesticides in surface waters of the River Nile's Rosetta Branch, Egypt

In Egypt, the shortage of freshwater resources and their pollution constitutes a growing concern. Therefore, the objectives of this study were to (i) monitor the occurrence and spatiotemporal variations of 100 pesticides in surface water samples collected monthly (from July 2018 to June 2019) from El-Rahawy, Sabal, and Tala sampling sites along the Rosetta branch of the River Nile in Egypt, (ii) identify potential non-carcinogenic health risks for the local people through the lifetime consumption of contaminated drinking water, and (iii) perform an ecological risk assessment of aquatic organisms upon exposure to pesticides detected in surface waters based on the risk quotients (RQs) method. Of the 100 pesticides analyzed, 22 belonging to 11 chemical families were detected, and 75.5% of surface water samples were contaminated with one or more pesticide residues. The most frequently detected pesticide was malathion (57%), followed by chlorpyrifos (54%), atrazine (23%), and carbendazim (20%). Spatial distribution showed that the El-Rahawy site had the highest pesticide load (38.47 μg/L), and Sabal had the lowest (16.29 μg/L). Temporal variations revealed that the highest total pesticide concentrations were detected in summer (27.98 μg/L) compared to spring (23.16 μg/L), winter (19.18 μg/L), and autumn (11.85 μg/L). For non-carcinogenic risks of pesticides detected in surface water, the target hazard quotient (THQ) values were less than one. This implies that there is no potential human risk from exposure to drinking water at the sites under study. However, 13 pesticides presented high-risk quotients (RQ > 1), posing potential ecological risks to aquatic organisms.

Occurrence and risk assessment of currently used organophosphate pesticides in overlying water and surface sediments in Guangzhou urban waterways, China

Organophosphate pesticides (OPPs) are one type of the most massively used pesticides and ubiquitously detected in aquatic environments, which may pose potential risks to the aquatic organisms and human health. In the present study, the spatiotemporal distribution and potential risks of OPPs were investigated in overlying water and surficial sediments from urban waterways of Guangzhou. For all studied sites, in general, four target OPPs (i.e., malathion, chlorpyrifos, terbufos, and diazinon) were present in the overlying water, with malathion and chlorpyrifos as major components. Higher concentrations of the four OPPs were found for the water and sediments collected in the dry season compared to the wet season, possibly because of the dilution effect of heavy rains. The results of Pearson's analyses and principal coordinate analyses (PCoA) suggested similar sources for target OPPs in the water and sediments across the Guangzhou urban waterways. Potential ecological risks of the OPPs to three representative taxons (algae, aquatic invertebrates, and fish) were evaluated via toxic units (TUs) and risk quotients (RQs), while risk assessment on human health was performed using hazard index (HI). Although TU results showed no acute risks to the aquatic organisms in the overlying water and surface sediments, RQ results of the mixture showed high risks to the aquatic invertebrate and fish in all water samples. Individual HI values and cumulative HI values were on the order of 10^-6-10^-3 for children and adults, suggesting no potential risks to either children or adults through drinking and bathing.

Pesticides in surface waters of tropical river basins draining areas with rice-vegetable rotations in Hainan, China: Occurrence, relation to environmental factors, and risk assessment

Pesticides are heavily applied in rice-vegetable rotations in tropical China, yet publicly available information on the contamination and risk of currently used pesticides (CUPs) and legacy pesticides (LPs) in surface waters of river basins draining these areas is very limited. Therefore, in two tropical river basins (Nandu River and Wanquan River basins) dominated by rice-vegetable rotations in Hainan, China, pesticides were analyzed in 256 surface water samples in wet and dry seasons. Forty-one pesticides were detected, and total concentrations ranged from not detectable to 24.2 μg/L. Carbendazim and imidacloprid were the two most prevalent CUPs, detected in 59.8% and 17.7%, respectively, of surface water samples at concentrations above 0.1 μg/L. Chlorpyrifos was the main LP, detected in 9.0% of samples at a concentration above 0.05 μg/L. The fungicides difenoconazole and emamectin benzoate, the herbicide butachlor, and the insecticide acetamiprid occurred in ≥12.5% samples at concentrations above 0.1 μg/L. Surface waters typically (85.2%) contained 5 to 15 residues, with an average of nine. Seasonally, the concentrations of the 41 pesticides were in the order January > July > November > September. Spatially, the composition of the main CUPs (not LPs) was significantly different depending on position in the drainage, which also changed with seasons. Crop and pest types and wet and dry seasons were the key factors controlling the spatiotemporal distribution of CUPs and LPs in surface waters. On the basis of evaluations of the exposures to individual pesticides and the dominant combinations with ≥8 pesticides, multiple pesticides were likely a significant risk to aquatic organisms, although noncarcinogenic and carcinogenic risks to humans were low. This study provides valuable data to better understand pesticide occurrence and ecological risks in river basins draining areas with rice-vegetable rotation systems in tropical China.

Metabolism-Coupled Cell-Independent Acetylcholinesterase Activity Assay for Evaluation of the Effects of Chlorination on Diazinon Toxicity

Drinking water quality guideline values for toxic compounds are determined based on their acceptable daily intake. The toxicological end point for determining the acceptable daily intake of most organophosphorus insecticides is inhibition of acetylcholinesterase (AChE). Although insecticides ingested with drinking water are partly metabolized by the liver before transport to the rest of the body, no current cell-independent AChE activity assay takes the effects of metabolism into account. Here, we incorporated metabolism into a cell-independent AChE activity assay and then evaluated the change in anti-AChE activity during chlorination of a solution containing the organophosphorus insecticide diazinon. The anti-AChE activities of solutions of diazinon or diazinon-oxon, the major transformation product of diazinon during chlorination, were dramatically changed by metabolism: the activity of diazinon solution was markedly increased, whereas that of diazinon-oxon solution was slightly decreased, clearly indicating the importance of incorporating metabolism into assays examining toxicity after oral ingestion. Upon chlorination, diazinon was completely transformed, in part to diazinon-oxon. Although diazinon solution without metabolism did not show anti-AChE activity before chlorination, it did after chlorination. In contrast, with metabolism, diazinon solution did show anti-AChE activity before chlorination, but chlorination gradually decreased this activity over time. The observed anti-AChE activities were attributable solely to diazinon and diazinon-oxon having been contained in the samples before metabolism, clearly suggesting that the presence not only of diazinon but also of diazinon-oxon should be monitored in drinking water. Further examination using a combination of tandem mass spectrometry and in silico site-of-metabolism analyses revealed the structure of a single metabolite that was responsible for the observed anti-AChE activity after metabolism. However, because this compound is produced via metabolism in the human body after oral ingestion of diazinon, its presence in drinking water need not be monitored and regulated.

Determination of OCPs, OPPs, and 21 SVOCs in water and sediment samples in five rivers of Shenzhen, China, during the period of 2017 and 2018

One hundred two semivolatile organic compounds (SVOCs), including 20 organochlorine pesticides (OCPs) and 12 organophosphorus pesticides (OPPs), were determined in the main rivers of Shenzhen, China. As a result, p,p'-dichlorodiphenyldichloroethane (DDD), aldrin, and benzoepin sulfate were the main OCPs detected in surface water, and p,p'-DDD, heptachlor, and endrin aldehyde were the main compounds in sediment. In addition, diazinon was the most frequent OPP detected in both water and sediment. At most sites, SVOCs were at similar concentration levels in 2017 and 2018. Compared with other areas, diazinon and malathion had comparative high concentrations in Maozhou River in this study. Analyzed from the SVOCs concentrations in water and sediment, p,p'-DDD was from the quick degradation of p,p'-dichlorodiphenyltrichloroethane (DDT), and no recent DDT was input around the investigated area. Besides, the interrelationships among these pollutants were calculated, revealing that OPPs were mainly from the chronically cumulative content, rather than the directly transferring from surface water to sediment. According to the risk assessment, the occurrence of p,p'-DDD and p,p'-DDT affected the aquatic community. All in all, further investigations on the occurrence and source of these pollutants are still needed to avoid the potential risk for human beings living around the contaminated environment.

Omnipresent distribution of herbicides and their transformation products in all water body types of an agricultural landscape in the North German Lowland

The research of the environmental fate of pesticides has demonstrated that applied compounds are altered in their molecular structure over time and are distributed within the environment. To assess the risk for contamination by transformation products (TP) of the herbicides flufenacet and metazachlor, the following four water body types were sampled in a small-scale catchment of 50 km2 in 2015/2016: tile drainage water, stream water, shallow groundwater, and drinking water of private wells. The TP were omnipresent in every type of water body, more frequently and in concentrations up to 10 times higher than their parent compounds. Especially metazachlor sulfonic acid, metazachlor oxalic acid, and flufenacet oxalic acid were detected in almost every drainage and stream sample. The transformation process leads to more mobile and more persistent molecules resulting in higher detection frequencies and concentrations, which can even occur a year or more after the application of the parent compound. The vulnerability of shallow groundwater and private drinking water wells to leaching compounds is proved by numerous positives of metazachlor-TP with maximum concentrations of 0.7 μg L-1 (drinking water) and 20 μg L-1 (shallow groundwater) of metazachlor sulfonic acid. Rainfall events during the application period cause high discharge of the parent compound and lower release of TP. Later rainfall events lead to high displacement of TP. For an integrated risk assessment of water bodies, the environmental behavior of pesticide-TP has to be included into regular state-of-the-art water quality monitoring.

Using zebrafish embryo bioassays combined with high-resolution mass spectrometry screening to assess ecotoxicological water bodies quality status: A case study in Panama rivers

Several studies show that many water bodies in developing countries are increasingly affected by anthropogenic pressure, such as agricultural activities, domestic and industrial wastewater. However, data is scarce in several of such countries, including Panama. Thus, in this work, the ecotoxicological status of selected rivers in Panama with distinct input sources were evaluated using the zebrafish (Danio rerio) embryo bioassays combined with a liquid chromatography-high resolution mass spectrometry screening of contaminants of emerging concern (CECs), using a library of over 3200 chemicals. A total of 68 CECs, including pharmaceuticals and metabolites, pesticides and several industrial chemicals, could be tentatively identified. Additionally, the zebrafish embryo bioassays showed a significant increase (p < 0.05) in embryo mortality/abnormalities when incubated with water samples from two rivers, Matasnillo and Curundú (47.5% and 32%, respectively). Importantly, a positive correlation between ecotoxicological endpoints and some of the detected CECs was observed. The findings demonstrate that both rivers are under strong anthropogenic pressure, and therefore, management actions are urgently needed to decrease their level of contamination. Overall, this study further supports the use of the zebrafish embryo bioassay as a fast, high throughput approach for screening the toxicity of water samples, and highlights the advantages of combining ecotoxicological assays with high-resolution mass spectrometry to an expedite assessment of the ecotoxicological status of water bodies.

Sorption Properties of Specific Polymeric Microspheres towards Desethyl-Terbuthylazine and 2-Hydroxy-Terbuthylazine: Batch and Column Studies

This work investigates the sorption properties of poly(divinylbenzene) modified in the Diels-Alder reaction towards persistent and mobile metabolites of terbuthylazine. The batch experiments were carried out to examine the efficiency of desethyl-terbuthylazine and 2-hydroxy-terbuthylazine adsorption on the specific adsorbent and the impact of different factors on the adsorption process. Results fit well to a pseudo-second order kinetic model. It was confirmed that hydrogen bonds play an important role in the studied systems. Five times greater sorption of 2-hydroxy-terbuthylazine than desethyl-terbuthylazine was observed. The molecular structures of both metabolites exhibit complementarity to the arrangement of functional groups in the polymer but the differences in the physicochemical properties of the desethyl derivative make it a highly mobile compound with higher affinity to the aqueous phase. The equilibrium data in the batch study fit the Freundlich isotherm for 2-hydroxy-terbuthylazine, and for desethyl-terbuthylazine the Temkin and Dubinin-Radushkevich models were better. The adsorption capacities obtained under dynamic conditions were comparable with batch results. For column adsorption modeling the Bohart-Adams, Wolborska, Thomas and Yoon-Nelson models were used. The proposed microspheres can be reused easily with no significant decrease in adsorption capacity by using ethanol as eluent in the desorption.

Effects of Prometryn Exposure Scenarios on Microcystis aeruginosa Growth and Water Qualities in Incubator Experiments

Although multiple herbicide exposures are more prospective to occur in water, many previous studies were carried out as single herbicide exposure. To investigate the toxic effect of prometryn on cyanobacteria and water qualities, single and double prometryn exposures (at different growth phases) on Microcystis aeruginosa growth and concentrations of nutrients were compared after a 44-day experiment. Results indicated that under single exposure, maximum inhibition rates were 4.7–12.0% higher than those under double exposures. Correspondingly, the maximum Microcystis aeruginosa densities and growth rates under single exposure were 10.3–21.1% and 19.5–37.7% lower than those under double exposures (p < 0.05), respectively. These findings revealed that repeated prometryn exposures resulted in a reduction in biological effects, because the time of application and the concentration injected during the first application were both significant factors in the biological effects of prometryn. Prometryn exposure scenarios did not have a significant effect on nutrient or nutrient consumption concentrations (p > 0.05). In general, the pattern of nutrient limitation showed a shift from phosphorus to nitrogen limitation. The quantified relationships between Microcystis aeruginosa growth rates and consumed nutrients were studied. Based on the above findings, we believe that a high-dose and single prometryn exposure is a more effective exposure pattern for limiting cyanobacteria growth.

Risk assessment and the adsorptive removal of some pesticides from synthetic wastewater: a review

Background

The need for environmental protection and remediation processes has been an increasing global concern. Pesticides are used as biological agents, disinfectants, antimicrobials, and also in a mixture of some chemical substances. Their modes of application are through selective dispensing and attenuation processes which act upon any pest that compete with the production, processing, and storage of foods and also in agricultural commodes. The pests might comprise weeds, insects, birds, fish, and microbes.

Main body

Pesticides are commonly found in water surface, landfill leachate, ground water, and wastewater as pollutant. An overview of recently studied adsorption processes for the pesticide elimination from polluted water has been reported in this study utilizing activated carbon, clay materials, biomass materials, metal organic frame work, graphene, and carbon-based materials as well as agricultural wastes as adsorbents. The risk assessment and cost analysis of adsorbents were also provided.

Conclusion

Evidences from literature recommend modified adsorbent and composite materials to have a prospective use in pesticide removal from wastewater. The adsorption data obtained fitted into different isotherm and kinetic models and also the thermodynamic aspect have been discussed.

Graphical abstract

An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 1: new molecules, metabolism, fate, and transport

With the exponential number of published data on neonicotinoids and fipronil during the last decade, an updated review of literature has been conducted in three parts. The present part focuses on gaps of knowledge that have been addressed after publication of the Worldwide Integrated Assessment (WIA) on systemic insecticides in 2015. More specifically, new data on the mode of action and metabolism of neonicotinoids and fipronil, and their toxicity to invertebrates and vertebrates, were obtained. We included the newly detected synergistic effects and/or interactions of these systemic insecticides with other insecticides, fungicides, herbicides, adjuvants, honeybee viruses, and parasites of honeybees. New studies have also investigated the contamination of all environmental compartments (air and dust, soil, water, sediments, and plants) as well as bees and apicultural products, food and beverages, and the exposure of invertebrates and vertebrates to such contaminants. Finally, we review new publications on remediation of neonicotinoids and fipronil, especially in water systems. Conclusions of the previous WIA in 2015 are reinforced; neonicotinoids and fipronil represent a major threat worldwide for biodiversity, ecosystems, and all the services the latter provide.

Analysis of the biochemical and histopathological impact of a mild dose of commercial malathion on Channa punctatus (Bloch) fish

The intensive application of pesticides without proper disposal management has led their excess residues to reach the neighbouring aquatic ecosystem and its inhabitants mainly fish. In natural water body pesticides get diluted, and therefore to study the silent toxic effect, a low dose of malathion (0.4 mg/L; 1/20th of 96-h LC50 value) for the different duration (1, 4, 8, 12 days) was evaluated through biochemical and histopathological biomarkers of the blood and hepatorenal tissues of Channa punctatus. With the increase in pesticide exposure periods, the biometric indices: Condition Factor (K), HSI and KSI and hepatorenal tissues weight decreased. Among the biochemical alterations in malathion exposed fish, serum glucose levels reduced by 72.23 % while protein amounts increased by 29.03 % in 12 days malathion exposed fish. Other parameters, viz., cholesterol, albumin, and phosphorous, remained the same as control fish after malathion exposure. Though serum bilirubin (total and direct) followed a biphasic response, it reduced by 60 % after 12 days of malathion exposure compared to control. Biochemical changes are reflecting the induction of compensatory energy mechanism to cope up with the malathion stress. The transaminases and ALP biomarker enzymes used for liver functionality test declined in the order of AST > ALP > ALT in a time-dependent manner in malathion exposed fish serum, indicating liver injuries in fish due to malathion. The elevated levels of urea, BUN, creatinine, and Ca2+ in the serum of 12 days of malathion exposed fish revealed renal dysfunction. In the treated fish, antioxidative (SOD and CAT) and LPO activities were significantly higher in the liver followed by the kidney than their controls. Further, histological examination registered progressive damages in the hepatorenal tissues of malathion exposed fish with the increased exposure periods compared to control. Thus, even a small dose of malathion in water could severely deteriorate the structure and function of tissue on its prolonged exposure, and therefore utmost care should be taken to prevent their seepage into the water bodies.

Investigative monitoring of pesticide and nitrogen pollution sources in a complex multi-stressed catchment: The lower Llobregat River basin case study (Barcelona, Spain)

The management of the anthropogenic water cycle must ensure the preservation of the quality and quantity of water resources and their careful allocation to the different uses. Protection of water resources requires the control of pollution sources that may deteriorate them. This is a challenging task in multi-stressed catchments. This work presents an approach that combines pesticide occurrence patterns and stable isotope analyses of nitrogen (δ¹⁵N-NO₃^-, δ¹⁵N-NH₄⁺), oxygen (δ¹⁸O-NO₃^-), and boron (δ¹¹B) to discriminate the origin of pesticides and nitrogen-pollution to tackle this challenge. The approach has been applied to a Mediterranean sub-catchment subject to a variety of natural and anthropogenic pressures. Combining the results from both analytical approaches in selected locations of the basin, the urban/industrial activity was identified as the main pressure on the quality of the surface water resources, and to a large extent also on the groundwater resources, although agriculture may play also an important role, mainly in terms of nitrate and ammonium pollution. Total pesticide concentrations in surface waters were one order of magnitude higher than in groundwaters and believed to originate mainly from soil and/or sediments desorption processes and urban and industrial use, as they were mainly associated with treated wastewaters. These findings were supported by the stable isotope results that pointed to an organic origin of nitrate in surface waters and most groundwater samples. Ammonium pollution observed in some aquifer locations is probably generated by nitrate reduction. Overall, no significant attenuation processes could be inferred for nitrate pollution. The approach presented here exemplifies the investigative monitoring envisioned in the Water Framework Directive.

Assessing Diazinon Pollution in the Three Major Rivers Flowing into the Caspian Sea (Iran)

The aim of this study was to investigate the seasonal and spatial variations in the concentrations of a widely used organophosphorous pesticide (OPP), diazinon, and the associated risk posed by this OPP in the surface water from the three largest rivers located in the northern province of Iran: the Haraz, the Talar and the Babolrood rivers. These rivers are located in the agriculture province of Mazandaran, and are exposed to high doses of organophosphorus pesticides, especially diazinon. The concentration of diazinon was determined using gas chromatography, while the potential risk posed by diazinon was elucidated using a Risk Quotient (RQ) calculated for general (RQm) and worst-case (RQex) scenarios. The obtained results demonstrated that the average diazinon concentrations ranged from 41 ± 76 ng/L in the Talar River and 57 ± 116 ng/L in the Haraz River, to 76.5 ± 145 ng/L in the Babolrood River, with a significant difference noted between summer and autumn seasons for all three rivers. For some stations, the concentration of diazinon is higher than the standard guidelines of Australian/New Zealand Guidelines for Fresh and Marine Water Quality (FMWQ) and the United States Criteria Maximum Concentration (CMC). The calculated RQs indicated a medium risk of diazinon, RQm = 0.73 and RQex = 2.27, in the Talar River; RQm = 1.02 and RQex = 2.49 in the Haraz River; and RQm = 1.35 and RQex = 4.54 in the Babolrood River. The overall exposure of diazinon was defined to have a high risk (RQm and RQex > 1); however, the summer sampling revealed a high risk (RQm and RQex > 1), while the autumn had a medium risk (RQm and RQex < 1). The obtained results revealed not only elevated concentrations of diazinon in the studied rivers but most importantly the high risk posed by this OPP for the aquatic organisms and the wellbeing of the whole river ecosystem. The current study showed that development and implementation of appropriate standards and regulations toward diazinon in countries such as Iran are required to reduce the pollution levels and risks related to elevated concentrations of the studied pesticide.

Environmental risk assessment of priority biocidal substances on Polish surface water sample

The EU directive 2013/39/EU has incorporated four biocidal compounds as priority substances: diuron, isoproturon, cybutryne, and terbutryn. The research was undertaken to determine the concentration of biocides in surface waters in three locations in southern Poland: the Wisła River in Kraków, the Wisłoka River in Mielec, and the drainage ditch draining water from arable fields located near Mielec. Environmental samples were taken in two series: winter (February) and spring (May and June). The analyses were carried out using gas chromatography with mass spectrometry. The seasonality of biocides in surface waters was observed. In winter samples, the concentrations were below MQL, while in spring, they ranged from a few to several dozen nanograms per liter. The highest concentrations of all analyzed compounds were recorded in water taken from the Wisła River. According to directive 2013/39/EU, the maximum allowable concentration was exceeded only in the case of cybutryne in water from the Wisła, both in May and in June. The assessment of the toxicity with the tested compounds was defined based on the Environmental Risk Assessment method. Low risk was estimated for diuron and isoproturon, while moderate risk for terbutryn and cybutryne.

Evaluation of physiological and biochemical effects of two Sophora alopecuroides alkaloids on pea aphids Acyrthosiphon pisum

BACKGROUND

Sophora alopecuroides alkaloids are the main constituents for the broad bioactivities on insect pests, especially on aphids. However, the aphicidal mode of action of S. alopecuroides alkaloids remains unclear. To clarify the aphicidal action, avermectin was selected as a positive control, and matrine, sophocarpine were chosen as the representative alkaloids to determine the physiological and biochemical effects on pea aphids (Acyrthosiphon pisum).

RESULTS

The aphids treated by matrine and sophocarpine developed the intoxication symptoms of convulsions, paralysis, and death. However, avermectin showed no convulsions. Moreover, the two alkaloids had a significant inducing effect on glutamic acid decarboxylase, and the specific enzyme activity was 1.14-1.22 times of the control group. In the meanwhile, both matrine and sophocarpine possessed a dose-response and time-response inhibitory effect on alanine aminotransferase in vivo and in vitro. Furthermore, the glutamate content in pea aphids treated with the two alkaloids increased significantly with time, which was about 1.5-2.0 times that of the control group. Similarly, the GABA content elevated significantly, with an increase of 1.0-1.3 times. In addition, all the treatments, except avermectin, presented inhibitory effects on Na+ , K+ -ATPase, Ca2+ and Mg2+ -ATPase, with dose-response and time-response effect. However, the three treatments had no significant effect on acetylcholinesterase and acetylcholine content.

CONCLUSION

The toxicological action of matrine and sophocarpine is related to the regulation on glutamate and γ-aminobutyric acid systems and has certain similarities to that of avermectin. These findings would provide a basis for further mechanism elucidation. © 2020 Society of Chemical Industry.

Sublethal effects of carbendazim in Jenynsia multidentata detected by a battery of molecular, biochemical and genetic biomarkers

The fungicide carbendazim (CBM) has been applied all around the world but its potential adverse effects other than its recognized activity as endocrine disruptor in non target organisms have been scarcely studied. The aims of this work were (1) to use a battery of biomarkers that can reflect potential negative effects such as oxidative stress, genotoxicity, neurotoxicity or altered immune response; and (2) to examine biomarkers of detoxification by analyzing the gene expression of cytochrome P4501A1 (CYP1A1) and the multi-xenobiotic resistance protein P-glycoprotein (P-gp) in the freshwater fish Jenynsia multidentata exposed to environmentally relevant concentrations of CBM during 24 h. Fish exposed to 5 μg/L showed inhibition of GST activity and an increase of TBARs contents in gills, the organ of direct contact with waterborne contaminants. Genotoxicity - measured in peripheral blood-was evidenced by the increases of micronuclei frequency when fish were exposed to 5, 10 and 100 μg/L CBM and of nuclear abnormalities (NA) frequency at 0.05, 0.5, 5, 10 and 100 μg/L CBM. The expression inhibition of interleukin (IL-1β) and tumor necrosis factor a (TNF-α) at 10, and 5 and 10 μg/L CBM, respectively, indicated an altered immune response. The expression of CYP1A1 was down regulated in liver at 10 μg/L and of P-gp at 5 μg/L CBM, indicating a possible slow on CBM metabolization. On the other hand, in gills CYP1A1 decreased at 5 and 10 μg/L while P-gp was induced at 5 and 100 μg/L CBM. Overall, most of these significant effects were detected below 10 μg/L CBM, in a range of realistic concentrations in aquatic ecosystems worldwide.

Improved fully automated method for the determination of medium to highly polar pesticides in surface and groundwater and application in two distinct agriculture-impacted areas

Water is an essential resource for all living organisms. The continuous and increasing use of pesticides in agricultural and urban activities results in the pollution of water resources and represents an environmental risk. To control and reduce pesticide pollution, reliable multi-residue methods for the detection of these compounds in water are needed. In this context, the present work aimed at providing an analytical method for the simultaneous determination of trace levels of 51 target pesticides in water and applying it to the investigation of the target pesticides in two agriculture-impacted areas of interest. The method developed, based on an isotopic dilution approach and on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry, is fast, simple, and to a large extent automated, and allows the analysis of most of the target compounds in compliance with European regulations. Application of the method to the analysis of selected water samples collected at the lowest stretches of the two largest river basins of Catalonia (NE Spain), Llobregat and Ter, revealed the presence of a wide suite of pesticides in the Llobregat basin, some of them at concentrations above the water quality standards (irgarol and dichlorvos) or the acceptable method detection limits (methiocarb, imidacloprid, and thiacloprid), and much cleaner waters in the Ter River basin. Risk assessment of the pesticide concentrations measured in the Llobregat River indicated high risk due to the presence of irgarol, dichlorvos, methiocarb, azinphos ethyl, imidacloprid, and diflufenican (hazard quotient (HQ) values>10), and moderate potential risk in the Ter River, associated to the occurrence of bentazone and irgarol (HQ > 1).

Sub-chronic carbendazim exposure induces hepatic glycolipid metabolism disorder accompanied by gut microbiota dysbiosis in adult zebrafish (Daino rerio)

Carbendazim (CBZ) as a broad spectrum fungicide is widely used in the whole world to contorl plant diseases. With the application of CBZ in the agriculture, it has been detected in vegetables and fruits. Nowadays, it even has been detected in the watercourse and indoor dust. However, the toxic effects of CBZ on aquatic organisms have received limited attention. In this study, male adult zebrafish were exposed at 0, 30 and 100 μg/L CBZ for 21 days to assess its effects on hepatic glycolipid metabolism. After exposure, the body weight and length decreased, but the condition factor increased significantly. Some hepatic biochemical parameters including the levels of glucose, pyruvate, low density lipoprotein (LDL) and triglyceride (TG) decreased significantly in the liver of zebrafish after exposure with CBZ. Two transaminases alanine transaminase (ALT) and aspartate transaminase (AST) also increased significantly, indicating that subchronic CBZ exposure influenced the liver function. Moreover, the relative mRNA levels of some key genes related to the glycolysis and lipid metabolism in the liver also changed significantly. Furthermore, the transcriptome analysis showed that the carbon metabolism, lipid metabolism and detoxification metabolism were also affected in the liver of CBZ exposed zebrafish. Interestingly, we also found the amounts of the Firmicutes, Bacteroidetes, Actinobacteria, α-Proteobacteria, γ-Proteobacteria and Verrucomicrobia at phylum level significantly decreased in the gut. Sequencing V3-V4 region of 16S rRNA also demonstrated gut microbiota composition changed significantly according to weighted UniFrac distance analysis. Consequently, subchronic CBZ exposure induced hepatic metabolic disorder accompanied by gut microbiota dysbiosis in adult male zebrafish.