Owing to the production and use of chemicals in chemical industry parks (CIPs), these areas are considered to be highly polluted. However, the type of pollutants presents in the wastewater from CIPs and the risk posed to the environment due to the release of these pollutants remains unclear. In this study, suspect screening was combined with traceability analysis to determine the type of pollutants present in wastewaters at 9 chemical enterprises and wastewater treatment plants (WWTPs) in the CIPs. Additionally, the distribution of nine pollutants from the WWTPs’ effluent stage and the risk they posed to the surrounding river was examined through target analysis. Upon conducting suspect analysis, the presence of 65 and 64 chemicals in the 9 chemical enterprises’ wastewaters and WWTPs, respectively, was tentatively identified. Traceability analysis of the compounds screened in the effluent from the WWTPs determined that 41 substances were identified as characteristic pollutants of the chemical enterprises, indicating that the suspect screening strategy enabled relatively more efficient identification of the characteristic pollutants compared to traditional quantitative analysis. Targeting analysis combined with ecological risk assessment showed that metolachlor, carbendazim, atrazine, diuron, and chlorpyrifos posed relatively higher risks to aquatic organisms in the surrounding river. Therefore, the refined management of the wastewater treatment plant in the CIPs is necessary.

Fungicides, usually refer to the chemical agents that can effectively control or kill the pathogenic microorganisms. Here, we revealed the effects of three different fungicides, imazalil (IMZ), chlorothalonil (CTL) and carbendazim (CBZ), which are typical broad-spectrum fungicides that are detected at high levels in the natural environment, on heterogeneous human epithelial colorectal cells (Caco-2 cells). All three fungicides had the potential to induce different degrees of toxicity, cause apoptosis, reactive oxygen species (ROS) and even change the cell cycle in the cells. The half maximal inhibitory concentration (IC50) of CTL is the lowest among these three fungicides, suggesting that it may have the highest exposure risk, followed by IMZ, and CBZ. The results of the real-time PCR, Western blotting, and mitochondrial membrane potential (MMP) assays and the activities of key enzymes suggested that CTL induced apoptosis in Caco-2 cells via a mitochondrial-dependent pathway, as indicated by the upregulation of the expression of the apoptotic p53 and bax genes, the increase of the apoptosis marker cytochrome-c, the decrease of mRNA level of bcl-2 gene, and the decrease in the MMP. Exposure to two other fungicides also upregulated the transcriptional level of bax and the expression of cytochrome-c, but the mRNA level of bcl-2 was increased (IMZ) or unchanged (CBZ), suggesting that other pathways may be involved in the induction of cellular apoptosis by these two fungicides. In addition, all three of the fungicides could induce oxidative stress in Caco-2 cells. Our data showed that the three different kinds of fungicides all caused toxic effects in Caco-2 cells through various pathways.

The quality of groundwater (GW) resources is decreasing partly due to chemical contaminations from a wide range of activities, such as industrial and agricultural enterprises and changes in land-use. In urban areas, one potential major pathway of GW contamination is associated with urban water management practices based on stormwater runoff infiltration systems (SIS). Data on the performance of the upper layer of soil and the unsaturated zone of infiltration basins to limit the contamination of GW by hydrophilic compounds are lacking. With this aim, the impact of infiltration practices on GW contamination was assessed for 12 pesticides and 4 pharmaceuticals selected according to their ecotoxicological relevance and their likelihood of being present in urban stormwater and GW. For this purpose, 3 campaigns were conducted at 4 SIS during storm events. For each campaign, passive samplers based on the use of Empore™ disk were deployed in GW wells upstream and downstream of SIS, as well as in the stormwater runoff entering the infiltration basins. Upstream and downstream GW contaminations were compared to evaluate the potential effect of SIS on GW contamination and possible relationships with stormwater runoff composition were examined. Our results showed two interesting opposite trends: (i) carbendazim, diuron, fluopyram, imidacloprid and lamotrigine had concentrations significantly increasing in GW impacted by infiltration, indicating a contribution of SIS to GW contamination, (ii) atrazine, simazine and 2 transformation products exhibited concentrations significantly decreasing with infiltration due to a probable dilution of historic GW contaminants with infiltrated stormwater runoff. The other 7 contaminants showed no general trend. This study demonstrates that passive samplers deployed in GW wells enabled the capture of emerging polar pollutants present at very low concentrations and allowed the assessment of infiltration practices on GW quality. New data on GW and urban stormwater are provided for poorly studied hazardous compounds.

Pesticides are used worldwide with potential harmful effects on both fauna and flora. The Kibale National Park in Uganda, a site renowned for its biodiversity is surrounded by tea, banana and eucalyptus plantations as well as maize fields and small farms. We previously showed presence of pesticides with potential endocrine disruptive effects in the vicinity. To further investigate the water pollution linked to agricultural pressure in this protected area, we implemented a complementary monitoring strategy based on: analytical chemistry, effects based methods and the deployment of Polar Organic Chemical Integrative Samplers (POCIS). Chemical analysis of the POCIS extracts revealed the presence of 13 pesticides: carbofuran, DEET, 2.4-D amine, carbaryl, ametryn, isoproturon, metolachlor, terbutryn, dimethoate, imidacloprid, picaridin, thiamethoxam, carbendazim, with the first three being present in the largest quantities. Water samples collected at the POCIS sampling sites exhibited thyroid and estrogen axis disrupting activities in vivo, in addition to developmental and behaviour effects on Xenopus laevis tadpoles model. Based on our observations, for the health of local human and wildlife populations, further monitoring as well as actions to reduce agrochemical use should be considered in the Kibale National Park and in regions exposed to similar conditions.

In this study, avoidance response of Enchytraeus albidus to LUFA 2.2 soil contaminated with pesticide carbendazim was investigated. The aim was to clarify minimal test duration and temporal changes in avoidance response due to contamination ageing. Firstly, the concentration causing 50% avoidance (EC50) was determined as 7.6 mg/kg. Then, test duration needed to reach this value (ET50 = approximately 18 h) was identified. Finally, the capability of E. albidus avoidance test to reflect the changes of pollutant bioavailability was tested. The soil was spiked with carbendazim at the EC50 concentration 1, 14, or 28 days before the test started and avoidance effects of fresh versus aged contamination were compared. The results indicated that enchytraeids preferred soil contaminated for 28 days prior to assay where carbendazim was probably less bioavailable than in freshly spiked soil. Our results open an interesting research area of potential use of avoidance tests for contaminant bioavailability assessment.

Climate impacts of elevated temperatures and more severe and frequent weather extremes like heatwaves are globally becoming discernible on nature. While a mechanistic understanding is pivotal for ecosystem management, stressors like pesticides may interact with warming, leading to unpredictable effects on freshwater ecosystems. These multiple stressor studies are scarce and experimental designs often lack environmental realism. To investigate the multiple stressor effects, we conducted a microcosm experiment for 48 days comprising benthic macroinvertebrates, zooplankton, phytoplankton, macrophytes, and microbes. The fungicide carbendazim (100 μg/L) was investigated combined with temperature scenarios representing elevated temperatures (+4 °C) or heatwaves (+0 to +8 °C), both applied with similar energy input on a daily fluctuating ambient temperature (18 °C ± 1.5 °C), which served as control. Measurements showed the highest carbendazim dissipation in water under heatwaves followed by elevated and ambient temperatures. Average carbendazim concentrations were about 50% in water and 16% in sediment of the nominal concentration. In both heated cosms, zooplankton community dynamics revealed an unexpected shift from Rotifera to Cladocera and Copepoda nauplii, indicating variations in their thermal sensitivity, tolerance and resilience. Notably, warming and heatwaves shaped community responses similarly, suggesting heat intensity rather than distribution patterns determined the community structure. Heatwaves led to significant early and longer-lasting adverse effects that were exacerbated over time with Cladocera and Copepoda being most sensitive likely due to significant carbendazim interactions. Finally, a structural equation model demonstrated significant relationships between zooplankton and macrophytes and significantly negative carbendazim effects on zooplankton, whereas positive on macroinvertebrate abundances. The relationship between macroinvertebrate feeding and abundance was masked by significantly temperature-affected microbial leaf litter decomposition. Despite the thermal tolerance of zooplankton communities, our study highlights an increased pesticide threat under temperature extremes. More intense heatwaves are thus likely to cause significant alterations in community assemblages which will adversely affect ecosystem's processes and functions.

Polyethylene (PE) and polypropylene (PP) microplastics (MPs), as carriers, can bind with pesticides, which propose harmful impacts to aqueous ecosystems. Meanwhile, carbofuran and carbendazim (CBD), two widely used carbamate pesticides, are toxic to humans because of the inhibition of acetylcholinesterase activity. The interaction between two MPs and two pesticides could start in farmland and be maintained during transportation to the ocean. Herein, the adsorption behavior and mechanism of carbofuran and carbendazim (CBD) by PE and PP MPs were investigated via characterization and density functional theory (DFT) simulation. The adsorption kinetic and thermodynamic data were best described by pseudo-second-order kinetics and the Freundlich models. The adsorption behaviors of individual carbofuran/CBD on both MPs were very similar. The CBD adsorption rate and capacity of PE and PP MPs were higher than those of carbofuran. This phenomenon explained the lower negative effects of DOM (oxalic acid, glycine (Gly)) on CBD adsorption relative to those of carbofuran. The presence of oxalic acid and Gly decreased the PE adsorption by 20.40–48.02% and the PP adsorption by 19.27–42.11%, respectively. It indicated the significance of DOM in carbofuran cycling. The adsorption capacities were negatively correlated with MPs size, indicating the importance of specific surficial area. Fourier transformation infrared spectroscopy before and after adsorption suggested that the adsorption process did not produce any new covalent bond. Instead, intermolecular van der Waals forces were one of the primary adsorption mechanisms of carbofuran and CBD by MPs, as evidenced by DFT calculations. Based on the zeta potential, the electrostatic interaction explained the higher adsorption CBD by MPs than carbofuran.

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.

This study investigated the occurrence and distribution of pesticides in surface water (lakes, major rivers and tributaries) and potential discharge sources (fish ponds, livestock and poultry farms, and sewage treatment plants) in Wujin District (northwest of Taihu Lake), Jiangsu province, China. An analytical liquid chromatography-tandem mass spectrometry method was developed for 38 pesticides, which was applied in the monitoring of 240 surface water samples and 76 potential discharge source samples. Eleven insecticides and five fungicides with temporal and spatial variation were detected in surface water. The total pesticide concentrations in surface water in different seasons were as follows: March > August > June > November. The two most polluting and widespread pesticides were carbendazim (maximum concentration 508 ng L⁻¹, detection rate 100%) and imidacloprid (maximum concentration 438 ng L⁻¹, detection rate 88%). Gehu Lake (S46) and Sanshangang River (S12) were seriously polluted water bodies. Seven insecticides and four fungicides were detected in the potential discharge sources; and their composition changed significantly with the seasons. The concentrations of detected organophosphorus pesticides and neonicotinoids (e.g. acetamiprid in March and dichlorvos in November) in a few non-agricultural planting sources were far greater than those detected in surface water, and hence a few fish ponds, livestock and poultry farms, and sewage treatment plants might be the potential discharge sources of pesticides in the surrounding surface water. The estimated input flux of the studied pesticides from upstream rivers to Taihu Lake was 141.95 kg a⁻¹. Furthermore, more attention should be paid to the medium or high aquatic ecotoxicological risk presented by the levels of organophosphorus pesticides, carbamates, and benzimidazoles.

Melatonin (Mel) serves as an important signalling molecule in various aspects of stress tolerance in plants. However, the function of Mel in pesticide metabolism remains unknown. Here, selecting the widely used fungicide carbendazim (MBC) as the model, we found that exogenous Mel had the ability to alleviate pesticide phytotoxicity and residues in tomato as well as in some other vegetables. Additionally, overexpression of the Mel biosynthetic gene caffeic acid O-methyltransferase 1 (COMT1) significantly enhanced the capacity of the tomato to reduce MBC phytotoxicity and residue. This outcome was mainly because of the Mel-induced antioxidant capability, as well as the key detoxification process. Indeed, levels of reactive oxygen species (ROS) and lipid peroxides significantly decreased after applying exogenous Mel or overexpressing COMT1, which resulted from direct ROS scavenging, and increased Mel levels significantly enhanced antioxidant enzymatic activity. More importantly, Mel activated the ascorbate-glutathione cycle to participate in glutathione S-transferase-mediated pesticide detoxification. A grafting experiment showed that rootstocks from COMT1 transgenic plants increased the Mel accumulation of wild-type scions, resulting in MBC metabolism in the scions. To our knowledge, this is the first report providing evidence of Mel-induced pesticide metabolism, which provides a novel approach for minimizing pesticide residues in crops by exploiting plant self-detoxification mechanisms.