Diffusion of organochlorine (OCPs) and cypermethrin pesticides from rohu (Labeo rohita) internal organs to edible tissues during ice storage: a threat to human health.

The migration of organochlorine pesticides (OCPs) and cypermethrin residues from internal organs to edible tissues of ice-held Labeo rohita (rohu) was investigated in this study. The liver (246 µg/kg) had the highest level of ∑OCP residues, followed by the gills (226 µg/kg), intestine (167 µg/kg), and muscle tissue (54 µg/kg). The predominant OCPs in the liver and gut were endosulfan (53-66 µg/kg), endrin (45-53 µg/kg), and dichloro-diphenyl-trichloroethane (DDT; 26-35 µg/kg). The ∑OCP residues in muscle increased to 152 µg/kg when the entire rohu was stored in ice, but they decreased to 129 µg/kg in gill tissues. On days 5 and 9, the total OCPs in the liver increased to 317 µg/kg and 933 µg/kg, respectively. Beyond day 5 of storage, total internal organ disintegration had led to an abnormal increase in OCP residues of liver-like mass. Despite a threefold increase in overall OCP residues by day 9, accumulation of benzene hexachloride (BHC) and heptachlor was sixfold, endrin and DDT were fourfold, aldrin was threefold, and endosulfan and cypermethrin were both twofold. Endosulfan, DDT, endrin, and heptachlor were similarly lost in the gills at a rate of 40%, while aldrin and BHC were also lost at 60 and 30%, respectively. The accumulation of OCP residues in tissues has been attributed to particular types of fatty acid derivatives. The study concluded that while pesticide diffusion to edible tissues can occur during ice storage, the levels observed were well below the allowable limit for endosulfan, endrin, and DDT.

Bioaccumulation of pesticide residue in earthworms collected from the agricultural soils of Kuttanad-a unique agroecosystem in India.

Earthworms encompass significant soil faunal biomass and have tremendous potential to provide vital ecosystem services. Earthworms are considered bioindicators of chemical contaminants and can provide early warnings of ecosystem deterioration. Studies pertaining to the accumulation of pesticide residues in earthworm in biomass in agrarian ecosystems are scarce. The Kuttanad agroecosystem (KAE), situated on the southwest coast of India, is one of the few regions globally supporting farming on land below the mean sea level. This investigation was conducted to assess the bioaccumulation of pesticide residues in earthworms from the KAE. The earthworms species Glyphidrilus annandalei collected from agricultural soils of the study area were analyzed for the presence of pesticides residues such as α-BHC, γ-BHC, atrazine, heptachlor, α-chlordane, γ-chlordane, 4,4-DDE, 4,4-DDD, 4,4-DDT, ß-endosulfan, and endrin ketone in their biomass. Analysis of the earthworm samples using a gas chromatograph revealed the presence of ten pesticide residues with notable concentrations (α-BHC, 0.36 ng/g; γ-BHC, 0.41 ng/g; heptachlor, 0.10 ng/g; atrazine, 0.89 ng/g; α-chlordane, 0.07 ng/g; γ-chlordane, 0.10 ng/g; 4,4-DDE, 0.05 ng/g; 4,4-DDD, 0.11 ng/g; 4,4-DDT, 0.31 ng/g; ß-endosulfan, 0.19 ng/g; and endrin ketone, 0.13 ng/g). Six groups of pesticide residues are ΣBHC, ΣDDT, atrazine, Σchlordane, endrin ketone, and ß-endosulfan were observed during bioaccumulation factor analysis, and the results show the following trend: atrazine > ΣBHC > ΣDDT > Σchlordane > Σendosulfan > Σendrin. As earthworms are a crucial component of this region's food chains, bioaccumulation of pesticide residues in earthworms can pause adverse consequences. Increasing trends in pesticide application in the KAE and bioaccumulation of pesticide residues in earthworm biomass can affect the entire food web.

Development and Validation of a Gas Chromatography-Mass Spectrometry Method for Determining Acaricides in Bee Pollen.

Pesticides can be found in beehives for several reasons, including contamination from surrounding crops or for their use by beekeepers, which poses a risk to bee ecosystems and consumers. Therefore, efficient and sensitive methods are needed for determining pesticide residues in bee products. In this study, a new analytical method has been developed and validated to determine seven acaricides (atrazine, chlorpyrifos, chlorfenvinphos, α-endosulfan, bromopropylate, coumaphos, and τ-fluvalinate) in bee pollen using gas chromatography coupled to mass spectrometry. After an optimization study, the best sample treatment was obtained when using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method employing an ethyl acetate and cyclohexane as the extractant mixture, and a mixture of salts for the clean-up step. A chromatographic analysis (<21 min) was performed in an Agilent DB-5MS column, and it was operated under programmed temperature conditions. The method was fully validated in terms of selectivity, limits of detection (0.2-3.1 µg kg-1) and quantification (0.6-9.7 µg kg-1), linearity, matrix effect (<20% in all cases), trueness (recoveries between 80% and 108%), and precision. Finally, the proposed method was applied to analyze commercial bee pollen samples, and some of the target pesticides (chlorfenvinphos, α-endosulfan, coumaphos, and τ-fluvalinate) were detected.

Nationwide assessment of atmospheric organochlorine pesticides over a decade during 2008-2017 in South Korea.

Long-term nationwide atmospheric monitoring of organochlorine pesticides (OCPs) was performed in South Korea during 2008-2017. Their occurrences, seasonal and temporal variability, sources, and effect of ambient temperature were investigated. The OCPs are pronounced with a mean concentration of total OCPs ranging from 5.2 to 256 pg/Sm3. However, a decrease of 54 % was observed in the mean concentration of total OCPs from 2008 to 2017 associated with regulatory actions. OCP concentrations did not show any variations between the different site types, and OCPs were ubiquitously present at all site types. The mean concentration of total OCPs in summer was two-fold higher than in winter. The concentrations of DRINs, DDTs, ENDOs, and HCHs were significantly higher in summer, but the concentrations of chlordane and heptachlor were higher in winter. The diagnostic ratios identified major sources as ongoing sources, past use, and atmospheric transport. Clausius Clapeyron plots strongly suggested the re-emission of α-endosulfan, ß-endosulfan, α-HCH, and ß-HCH, and ΔHsa (enthalpy of surface air exchange) values suggested the influence of the transport and/or new sources on aldrin, dieldrin, and chlordane. The occurrence of OCPs due to re-emissions, ongoing sources, and long-range atmospheric transport could be a challenge towards the complete phase-out of OCPs in South Korea.

Putative interactions between transthyretin and endosulfan II and its relevance in breast cancer.

The unregulated use of organochlorine pesticides (OCPs) has been linked to spread of breast cancer (BC), but the underlying biomolecular interactions are unknown. Using a case-control study, we compared OCP blood levels and protein signatures among BC patients. Five pesticides were found in significantly higher concentrations in breast cancer patients than in healthy controls: p',p' dichloro diphenyl trichloroethane (DDT), p'p' dichloro diphenyl dichloroethane (DDD), endosulfan II, delta-hexachlorocyclohexane (dHCH), and heptachlor epoxide A (HTEA). According to the odds ratio analysis, these OCPs, which have been banned for decades, continue to raise the risk of cancer in Indian women. Proteomic analysis of plasma from estrogen receptor-positive breast cancer patients revealed 17 dysregulated proteins, but transthyretin (TTR) was three times higher than in healthy controls, which is further validated by enzyme-linked immunosorbent assays (ELISA). Molecular docking and molecular dynamics studies revealed a competitive affinity between endosulfan II and the thyroxine-binding site of TTR, pointing towards the significance of the competition between thyroxin and endosulfan, resulting in endocrine disruption leading to breast cancer. Our study sheds light on the putative role of TTR in OCP-mediated BC, but more research is needed to decipher the underlying mechanisms that can be used to prevent the carcinogenic effects of these pesticides on women's health.

Large-scale spatiotemporal variations, sources, and risk assessment of banned OCPs and PAHs in suspended particulate matter from the Negro river, Argentina.

Organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) threaten the environment due to their wide environmental resistance. Environmental paradigms coexist along the Negro River (NR) in Argentina, South America, which flows to the sea below the latitude of 40o S; however, this is the first environmental assessment of OCPs and PAHs in water of the NR for more than 15 years. With 21 sampling sites covering a range of 600 km of river extension, we assessed 16 OCPs and 16 PAHs in suspended particulate material (SPM) with regard to their levels, seasonality, sources, and potential biological risk assessment. Using gas chromatography-mass spectrometry and gas chromatography coupled with electron capture detection, we found an overall mean value for Σ16 OCPs of 648.56 ng. g-1, d.w. Despite a ban spanning 25 years, an increasing trend of accumulation of hexachlorocyclohexanes (HCHs) and endosulfan was shown in the lower valley. The ɑ-HCH/ɤ-HCH and ß-HCH/(ɑ + É¤)-HCH ratios indicated a prevalent usage of technical HCH over lindane and recent HCH inputs. The most abundant compound, α-endosulfan, averaged 141.64 ng. g-1, d.w. and DDX (Σ 4,4'-DDE, 4,4'-DDD, and 4,4'-DDT) averaged 99.98 ng. g-1, d.w. Winter OCP loads in the NR reflected the runoff of the heaviest pesticide application period. We estimated the total discharge of DDT into the Atlantic ocean was 96 g.day-1, added to 458 g of HCHs and 257 g of endosulfans (ɑ + ß + epoxide) adsorbed by the SPM. PAHs occurred widely along the river (38.83 ± 43.52 µg. g-1) and the highest levels coincided with locations with marked anthropogenic-related activity, such as petroleum/gas exploitation facilities. Risk quotient analysis showed a low risk posed by OCPs, but a high risk of potential effects on biota posed by the PAHs, highlighting the need for mitigation measures.

Organochlorines in the riverine ecosystem of Punjab province, Pakistan: contamination status, seasonal variation, source apportionment, and ecological risk assessment.

The aim of the present study was to determine the occurrence, spatio-temporal variations, source apportioning, and ecological risk assessment of selected PCBs and OCPs in surface water and sediments collected riverine environment of Punjab province, Pakistan. The concentration of ΣOCPs (water: 64-455 ng/L; sediments: 117-616 ng/g) and ΣPCBs (water: 2-132 ng/L; sediments: 3.27-200 ng/g) was found comparatively higher than the levels reported from other parts of the world. The higher concentrations of DDTs and HCHs were detected in both studied matrices, whereas among PCBs, CB-28, 49 and CB-37, 82 were dominant in water and sediments, respectively. The isomeric ratios including α-HCH/γ-HCH, (DDE + DDD) / DDTs, and α /ß-endosulfan reflected the recent use of lindane, technical DDT, and endosulfan in the study area. The WHO-TEQ values of DL-PCBs ranged from 3.6 × 10-6 to 0.115 ng/L and 8.7 × 10-6 to 0.157 ng/g in surface water and sediments in both seasons, respectively. The spatial variation analysis revealed that the sites in the industrial and agricultural zones were highly contaminated. The OCPs and PCBs fluxes to downstream areas were estimated to be 12.4 tons/year and 1.9 tons/year, respectively. The significant ecological risks were estimated to be posed by OCPs and PCBs, as their levels in 67% and 62% of surface water and sediment samples were exceeding the threshold limits, highlighting effects to ecological integrities.

Remediation of endosulfan-contaminated water by hairy roots: removal and phytometabolization assessment.

Although many countries banned the insecticide endosulfan, it is still an environmental pollutant. Plants metabolize the two diastereomers of the formulations known as technical grade endosulfan (TGE) by two phase I pathways: hydrolysis leading to less toxic derivatives and oxidation giving endosulfan sulfate which is as toxic as endosulfan itself. We assessed the removal, bioaccumulation and phase I metabolization of TGE from water matrices using hairy root clones (HRs) of three edible species, Brassica napus, Raphanus sativus and Capsicum annuum. B. napus and C. annuum HRs removed 86% of TGE from the bioreaction media in 2 and 96 h, respectively, whereas R. sativus HRs removed 91% of TGE within 6 h of biotreatment. In the experiments with B. napus, only endosulfan sulfate was detected in both biomass and medium, whereas R. sativus and C. annuum accumulated endosulfan sulfate and endosulfan alcohol. Besides, endosulfan lactone was detected in C. annuum reaction medium. Acute ichthyotoxicity assays toward Poecilia reticulata showed that media contaminated with TGE lethal levels did not produce mortality after the phytotreatments. This research highlights the feasibility of using HRs to evaluate plant enzymatic abilities toward xenobiotics and their potential for the design of ex situ decontamination processes.

Profiles and determinants of dicofol, endosulfans, mirex, and toxaphenes in breast milk samples from 10 prefectures in Japan.

Human exposure to persistent organic pollutants (POPs) is reflected by POP concentrations in breast milk. Many studies of POPs in breast milk have been performed in Japan, but insufficient information is available about some legacy POPs (e.g., mirex and toxaphenes, included in the Stockholm Convention in 2001) and novel POPs (e.g., dicofol and endosulfans, included in the Stockholm Convention in 2019 and 2011, respectively). In this study, dicofol, endosulfan, mirex, and toxaphene concentrations in breast milk from 10 prefectures in Japan were determined. The samples were collected between 2005 and 2010, before Stockholm Convention restrictions on endosulfans and mirex were implemented. Common POPs (e.g., polychlorinated biphenyls) were also analyzed to allow the contamination statuses to be compared. The α-endosulfan and ß-endosulfan concentrations were 0.26-13 and 0.012-0.82 ng/g lipid, respectively. The toxaphene #26 and #50 concentrations were <0.08-5.6 and < 0.1-8.5 ng/g lipid, respectively. The dicofol concentrations were <0.01-4.8 ng/g lipid. The mirex concentrations were <0.2-3.5 ng/g lipid. The α- and ß-endosulfan concentrations on a lipid weight basis negatively correlated with the lipid contents of the milk samples (ρ = -0.65, p < 0.01 for α-endosulfan; ρ = -0.58, p < 0.01 for ß-endosulfan). The toxaphene concentrations positively correlated with the lipid contents. The mirex concentrations positively correlated with the maternal age but negatively correlated with the maternal body mass index. No correlations between the dicofol concentrations and the factors were found. Principal component analysis divided the data into four groups, (1) chlordanes, dichlorodiphenyltrichloroethanes and related compounds, hexachlorobenzene, hexachlorocyclohexanes, hexachloroethane, and polychlorinated biphenyls, (2) endosulfans, (3) dicofol, dieldrin, and toxaphenes, and (4) bromodiphenyl ether 47. This indicated that bromodiphenyl ether 47, dicofol, endosulfans, and toxaphenes have different exposure routes or different kinetics to the other legacy POPs.

A national-scale distribution of organochlorine pesticides (OCPs) in cropland soils and major types of food crops in China: Co-occurrence and associated risks.

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) that resist degradation in the environment. OCPs remain detectable in cropland systems in China. However, spatial distribution of OCPs across China and associated ecological and health risks, as well as the relationship between levels of OCPs in cropland soils and crops, remain to be elucidated. To fill these gaps, we conducted a national-scale characterization of 19 individual OCPs in cropland soils and food crops including cereals and legumes in China, which were on-spot sampled simultaneously. Sparse canonical correlation analysis was employed to investigate the co-occurrence of OCPs in cropland soils and corresponding food crops. The ecological soil screening levels and risk quotient method were adopted for ecological and health risk assessment, respectively. Dichlorodiphenyltrichloroethanes (DDTs) were dominant in cropland systems, with its levels ranging up to 337 and 22.8 µg/kg in cropland soils and food crops, respectively. The mean ∑OCP levels in cropland soils varied from below the limit of detection to 337 µg/kg. Peanuts were the most contaminated crop, in which endosulfans and hexachlorobenzene (HCB) were co-occurrent with those in cropland soils (correlation coefficient R = 0.999 and 0.947, respectively). Besides, lindane and ß-endosulfan in rice were co-occurrent with those in cropland soils (R = 0.810 and 0.868, respectively). The componential ratio analysis indicated fresh inputs of technical DDT, lindane, chlordane, endosulfan, HCB and aldrin. Among these pesticides, ecological impacts of DDTs, lindane, aldrin and ß-endosulfan could be expected. Human health risk assessment suggested that daily consumption of the OCP-contaminated food crops raises a health concern especially for male teens. It is concluded that OCPs remain present in cropland systems in China at levels that raise a concern for both environment and human health.

Honey as a bioindicator of environmental organochlorine insecticides contamination / Mel como bioindicador de contaminação ambiental de inseticidas organoclorados

Abstract Honey is a suitable matrix for the evaluation of environmental contaminants including organochlorine insecticides. The present study was conducted to evaluate residues of fifteen organochlorine insecticides in honey samples of unifloral and multifloral origins from Dir, Pakistan. Honey samples (5 g each) were extracted with GC grade organic solvents and then subjected to Rotary Evaporator till dryness. The extracts were then mixed with n-Hexane (5 ml) and purified through Column Chromatography. Purified extracts (1μl each) were processed through Gas Chromatograph coupled with Electron Capture Detector (GC-ECD) for identification and quantification of the insecticides. Of the 15 insecticides tested, 46.7% were detected while 53.3% were not detected in the honey samples. Heptachlor was the most prevalent insecticide with a mean level of 0.0018 mg/kg detected in 80% of the samples followed by β-HCH with a mean level of 0.0016 mg/kg detected in 71.4% of the honey samples. Honey samples from Acacia modesta Wall. were 100% positive for Heptachlor with a mean level of 0.0048 mg/kg followed by β-HCH with a mean level of 0.003 mg/kg and frequency of 83.3%. Minimum levels of the tested insecticides were detected in the unifloral honey from Ziziphus jujuba Mill. Methoxychlor, Endosulfan, Endrin and metabolites of DDT were not detected in the studied honey samples. Some of the tested insecticides are banned in Pakistan but are still detected in honey samples indicating their use in the study area. The detected levels of all insecticides were below the Maximum Residue Levels (MRLs) and safe for consumers. However, the levels detected can cause mortality in insect fauna. The use of banned insecticides is one of the main factors responsible for the declining populations of important insect pollinators including honeybees.

Resumo O mel é uma matriz adequada para a avaliação de contaminantes ambientais, incluindo inseticidas organoclorados. O presente estudo foi conduzido para avaliar resíduos de 15 inseticidas organoclorados em amostras de mel de origem unifloral e multifloral de Dir, Paquistão. Amostras de mel (5 g cada) foram extraídas com solventes orgânicos de grau GC e, em seguida, submetidas ao evaporador rotativo até a secura. Os extratos foram então misturados com n-hexano (5 ml) e purificados por cromatografia em coluna. Os extratos purificados (1μl cada) foram processados através de cromatógrafo gasoso acoplado a detector de captura de elétrons (GC-ECD) para identificação e quantificação dos inseticidas. Dos 15 inseticidas testados, 46,7% foram detectados enquanto 53,3% não foram detectados nas amostras de mel. O heptacloro foi o inseticida mais prevalente com um nível médio de 0,0018 mg / kg detectado em 80% das amostras, seguido por β-HCH com um nível médio de 0,0016 mg / kg detectado em 71,4% das amostras de mel. Amostras de mel da parede de Acacia modesta foram 100% positivos para heptacloro com um nível médio de 0,0048 mg / kg seguido por β-HCH com um nível médio de 0,003 mg / kg e frequência de 83,3%. Níveis mínimos dos inseticidas testados foram detectados no mel unifloral de Ziziphus jujuba da usina. Metoxicloro, Endosulfan, Endrin e metabólitos do DDT não foram detectados nas amostras de mel estudadas. Alguns dos inseticidas testados são proibidos no Paquistão, mas ainda são detectados em amostras de mel, indicando seu uso na área de estudo. Os níveis detectados de todos os inseticidas estavam abaixo dos Níveis Máximos de Resíduos (MRLs) e seguros para os consumidores. No entanto, os níveis detectados podem causar mortalidade na fauna de insetos. O uso de inseticidas proibidos é um dos principais fatores responsáveis pelo declínio das populações de importantes insetos polinizadores, incluindo as abelhas.

Occurrence, behavior and the associated health risk of organochlorine pesticides in sediments and fish from Bahía Blanca Estuary, Argentina.

Organochlorine pesticides (OCPs) were assessed for their occurrence, behavior and the associated human health and ecological risks in four fish species (Micropogonias furnieri, Cynoscion guatucupa, Mustelus schmitti, and Ramnogaster arcuata) and sediments from the Bahía Blanca estuary, Argentina, an important coastal environment of South America. Total OCPs values ranged from 0.86 to 6.23 ng/g dry weight in sediments and from

Accumulation of organochlorine pesticide (OCP) residues in surface water and sediment from the Iznik Lake in Turkey.

This study was carried out to evaluate organochlorinated pesticide (OCPs) concentrations in the water column and sediments of Iznik Lake. Water samples and sediment were collected in different regions (six sampling sites) of the lake between January and December 2019 and tested for OCPs by gas chromatography-mass spectrometry (GC-MS). The results revealed that OCP residues throughout the sites varied depending on the anthropogenic activities of the region. OCPs detected in surface waters ranged from 0.01 to 60.80 µg/L and sediments from 0.06 to 14.21 ng/g dw. Endrin ketone, endrin aldehyde, endosulfan II, endrin, heptachlor epoxy, beta-BHC, gamma-BHC, ppDDD, and ppDDT concentrations exceeded the maximum residue limits indicated by the World Health Organization (WHO) for surface waters. Of the 18 analyzed OCP components, 17 were detected in sediment samples, and it was noted that they reached the highest concentration in summer. The presence of relatively high OCP levels according to WHO regulations in the waters of Iznik Lake, around which agricultural activities have been increasing rapidly in recent years, is a serious concern, and therefore, appropriate actions should be taken into consideration by the regulatory authorities.

Uptake of endosulfan isomers from soils by leafy vegetable lettuce: A comparative study between model-predicted and field-experimented results.

The organochlorine insecticide endosulfan has been classified as a persistent organic pollutant due to its long persistence and high toxicity, and banned in most countries. However, endosulfan residues are still detected in various environmental sites (even in non-agricultural areas) and have a likelihood to return to agricultural soils through various routes. In this study, time-dependent uptake of α- and ß-isomers of endosulfan by lettuce from soils was estimated using theoretical models which include parameters describing sorption/dissipation in soil and plants, plant transpiration, root-soil transfer, and plant growth. A chemical-specific residue (CSR) model developed in a previous study was used as a sub-model to estimate the portion of endosulfan residues in soils ready to be absorbed by lettuce, and the accuracy of the CSR model was verified by properly estimating concentrations of endosulfan isomers in soils with different organic matters; a low mean deviation (18.8 %) was observed between the modeled and measured values. Modeled results of ß-endosulfan using a soil-lettuce uptake model satisfactorily matched the experimentally measured results, with a moderate correlation (R2 > 0.79) and a low residual error (0.42) against a mean factor of -1.04. However, the uptake model showed the low potential to predict the soil-lettuce uptake of α-endosulfan (176.3 % mean deviation), probably due to not considering an intrinsic trait of ß-isomer converting to α-isomer. Although the improvement with more sophisticated parameters is needed, the plant uptake model developed in this study could be utilized to predict soil-lettuce uptake of at least ß-endosulfan and as a model template that may apply for other types of plants and contaminants.

Study on the characterization of endosulfan-degrading bacterial strains isolated from contaminated rhizospheric soil.

In the present study, we have isolated endosulfan tolerant bacterial strains from the rhizosphere of plants growing in a pesticide-contaminated area. The tolerance capacities of these strains were tested up to 50,000 µg ml-1 of endosulfan. It was found that out of nineteen, four strains (EAG-EC-12, EAG-EC-13, EAG-EC-14, and EAG-EC-15) were capable of surviving up to 50,000 µg ml-1 endosulfan concentration in the media; thus, these four strains were selected for the characterization. Among four, two strains were identified as Serratia liquefaciens, while the other two strains were Bacillus sp. and Brevibacterium halotolerans. The result shows that growth of strain Serratia liquefaciens 1 and Serratia liquefaciens 2 in treated medium was statistically similar to that of control (cfu 6.8 × 107) after 24 h, while strains Bacillus sp. and Brevibacterium halotolerans have shown growth significantly less than the control. The degradation potential of these strains was analyzed against 100 to 250 µg ml-1 of endosulfan in a Minimal Broth Medium (MBM), and it was recorded that only 9, 2, 7, and 19% of endosulfan (100 µg ml-1) remain after a 72 h incubation period of Bacillus sp., Serratia liquefaciens 1, Serratia liquefaciens 2, and Brevibacterium halotolerans, respectively. This endosulfan removal potential of studied strains was decreased with an increase in concentration of endosulfan.

Signatures of Indian endosulfan usage in China's environment.

Endosulfan, as an organochlorine pesticide (OCPs), was widely used in agriculture. As the largest endosulfan user country in the world and adjacent to China, it is interesting to know to what extent the endosulfan usage of India could affect the environment in China. In this study, we established gridded endosulfan usage, atmospheric emission, and soil residue inventories in 2010 based on its application in different crops in China and India. We employed an atmospheric transport model CanMETOP to simulate atmospheric and soil concentrations, as well as dry and wet deposition flux of α- and ß-endosulfan. Results were used to assess the signatures of Indian endosulfan usage in the China's environment. In 2010, endosulfan usage, atmospheric emissions, and highest soil residue in China were 3083.9, 1312.7, and 587.5 tonnes, and 3204.8, 1441.4, and 463.7 tonnes in India, respectively. The spatial distribution of modeled atmospheric and soil concentrations, and dry deposition fluxes of endosulfan were in line with its usage but wet deposition fluxes were mainly identified in Southern China and Sichuan basin with heavy rainfall, especially for α-endosulfan. Endosulfan tended to transport from India to Tibetan plateau, Yunnan-Kweichow Plateau, and some provinces in southern China under the Indian Summer Monsoon regime. Due to its stronger volatility, α-endosulfan posed a more significant impact on China's environment via the atmospheric transport from India compared to ß-endosulfan. Although rainfall during Indian Summer Monsoon reduced endosulfan levels in the air during its journey from India to China, it was observed that Indian endosulfan usage in 2010 contributed more than 50% of atmospheric concentrations and 30% of soil concentrations of α-endosulfan in some regions in Tibetan plateau.

A nationwide survey on the endosulfan residues in Chinese cotton field soil: Occurrence, trend, and ecological risk.

The nationwide occurrence of endosulfan residues in cotton fields has not yet been investigated. Therefore, in this study, 202 surface soil samples from 27 cities were collected from cotton fields in 8 major cotton-planting provinces of China, covering more than 97% of the national cotton sown area. The results showed that endosulfan residues were detected in cotton fields throughout the country. The main type of residue found was endosulfan sulfate (ES-sulfate), followed by ß-endosulfan and α-endosulfan, with average concentrations of 0.475, 0.129, and 0.048 µg/kg, respectively. Significant spatial variations in the endosulfan residues was noted, and the highest concentration of endosulfan residues was observed in the northwest inland cotton-growing area, followed by that in the Yellow River basin and Yangtze River basin cotton-growing areas. The endosulfan residues showed significant positive correlations with soil organic matter and soil clay contents. The α/ß endosulfan ratio was determined to be in the range of 0.02-1.20, indicating that endosulfan residues originated from the endosulfan application performed in historical cotton cultivation efforts. Together with the literature data, the concentrations of α-endosulfan and ß-endosulfan residues peaked in 2015 and 2017, respectively, and showed an overall decreasing trend from 2002 to 2021. The results of the ecological risk assessment suggested that Folsomia candida was most sensitive to endosulfan residues, with 20.8% of the sites presenting a high risk. However, in general, the soil ecological risk of cotton fields across the country was low. Our study demonstrated that China has achieved promising results in controlling the use and pollution of endosulfan, especially after 2014.

Dissipation kinetics, residue modeling and human intake of endosulfan applied to okra (Abelmoschus esculentus).

The non-judicious application of the harmful pesticide endosulfan on okra, one of India's most consumed vegetable crops, has resulted in the frequent detection of residues in food samples. This can lead to resistance and the resurgence of various pests and diseases. In this context, combined dissipation and residue dynamics of different endosulfan components or mixtures (isomers and metabolites) in crop compartments are not yet well understood. To address this research gap, the present study evaluates the dissipation and persistence behavior of different endosulfan isomers (alpha-, beta-isomers) and major metabolite (endosulfan sulfate) on okra during 2017 and 2018. The half-life of endosulfan on okra leaves was found to be between 1.79 and 3.47 days. Half of the endosulfan deposits on okra fruits at the recommended doses were dissipated after 2.39 days compared to 1.99 days at double recommended doses (mean of 2017 and 2018 residue data). Measured endosulfan residues were evaluated against the dynamic plant uptake model dynamiCROP. The better fits were observed between modeled and measured residues for fruits (R2 from 0.84 to 0.96 and residual standard error (ER) between 0.6 and 1.47) as compared to leaves (R2 from 0.57 to 0.88). We also report fractions of endosulfan components ingested by humans after crop harvest. Intake fractions range from 0.0001-7.2 gintake/kg of applied pesticide. Our results can evaluate pesticide residues in different crops grown for human consumption, including their isomers and metabolites. They can be combined with dose-response information to evaluate human exposure and/or health risk assessment.

Multi-residue determination of pesticides in vegetables and assessment of human health risks in Western Himalayan region of India.

This study was aimed to determine pesticides concentrations in fresh vegetables and assess human health risks in North-Western Himalayan region of India. Vegetable samples (n = 300) collected randomly from different agro-climatic zones were analyzed for 19 pesticides using gas chromatography. Pesticide residues were detected in 116 samples, of which 49 samples exceeded maximum permissible limits established by European Commission. Hexaconazole was most frequently detected in 9.3% samples followed by aldrin (8.3%), alachlor (5.3%), bifenthrin (4.3%), chlorpyrifos (3.7%), metribuzin (2.7%), ß-endosulfan, ethion, ß-HCH (2%, each), γ-HCH (1.3%), α-HCH, δ-HCH, malathion, heptachlor (1%, each), and α-endosulfan, pendimethalin in 0.7% samples. Human health risk assessment revealed that the percent contribution to acceptable daily intakes of pesticides via dietary intake of vegetables ranged from 0.014 to 39.4% in children and 0.003 to 9.85% in adults. Although hazard index values were < 1 but considering the concentrations of detected pesticide in samples, children were found to be at more risk. Since pragmatic investigations on occurrence of pesticides in vegetables and human health risk assessment from study area have not yet been worked out, so, this study highlights the importance of adopting good agricultural practices, awareness on food safety, monitoring of harmful chemicals in food commodities, and execution of food safety regulations to safeguard environmental and human health.

Spatiotemporal evaluation of organochlorine pesticide residues in bottom sediments of the Rio de Ondas hydrographic basin, western Bahia, Brazil.

The Rio de Ondas Hydrographic Basin (ROHB), Bahia state, Brazil, is located in a region with abundant water resources and is highly impacted by intense agricultural activity. In such a scenario, the use of organochlorine pesticides can represent a potential risk to the aquatic environments, due to their persistence, high bioaccumulation capacity, and high toxicity. Thus, organochlorine pesticide residues in bottom sediment samples from rivers on eighteen sites distributed along the ROHB in the dry and rainy periods were analyzed by gas chromatography coupled with mass spectrometry. The validated method showed no matrix effect, recoveries ranging from 82% (ß-HCB) to 118% (DDD), limits of detection between 0.003 ng g-1 (α-HCH) and 0.011 ng g-1 (DDT), limits of quantification of 0.010 ng g-1 (α-HCH) to 0.036 ng g-1 (DDT), repeatability with the highest relative standard deviation of 0.97% (α-hexachlorocyclohexane at 2.000 ng g-1), and inter-day precision ranging from 10% (aldrin at 0.050 ng g-1 and 0.600 ng g-1 and α-endosulfan at 0.600 ng g-1) to 25% (ß-endosulfan at 0.050 ng g-1). Although most compounds were banned since 1985, it was observed that their residues were widely distributed in the ROHB, with the total concentrations varying from 3.242 ng g-1 (P02) to 12.052 ng g-1 (P17) and from 0.313 ng g-1 (P14) to 30.861 ng g-1 (P13) in the dry and rainy periods, respectively, which may be related to historical contamination and/or prohibited use. Moreover, the spatiotemporal variation showed the highest concentrations of organochlorine pesticide residues in the rainy season, coinciding with the planting period.