Persistent endosulfan sulfate is found with highest abundance among endosulfan I, II, and sulfate in German forest soils

Organochlorine pesticide contamination of soils and dust from an urban environment in the Niger Delta of Nigeria

The concentrations, sources, and risk of twenty organochlorine pesticides (OCPs) in soils and dusts from a typical urban setting in the Niger Delta of Nigeria were examined. The Σ20 OCP concentrations (ng g-1) varied from 4.49 to 150 with an average value of 32.6 for soil, 4.67 to 21.5 with an average of 11.7 for indoor dust, and 1.6 to 96.7 with an average value of 23.5 for outdoor dust. The Σ20 OCP concentrations in these media were in the order: soil > outdoor dust > indoor dust, which was in contrast with the order of the detection frequency, i.e., indoor dust (95 to 100 %) > soil (60 to 90 %) > outdoor dust (30 to 80 %). The concentrations of the different OCP classes in these media followed the order: aldrin + dieldrin + endrin and its isomers (Drins) > chlordanes > dichlorodiphenyltrichloroethane (DDTs) > hexachlorocyclohexane (HCHs) > endosulfans for outdoor dust and soil, while that of the indoor dust followed the order: Drins > chlordanes > endosulfans > DDTs > HCHs. The cancer risk values for human exposure to OCPs in these sites exceeded 10-6 which indicates possible carcinogenic risks. The sources of OCPs in these media reflected both past use and recent inputs.

Development and validation of CYP26A1 inhibition assay for high-throughput screening

All-trans retinoic acid (atRA) is an endogenous ligand of the retinoic acid receptors, which heterodimerize with retinoid X receptors. AtRA is generated in tissues from vitamin A (retinol) metabolism to form a paracrine signal and is locally degraded by cytochrome P450 family 26 (CYP26) enzymes. The CYP26 family consists of three subtypes: A1, B1, and C1, which are differentially expressed during development. This study aims to develop and validate a high throughput screening assay to identify CYP26A1 inhibitors in a cell-free system using a luminescent P450-Glo assay technology. The assay performed well with a signal to background ratio of 25.7, a coefficient of variation of 8.9%, and a Z-factor of 0.7. To validate the assay, we tested a subset of 39 compounds that included known CYP26 inhibitors and retinoids, as well as positive and negative control compounds selected from the literature and/or the ToxCast/Tox21 portfolio. Known CYP26A1 inhibitors were confirmed, and predicted CYP26A1 inhibitors, such as chlorothalonil, prochloraz, and SSR126768, were identified, demonstrating the reliability and robustness of the assay. Given the general importance of atRA as a morphogenetic signal and the localized expression of Cyp26a1 in embryonic tissues, a validated CYP26A1 assay has important implications for evaluating the potential developmental toxicity of chemicals.

Evidence of transboundary movement of chemicals from Mexico to the U.S. in Tijuana River Estuary sediments

The Tijuana River Estuary (TRE) has been a public health hazard and point of contention between the United States and Mexico for decades, with sources of pollution on both sides of the border. The goal of our study is to determine the presence and dynamics of chemical contamination in the TRE. We sampled sediment from four TRE locations in the U.S. during stable dry conditions and immediately after a wet weather period. Organic chemicals were initially screened with non-targeted analysis using gas chromatography high-resolution mass spectrometry (GC/HRMS) that tentatively identified 6978 chemicals in the NIST 20 database. These tentative identifications were filtered using the USEPA CompTox database to guide quantitative targeted analysis at detection limits below 1 ng/g dry weight sediment. Quantitative targeted analysis of 152 organic pollutants and 18 inorganic elements via GC/HRMS revealed generally higher concentrations of contaminants in dry weather sediments compared to wet weather sediments. The highest concentrations of all chemical classes were detected at the site closest to the U.S.-Mexico border, followed by an urban area near Imperial Beach, California, U.S. All sites exhibited a mixture of petrogenic and pyrogenic polycyclic aromatic hydrocarbons (PAHs). Current-use pesticides were dominated by pyrethroid insecticides and the thiocarbamate herbicide s-Ethyl dipropylthiocarbamate (EPTC), while the U.S.-banned organochlorine pesticides were dominated by chlordanes, dieldrin, and dichlorodiphenyltrichloroethane (DDT) and its degradation byproducts. Polychlorinated biphenyl (PCB) concentrations were greatest at the site closest to the U.S.-Mexico border but in the low nanogram-per-gram range. Phthalates were only found at the same site, with relatively high concentrations of bis(2-ethylhexyl) phthalate. This study provides positive identification and quantitative concentrations for organic pollutants in TRE sediments. Our data suggest that there are multiple sources of chemical contamination in the estuary, including possible transboundary movement of pollutants from Mexico.

Occurrence of chlorpyrifos and organochlorine pesticides in a native bumblebee (Bombus pauloensis) living under different land uses in the southeastern Pampas, Argentina

Pollinators such as Apidae bees are vital for ecosystems and food security. Unfortunately, their populations have declined due to several factors including pesticide use. Among them, the organophosphate insecticide chlorpyrifos, poses a global threat, while legacy compounds like organochlorine pesticides (OCPs) easily bioaccumulate, increasing the concern. Bombus pauloensis, a widely distributed native bee in Argentina, is used for commercial pollination; however, information regarding their health status is scarce. This study assessed chlorpyrifos and OCP levels in B. pauloensis (workers and males) and related environmental matrices living from three different land uses schemes, by means of GC-ECD and GC-MS. The ornamental horticulture field (OP) showed the highest total pesticide concentrations in workers (13.1 ng/g), flowers and soils, whereas the organic agriculture field (OA) exhibited the lowest. Chlorpyrifos was the most abundant compound, accounting for at least 20 % of pesticide load across all matrices. The food production horticulture field (FH) had the highest chlorpyrifos concentration in workers, males and soils (5.0, 4.4 and 3.3 ng/g, respectively), suggesting a local greater usage, whereas OA showed the lowest. Regarding OCPs groups, Drins and DDTs were predominant in most matrices, with FH males registering the highest levels (4.0 and 2.5 ng/g, respectively), closely followed by OP. However, metabolites' contribution indicated historical use and atmospheric inputs in all sites. Multivariate analyses confirmed the significance of site and bumblebee sex to explain pesticide composition. Males from all sites exhibited higher chlorpyrifos levels than workers and this trend was similar for some OCP groups. Overall, OA differed from FH and OP, indicating a correlation between production modes and pesticide profiles. This study demonstrates the value of B. pauloensis as a pesticide biomonitor but also offers insights into its populations' health in the area. In this sense, this information could be useful towards the preservation of this crucial pollinator.

Hyperspeed method for analyzing organochloride pesticides in sediments using two-dimensional gas chromatography–time-of-flight mass spectrometry

Pesticides are traditionally analyzed using conventional gas chromatography. When fast chromatography is associated with comprehensive two-dimensional gas chromatography (GC × GC), the resulting method presents high-resolution separation associated with a higher chromatographic speed. In the present work, a method for pesticide analysis in sediment samples was developed using quick, easy, cheap, effective, rugged, and safe extraction (QuEChERS) and a hyperspeed GC × GC separation. The QuEChERS procedure reported in the literature was extended to incorporate the analytes tetrachloro-m-xylene, decachlorobiphenyl, trans-chlordane, chlordane, endosulfan lactone, and endosulfan ether. To understand the chromatographic method improvement achieved, the recent concept of average theoretical peak time (ATPT) was used. The ATPT improved from that of the traditional GC × GC separation to the proposed method, and the separation speed can be classified as a hyperspeed separation. The limit of detection and quantitation of the compounds in the standard mix ranged from 0.39 to 17.96 µg L^-1 and 1.18 to 54.43 µg L^-1, respectively. The method showed acceptable RSD% (relative standard deviation) values and little interference of the sediment matrix in the extraction procedure. The developed method was applied to the determination of a mixture of 19 compounds in 16 sediment samples from the Pirapetinga River and Paraíba do Sul River in Brazil.

Study of the Potential Accumulation of the Pesticide Alpha-Endosulfan by Microplastics in Water Systems

Microplastics (MP) are spread into all ecosystems and represent a threat to the equilibrium of the environment and human health, not only due to their intrinsic characteristics but also to their action as effective carriers of contaminants, such as pesticides, pharmaceuticals, polychlorinated biphenyls and polycyclic aromatic hydrocarbons. The pesticide α-endosulfan is persistent and spread in the environment. The MP are another possible way of dissemination to be considered in the fate of this pesticide. The adsorption dynamics of α-endosulfan by six different MP (low-density polyethylene—LDPE, polyethylene-co-vinyl acetate, unplasticized polyvinyl chloride, polyamide 6, polystyrene granule, polypropylene granule) with different sizes/shapes and chemical compositions were evaluated. The most critical situation was identified for the system LDPE (particle size < 300 μm). Equilibrium studies (48 h equilibrium time) were performed for distilled, tap and filtered river water. Based on the Langmuir model parameters, the highest maximum adsorption capacity was obtained for distilled water, followed by filtered river and tap waters (i.e., 366 ± 39, 247 ± 38, 157 ± 22 μg/g). The obtained results demonstrate the important role that microplastics may have in the fate and transport of pesticides and their potentially harmful effect on the environment, which requires further investigation.

Effects of incremental endosulfan sulfate exposure and high fat diet on lipid metabolism, glucose homeostasis and gut microbiota in mice

The influence of pollutants on metabolic diseases such as type 2 diabetes mellitus is an emerging field in environmental medicine. Here, we explored the effects of a low-dose endosulfan sulfate (ES), a major metabolite of the pesticide endosulfan and a bio-persistent contaminant detected in environmental and human samples, on the progress of obesity and metabolic disorders. Pregnant CD-1 mice were given ES from gestational day 6 to postnatal day 21 (short-term). After weaning, male pups of exposed dams were provided with a low-fat or a high-fat diet (LFD or HFD) and assessed after an additional 12 weeks. At the same time, one group of male pups continuously received ES (long-term). Treatment with low-dose ES, short or long-term, alleviated the development of obesity and accumulation of hepatic triglycerides induced by HFD. Analysis of gene expression, metabolic profile and gut microbiome indicates that ES treatment inhibits adipogenesis induced by HFD due to enhanced lipid catabolism, fatty acid oxidation and disturbance of gut microbiota composition. However, impaired glucose and insulin homeostasis were still conserved in HFD-fed mice exposed to ES. Furthermore, ES treatment impaired glucose tolerance, affected hepatic gene expression, fatty acids composition and serum metabolic profile, as well as disturbed gut microbiota in LFD-fed mice. In conclusion, ES treatment at levels close to the accepted daily intake during fetal development directly impact glucose homeostasis, hepatic lipid metabolism, and gut microbiome dependent on the type of diet consumed. These findings provide a better understanding of the complex interactions of environmental pollutants and diet at early life stages also in the context of metabolic disease.

Ecological Risk Assessment (ERA) of pesticides from freshwater ecosystems in the Pampas region of Argentina: Legacy and current use chemicals contribution

Agricultural production in the Pampas region is one of the most important economic activities in Argentina. However, the possible environmental effects related to the growth of this activity in the last years have not been studied enough. Particularly, the effects of pesticides mixtures are a topic of great concern both for society and regulatory authorities worldwide, given the possible additive and synergistic relationships between these chemicals and their possible effects on aquatic biota. Based on a concentration addition model, this study developed an Ecological Risk Assessment (ERA) of pesticides from freshwater ecosystems in the Pampas region. For this purpose, reported pesticides concentrations available in public bibliography and a Risk Quotients (RQs) approach were used. A cumulative risk map was established to display RQs for current use pesticides (CUPs) and legacy chemicals. The ΣRQs were calculated for 66 sites, using available reported measured environmental concentrations (MECs) and predicted no effect concentrations (PNECs) of pesticides. While ΣRQ for only CUPs resulted in a high and very high risk (ΣRQ > 1) for 29% of the sites, when legacy pesticides were incorporated this percentage reached the 41% of the sites, increasing significantly the absolute values of RQ. Herbicides like glyphosate and atrazine contributed considerably to the ΣRQ_CUPs while organochlorines were the major contributors for ΣRQs when legacy pesticides were incorporated. Moreover, some active ingredients (acetochlor, carbendazim and fenitrothion) which are approved for their use in Argentina but banned in EU showed high contribution to ΣRQ_CUPs. The present study is the first attempt to develop an ERA in surface water of the Pampas region of Argentina and it provides a starting point for a more comprehensive pesticides monitoring and a further risk assessment program.

Different effects of α-endosulfan, β-endosulfan, and endosulfan sulfate on sex hormone levels, metabolic profile and oxidative stress in adult mice testes

In the environment, endosulfan persists in forms of two isomers (α and β) and a toxic metabolite, endosulfan sulfate. The toxicity of endosulfan on various mammalian tissues has been investigated, but whether the different isomers and metabolites of endosulfans affect mammalian reproductive function remains unclear. This study is aimed to elucidate the different toxicological effects of α-endosulfan, β-endosulfan, and endosulfan sulfate on adult mice testes. We found that the three endosulfans (α endosulfan, β endosulfan and endosulfan sulfate) altered serum sex steroid hormone levels, and changed expression of steroidogenesis genes. By comparing results of ¹H-NMR and LC-MS/MS metabolomics between samples treated with different endosulfans, we found that endosulfans changed levels of metabolites involved in energy metabolism and oxidative stress, and these were associated with the imbalance of sex sterol hormone synthesis. Moreover, endosulfan isomers and sulfate metabolite treatment disrupted the mice testicular antioxidant systems and caused an increase in lipid peroxidation. Interestingly, the three endosulfans tested in this study each yielded different effects on serum sex hormone levels and testicular metabolic profiles in the adult mice. Beta-endosulfan exposure caused the strongest disturbance in the testes compared to the other endosulfans, with significantly higher testosterone levels and more pronounced changes to endogenous metabolites. Taken together, we identified the different effects of endosulfans on the testis by exposing mice to α endosulfan, β endosulfan and endosulfan sulfate, and we found that changes in sex sterol hormone levels induced by treatment with endosulfans were correlated to changes in endogenous metabolites. These findings provide new insight into mechanism of endosulfan-induced testicular toxicity.

Discrepant effects of α-endosulfan, β-endosulfan, and endosulfan sulfate on oxidative stress and energy metabolism in the livers and kidneys of mice

Endosulfan, an organochloride pesticide, has been used for many commercial purposes. Endosulfan is composed of two isomers, α-endosulfan and β-endosulfan. In biological and soil systems, endosulfan is metabolized into endosulfan sulfate. In this study, the different toxicological effects of α-endosulfan, β-endosulfan, and endosulfan sulfate on the livers and kidneys of mice were comprehensively investigated. The results demonstrated that both endosulfan isomers and endosulfan sulfate disturbed the hepatic and renal antioxidant systems. Furthermore, ¹H NMR metabolomics analysis revealed that endogenous metabolites involved in oxidative stress and energy metabolism were altered after exposure to these compounds. In the liver, the changes in hepatic endogenous metabolites and the induction of hepatic CYP450 mRNA isoforms were similar among mice treated with the three compounds, and the sulfate metabolite was the exclusive exogenous compound detected. Therefore, the metabolism of α- and β-endosulfan to endosulfan sulfate is likely the main cause of toxicological effects in the livers of mice. However, in kidneys, the changes in the metabolome and in CYP450 mRNA expression induced by α-endosulfan and β-endosulfan were stereoselective. Additionally, endosulfan sulfate, which induced a significant increase of renal Cyp3a11, showed a more robust disturbance of renal metabolites than either of the two isomers. These findings revealed that more attention should be given to the toxicological evaluation of endosulfan sulfate in the future.

Latitudinal distribution of OCPs in the open ocean atmosphere between the Argentinian coast and Antarctic Peninsula

Long-range atmospheric transport is one of the most important ways in which persistent organic pollutants can be transported from their source to remote and pristine regions. Here, we report the results of the first Argentinian measurements of organochlorine pesticides in the Antarctic region. During a 9665-km track onboard OV ARA Puerto Deseado, within the framework of Argentinian Antarctic Expeditions, air samples were taken using high-volume samplers and analyzed using GC-μECD. HCB, HCHs, and endosulfans were the major organic pollutants found, and a north-south gradient in their concentrations was evident by comparing data from the Argentinian offshore zone to the South Scotia Sea.

Results of the second national forest soil inventory in Germany - Interpretation of level and stock profiles for PCDD/F and PCB in terms of vegetation and humus type

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) were detected in 86 humic topsoil layers and in a subset of 11 randomly selected top mineral forest soils at the depths of 0-5cm and 5-10cm collected from different federal states of Germany. The distribution of these persistent organic pollutants (POPs) in humic topsoils with respect to vegetation cover (coniferous vs. deciduous vs. mixed), total organic carbon (TOC), altitude and latitude data was investigated. There is cross correlation between the contents and TOC while the correlation with latitude indicates higher abundances of POPs in central Germany where there is high population density accompanied with industrial activities. The calculated stocks suggest that humus type (mor, mull, or moder) in conjunction with forest type can explain the relative POPs abundances in different soil layers. Generally, humic topsoils show highest contents of POPs compare to the two mineral soils with a ratio of 100:10:1. However, the stock humic layers of coniferous stands contribute about 50% to the total stock, whereas at deciduous stands the stock is mainly located in the upper mineral soil layer (0-5cm). The soil-water distribution coefficients (Kd) were calculated to estimate the potential translocation in the different soil types. The Kd values vary among the PCBs and PCDD/Fs congeners and are most variable for humic topsoils. There is pronounced chemical abundance in the top mineral soils with increasing Kd and this points to non-water bound transport processes for superlipophilic compounds.

Residue patterns of currently, historically and never-used organochlorine pesticides in agricultural soils across China and associated health risks

Organochlorine pesticides (OCPs) with different usage states, such as currently, historically or never used, may show different behaviors and potential risks in the environment. It is essential to identify their distribution patterns and fates and to assess their associated health risks to humans. In this study, based on a nationwide sampling campaign across China, we determined the concentrations of currently (endosulfan), historically (chlordane and heptachlor) and never-used (aldrin, dieldrin and endrin) OCPs in agricultural soils. The total residue inventories of ∑Endosulfans, ∑Chlordanes, heptachlor and ∑Drins in soils were 260, 64.3, 54.2 and 88.6 t, respectively. The residues of endosulfan were influenced by current usage, showing a latitude transect trend. Drins were mainly from long-range transport, but the illegal usage in China still affected their residues. This finding indicates that endosulfan and drins in Chinese agricultural soils mainly follow the primary and secondary distribution pattern, respectively. Both primary and secondary distribution have a great impact on the distribution pattern of chlordane, which had been banned for only 4 years at the time we sampled. The health risks of these OCPs were estimated based on their concentrations. There were 0.813% and 1.63% of samples that exceeded the target values for chlordane and endrin according to the Netherlands guideline for unpolluted soil. Their residues in most of the samples posed no or few non-carcinogenic and carcinogenic risks to human beings. The results from this study will provide powerful support for pollution control and management.

Spatial distribution, transport dynamics, and health risks of endosulfan at a contaminated site

We analyzed concentrations, distribution characteristics, and health risks of endosulfan (α and β isomers, and endosulfan sulfate) in soils (top soils and soil profiles) and air, at and around a typical endosulfan production site in Jiangsu, China. The air-soil surface exchange flux is calculated to investigate transport dynamics of endosulfan. Concentrations at the production site ranged from 0.01 to 114 mg/kg d.w. in soil and 4.81-289 ng/m(3) in air, with very high concentrations occurring at the location of endosulfan emulsion workshop. In the surrounding area, endosulfan was detected in all samples, with concentrations ranging from 1.37-415 ng/g d.w. in soil and 0.89-10.4 ng/m(3) in air. In the contaminated site, endosulfan concentrations fluctuated with depth in the upper soil layers, then decreased below 120 cm. Soil and air within a distance of 2.0 km appear to be affected by endosulfan originating from the site. Even the health risk at the location of the endosulfan emulsifiable solution workshop was over seven times the acceptable value, the risk to nearby adults and children was low.