Organochlorine pesticides (OCPs) have been reported to cause mitochondrial dysfunction. However, most studies reported its mitochondrial toxicity with respect to a single form, which is far from the environmentally relevant conditions. In this study, we exposed zebrafish embryos to five OCPs: chlordane, heptachlor, p,p’-dichlorodiphenyltrichloroethane (p,p’-DDT), β-hexachlorocyclohexane (β-HCH), and hexachlorobenzene (HCB), as well as an equal ratio mixture of these OCPs. We evaluated mitochondrial function, including oxygen consumption, the activity of mitochondrial complexes, antioxidant reactions, and expression of genes involved in mitochondrial metabolism. Oxygen consumption rate was reduced by exposure to chlordane, and β-HCH, linking to the increased activity of specific mitochondrial complex I and III, and decreased GSH level. We found that these mitochondrial dysfunctions were more significant in the exposure to the OCP mixture than the individual OCPs. On the mRNA transcription level, the individual OCPs mainly dysregulated the metabolic cycle (i.e., cs and acadm), whereas the OCP mixture disrupted the genes related to mitochondrial oxidative phosphorylation (i.e., sdha). Consequently, we demonstrate that the OCP mixture disrupts mitochondrial metabolism by a different molecular mechanism than the individual OCPs, which warrants further study to evaluate mitochondrial dysregulation by chronic exposure to the OCP mixture.

Agricultural use of organochlorine pesticides (OCPs) increased during the twentieth century but many of them have been progressively banned several decades after their introduction. Nevertheless, these lipophilic chemical compounds may persist in soils and sediments. From sediment deposits, it is possible to reconstruct the chronology of OCP releases in relation to former applications through time. Nevertheless, long-term fate of OCPs i.e. source, transfer, and storage through the watershed, is also related to the OCPs-sediment characteristics interactions, and our study showed the significant links between OCPs and labile or refractory organic matter. From sediment cores collected in a mainly agricultural watershed, the Eure River watershed (France), aldrin and lindane widespread applications during the 1950s–1970s have been recorded. While lindane applications declined after that date, according to the temporal trend of the stable isomer of hexachlorocyclohexane (β-HCH), α-, and γ-HCH have been recorded at significant levels in the 2000s, suggesting first local post-ban applications. Nevertheless, the relationships between these OCPs and labile organic matter resulted in an overestimation of the post-ban releases. Also, the detection of stable metabolites of dichlorodiphenyltrichloroethane (DDT) (i.e. 4,4′-DDE) and heptachlor (i.e. heptachlor epoxide) several decades after their ban, revealed the role of old deep soils erosion in the chronology of OCP releases and thus the reemergence of stable transformation products from historical OCPs.

Studies have documented that exposure to organochlorine pesticides (OCPs) is linked with breast cancer, but the underlying biological mechanisms are still unknown. This study included 313 women diagnosed with breast cancer and 313 controls in Wuhan, China, and measured 18 OCPs in serum and 3 oxidative stress biomarkers in urine. Multivariable adjusted regression models were used to evaluate the associations among OCPs, oxidative stress biomarkers, and breast cancer. The mediating effect of oxidative stress was assessed by mediation analysis. We observed that most OCPs were positively associated with risk of breast cancer (all FDR-P values < 0.05 or 0.10). Moreover, we found that p,p'-DDT, p,p'-DDD, dieldrin, heptachlor, and heptachlor epoxide were positively associated with 4-hydroxy-2-nonenal-mercapturic acid (HNE-MA) and 8-iso-prostaglandin F₂α (8-isoPGF₂α), which in turn were positively associated with risk of breast cancer. Mediation analysis indicated that HNE-MA and 8-isoPGF₂ɑ mediated the positive associations between these OCPs and risk of breast cancer, with mediating proportion ranging from 6.23% to 19.9%. Our results suggest that lipid peroxidation may mediate the positive associations between OCP exposures and risk of breast cancer.

In Yucatan, Mexico, chronic exposure of Mayan population to pesticides is expected as about 30 per cent are drinking polluted water. Residues of organochlorine pesticides (OCP) were monitored in 18 municipalities of Yucatan with high mortality rates due to uterine cervix cancer. 70 blood samples collected from Mayan women living in livestock, agricultural and metropolitan area were analyzed for OCP. Solid Phase Extraction was performed on C18 cartridges and analyzed by Gas Chromatography with Electron Capture Detector. The results showed that the highest OCP levels were detected in blood of women living in the livestock area. OCP detected were endosulfan I (7.35 μg/mL), aldrin (3.69 μg/mL), 4,4′ DDD (2.33 μg/mL), 1.39 and 1.46 μg/mL of δ-HCH. Women from the agricultural area had high concentrations of OCP in their blood, particularly dieldrin (1.19 μg/mL), and 1.26 μg/mL of 4,4′ DDE. In the metropolitan area, 0.080 μg/mL of γ-HCH and 0.064 μg/mL of heptachlore were detected. This monitoring study was also based on epidemiological data of uterine cervical cancer. It was found that environmental factors may have facilitated the infiltration of OCP to the aquifer used for potable water supply. These factors in addition to poverty can have impacts on public health. This first exploratory study suggests that monitoring of OCP in human is important for the establishment of health promotion programs. The integrative analysis of both, environmental and social factors would be helpful to characterize the bioaccumulation of pesticides in humans.

A systematic grid sampling method and geostatistics were employed to investigate the spatial distribution, inventory, and potential ecological and human health risks of the residues of hexachlorobenzene (HCB) and chlorinated cyclodiene pesticides in soils of the Campanian Plain, Italy, and explore their relationship with the soils properties. The geometric mean (Gmean) concentrations of HCB and cyclodiene compounds followed the order CHLs (heptachlor, heptachlor epoxide, trans-chlordane, and cis-chlordane) > DRINs (aldrin, dieldrin, and endrin) > SULPHs (α-endosulfan, β-endosulfan, and endosulfan sulfate) > HCB. The residual levels of most cyclodienes in agricultural soils were generally higher than those of corresponding counterparts in the other land uses. Significant differences in the concentration of HCB and cyclodienes in the soils across the region are observed, and the Acerra-Marigliano conurbation (AMC) and Sarno River Basin (SRB) areas exhibit particularly high residual concentrations. Some legacy cyclodienes in the Campanian Plain may be attributed to a secondary distribution. The Gmean inventory of HCB, SULPHs, CHLs, and DRINs in the soil is estimated to be 0.081, 0.41, 0.36, and 0.41 metric tons, respectively. The non-cancer and cancer risks of HCB and cyclodienes for exposed populations are deemed essentially negligible, however, endosulfan poses significant ecological risks to some terrestrial species.

The Antarctic continent is among the most pristine regions; yet various organic contaminants have been measured there routinely. Air and snow samples were collected during the austral spring (October–November, 2010) along the western Antarctic Peninsula and analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) to assess the relative importance of long-range transport versus local primary or secondary emissions. Highest concentrations of PCBs, PBDEs and DDTs were observed in the glacier’s snow sample, highlighting the importance of melting glaciers as a possible secondary source of legacy pollutants to the Antarctic. In the atmosphere, contaminants were mainly found in the vapor phase (>65%). Hexachlorobenzene (33.6 pg/m3), PCBs (11.6 pg/m3), heptachlor (5.64 pg/m3), PBDEs (4.22 pg/m3) and cis-chlordane (2.43 pg/m3) were the most abundant contaminants. In contrast to other compounds, PBDEs seem to have originated from local sources, possibly the research station itself. Gas-particle partitioning for analytes were better predicted using the adsorption partitioning model than an octanol-based absorption approach. Diffusive flux calculations indicated that net deposition is the dominant pathway for PBDEs and chlordanes, whereas re-volatilization from snow (during melting or metamorphosis) was observed for PCBs and some OCPs.

Organochlorine pesticides (OCPs) and stable isotopes were measured in muscle from 4 bird and 5 fish species from the Ethiopian Rift Valley region where DDT is used for malaria control and vast agricultural activities are carried out. We investigated the bioaccumulation of OCPs such as DDTs, HCHs, chlordanes, and heptachlors between the species, and examined the potential risk posed by these compounds for bird species. Significant differences in contaminant profiles and levels were observed within the species. Levels of total OCPs ranged from 3.7 to 148.7 μg/g lipid in bird and 0.04 to 10.9 μg/g lipid in fish species. DDTs were the predominant contaminant, and a positive relationship between δ15N and ΣDDT concentrations was found. The main DDT metabolite, p,p′-DDE was the most abundant and significantly greater concentrations in bird species (up to 138.5 μg/g lipid), which could have deleterious effects on survival and/or reproduction of birds.

During a decade (1996-2006), ecotoxicological studies were carried out in biota of the Vaccarès Lagoon (Biosphere Reserve in Rhone Delta, France). A multicontamination was shown at all levels of the trophic web due to a direct bioconcentration of chemical from the medium combined with a food transfer. Here, the pollutants investigated were organochlorines, among which many compounds banned or in the course of prohibition (or restriction) (PCB, lindane, pp'-DDE, dieldrin, aldrin, heptachlor, endosulfan ...) and some substances likely still used in the Rhone River basin (diuron, fipronil). The results confirmed the ubiquity of contamination. It proves to be chronic, variable and tends to regress; however contamination levels depend on the trophic compartment. A biomagnification process was showed. A comparison of investigation methods used in other Mediterranean wetlands provides basis of discussion, and demonstrates the urgent need of modelling to assess the ecotoxicological risk in order to improve the management of such protected areas. The Vaccarès Lagoon trophic web biomagnifies organochlorine pollutants.

The iSimangaliso Wetland Park World Heritage site, located on the east coast of South Africa, spans ∼3300 km2 and constitutes the largest protected estuarine environment for hippopotami, crocodiles and aquatic birds in Africa. Given the ecological importance of this site and continued use of organochlorine pesticides (OCPs) in the region, this study focused on the nature, distribution and potential sources of organochlorine contamination within iSimangaliso Wetland Park. OCPs were widely distributed in surface sediment samples obtained from the four main Ramsar wetland systems within the park (Lake St Lucia, Mkhuze, Lake Sibaya and Kosi Bay). ∑HCH and ∑DDT were the dominant contaminants detected with concentrations in the range of 26.29–282.5 ng/g and 34.49–262.4 ng/g, respectively. ∑DDT concentrations revealed a distinctive gradient, with significantly higher concentrations at Kosi Bay and Lake Sibaya attributed to the application of DDT for malaria control. p,p'-DDE and p,p'-DDD were the dominant isomers detected, but the detection of p,p'-DDT in a number of samples reflects recent inputs of technical DDT. Highest concentrations of HCH, endosulfan and heptachlor were detected in sediments from Mkhuze and reflect the substantial residue load these wetlands receive from agricultural activities within the catchment area. Isomeric compositions indicate that endosulfan and heptachlor residues are derived mainly from historical application, while inputs of HCH, aldrin and endrin could be attributed to more recent usage at several sites. OCP sediment concentrations from iSimangaliso represent the highest yet recorded in South Africa and some of the highest reported globally this century. Sediments found within the lakes and wetlands of iSimangaliso represent large reservoirs of contaminants that pose ecotoxicological threats to this globally important biodiversity hotspot. Detailed investigation into the bioaccumulation and toxicological risks of OCPs within the wetland park is urgently required.

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.