Search

Abstract Soil organic matter (SOM) is the principal aggregating agent for soil aggregation and also the main adsorbent for organochlorine pesticides (OCPs) such as dichlorodiphenyltrichloroethane (DDT) and hexachlorocyclohexane (HCH), which may thereby affect OCP distribution in soils subjected to different land use types. However, the potential effects of land use on SOM and OCP distribution patterns in soil aggregates are not well understood. In this study, soils from farmlands and barelands in the Danjiangkou Reservoir area were analyzed to determine the influence of land use on OCP distribution and composition in different aggregate fractions (>3, 1–3, 0.25–1, and <0.25 mm). The results showed that the levels of ∑DDTs ranged from 9.01 to 27.48 with a mean of 14.40 ng g−1, and ∑HCHs ranged from 2.06 to 4.66 with a mean of 3.19 ng g−1 in farmland soils. In comparison, bareland soils were less contaminated, with total DDTs and HCHs fell in the range of 0.75–5.01 ng g−1 and not detected (n.d.)-1.40 ng g−1 respectively. In regard to the distribution patterns in soil aggregates, the residual levels of ∑DDTs and ∑HCHs tended to a certain degree to enrich in microaggregates (<0.25 mm) relative to bulk soils. A further analysis revealed that the enrichment of ∑DDTs and ∑HCHs in microaggregates were mainly attributed to the accumulation of p,p' -DDE and β -HCH. Moreover, SOM was found also enriched in microaggregates. The enrichment of SOM was significantly and positively correlated with these of ∑DDTs, ∑HCHs, and the dominant metabolites (i.e., DDE and β -HCH) in both land use types. Such results indicated that the variations in behavior of OCPs could be linked to the processes of soil aggregate turnover. These findings may help to enrich the theory of soil OCPs sequestration and establish targeted strategies to mitigate their health risks in the environment. Graphical abstract Image 1 Highlights • Farmland significantly increased OCPs concentrations compare to bareland. • The microaggregates exhibited a degree of OCPs enrichment. • The OCPs enrichments in microaggregates were mainly attributed to the p,p' -DDE and β -HCH. • SOM was the crucial factor driving the distributions of OCPs in soil aggregates. [ABSTRACT FROM AUTHOR]

Highlights: [•] The residues of organochlorine pesticides in dog sharks were 10.75–30.35ng/g. [•] DDTs and chlordanes has a tendency to accumulate in the liver. [•] Direct gill penetration may be an important means of entrance for HCHs. [•] The compositional profiles suggest historical usage of HCHs and chlordanes. [•] The predominant o,p′-DDT/p,p′-DDT ratios reflected a recent use of dicofol. [ABSTRACT FROM AUTHOR]

Abstract: Four typical freshwater fish species in Lake Taihu (TH), China, were collected and analyzed for the residue levels of DDT and its metabolites DDD and DDE (sum of o,p′- and p,p′-DDT, DDD, and DDE is designated as DDTs). The DDTs concentrations ranged from 3.24 to 37.1ng/g, and p,p′-DDE was the dominant isomer, followed by p,p′-DDD and o,p′-DDT. Source identification indicated that DDTs in TH was mostly stemmed from the historical usage of technical DDT mixture, but a new source of DDT, i.e., dicofol-type DDT, also occurred. The results from the present work, together with previously published data, clearly indicate that dicofol-type DDT was widespread and was an important continual source of DDTs in China. [Copyright &y& Elsevier]

Abstract: Concentrations of dichlorodiphenyltrichloroethane (DDT) and its metabolites (designated as DDTs, the sum of o,p′- and p,p′-DDT, o,p′- and p,p′-DDE, and o,p′- and p,p′-DDD) in air and precipitation from the Pearl River Delta (PRD) of China were determined. Total concentrations of DDTs in air (gas+particle) and precipitation (dissolved+particle) were 170±120pgm−3 and 940±180pgL−1 for Dongguan (rural) and 240±120pgm−3 and 790±140pgL−1 for Shunde (rural), respectively, while they were 1550±640pgL−1 in precipitation from Guangzhou (urban). Log-transformed partition coefficients between air and particulate organic matter (log ) of p,p′-DDT, p,p′-DDE, p,p′-DDD, o,p′-DDT, o,p′-DDE, and o,p′-DDD were 9.64±0.58, 10.07±0.56, 9.90±0.76, 10.06±0.66, 10.02±0.72, and 10.13±0.57, respectively; while those between water and particulate organic matter (log ) were 6.58±0.66, 6.36±0.53, 6.01±0.62, 6.41±0.42, 5.98±0.76, and 5.95±0.66, respectively. Total washout ratios by bulk rainfalls ranged from 4600 for o,p′-DDT to 54,000 for p,p′-DDT. Estimated average dry particle and wet depositional intensities in the PRD were 2.1×10−6 and 1.6×10−6 gm−2 y−1. [Copyright &y& Elsevier]

A total of 602 seafood samples, including fish, shrimps, crabs and molluscs, were analyzed for a suite of persistent halogenated compounds. The residual levels of DDTs (sum of o,p′- and p,p′-DDT, DDD, and DDE) and polybrominated diphenyl ethers (PBDEs) varied significantly among different species, and ranged from non-detectable (nd) to 699ng/g and nd to 5.93ng/g, respectively. Comparison of the levels of DDTs and PBDEs in mussel samples worldwide suggested that South China is probably one of the most DDT-polluted areas, but is moderate at most in terms of PBDE contamination. Combined with a recent dietary survey at the same sampling locations, dietary intakes of DDTs and PBDEs by local residents via seafood consumption for all age groups were estimated to be 147–564 and 4.7–18.5ng/day, or 8.5−12.9 and 0.27−0.46ng/kgbw/day, respectively. Among the different seafood types, fish contributed the largest portion of the dietary intakes of DDTs (57%), followed by molluscs (38%). Similarly, the dietary intakes of PBDEs were also dominated by fish (45%) and molluscs (45%). Assessment based on several available guidelines suggested that though no significant human health risk associated with the dietary intake of PBDEs, a lifetime cancer risk from dietary exposure to DDTs remains a probability. Because dietary intake of DDTs was dominated by fish and molluscs, added concern should be paid to fish and molluscs. [Copyright &y& Elsevier]

Seafood consumption is an important route of human exposure to organic contaminants. Residual levels of organochlorine pesticides (OCPs), including DDTs, hexachlorocyclohexanes (HCHs), heptachlor, aldrin, α-endosulfan, β-endosulfan, dieldrin, endrin, endrin aldehyde, endrin ketone, methoxychlor, endosulfan sulfate, and heptachlor epoxide, were determined in a wide variety of seafood products collected from 11 coastal cities in southern China in June and October 2005. The results indicated that OCPs were predominated by DDTs and HCHs. The concentrations of other OCP components generally were low and were detectable in a small number of seafood samples only, probably reflective of the generally low levels of these OCPs in the study region and low bioaccumulation potentials in the species under investigation. Risk assessment against various standards clearly showed that seafood products were highly contaminated by DDTs and may pose health threat to local residents and the consumers all over the world. Furthermore, other OCP components, such as dieldrin and heptachlor, also impose lifetime cancer risk, especially to residents of coastal regions who often consume more seafood than those living inland. Therefore, continual monitoring of OCPs in various environment compartments, including biota and abiota, urgently is needed to mitigate effectively the impact of OCPs, particularly DDTs, on human health and the ecological environment. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the residual levels and distribution characteristics of 10 organochlorine pesticides (OCPs) in the soil of agricultural lands (paddy field, vegetable field, and orchard, n = 150) nationwide. As a result of the investigation, 3-10 types of OCPs were detected in combination in 144 locations (96%) of the total 150 locations. Among those OCPs, dichlorodiphenyltrichloroethane (DDT) and endosulfan were detected in high amounts. The geometric mean concentrations of DDT and endosulfan were ∑DDT 0.31 ng g -1 (ND-2187.18 ng g -1 ) and ∑endosulfan 0.33 ng g -1 (ND-312.68 ng g -1 ), respectively. OCP concentrations were generally higher in orchards than in other agricultural fields due to a large amount of pesticides used. DDT in two orchards was detected at 2187.18 ng g -1 and 1061.78 ng g -1 , exceeding the levels stated in the Canadian DDT Soil Quality Guidance (SQG, 700 ng g -1 ). The result of applying the isomer ratio to evaluate the recent or past use of DDT, endosulfan, and hexachlorocyclohexane (HCH), which had a high detection rate, showed that it could be attributable to historical usage. DDT and HCH showed statistically similar residual distribution patterns; however, endosulfan did not show a clear correlation with DDT and HCH due to the effect of its recent use. Thus, the results of evaluation of OCP residual levels and distribution characteristics can be used for the soil management policy of OCPs in agricultural lands in Korea., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Previous epidemiological studies have shown that prenatal exposure to organochlorine pesticides (OCPs) entails a variety of adverse impacts on fetal health, but it is not yet known whether it is associated with risk for orofacial clefts (OFCs). This study of 103 fetuses or newborns with a diagnosis of OFCs (cases) and 103 healthy newborns without malformations (controls) examined whether prenatal exposure to OCPs, as indicated by their concentrations in placental tissue, is a risk factor for OFCs. No differences were found in the median concentrations of OCPs between cases and controls, with exception of o,p'-dichlorodiphenyldichloroethylene, o,p'-dichlorodiphenyldichloroethane, and total o,p'-dichlorodiphenyltrichloroethane (DDTs), whose concentrations were higher in controls than in cases (Ps < 0.05). Although higher concentrations of placental δhexachlorocyclohexane and isodrin were found to be associated with decreased risk for OFCs in logistic regression, no association was observed in the Bayesian kernel machine regression, a novel statistical model in analyzing exposure mixtures. Women who reported periconceptional folic acid supplementation had lower placental concentrations of DDTs than women who did not. In conclusion, no association between levels of OCPs in placental tissue and risk for OFCs was observed in this population. Supplementation with folic acid may help decrease the levels of DDTs in placental tissue, but further studies are needed to confirm this unexpected finding., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Yangtze finless porpoises (Neophocaena asiaeorientalis asiaeorientalis), inhabiting the Yangtze River, are an endangered species in China. They are threatened by various kinds of pollutants, among which persistent organic pollutants (POPs) are of special concern due to their toxicities, high persistency and bioaccumulation potential. To better understand the POP contamination status of Yangtze finless porpoises, an investigation of stranded porpoises along the Yangtze River and adjacent two major lakes in the Yangtze River basin was conducted; the concentrations of four groups of legacy POPs, i.e., hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyl (PCBs), were determined in the blubber samples. The mean concentrations of ΣHCHs (the sum of all congeners/isomers), ΣDDTs, ΣPBDEs and ΣPCBs, were 1670 ± 4210, 28,800 ± 52,300, 141 ± 174, and 1020 ± 1070 ng/g lipid weight, respectively; the high DDTs/PCBs ratio reflected a strong influence of agricultural pollution in the Yangtze River basin, and the high α/γ ratio of HCH isomers indicated the usage of lindane in the corresponding areas; the predominance of low-brominated congeners of PBDEs may be related to congruent patterns in the related environmental matrices. A hazard quotient risk assessment revealed that DDTs could pose a relatively high risk to Yangtze finless porpoises compared with the risks posed by the other POPs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2019. Published by Elsevier B.V.)

Currently, there is limited information about the mechanism of the human transplacental transfer for organochlorine pesticides (OCPs). This study aimed to evaluate the transplacental transfer of OCPs to better understand the influencing factors of exposure and transplacental efficiency. The study involved quantitative determination of OCPs and the enantiomer fraction (EF) of chiral OCPs in pregnant women from Wuhan, China. The results indicate that the exposure levels of OCPs varied in the order: maternal serum > cord serum > placenta. Chiral contaminants, such as α-HCH, o,p ′ - DDD and o,p ′ - DDT, were non-racemic in the three biological matrices, wherein EF α-HCH < 0.5, EF o,p ′ - DDD < 0.5, EF o,p ′ - DDT > 0.5. For HCHs, the concentration ratio between cord serum and maternal serum (R cm) <1, while for DDXs, the R cm ≈ 1, indicating that the transport efficiency of different pollutants is related to the physicochemical properties. These results showed that placenta seems to be a more efficient barrier for β-HCH than for p,p ′ - DDE. The concentration ratios across placenta significantly lower than 1 and the enantiomeric selective transfer imply that some OCPs may have more complicated maternal-fetus transfer mechanisms, involving both simple diffusion and active transport. To the best of our knowledge, this is the first study to investigate the transfer of OCPs and their enantiomer fractions across placenta. These findings could expand the database of chemical exposure in biological matrices and improve the understanding of the mechanisms of transplacental transfer of OCPs. Unlabelled Image • OCPs exposure varied in the order: maternal serum > cord serum > placenta. • Chiral contaminants were non-racemic in all three biological matrices. • OCPs have different transport efficiency related to the physicochemical properties. • Enantiomeric selective transfer observed for α-HCH. • Placenta seems to be a more efficient barrier for β-HCH than for p,p′- DDE. [ABSTRACT FROM AUTHOR]

Organochlorine pesticides are groups of chemicals applied to prevent pest and insect infestation. This study was aimed at investigating the concentration, potential sources, cancer risk and ecological toxicity of organochlorine pesticides (OCPs) in Huangpi district, Wuhan, China. Eight OCPs in soil samples collected from four land-use types at depths of 0⁻10 and 10⁻20 cm were examined. Sample extraction was carried out by solid phase matrix extraction method and analyzed using Agilent gas chromatograph 7890B equipped with electron capture detectors (ECD). The total concentration of OCPs ranged from 0.00⁻32.7 ng g -1 in the surface and 0.01⁻100.45 ng g -1 in the subsurface soil layer. Beta hexachlorocyclohexanes (β-HCH) with 2.20 and 7.71 ng g -1 in the surface and subsurface soil layers, respectively, was the dominant compound. The mean concentrations of OCPs in all samples were less than the threshold values for hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethane (DDTs) in China soil. Concentration of OCPs in the four land-use types were in the order of: paddy field > barren land > farmland > plastic greenhouse. Results of composition analysis revealed recent application of lindane as a major and historical use of new technical HCHs as a minor source of HCHs. On the other hand, application of new technical p,p'-DDT is the main source of DDTs in the study area. The estimated lifetime average daily dose, incremental lifetime cancer risks and hazard quotient values revealed that there is less likelihood of carcinogenic and noncarcinogenic health risks on the local residents.

A total of 27 shallow groundwater samples were collected from the Taihu Lake region (TLR), to determine the concentrations of 14 organochlorine pesticide (OCP) species, identify their possible sources, and estimate health risk of drinking the shallow groundwater. All OCP species occurred in the shallow groundwater of TLR with high detection frequency except p, p'-dichlorodiphenyldichlorothane (p, p'-DDD) and p, p'-dichlorodiphenyltrichloroethane (p, p'-DDT). DDTs and hexachlorocyclohexanes (HCHs) were the dominant OCP contaminants in the shallow groundwater of TLR, and they account for 44.2% total OCPs. The low α-HCH/γ-HCH ratio, high β-HCH/(α+γ)-HCH ratio and β-HCH being the dominant HCH isomers for the majority of samples suggest that the HCHs were mainly from the historical use of lindane after a period of degradation. p, p'-DDE being the dominant DDT metabolite for all the samples indicated that the DDTs were mainly from the historical residues. Compositional analysis also suggested that there were fresh input sources of heptachlors, aldrins and endrins in addition to the historical residues. Correlation analysis indicated the hexachlorobenzene (HCB) impurity in the shallow groundwater of TLR was likely from the historical application of lindane and technical HCH (a mixture of HCH isomers that is produced by photochlorination of benzene). Carcinogenic risk values for α-HCH, heptachlor, heptachlor epoxide, aldrins and dieldrin in the shallow groundwater in majority area of TLR were found to be >10(-6), posing a potentially serious cancer risk to those dependant on shallow groundwater for drinking water., (© 2013.)