Accumulation Of Organochlorine Pesticides Research Articles

Levels and enantiomeric signatures of organochlorine pesticides in Chinese forest soils: Implications for sources and environmental behavior

We investigated the levels and distributions of organochlorine pesticides (OCPs) in 159 background soil samples collected from 30 forested mountain sites across China. The sum of DDT was the most abundant OCP, with the concentrations of 0.197–207 ng/g and 0.033–122 ng/g in the O-horizon and A-horizon, respectively. High concentrations of OCPs usually occur near agricultural regions or high consumption areas. The spatial distribution was mainly influenced by the emission sources and soil total organic contents (TOC). The chiral compounds were generally nonracemic in the soils and showed preferential degradation of (−) o,p′- dichlorodiphenyltrichloroethane, (+) trans-chlordane, and (−) cis-chlordane in both the O- and A-horizons. The enantiomeric fraction (EF) distributions of chiral OCPs displayed no differences across the forest sites in the O-horizon or the A-horizon. Comparing the deviation of EFs from racemic (DEVrac = absolute value of 0.500 - EF) with environmental parameters, we found that DEVrac of cis-chlordane demonstrated a strong positive correlation with TOC (p < 0.05) and the C/N ratio (p < 0.01). This relationship suggests that these factors could affect the microbial activity and significantly impact the extent of enantioselective degradation of chiral compounds in the soils. Fresh and historical applications of DDT and historical chlordane and endosulfan uses may be prominent sources of OCP accumulation in Chinese forest soils.

Age dependence accumulation of organochlorine pesticides and PAHs in needles with different forest types, southeast Tibetan Plateau.

In this study, organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in needle leaves with different ages were measured in three prevalent coniferous forests including spruce, fir and pinus in southeast Tibetan Plateau (TP) to investigate accumulation behavior of persistent organic pollutants (POPs) during entire growth cycle of needles. The accumulation concentration of POPs was higher in pinus and fir needles than in spruce needles. Concentrations for most of OCPs significantly increased with needle ages, especially dichlorodiphenyltrichloroethane (DDT) and its metabolites showed more remarkable increasing trend than hexachlorocyclohexane isomers (HCHs) and hexachlorobenzene (HCB) in the three tree species. However, age dependence accumulation of PAHs was not observed in most cases, possibly due to its easier degradation property and the influence by dramatic change of ambient atmospheric concentration of PAHs. The lipid normalized concentrations in needles exhibited similar accumulation pattern with that of dry weight basis. The controlling factors for concentration variation in needles were identified using multiple linear regression. The suitability of these needle species acting as potential passive sampler for atmospheric POPs was evaluated. The different-age needles could reflect atmospheric OCP concentrations in the past long-term trend. Findings of this study provide guidance in use of needle as passive samples for the background monitoring of the atmospheric contamination at remote and poorly accessible locations such as the TP.

Environmental monitoring and recommendations on decreasing the levels of pesticide pollution in Zhytomyr region of Ukraine

Environmental monitoring was conducted of facilities for storage and disposal of banned and unsuitable pesticides. Pesticide content in the soil, water, and products of agriculture in the Zhytomyr region of Ukraine was examined, and the accumulation of organochlorine pesticides by freshwater bivalve mollusks was assessed. Storage facilities of the Zhytomyr region contain nearly 392.18 t of pesticides in 137 warehouses, of which 11 meet the requirements, 36 are tolerable, and 90 are in poor condition. In 2018–2019, pesticide content (dichlorodiphenyltrichloroethane (DDT), heptachlor, dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), hexachlorocyclohexane (HCH)) was studied in soil and sediments in the Zhytomyr region. The content ranged from 0.0007 to 0.07 mg/kg, which is lower than MPC (0.1 mg/kg). The content of HCH, DDT, DDE, DDD, and heptachlor was at 0.0007–0.01 mg/dm3 levels in water bodies of the Zhytomyr region in 2018–2019, also lower than MPC. In some samples of soil, water and vegetables, the recorded levels of DDT and organophosphate pesticides Dragon, Dorpan, and Dursban exceeded MPC in 1.5–3.0 times. Traces of organochlorine pesticide Aldrin were found in soft tissues of bivalve mollusks and in the sediments of water bodies they inhabit. Recommendations are proposed to lower the pesticide content in the environment.

Dietary exposure and risk assessment of organochlorine pesticide residues in rural communities living within catchment areas of iSimangaliso World Heritage Site, South Africa.

Dietary intake of contaminated food is a major route of human exposure to organochlorine pesticides (OCPs). Despite the prevalence of OCP usage in southern Africa for several decades, their impact on socioeconomically vulnerable communities remains largely overlooked. We investigated the accumulation of OCPs in crops commonly cultivated by rural communities surrounding iSimangaliso Wetland Park, South Africa. All samples analysed were found to be contaminated, with total OCP concentrations ranging between 190 and 240ngg-1 ww. Elevated levels of OCP residues were detected in all products, with the majority of samples exceeding European Commission's maximum residue limits (MRLs). We combine these results with local OCP fish tissue estimates to assess potential dietary risks. Cumulative risk assessment indicated potential non-cancer risks associated with heptachlor epoxide, while a cancer risk as high as 1 in 10 was found to be associated with aldrin and dieldrin. This far exceeds USEPA guidelines and indicates that OCP residues in crops and fish from the study area pose a high risk to human health. The results of this study call for further attention to be given to the health implications of continued OCP use not only within the study area but also in Southern Africa in general.

Evaluation of the accumulation of organochlorine pesticides (ocps) in &lt;i&gt; Bostrychus sinensis &lt;/i&gt; fish growing the soai rap estuary - Ho Chi Minh city

Evaluation of the accumulation of organochlorine pesticides (ocps) in &lt;i&gt; Bostrychus sinensis &lt;/i&gt; fish growing the soai rap estuary - Ho Chi Minh city

Analysis for Organochlorine Pesticide Residues in Honey from Kabale District, South-Western Uganda

This study was motivated by the reported accumulation of Organochlorine Pesticides (OCPs) residues in the various environmental matrices within Uganda, resulting from their use in agriculture and health sectors. This raised a concern of the likelihood of the accumulation of the OCPs residues in the honey produced within the country which would affect its purity as well as quality and consequently its competition on the world market. Sixty representative honey samples were collected from selected local beekeepers from four sampling stations in Muko sub-county, Kabale, and extracted for OCPs using a solid-phase procedure followed by a florisil column packed clean-up method and Gas Chromatography-Electron Capture Detector (GC-ECD) analysis. Confirmation of the selected samples was done using an Agilent (6890N, USA) gas chromatograph combined with a mass spectrometer. Recoveries of spiked samples ranged from 71% to 96%, except for pp-DDE (54%), with relative standard deviations from 2% to 14% in terms of repeatability, and from 4% to 17% in terms of reproducibility. Limits of quantification were from 0.003 to 0.1 mg·kg-1. Endosulfan sulfate was the most frequently detected in 38% of the samples, followed by HexaChloroBenzene (Lindane) in 21% of the samples. Residues of DDT and their metabolites were detected in 17% of the samples. Mean concentrations of the pesticide residues detected range from ND (not detected) to 1.53 μg/Kg. The acceptable Maximum residual limits (MLRs) are 200 - 300 μg·kg-1 fresh weight for dieldrin, 500 μg·kg-1 for DDT and break down products, and 50 μg·kg-1 wet weight for Lindane (WHO/FAO 2011). Results indicate that the levels of OCP residues detected in honey from the country’s South Western District of Kabale were within the acceptable limits, and hence this honey was safe for human consumption.

Accumulation of organochlorine pesticides in reef organisms from marginal coral reefs in South Africa and links with coastal groundwater

Coral reefs support rich levels of biodiversity, but are globally threatened by a multitude of factors, including land-sourced pollutants. Concentrations of organochlorine pesticides (OCPs) in three species of coral reef invertebrate at five sites along the Maputaland coast, South Africa were quantified. We aimed to assess spatial and interspecies variations in pesticide accumulation. Markedly high levels of a range of OCP residues were detected within tissues, with total concentrations (ng g−1 ww) ranging from 460 to 1200 (Sarcophyton glaucum), 1100–3000 (Sinularia gravis) and 450–1500 (Theonella swinhoei), respectively. A decreasing gradient in total pesticide concentrations was detected southward from Regal Reef, opposite Lake Sibaya, the hypothesised source of the pollutants. Observed gradients in pesticide concentrations and nitrogen isotope signatures indicated coastal groundwater to be the likely source of the pollutants. Further studies are required to assess the potential ecotoxicological impacts of these contaminants at the organismal and ecosystem level.

Investigating the Spatial Trends in the Level of Organic Contaminants in the Ethiopian Rift Valley Lakes Using Semipermeable Membrane Devices.

Organic pollutants in the Ethiopian Rift Valley Lakes are the major factors that contribute to severe environmental problem. SPMDs were deployed for the analysis of selected organic pollutants for 1 month at 2 sites in Lakes Hawassa, Ziway and Koka, Ethiopia. From SPMDs placed in the three lakes, the predominant OCPs were DDT which comprise 67% and followed by endosulfan 23% of the total organochlorine pesticides (OCPs) retrieved. The highest level of OCPs, in general, was found in the SPMDs deployed in Lake Ziway with the mean concentration of 308.5ng/SPMD. However, the concentrations of polychlorinated biphenyls (PCBs) were the highest in the SPMDs deployed in Lake Hawassa with mean concentration of 50.2ng/SPMD. Spatial variation on the accumulation of OCPs and PCBs among the lakes depends on the shoreline activities, distance of the lakes from point and non-point sources, and the biofouling factors.

Organochlorine pesticide accumulation in seabirds and marine mammals from the Northwest Pacific

Bioaccumulation of organochlorine pesticides by marine organisms is one of the methods of environmental quality. Concentrations of organochlorine pesticides (HCH isomers (α-, β-, γ-HCH), p,p′-DDT and its metabolites (p,p′-DDD, p,p′-DDE)) in samples of seabirds (Northern fulmar Fulmarus glacialis, Crested auklet Aethia cristatella, Auklet-crumb Aethia pusilla, Pacific gull Larus schistisagus, and Gray petrel Oceanodroma furcate) and marine mammals (Gray whales Eschrichtius robustus and Pacific walrus Odobenus rosmarus divergens) were measured by a GC–MS. The total concentration of OCPs in mammals was higher than in seabirds. Environmental biomonitoring with the use of seabirds and marine mammals, as a long-lived species, is used for global monitoring, since bioaccumulation in these organisms occurs throughout life. The environmental assessment of the Northwest Pacific marine ecosystems revealed that the levels of OCP contamination in this area are similar to the other subarctic regions of the World Ocean.

Accumulation of organochlorine pesticides in fat tissue of wild Nile crocodiles (Crocodylus niloticus) from iSimangaliso Wetland Park, South Africa

Nile crocodiles (Crocodylus niloticus) are important apex predators in many tropical and subtropical aquatic habitats throughout much of sub-Saharan Africa. In South Africa, large crocodile populations inhabit lakes and wetlands that are impacted by organochlorine pesticides (OCPs). Despite the continued use of these compounds and their potential adverse effects on key wildlife populations in southern Africa, limited ecotoxicoloigcal data exist. In this study, we examined the accumulation of OCPs in fat tissues of live, wild Nile crocodiles from iSimangaliso Wetland Park, a region of significant biological importance. All samples (n = 15) contained multiple contaminants in highly elevated concentrations, with total residue burdens varying between 3600 and 8000 ng g−1 ww. DDT and its metabolites were the dominant compounds detected in most samples, with ∑DDT concentrations ranging between 520 and 3100 ng g−1 ww. Elevated levels of other OCPs were also detected, including lindane (67–410 ng g−1 ww), aldrin (150–620 ng g−1 ww) and heptachlor (170–860 ng g−1 ww). Our findings show that crocodiles are exposed to OCPs throughout their range within iSimangaliso Wetland Park and contain some of the highest concentrations ever recorded in crocodilian tissue. Results indicate the need for a greater understanding of the impacts of OCP exposure and toxicological responses in crocodiles from iSimangaliso, and in Nile crocodile populations in general. The novel surgical technique described in this study provides an effective method for assessing relationships between contaminant body burdens and their potential reproductive and developmental consequences in crocodilians.

Multi-residue determination of organochlorine pesticides in vegetables in Kirklareli, Turkey by gas chromatography–mass spectrometry

The aim of this study was to investigate the level of organochlorine pesticides use for treatment of tomatoes, eggplants and cucumbers in Kirklareli, Turkey. Eighteen organochlorine pesticides were identified in vegetable samples using microwave or Soxhlet extraction, and results were obtained by gas chromatography–mass spectrometry. The optimized conditions were 1 mL/min for flow rate in the mobile phase, 1 μL for injection volume and 70 V for fragmentation potential. The analytical parameters show that the microwave oven extraction procedure provided the best results when compared to the Soxhlet extraction procedure. Samples were prepared for analysis with hexane‒dichlormethane (1: 1, v/v, 40 mL) using a solid-phase extraction method. The limits of detection and quantitation for the eighteen analytes were between 0.02–0.26 and 0.06–0.87 μg/L, respectively, and the relative standard deviations of the migration time ranged from 2.4 to 8.9%. The recoveries of surrogate spiked in vegetable samples ranged from 70 to 116%, respectively. The obtained concentrations of pesticides in all vegetables studied were proved in the range of ND–123 μg/kg. The organochlorine pesticide sum was below the legal limit, except for Endrin and Methoxychlor, which requires a further elucidation of the organochlorine pesticides pollution sources in the region. These studies on accumulation of organochlorine pesticides were necessary for accomplishing a comprehensive ecological risk assessment.

Organochlorine pesticides accumulation and breast cancer: A hospital-based case-control study.

The aim of this study is to detect the accumulation status of organochlorine pesticides in breast cancer patients and to explore the relationship between organochlorine pesticides contamination and breast cancer development. We conducted a hospital-based case-control study in 56 patients with breast cancer and 46 patients with benign breast disease. We detected the accumulation level of several organochlorine pesticides products (β-hexachlorocyclohexane, γ-hexachlorocyclohexane, polychlorinated biphenyls-28, polychlorinated biphenyls-52, pentachlorothioanisole, and pp'-dichlorodiphenyldichloroethane) in breast adipose tissues of all 102 patients using gas chromatography. Thereafter, we examined the expression status of estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 (HER2), and Ki-67 in 56 breast cancer cases by immunohistochemistry. In addition, we analyzed the risk of breast cancer in those patients with organochlorine pesticides contamination using a logistic regression model. Our data showed that breast cancer patients suffered high accumulation levels of pp'-dichlorodiphenyldichloroethane and polychlorinated biphenyls-52. However, the concentrations of pp'-dichlorodiphenyldichloroethane and polychlorinated biphenyls-52 were not related to clinicopathologic parameters of breast cancer. Further logistic regression analysis showed polychlorinated biphenyls-52 and pp'-dichlorodiphenyldichloroethane were risk factors for breast cancer. Our results provide new evidence on etiology of breast cancer.

Organochloride pesticides impaired mitochondrial function in hepatocytes and aggravated disorders of fatty acid metabolism

p,p’-dichlorodiphenyldichloroethylene (p, p’-DDE) and β-hexachlorocyclohexane (β-HCH) were two predominant organochlorine pesticides (OCPs) metabolites in human body associated with disorders of fatty acid metabolism. However, the underlying mechanisms have not been fully clarified. In this study, adult male C57BL/6 mice were exposed to low dose of p, p’-DDE and β-HCH for 8 wk. OCPs accumulation in organs, hepatic fatty acid composition, tricarboxylic acid cycle (TCA) metabolites and other metabolite profiles were analyzed. Expression levels of genes involved in hepatic lipogenesis and β-oxidation were measured. Mitochondrial function was evaluated in HepG2 cells exposed to OCPs. High accumulation of p, p’-DDE and β-HCH was found in liver and damaged mitochondria was observed under electron microscopy. Expression of genes in fatty acid synthesis increased and that in mitochondrial fatty acid β-oxidation decreased in OCPs treatment groups. OCPs changed metabolite profiles in liver tissues, varied hepatic fatty acid compositions and levels of several TCA cycle metabolites. Furthermore, MitoTracker Green fluorescence, ATP levels, mitochondrial membrane potential and OCR decreased in HepG2 cells exposed to OCPs. In conclusion, chronic exposure to OCPs at doses equivalent to internal exposures in humans impaired mitochondrial function, decreased fatty acid β-oxidation and aggravated disorders of fatty acid metabolism.

Sources, atmospheric transport and deposition mechanism of organochlorine pesticides in soils of the Tibetan Plateau

Because of mountain cold-trapping, the soil in the Tibetan Plateau may be an important global sink of organochlorine pesticides (OCPs). However, there are limited data on OCPs in the soils of the Tibetan Plateau. In addition, the atmospheric transport and deposition mechanisms of OCPs also need to be further studied. In this study, the sampling area covered most regions of the Tibetan Plateau. The detection frequencies of ΣChlordane (sum of trans-chlordane, cis-chlordane and oxychlordane), HCB, ΣNonachlor (sum of trans- and cis-nonachlor), DDTs, ΣEndo (sum of endosulfan-I, endosulfan-II and endosulfate), aldrin, HCHs, ΣHeptachlor (sum of heptachlor and heptachlor epoxide), mirex and dieldrin were 100%, 98.3%, 96.6%, 94.8%, 89.7%, 87.9%, 62.1%, 55.2%, 32.8% and 6.9%, respectively. DDTs (with arithmetic mean values of 1050ngkg−1 dw) and HCHs (393ngkg−1) were the principal OCPs in cultivated soils, whereas ΣEndo (192ngkg−1) and ΣChlordane (152ngkg−1) were the principal OCPs in non-cultivated soils. Local use of DDTs, dicofol and HCHs may be an important source of OCP accumulation in the soil of the Tibetan Plateau. Aldrin and endosulfan are considered to be good indicators for studying atmospheric transport and deposition of OCPs from South Asia and Southeast Asia. Two zones with high OCP levels were found in the southeast and northwest of the Tibetan Plateau. The zones have dissimilar pollution sources of OCPs and are influenced by different factors that affect their precipitation scavenging efficiency. The amount of precipitation was the dominant factor in the southeast, whereas large differences in temperature and wind speed were the dominant factors in the northwest.

Organochlorine pesticides in agricultural soils and associated biota

The behavior of organochlorine pesticides (OCPs), such as DDTs, endosulfans, HCHs, heptachlors, drins and chlordanes, has been evaluated in the Quequen Grande River agricultural watershed including different matrices. Soil profiles from fields dedicated to soybean cultures and the associated terrestrial biota (earthworms, coleopteran larvae, collembolan and mites), stream water, suspended particle matter and surface sediment were sampled during the pre-application pesticide period. Pesticide analyses were carried out using gas chromatography with an electron capture detector. Soils samples showed a differential pesticide pattern throughout the profile. Control soils, settled 200 m from agricultural plots showed similar pesticide levels but with higher variety of compounds, denoting the historical use of OCPs in the zone. However, in agricultural plots DDTs and endosulfans constituted 90 % of the pesticides found with a further enrichment of endosulfan sulfate at depth. The relatively high p,p′-DDT levels in surface agricultural soil would be a consequence of pesticide impurities in technical acaricide Dicofol, which is widely used in the region; and it represents a new threat of fresh p,p′-DDT input into environment despite its use being forbidden. Terrestrial biota, mainly mesofauna showed high capacity to OCP accumulation, the aforementioned organisms being a good option in the monitoring of trace pesticides. Furthermore, the high OCP levels found constitute a hazard to food web since these organisms are one of the first steps in the food chain and the biomagnification is a common process with these compounds. As a result of runoff and volatilization the occurrence of OCPs in the aquatic environment was observed, draining a load of around 7.3 kg of pesticides into the river annually. As a whole, these results suggest the importance of using terrestrial biota for studying recalcitrant pesticides and a continuous monitoring is strongly advised as a first step in minimizing environmental risks.

Assessment of Pesticide Residues in Commonly Used Vegeta-Bles in Meerut District, Western Uttar Pradesh, India

The study was conducted on 07 vegetable samples collected from the near vicinity of Meerut district, under Western Uttar Pradesh, where variable kinds of vegetables are grown. The results indicate that the contents of OCPs range varied from ND to 3.80 ig/kg and the pollution among the samples is classified as a low level in comparison with other investigations. Among the samples, organo-chlorine pesticides like â-BHC varied from ND to3.68 (ig/kg) and it was maximum detected in radish collected from Jalalpur village followed by in brinjal from Senni village. Heptachlor epoxide found in two vegetable samples in ranged from ND to 3.80 (ig/kg) and observed in radish from Jalalpur (3.80ig/kg) and okra collected from Lawar (1.20ig/kg). Endosulphan I (2.46 ig/kg) and endrin (1.40 ig/kg) found only in one sample of radish which was collected from Jalalpur. However, Aldrin, heptachlore, fipronil, a-BHC, 4,4 DDT and 4,4 DDE not found in samples. Among all the vegetable samples, redish collected from the Jalalpur village was not found suitable for human consumption due to more accumulation of organo-chlorine pesticides.

Fish Oil Contaminated with Persistent Organic Pollutants Reduces Antioxidant Capacity and Induces Oxidative Stress without Affecting Its Capacity to Lower Lipid Concentrations and Systemic Inflammation in Rats1–3

Background: Numerous studies have investigated the benefits of fish, fish oil, and ω-3 (n–3) polyunsaturated fatty acids against cardiovascular diseases. However, concern surrounding contamination with persistent organic pollutants (POPs) prompts caution in the recommendation to consume fish and fish oil.Objective: The present study compared the effects of fish oil contaminated with polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) on serum lipid profiles, inflammation, and oxidative stress.Methods: Twenty eight-day-old male Sprague-Dawley rats (n = 30) consumed diets of unmodified fish oil (FO) consisting of 15% fat by weight, persistent organic pollutant–contaminated fish oil (POP FO) (PCBs at 2.40 μg/g; OCs at 3.80 μg/g FO), or corn oil (control; CO) for 9 wk. Lipid profiles and C-reactive protein concentrations were assessed. Hepatic gene expression related to lipid metabolism was determined by real time quantitative polymerase chain reaction analysis.Results: After 9 wk of feeding, accumulation of PCBs and OCs in the fat tissue of the POP FO group compared with the other 2 groups was confirmed (P < 0.01). Both fish oil groups showed greater HDL cholesterol (FO 53 ± 5.3 and POP FO 55 ± 7.7 vs. CO 34 ± 2.3 mg/dL), but lower triglycerides (24 ± 2.8 and 22 ± 3.0 vs. 43 ± 5.6 mg/dL), LDL cholesterol (38 ± 14 and 34 ± 9.2 vs. 67 ± 4.4 mg/dL), and C-reactive protein (113 ± 20 and 120 ± 26 vs. 189 ± 22 μg/dL) compared with the CO group (P < 0.05). Gene expression of fatty acid synthase in both fish oil groups was also less than in the CO group (P < 0.05). However, the POP FO group showed greater lipid peroxidation (5.1 ± 0.7 vs. 2.9 ± 0.9 and 2.6 ± 0.6 μM) and less antioxidant capacity (0.08 ± 0.06 vs. 0.5 ± 0.1 and 0.4 ± 0.1 mM) than the CO and FO groups (P < 0.05).Conclusions: These findings indicate that, despite exhibiting benefits on serum lipid concentrations and inflammation, contamination with PCBs and OCs showed significant negative effects on oxidative stress and antioxidant capacity in rats. Future studies should investigate the effects of different contaminant doses and the possibility of a dose-dependent response, a lengthened feeding time, and interactions between contaminant mixtures and oils of varying composition to advise on dietary consumption of fish and fish oil.

Organochlorine pesticide level differences among female inhabitants from Veracruz, Puebla and Tabasco, Mexico.

Organochlorine pesticides have been used in Mexico in malaria control programs and against ectoparasites. The objective of this study was to compare the levels of organochlorine pesticides: HCB, α-β-γ-HCH, pp'-DDE, op'-DDT and pp'-DDT in adipose tissue of female inhabitants from three Mexican states: Veracruz, Puebla and Tabasco. Data analyses indicated higher β-HCH levels in Puebla inhabitants. When comparing the mean values of the pp'-DDE concentrations among the three states, no statistically significant differences were noted. A trend of increasing concentrations of op'-DDT from Veracruz to Puebla and Tabasco was observed. Significantly higher pp'-DDT concentrations in Veracruz as compared to Puebla and Tabasco were determined. Using factorial analysis of three age categories (>30, 31-50, <51) organochlorine pesticide concentrations increases with age of participants, indicating time of exposure as a principal factor of organochlorine pesticides accumulation in adipose tissue.

Factors influencing the accumulation of organochlorine pesticides in the surface soil across the Central Tibetan Plateau, China

Forty-four soil samples were collected across the Central Tibetan Plateau (CTP) at elevations of between 3711 and 5352 m. The scatter diagram shows that the soil concentrations of organochlorine pesticides (OCPs) were associated with the altitude of sampling site, soil clay minerals, soil organic carbon (SOC) and the fine particle fractions of soil. Pearson correction analysis and principle component analysis were used to deduce the relationship between the OCP concentrations and these factors logically. It was determined that the altitude and clays functioned as the primary factors influencing OCP accumulation, and SOC was weakly related to OCPs. The fitting equation closely matches the observations in the field while only taking the altitude and clay minerals into account. Our study found that clay minerals dominated the sorption of OCPs in soil, whereas the altitude contributed to temperature-driven condensation for the accumulation of OCPs at high altitudinal CTP.

Assessment of persistent organic pollutants accumulation and lipid peroxidation in two reproductive stages of wild silverside (Odontesthes bonariensis)

Persistent organic pollutants (POPs) in streamwater can sometimes exceed the guidelines values reported for biota and human protection in watersheds with intensive agriculture. Oxidative stress and cytotoxicity are some of the markers of exposure to POPs in fish. Accumulation of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) as well as lipid peroxidation (LPO) was assessed in wild silverside (Odontesthes bonariensis) from maturation and pre-spawning stages sampled in a typical soybean growing area. Pollutants were quantified by gas chromatography with electron capture detection and LPO by the method of thiobarbituric acid reactive substances. Concentrations of POPs were in the following order: OCPs>PCBs>PBDEs in all organs and stages. Liver, gills and gonads had the highest OCP concentrations in both sexes and stages with a predominance of endosulfan in all samples. Matured individuals, sampled after endosulfan application period, showed higher endosulfan concentrations than pre-spawning individuals. The predominance of endosulfan sulfate could be due to direct uptake from diet and water column, as well as to the metabolism of the parent compounds in fish. The prevalence of p,p′-DDE in liver would also reflect both the direct uptake and the metabolic transformation of p,p′-DDT to p,p′-DDE by fish. The highest levels of PBDEs and PCBs were found in gills and brain of both stages of growth. The pattern BDE-47>BDE-100 in all samples corresponds to pentaBDE exposure. In the case of PCBs, penta (#101 and 110) and hexa-CB congeners (#153 and 138) dominated in the maturation stages and tri (#18) and tetra-CB (#44 and 52) in pre-spawning stages, suggesting biotransformation or preferential accumulation of heavier congeners during gonadal development. Differences in LPO levels in ovaries were associated with growth dilution and reproductive stage. Differences in LPO levels in gills were related with pesticide application periods. As a whole, endosulfan, a current-use pesticide, constituted the main pollutant found in wild silverside reflecting the intense agriculture activity in the study area. Moreover endosulfan was positively correlated with LPO.