Organochlorine pesticides (OCPs) in freshwater resources of Pakistan: A review on occurrence, spatial distribution and associated human health and ecological risk assessment.

The extensive use of organochlorine pesticides (OCPs) has resulted in the widespread contamination of different environmental matrices in Pakistan. Freshwater bodies are also prone to OCPs contamination as they receive agricultural and industrial runoff from different sources. In the present study, the data regarding OCPs' fate and distribution in freshwater resources of Pakistan was reviewed and associated risks to human and ecological health were assessed. Among all the OCPs, DDTs were more prevalent with the highest mean concentration of 2290 ng/L observed in River Ravi (Lahore and Sahiwal District). Human health risk assessment showed a higher risk to the children with high Hazard Quotient (HQ) values ranging between 4.1 × 10-9- 295 for Aldrin. The River Ravi (Lahore and Sahiwal District), the River Sutlej (Kasur & Bahawalpur District), and the River Kabul (Nowshehra District) were categorized as high-risk water bodies based on Hazard Index (HI) and Non-Cancer Risk (CRI) index values > 10. Ecological risk assessment revealed a higher risk posed to invertebrate species from DDT exposure. In summary, this review highlights the occurrence and distribution of OCPs and their associated human health and ecological risks in freshwater bodies of Pakistan and also contributes to signifying the need for proper management and regulation of banned pesticides and future research perspectives.

Organochlorine pesticides (OCPs) in corals and plankton from a coastal coral reef ecosystem, south China sea.

Recent studies have indicated that coral mucus plays an important role in the bioaccumulation of a few organic pollutants by corals, but no relevant studies have been conducted on organochlorine pesticides (OCPs). Previous studies have also indicated that OCPs widely occur in a few coral reef ecosystems and have a negative effect on coral health. Therefore, this study focused on the occurrence and bioaccumulation of a few OCPs, such as dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzene (HCB) and p,p'-methoxychlor (MXC), in the coral tissues and mucus as well as in plankton and seawater from a coastal reef ecosystem (Weizhou Island) in the South China Sea. The results indicated that DDTs were the predominant OCPs in seawater and marine biota. Higher concentrations of OCPs in plankton may contribute to the enrichment of OCPs by corals. The significantly higher total OCP concentration (∑8OCPs) found in coral mucus than in coral tissues suggested that coral mucus played an essential role in resisting enrichment of OCPs by coral tissues. This study explored the different functions of coral tissues and mucus in OCP enrichment and biodegradation for the first time, highlighting the need for OCP toxicity experiments from both tissue and mucus perspectives.

Selected Persistent Organic Pollutants in Ambient Air in Turkey: Regional Sources and Controlling Factors.

As a result of its unique location, Turkey receives air masses from Europe, Russia, Middle East, and Africa, making it an important place in terms of long-range atmospheric transport (LRT) of contaminants. Atmospheric levels of 22 organochlorine pesticides (OCPs), 45 polychlorinated biphenyls (PCBs), and 14 polybrominated diphenyl ethers (PBDEs) were measured in two metropolitan cities, Istanbul and Izmir, on a weekly basis from May 2014 to May 2015. Dichlorodiphenyltrichloroethane (DDT) and its derivatives were dominant OCP species, followed by isomers of hexachlorocyclohexane (HCH) at both sites. The annual mean concentration of ∑DDX (sum of o,p'-DDT, p,p'-DDT, o,p'-DDD, p,p'-DDD, o,p'-DDE, and p,p'-DDE) was 82 pg/m3 for Istanbul and 89 pg/m3 for Izmir, while these levels were about 46 pg/m3 for ∑HCHs (sum of α-, ß-, γ-, and δ-HCH) at both of the sites. At both stations, tri- and tetra-PCBs and tetra- and penta-PBDEs were dominant congeners. The temperature dependence indicates that both LRT and local contaminated areas contribute to the elevated levels. A Lagrangian particle dispersion model (FLEXPART) showed a few potential source regions in northern Africa and Middle East, southern-southwestern and eastern Europe including Russia, as well as from local domestic metropolitan areas.

Novel Bayesian Method to Derive Final Adjusted Values of Physicochemical Properties: Application to 74 Compounds.

Accurate values of physicochemical properties are essential for screening semivolatile organic compounds for human and environmental hazard and risk. In silico approaches for estimation are widely used, but the accuracy of these and measured values can be difficult to ascertain. Final adjusted values (FAVs) harmonize literature-reported measurements to ensure consistency and minimize uncertainty. We propose a workflow, including a novel Bayesian approach, for estimating FAVs that combines measurements using direct and indirect methods and in silico values. The workflow was applied to 74 compounds across nine classes to generate recommended FAVs (FAVRs). Estimates generated by in silico methods (OPERA, COSMOtherm, EPI Suite, SPARC, and polyparameter linear free energy relationships (pp-LFER) models) differed by orders of magnitude for some properties and compounds and performed systematically worse for larger, more polar compounds. COSMOtherm and OPERA generally performed well with low bias although no single in silico method performed best across all compound classes and properties. Indirect measurement methods produced highly accurate and precise estimates compared with direct measurement methods. Our Bayesian method harmonized measured and in silico estimated physicochemical properties without introducing observable biases. We thus recommend use of the FAVRs presented here and that the proposed Bayesian workflow be used to generate FAVRs for SVOCs beyond those in this study.

The biological pump effects of phytoplankton on the occurrence and benthic bioaccumulation of hydrophobic organic contaminants (HOCs) in a hypereutrophic lake.

The distribution of hydrophobic organic contaminants (HOCs) in eutrophic ecosystems has been widely studied, but how phytoplankton blooms affect their occurrence and benthic bioaccumulation is poorly understood. To fill this knowledge gap, the biological pump effects of phytoplankton on the fate of organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in sediments and benthos (Corbicula fluminea) from Lake Taihu, a hypereutrophic lake in China, were identified. The spatial-temporal distribution of HOCs suggests that higher phytoplankton biomass, coupled with sediment organic matter (SOM) content, greatly increased the concentration of HOCs in sediments in both winter and summer seasons. This could be attributed to the biological pump effects sequestering more HOCs from water to sediments with settling phytoplankton, especially during the summer. The biological pump effects further promoted the uptake of sediment-bound HOCs by benthos. The significant positive relationships between concentrations of HOCs in sediments and benthos were observed during the winter dormancy phase of benthos. Furthermore, the benthic bioaccumulation of HOCs could be strengthened by phytoplankton, due to their contribution to SOM and the following increased bioavailability of HOCs in sediments. Further research is needed to elucidate the phytoplankton biological pump effects on the fate of HOCs in benthic food chain, especially for hypereutrophic waters.

The state of persistent organic pollutants in South African estuaries: A review of environmental exposure and sources.

The long-term health of many South African estuaries is impacted by pollutants entering these systems through industrial and agricultural runoff, sewage outfalls, contaminated storm water drainage, flows from informal settlements, and plastic materials in marine debris. Uncontrolled inputs combined with poor environmental management often result in elevated levels of persistent organic pollutants (POPs) in affected estuaries. Data on POPs research from 1960 to 2020 were analysed in terms of their sources, environmental investigations, and health implications. The outcome showed polychlorinated biphenyls (PCBs) and per- and poly-fluoroalkyl sulphonates (PFASs) to exceed the US EPA health advisory levels for drinking water. Concentration of organochlorine pesticides (OCPs) in water were below the WHO limits, while those in fish tissues from most estuaries were found to be below the US FDA limits. Although environmental compartments in some estuaries (e.g. Rooiels and uMngeni estuaries) seem to be less contaminated relative to other marine systems around the world, many others were polluted and critically modified (e.g. Durban Bay, Swartkops, Sundays, and Buffalo systems). Due to inconsistent monitoring methods coupled with limited data availability, temporal trends were unclear. Of the 290 estuaries in South Africa, 65 were prioritised and recommended for POPs evaluation based on their pollution sources, and a monitoring strategy was defined in terms of sampling. Government policies to curb marine pollution need to be enforced to prevent chronic contamination that leads to water quality deterioration and loss of ecosystem services.

Organochlorines burden in moss H. cupressiforme and topsoil across Serbia.

Following up-to-date initiatives of the Stockholm Convention, its global monitoring plan, and the International Cooperative Programme on Natural Vegetation and Crops (ICP Vegetation 2015) under the convention on long-range transboundary air pollution, this study examined 17 polychlorinated biphenyls (PCBs) and seven organochlorine pesticides (OCPs) in the moss Hypnum cupressiforme Hedw. and topsoil sampled across Serbia. In the topsoil, OCPs ranged from 0.0158 to 9.6804 ng g-1 while concentrations of individual PCB congeners were in the range between 0.0185 and 0.3107 ng g-1. The levels of OCPs and PCBs in the moss H. cupressiforme ranged from 2.7785 to 23.9501 ng g-1, and from 0.4325 to 15.8013 ng g-1, respectively. POP relationships between topsoil and moss investigated by fugacity model equations indicated that the moss POP enrichment was a result of atmospheric long-range transport rather than secondary reemissions from soil.

Legacy persistent organochlorine pollutants and polycyclic aromatic hydrocarbons in the surface soil from the industrial corridor of South India: occurrence, sources and risk assessment.

Conversion of agricultural fields into the industrial corridor under the State Industries Promotion Corporation of Tamil Nadu Limited (SIPCOT) necessitated the investigation of soil-borne organic contaminants. This study is the first attempt to evaluate the occurrence of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in soils from Mambakkam and Cheyyar SIPCOT belt, along the residential, industrial and agricultural transects. Concentrations of Σ28PCBs, Σ16PAHs and OCPs were in the range 0.3-9 ng/g, 33-2934 ng/g and nd-81.4 ng/g, respectively. Residential areas showed higher OCP concentrations than other site types, probably due to their frequent use in vector control programmes. DDT isomers and α-isomer of endosulfan showed low concentrations indicating past usage of these OCPs. Principal component analysis indicated that high-temperature combustion and industrial processes might be the major sources of high molecular weight PAHs, while low-temperature combustion processes might be responsible for low molecular weight PAHs. PCBs in soil were probably attributed to unaccounted combustion processes of e-waste in the region. Carcinogenic PAHs and Σ28PCBs were higher in the industrial sites. Mean Σ28PCBs at Mambakkam (4.8 ng/g) was significantly higher (p < 0.05) than that at the incipient industrial corridor Cheyyar (2.7 ng/g). Lower chlorinated PCBs (3-Cl and 4-Cl) amounted to more than half of Σ28PCBs in 75% of the sites. Total toxic equivalents (TEQs) of PAHs (total BaPeq) were found to be maximum in industrial areas. Maximum contribution to TEQs due to dioxin-like-PCBs was from PCB-157, followed by PCB-189.

Sources, distribution, and risk assessment of organochlorine pesticides in Nairobi City, Kenya.

The distribution and sources of organochlorine pesticides (OCPs) in air and surface waters were monitored in Nairobi City using triolein-filled semipermeable membrane devices (SPMDs). The SPMDs were extracted by dialysis using n-hexane, followed by cleanup by adsorption chromatography on silica gel cartridges. Sample analysis was done by GC-ECD and confirmed by GC-MS. Separation of means was achieved by analysis of variance, followed by pair-wise comparison using the t-test (p≤ 0.05). The total OCPs ranged between 0.018 - 1.277 ng/m3 in the air and Kibera > Industrial Area > City Square > Ngong' Forest. However, these were lower than the USEPA acceptable risks, 10-6 - 10-4. This study concluded that atmospheric OCPs did not pose significant cancer risks to the residents.

Patterns of PCBs and OCPs exposure in a sample of Lebanese adults: The role of diet and physical activity.

BACKGROUND: Exposure to persistent organic pollutants (POPs) in the general population is 90% from food intake. Dietary patterns provide a global estimation of exposure to POPs, taking into account multiple food sources of environmental contaminants. OBJECTIVES: To evaluate the association of dietary, socio-demographic, anthropometric, and lifestyle-related variables with clusters of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in a sample of students and employees of Saint Joseph University of Beirut. METHODS: A total of 302 participants were randomly recruited. Questionnaires covering dietary, socio-demographic, and lifestyle-related characteristics were administered. Anthropometric measurements were obtained. Serum concentrations of six indicator PCBs (PCB 28, 52, 101, 138, 153 and 180) and four OCPs, hexachlorobenzene (HCB), ß-hexachlorocyclohexanes (ß-HCH), p,p'-dichlorodiphenyltrichloroethane (DDT) and its metabolite p,p'-dichlorodiphenyldichloroethylene (DDE) were measured, and cluster analysis was applied. We evaluated the association of dietary intake with PCBs/OCPs exposure using two different approaches: food consumption categories and dietary patterns retrieved from principal component analysis (PCA). RESULTS: Three clusters of PCBs/OCPs were obtained: middle-level, high-level, and low-level. Practicing physical activity was associated with a three times higher risk of having high-level PCBs/OCPs, after adjustment for confounding variables (ORa = 2.97; CI = 1.23-7.19; p < 0.05). The highest tertile of fish and shellfish consumption increased by three-folds the odds of having high-level PCBs/OCPs (ORa = 3.41; CI = 1.07-10.84; p < 0.05). PCA revealed six dietary patterns. A "cereals, fats and oils, and eggs" dietary pattern was associated with 50% increase in the risk of having high-level PCBs/OCPs (ORa = 1.48; CI = 1.03-2.13; p < 0.05). CONCLUSION: The present results offer a valuable contribution to the understanding of the factors increasing exposure to POPs, namely fish consumption and the "cereals, fats and oils, and eggs" dietary pattern. We also demonstrated that physical activity was positively associated with a higher risk of exposure to PCBs and OCPs, knowing that data on this matter are scarce.

Risk assessment of organochlorine pesticides in drinking water source of the Yangtze River.

Organochlorine pesticides have been banned for many years, but the residual trace amount of organochlorine in water may still pose ecotoxicological risk. Meanwhile, the potential risk of organochlorine pesticides released from sediments, especially into drinking water sources, is receiving increasing attention. The present study assessed the pollution and potential risk of drinking water sources along the midstream and downstream Yangtze River. Residues of organochlorine pesticides (OCPs) in water, suspended particle matter (SPM), and sediment were evaluated with isotope dilution HRGC/HRMS. The results indicated that OCPs in water, SPM, and sediment ranged in 0.52-92.97 ng/L, 0.10-4.10 ng/L, and 0.038-11.36 ng/g, respectively. The predominant OCPs in water, SPM, and sediment were ß-HCH, p,p'-DDE and PeCB. At site Y1, 8, 13, 18, ß-HCH has a higher proportion in sediment samples, while, α-HCH has a higher proportion in SPM samples. The industrial use of HCHs in the history was the main HCHs source for most water and sediment samples, which indicated an absence of fresh inputs of industrial HCHs. Meanwhile, the abundance of p,p'-DDE in water, sediment and SPM samples could be attributed to long-term aerobic degradation of DDTs. The values of ffsw of HCHs, DDTs and PeCB indicate the transfer from water to sediment. Risk assessment showed that HCHs and DDTs posed low ecotoxicological risk to the Yangtze River.

Organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in Cyprinidae fish: Towards hints of their arrangements using advanced classification methods.

To tackle the ever-present global concern regarding human exposure to persistent organic pollutants (POPs) via food products, this study strived to indicate associations between organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in lake-fish tissue depending on the species and sampling season. Apart from the monitoring initiatives recommended in the Global Monitoring Plan for POPs, the study discussed 7 OCPs and 18 PCB congeners determined in three Cyprinidae species (rudd, carp, and Prussian carp) from Vransko Lake (Croatia), which are widely domesticated and reared as food fish across Europe and Asia. We exploit advanced classification algorithms, the Kohonen self-organizing maps (SOM) and Decision Trees (DT), to search for POP patterns typical for the investigated species. As indicated by SOM, some of the dioxin-like and non-dioxin-like PCBs (PCB-28, PCB-74, PCB-52, PCB-101, PCB-105, PCB-114, PCB-118, PCB-156 and PCB-157), α-HCH and ß-HCH caused dissimilarities among fish species, but regardless of their weight and length. To support these suggestions, DT analysis sequenced the fish species and seasons based on the concentration of heavier congeners. The presented assumptions indicated that the supplemental application of SOM and DT offers advantageous features over the usually rough interpretation of POPs pattern and over the single use of the methods.

Assessment of organochlorine pesticide contamination in waterbirds from an agricultural region, Central China.

Twenty-one organochlorine pesticides (OCPs) were measured in the muscle of six predominant waterbird species from Jianghan Plain, Hubei Province, Central China. Among OCPs, DDTs were the most prevalent compounds, with average concentration ranging from 31.1 to 1445 ng/g lipid weight. Little egrets (Egretta garzetta) and Chinese pond herons (Ardeola bacchus) showed significantly higher concentrations of OCPs (p < 0.05) due to their dietary habits and migratory patterns. There were no statistically significant differences (p > 0.05) for most OCPs between sex and age groups. The accumulation profiles of HCHs and DDTs suggested that these OCPs in Jianghan Plain were largely derived from historical usage. Risk assessment indicated that heptachlor could be likely to pose adverse health effects on people consuming ducks in Jianghan Plain.

Historical Trends and Chiral Signatures of Organochlorine Pesticides in Sediments of Qiandao Lake, China.

This study investigated the enantiomeric and depth profiles of organochlorine pesticides (OCPs) accumulated in the sediments of Qiandao Lake, China. OCP concentrations in sediments have increased gradually since the early 1960s, when extensive OCPs application in China began. Concentrations reached maximum levels after 1992, this timing corresponds with the emerging of the "new" usage of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethane (DDTs). In addition, the degradation of chiral OCPs were enantioselective, resulting in enriched (-)-enantiomers for α-HCH and o, p'-DDD. However, both preferential depletions of (-) enantiomers and (+) enantiomers were observed for o, p'-DDT. This outcome was indicated by enantiomer fractions (EF) values either greater or less than 0.5.

Concentrations and distributions of 18 organochlorine pesticides listed in the Stockholm Convention in surface sediments from the Liaohe River basin, China.

Organochlorine pesticides (OCPs) were analyzed in 26 surface sediment samples from the Liaohe River basin, and the distributions of and potential environmental risks posed by OCPs in the basin were evaluated. Eighteen OCPs listed in the Stockholm Convention were determined using isotope-dilution gas chromatography-high resolution mass spectrometry. This is the first study of hexachlorobenzene (HCB) in the Liaohe River basin sediments. The total OCP concentrations were 0.39-68.06 ng g(-1) dry weight. The total α-, ß-, γ-, and δ-hexachlorocyclohexane (HCH), the total dichlorodiphenyltrichloroethane (DDT - p,p'-dichlorodiphenyldichloroethane (DDD), p,p'-dichlorodiphenyldichloroethylene (DDE), o,p(')-DDT, and p,p'-DDT), and the HCB concentrations in the sediment samples were 0.1-28.48 ng g(-1) (mean 4.01 ng g(-1)), 0.08-6.52 ng g(-1) (mean 3.07 ng g(-1)), and 0.18-24.8 ng g(-1) (mean 4.38 ng g(-1)), respectively. The HCB concentrations were higher than the concentrations of the other OCPs, and the HCHs and HCB together were the dominant OCPs. ß-HCH was the most abundant HCH isomer. The concentrations of DDTs and other OCPs were relatively low, and the (DDE+DDD)/DDT ratios (>0.5) and DDD/DDE ratios (<1) indicated that no recent DDT inputs had occurred in the Liaohe River system. The main sources of HCHs were probably the historical production and agricultural use of HCH in the study area. The DDT and HCH concentrations were generally below or similar to the concentrations that have been found in other parts of the world. An ecotoxicological evaluation indicated that HCHs in surface sediments pose slight risks to human and ecological health in the Liaohe River basin.

The estimation of consumer health risk associated with organochlorine xenobiotics in hard smoked cheese in Poland.

The aim of this study was to estimate the health risks associated with consumption of smoked cheeses, which are popular in Poland. The analysis covered polychlorinated biphenyl (PCB) indicator congeners (ndl-PCBs: PCB 28, PCB 52, PCB 101, PCB 138, PCB 153, PCB 180), dioxin-like PCBs (dl-PCBs): non-ortho (PCB 77, PCB 81, PCB 126, PCB 169) and mono-ortho (PCB 105, PCB 114, PCB 118, PCB 156, PCB 157), as well as organochlorine pesticides (OCPs: αHCH, ßHCH, γHCH, heptachlor, aldrin, heptachlor epoxid isomer B, dieldrin, pp'DDE op'DDD, pp'DDT, pp'DDD, op'DDT, endrin). The pesticide residues detected in the examined cheese were below the maximum residues levels. The estimated daily intake [lifetime average daily dose (LADD)] referring to the sum of the compounds varied within 4.21 · 10(-7)-3.92 · 10(-6) mg · kg(-1) · day(-1) and was significantly lower than the tolerable daily intake/acceptable daily intake (TDI/ADI) for individual compounds. The health hazard quotient, being the exact measure of the magnitude of exposure potential or a quantifiable potential for developing non-carcinogenic health effects after an averaged exposure period, was also very low, ranging from 2.87 · 10(-6) to 5.32 · 10(-5). The obtained results confirmed that the intake of rennet cheese does not pose any consumer health risk in Poland.

Residues and potential health risks of DDTs and HCHs in commercial seafoods from two coastal cities near Yangtze River Estuary.

Five species of commercial seafoods collected from the local markets in two coastal cities near Yangtze River Estuary (Ningbo and Zhoushan) in 2010 were analyzed to study the residues, potential sources, and health risks of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in these areas. The total levels of DDTs and HCHs in the samples ranged from 1.13-20.2 ng g(-1) and 1.23-3.05 ng g(-1) wet weight, respectively, and were at a middle level compared with those from other marine systems. Results from one-way analysis of variance (ANOVA) indicated species-specific distributions of DDTs and HCHs in the seafoods of the studied area, which may be related to their different lipid contents and ecological characteristics. Compositional analysis suggested that historical usage dominates in this area, and fresh inputs of lindane and dicofol may also have part contributions. With respect to DDTs, it can be metabolized into both DDD and DDE simultaneously in seafoods tested. Assessment based on maximum residue levels, acceptable or tolerable daily intakes, and hazard ratios for non-carcinogens suggested no obvious adverse health effects, while the lifetime cancer risks may be increased from dietary exposure to DDTs and HCHs.

Residues, Sources and Potential Biological Risk of Organochlorine Pesticides in Surface Sediments of Qiandao Lake, China.

Sediment samples were analyzed to comprehensively characterize the concentrations, distribution, possible sources and potential biological risk of organochlorine pesticides in Qiandao Lake, China. Concentrations of sumHCH and sumDDT in sediments ranged from 0.03 to 5.75 ng/g dry weight and not detected to 14.39 ng/g dry weight. The predominant ß-HCH and the α-HCH/γ-HCH ratios indicated that the residues of HCHs were derived not only from historical technical HCH use but also from additional usage of lindane. Ratios of o,p'-DDT/p,p'-DDT and DDD/DDE suggested that both dicofol-type DDT and technical DDT applications may be present in most study areas. Additionally, based on two sediment quality guidelines, γ-HCH, o,p'-DDT and p,p'-DDT could be the main organochlorine pesticides species of ecotoxicological concern in Qiandao Lake.

CombiSimilarity, an innovative method to compare environmental and health data sets with different attribute sizes example: eighteen Organochlorine Pesticides in soil and human breast milk samples.

Human health and the health of the environment have entwined. In this paper we underpin this position by presenting a modeling approach named CombiSimilarity, which has been developed by the first author in the software tool PyHasse comprising a wide variety of partial ordering tools. A case study of 18 Organochlorine Pesticides (OCPs) detected in soil as well as in human breast milk samples in the Taurus Mountains in Turkey is carried out. Seven soil samples and 44 breast milk samples were measured. We seek to answer the question whether the contamination pattern in breast milk is associated with the contamination pattern in soil by studying the mutual quantitative relationships of the chemicals involved. We could demonstrate that there is a similarity with respect to the concentration profiles between the soil and breast milk pollution. Therefore the hypothesis may be formulated that the concentrations of chemicals in the milk samples are strongly related to the soil contamination. This supports the concept that soil could be a surrogate for human exposure at background locations.

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.