Individual Organochlorine Pesticides Research Articles

Investigation of the Dispersed-Phase Distribution of Organochlorine Pesticides, Polychlorinated Biphenyls and Polycyclic Aromatic Hydrocarbons in Natural Water Systems

The article analyzes the patterns of the dispersed-phase distribution of organic ecotoxicants, namely organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs), in natural water systems. The relationship between the dispersed-phase distribution of individual OCPs, PCBs, and PAHs and the logarithm of the octanol-water partition coefficient log Ko/w (hydrophobicity coefficient) was established. It was shown that the water-soluble part of individual organic ecotoxicants decreases with an increase in their hydrophobicity coefficient. Eight of the given eleven correlations are clear, significant and reliable. The influence of the characteristics of the water system on the dispersed-phase distribution of organic ecotoxicants was also investigated. It was shown that the total water-soluble part of OCPs, PCBs, and PAHs decreases with an increase in the chemical oxygen demand (COD), biological oxygen demand (BOD), and the total concentration of heavy metals (Cr, Ni, Cu, Mn, Zn, Cd, Pb). Four of the nine relevant correlations are clear, significant, and reliable.

Exposure to organochlorine pesticides and polychlorinated biphenyls, adherence to an ideal cardiovascular health, and arterial stiffness among Chinese adults.

This study aimed to assess the relationships between exposure to individual organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and their mixture and arterial stiffness and explore whether adherence to an ideal cardiovascular health (CVH) could mitigate these associations. The cross-sectional study enrolled 1437 Chinese adults between March and May 2019 in Wuhan, China. OCPs and PCBs concentrations were measured using solid phase extraction coupled with gas chromatography-tandem mass spectrometry. Arterial stiffness was evaluated by brachial-ankle pulse wave velocity (baPWV). CVH was determined by three behavioral and four biological metrics and categorized as ideal, intermediate, and poor CVH. We applied generalized linear model and weighted quantile sum (WQS) regression to evaluate the associations of exposure to individual OCPs or PCBs and their mixture with baPWV, respectively. We found that participants with detectable levels of heptachlor epoxide, PCB-153, and PCB-180 had higher baPWV (β: 34.25, 95% CI 14.28-54.22; β: 27.64, 95% CI 7.90-47.38; and β: 30.51, 95% CI 10.68-50.35) than those with undetectable levels. In WQS regression, the mixture of OCPs and PCBs was related to a higher baPWV (β: 24.93, 95% CI 2.70-47.15). Compared with participants with ideal CVH and undetectable OCPs or PCBs levels, those with poor CVH and detectable OCPs or PCBs levels had the highest increase in baPWV (heptachlor epoxide: β: 147.94, 95% CI 112.52-183.55; PCB-153: β: 150.22, 95% CI 115.40-185.04; PCB-180: β: 147.02, 95% CI 111.66-182.38). Our findings suggested that individual OCPs, PCBs, and their mixture exposure were positively associated with arterial stiffness, and adherence to an ideal CVH may mitigate the adverse effect.

Cross-regional scale studies of organochlorine pesticides in air in China: Pollution characteristic, seasonal variation, and gas/particle partitioning

Few simultaneous studies of organochlorine pesticides (OCPs) in the atmosphere have been conducted across Southeast and Northeast China, and no data on the gas/particle (G/P) partitioning behaviors of several current-use OCPs are available. In this study, a one-year synchronous monitoring program was conducted for OCPs in Chinese atmosphere spanning 30° latitude and 60 °C temperature. A total of 111 pairs of gas and particle samples were collected from Mohe and Harbin in Northeast China and from Shenzhen in Southeast China. The detection frequency for 66.7 % of the OCPs exceeded 80 %, indicating their prevalence in the atmosphere. The concentrations of individual OCPs spanned six orders of magnitude, indicating different pollution levels. Highest levels of hexachlorobenzene were observed at all sites. Banned OCPs were found predominantly in secondary distribution patterns, whereas current-use OCPs were dominated by primary distribution patterns. In Harbin and Mohe, the concentrations of OCPs were highest in summer, followed by autumn and winter. No obvious seasonal variation was observed in Shenzhen associated with different cultivation types. At all three sites, OCPs were predominantly found in the gas phase, and higher percentages of particle-phase OCPs were observed in Harbin and Mohe than in Shenzhen. In this study, G/P partitioning models were used to study the G/P partitioning mechanism of OCPs. The Li–Ma–Yang model provided the most accurate prediction of the G/P partitioning behavior of OCPs with high molecular weights and low vapor pressures, particularly at low temperatures. However, OCPs with lower molecular weights and higher vapor pressures were predominantly in the equilibrium state, for which the Junge–Pankow model was suitable. This systematic cross-scale study provides new insights into pollution, G/P partitioning, and the environmental behavior of OCPs in the atmosphere.

Maternal exposure to organochlorine pesticides and anthropometrics of newborns – a hospital-based cross-sectional study in rural and urban settings in Armenia

The study objective was to determine a possible association between maternal exposure to organochlorine pesticides (OCPs) and anthropometric measures at birth in group of postpartum women in urban and rural areas of Armenia. The anthropometric measures of infants were obtained from birth records and gamma-hexachlorocyclohexane (γ-HCH), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene, and dichlorodiphenyldichloroethane were measured in breast milk. Gas-liquid chromatography with electron capture detection was used to identify OCPs. Total OCPs and DDTs were calculated, and the anthropometrics were analyzed for sex and areas, and group differences were compared (Student’s t-test). Both individual OCPs and total OCPs and DDTs were significantly higher in rural samples than in urban ones (P < 0.01–0.000), with lower and upper quartiles differing by 2.6-fold and 3.1-fold, respectively (P < 0.000). There was no association between the anthropometrics and OCPs levels in rural or urban areas. However, this does not rule out the possibility of OCPs impact on health later in life. To our knowledge, this was the first study addressing these issues in Armenia. The results obtained will provide data on the current situation regarding birth outcomes in terms of prenatal exposure to OCPs in Armenia and will contribute to the available results from previous studies.

Spatio-temporal distribution of organochlorine pesticides in agricultural soils of southeast China during 2014-2019

Organochlorine pesticides (OCPs) are organic pollutants that are persistent and undegradable in the environment. To investigate their residual concentrations, spatial and temporal distributions, and the relationship with the crops planted, 12 individual OCPs in 687 soil samples from Jiangsu, Zhejiang and Jiangxi provinces of southeast China were examined. The detection frequencies of OCPs in the studied areas were 1.89%–64.9%. The concentrations of dichloro-diphenyl-trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and endosulfans ranged from 0.01 to 5659 μg/kg, 0.03–3.58 μg/kg, and 0.05–3235 μg/kg, respectively. Jiangsu was mainly contaminated by p,p'-DDT, p,p'-DDD and endosulfan sulfate, Zhejiang was more polluted by OCPs except δ-HCH, and Jiangxi was more vulnerable to the contamination of OCPs except o,p'-DDE. The partial least-squares discrimination analysis (PLS-DA) model with RX2 36.3–36.8% revealed that compounds with similar chemical properties tended to appear in the same year and month. All crop lands were polluted by DDTs and Endosulfans. The highest concentrations of DDTs and Endosulfans were found in citrus and vegetable fields, respectively. This study offers new insight into the layout and partitioning of OCPs in agricultural land and into insecticide management on public health and ecological safety.

A national-scale distribution of organochlorine pesticides (OCPs) in cropland soils and major types of food crops in China: Co-occurrence and associated risks

Organochlorine pesticides (OCPs) are persistent organic pollutants (POPs) that resist degradation in the environment. OCPs remain detectable in cropland systems in China. However, spatial distribution of OCPs across China and associated ecological and health risks, as well as the relationship between levels of OCPs in cropland soils and crops, remain to be elucidated. To fill these gaps, we conducted a national-scale characterization of 19 individual OCPs in cropland soils and food crops including cereals and legumes in China, which were on-spot sampled simultaneously. Sparse canonical correlation analysis was employed to investigate the co-occurrence of OCPs in cropland soils and corresponding food crops. The ecological soil screening levels and risk quotient method were adopted for ecological and health risk assessment, respectively. Dichlorodiphenyltrichloroethanes (DDTs) were dominant in cropland systems, with its levels ranging up to 337 and 22.8 μg/kg in cropland soils and food crops, respectively. The mean ∑OCP levels in cropland soils varied from below the limit of detection to 337 μg/kg. Peanuts were the most contaminated crop, in which endosulfans and hexachlorobenzene (HCB) were co-occurrent with those in cropland soils (correlation coefficient R = 0.999 and 0.947, respectively). Besides, lindane and β-endosulfan in rice were co-occurrent with those in cropland soils (R = 0.810 and 0.868, respectively). The componential ratio analysis indicated fresh inputs of technical DDT, lindane, chlordane, endosulfan, HCB and aldrin. Among these pesticides, ecological impacts of DDTs, lindane, aldrin and β-endosulfan could be expected. Human health risk assessment suggested that daily consumption of the OCP-contaminated food crops raises a health concern especially for male teens. It is concluded that OCPs remain present in cropland systems in China at levels that raise a concern for both environment and human health.

A large geographic-scale characterization of organochlorine pesticides (OCPs) in surface sediments and multiple aquatic foods of inland freshwater aquaculture ponds in China: Co-occurrence, source and risk assessment

Inland freshwater aquaculture ponds (IFAPs) represent the key component of the global lentic freshwater environment and are increasingly important for global aquaculture production, yet the occurrence of organochlorine pesticides (OCPs) in these pond systems remains largely unknown. Here, we characterized the residual concentrations of 19 individual OCPs in sediments and in cultured fish and crustacean species (crabs, shrimp, crayfish and lobster), which were on-spot sampled from the IFAPs at a large region-scale in China. The total OCP levels in sediments varied dramatically between regions. Crabs presented the greatest OCP contamination among the studied species. Dichlorodiphenyltrichloroethanes (DDTs) was the dominating contaminant in sediments and crabs and its stable degradation products 4,4′-DDE and 4,4′-DDD were co-occurrent between these two compartments. The diagnostic ratio analysis indicated fresh inputs of DDTs, lindane and aldrin in multiple regions, which may be resulted from agricultural soil erosion, surface runoff and local anthropogenic activities. Ecological impacts of these pesticides could be expected at some sites due to their levels in sediments above the risk level. Risk assessment based on the OCP levels corrected by the cooking loss revealed that daily consumption of the IFAPs-derived aquatic foods may pose carcinogenic risks in humans.

Distribution and Potential Sources of OCPs and PAHs in Waters from the Danshui River Basin in Yichang, China.

To investigate the concentrations, spatial distribution, potential sources and mass fluxes of organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) in waters from the Danshui River Basin, a total of 20 water samples were collected and analyzed from a karstic river in Western Hubei of Central China. The average concentrations of total OCPs and PAHs in the river water were 4719 pg·L−1 and 26.2 ng·L−1, respectively. The characteristic ratios of different isomers and the composition analysis of individual OCPs and PAHs revealed that HCHs originated from a mixed input of technical HCHs and Lindane, DDTs were mainly from technical DDTs, and PAHs mainly originated from biomass and coal combustion. The mass flux analysis showed that PAHs had a higher emission and heavier burden than OCPs in the Danshui River Basin. OCPs and PAHs emitted from agricultural or other human activities could enter the groundwater and then be transported to the surface/river water in the karst area. The adsorption of OCPs and PAHs by particles and the sedimentation of particles could be the primary processes to intercept these pollutants in the water of the karstic river system.

Occurrences, Potential Sources and Health Impacts of Organochlorine Pesticides in Soil from Wuhan, Central China.

This study was designed to determine the occurrence, potential sources, human and ecological risks of organochlorine pesticides (OCPs) in soil from Wuhan, central China. The soil samples were collected from twenty-six sites at soil depth of 1-20cm from three land-use types and analyzed for the presence of eight OCPs. The instrumental analysis was carried out using Gas Chromatography-Electron Capture Detector (GC-ECD). The obtained result ranged from 0.193 to 135.277ngg-1 with the mean value of 17.337ngg-1 for ΣHCHs and 2.479 to 987.248ngg-1 with the mean value of 80.056ngg-1 for ΣDDTs. The total sum (ΣOCPs) ranged from 5.44 to 994.44ngg-1 with the mean value of 97.39ngg-1. p, p'- DDE was the highest OCP (976ngg-1) detected in the soil followed by p, p'-DDD (287.454ngg-1). Pearson correlation analysis indicated that there was a significant correlation between individual OCPs, while a weak and negative correlation between OCPs and selected soil properties. Isomeric ratio results indicated that DDTs in the soil came from historical (early use of DDTs) and HCHs originated from the use of lindane. Incremental lifetime cancer risks (ILCR) indicated that HCHs can cause very low risk for adults while, low risks for children and DDTs can cause low risk on adults and high risks on children.

Prenatal exposure to organochlorine pesticides is associated with increased risk for neural tube defects

Neural tube defects (NTDs) are among the most common and disabling fetal congenital defects. Organochlorine pesticides (OCPs) are ubiquitous in the environment. In this study, 119 women who had NTD-affected pregnancies (cases) and 119 women who delivered healthy neonates (controls) were recruited in a rural area of Northern China. We used concentrations of OCPs in umbilical cord tissue as markers of prenatal exposure to investigate the association between in utero exposure to OCPs and NTD risk. Concentrations of 20 OCPs were quantified by gas chromatography–mass spectrometry, and 16 of the 20 OCPs were included in the analyses. Odds ratios and 95% confidence intervals (95% CIs) for the associations between levels of individual OCPs and NTD risk were estimated separately with logistic regression adjusting for potential confounders. The combined effects of exposure to the 16 OCPs as a mixture were analyzed with Bayesian kernel machine regression (BKMR). Logistic regression showed that the risk for NTDs increased 5.44-fold (95% CI, 2.21–13.41) for β-hexachlorocyclohexane, 2.51-fold (95% CI, 1.07–5.86) for endosulfan I, 3.78-fold (95% CI, 1.60–8.89) for endosulfan II, 3.42-fold (95% CI, 1.44–8.12) for ο,ρ'-dichlorodiphenyldichloroethane, and 2.89-fold (95% CI, 1.22–6.86) for ρ,ρ'-dichlorodiphenyltrichloroethane when the concentration of each of these OCPs was above its median (exposed) compared to below its median (non-exposed). Other OCPs were not associated with NTD risk in multivariate models. In BKMR, NTD risk increased almost linearly with concentrations of the 16 OCPs as a mixture, which suggests joint effects on NTD risk. Exposure to α-hexachlorocyclohexane, β-hexachlorocyclohexane, endosulfan II, ο,ρ'-dichlorodiphenyldichloroethane, and ρ,ρ'-dichlorodiphenyldichloroethane was associated with an increased risk for NTDs when levels of the remaining 15 OCPs were taken into account. Taken together, these findings show that prenatal exposure to OCPs is associated with increased risk for NTDs.

Differential mitochondrial dysregulation by exposure to individual organochlorine pesticides (OCPs) and their mixture in zebrafish embryos.

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.

Bioaccumulation of organochlorine pesticides in the Western Sandpiper (Calidris mauri) during the wintering season in Sinaloa, Mexico

The Western Sandpiper, Calidris mauri, is one of the most abundant migratory shorebirds in the Western Hemisphere. Both Bahia Santa Maria (SM) and Ensenada Pabellones (EP) in Sinaloa, Mexico, are critical wintering sites for this species. We described the presence and concentration of 16 organochlorine pesticides (OCPs) in Western Sandpiper muscle and liver tissues collected from SM and EP during the wintering (December-January) and premigration (March-April) periods of 2010 and 2011, respectively. The individual OCP concentrations varied from 0.003 to 0.127 μg/g dry weight (dw) and were lower than the established thresholds for either acute or chronic effects. Western Sandpipers in SM-Premigration had the highest frequency of OCPs (39.3%), followed by EP-Winter (32.1%) and SM-Winter (28.5%). The frequency of occurrence of all OCPs in the liver presented differences between sites during the wintering period as well as between the wintering and premigration periods in SM. As the primary organ responsible for pollutant detoxification, the liver may bioaccumulate these compounds. No clear trends were observed in muscle tissues or among age-sex groups. Our results showed evidence of OCP bioaccumulation in the Western Sandpiper during the wintering period, which may be related to hyperphagia during the premigration period and to the differential intake of OCP types and quantities between sites due to differences in their availability. However, these conclusions are based on relatively low sample sizes for some groups and require further study with non-pooled samples.

Spatial Distribution and Ecological Risk Assessment of Residual Organochlorine Pesticides (OCPs) in South American Marine Environments.

Organochlorine pesticides (OCPs) have been intensely used and produced in South America. Although they were banned before the year 2000 (excepting endosulfan, which has been recently banned in several countries), OCPs remain detectable in marine environments of this continent, sometimes at risky levels for biota. This manuscript summarizes studies on OCP levels in the air, water, sediment, bivalves, fish, and marine mammals of the South American coasts and open waters over the last 20years, tackling their spatial distribution and analyzing their associated ecotoxicological risk. To the best of our knowledge, this is the first study integrating all available information on current levels of OCPs in South American marine environments. The 63 researches reviewed studied punctual sites or environmental compartments. The OCP levels were higher in semi-enclosed environments such as bays and estuaries, close to large cities. In terms of individual OCPs, dichlorodiphenyltrichloroethane (DDT) and its degradation products were more abundant than other OCPs in all the environmental compartments, excepting air, for which the most abundant OCP was endosulfan. Depending on the location and the environmental matrix, hexachlorocyclohexanes (HCHs), heptachlors, mirex, and endosulfans followed DDTs. Aldrin, dieldrin and endrin, hexachlorobenzene (HCB), and chlordanes were found at very low levels in most matrices and sites, with some exceptions. Considering their potential ecotoxicological risk, most sites would be safe for biota; however, the levels of some OCPs could damage the structure and function of the communities of several coastal sites in a short or long term, mainly in southeastern Brazil and on the coast of the Argentine Pampas. Moreover, it remains to evaluate many sites potentially contaminated by OCPs.

Organochlorine pesticides in the soils of Cardamom Hill Reserve (CHR), Kerala, India: Geo spatial distribution, ecological and human health risk assessment

The present study assessed the organochlorine pesticides (OCPs) residues in the soils of Cardamom Hill Reserve (CHR), a tropical humid forest landscape of Idukki District of Kerala, India. The concentrations, spatial distribution, health risk for human (both adults and children) due to individual OCPs and ecological risks were estimated. Soil samples were collected randomly from 22 different sampling locations during May 2017 and 2018. The sample preparation was done by QuEChERS method. A total of 17 persistent Organochlorine pesticides (OCPs) were determined by Gas chromatography in split less mode using Electron Capture Detector (ECD). The limit of detection and quantification for OCPs in the soils ranged from 1.57 to 3.74 ng/g and 4.78 to11.33 ng/g respectively. Spatial distributions of OCPs were evaluated using Arc GIS10.5.1 software. The most frequently found OCPs in the soils of the study area were endrin, β-endosulfan, the isomers of HCH, 4, 4′-DDD, dieldrin and endrin aldehyde. The concentration of ∑OCPs were ranged from 6.35 to 118.29 ng/g. Occurrence of pesticides residues in the soils of CHR is due to both ongoing and past usage. Human health risk assessment parameters like Lifetime average daily dose (LADD), incremental lifetime cancer risk (ILCR) and hazard quotient (HQ) for human adults and children due to individual OCPs were also estimated. Estimated LADD were lower than the reference dose and acceptable daily intake. The estimated human health risks were lower than safe limit of non- cancer risk (HQ ≤ 1.0) and low carcinogenic risks (ILCR below 10–6) in these soils. Finding from the present study provided an overview of the current status of OCPs contamination in the soils for the exposed populations are essentially negligible.

Is dietary macronutrient intake associated with serum concentrations of organochlorine pesticides in humans?

In the general population, chronic exposure to low-dose persistent organic pollutants (POPs), particularly organochlorine pesticides (OCPs), has been recently linked to many chronic diseases. Widespread contamination of the food chain and human adipose tissue has made avoiding exposure to these chemicals impossible; thus, alternative strategies for decreasing the chemical burden must be investigated. Recently, macronutrient intake was found to significantly modify the toxicokinetics of POPs in animal experimental studies. Thus, we evaluated whether macronutrient intake was related to serum concentrations of OCPs in healthy adults without cardio-metabolic diseases. Subjects included 1,764 adults, aged 20 years or above, who participated in the National Health and Nutrition Examination Survey 1999–2004. Macronutrient intake was assessed based on a 24-h dietary recall interview. Six individual OCPs commonly detected among the general population were evaluated as markers of OCPs and other coexisting lipophilic chemicals stored in adipose tissue and released into circulation. High fat intake was associated with lower concentrations of OCPs, while high carbohydrate intake showed the opposite result. When three types of fats were individually evaluated, both saturated fatty acids and monounsaturated fatty acids, but not polyunsaturated fatty acids, were inversely associated with serum concentrations of OCPs. Adjustment for possible confounders did not change the results. When stratified by age, gender, body mass index, and physical activity, these associations were similar in most subgroups. Thus, similar to the findings observed in animal experimental studies, a moderate-fat diet with low carbohydrate intake was related to low serum concentrations of OCPs in humans. Although these findings need to be replicated, changing dietary macronutrient intake can be investigated as a practical strategy for dealing with unavoidable lipophilic chemical mixtures such as OCPs in modern society.

Monitoring And Distribution Of Organochlorine Pesticides, Polychlorinated Biphenyls And Polycyclic Aromatic Hydrocarbons In Surface River Water And Suspended Particulate Matter

The monitoring results of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) in Ukranian and world surface river waters were summarized. Total concentrations of OCPs, PCBs and PAHs in surface waters of Ukrainian rivers (Dnieper and Dniester) were 1.4–17.1; 2.8–57.2; 7.5–378.6 ng/dm3 , respectively. These pollution levels are medium on a global scale. Higher concentrations were recorded in the surface water of China, India and other Asian countries. Distribution of these organic ecotoxicants between water and suspended particulate matter (dispersionphase distribution) was analyzed and it was shown that in the majority of river waters ≥50% of them are associated with suspended particles. By the case of River Dnieper antibate correlations between watersoluble parts of individual OCPs, PCBs and PAHs and coefficient of their hydrophobicity were recorded. These correlations were presented graphically. In addition, relevant correlation coefficients and criterions of probability were calculated. The clearest correlation was established for PCBs.

Partition distribution of selected organochlorine pesticides in water, sediment pore water and surface sediment from uMngeni River, KwaZulu-Natal, South Africa

Organochlorine pesticides (OCPs) were analysed in surface water, pore water and surface sediment samples collected from the uMngeni River, which is one of the largest rivers in the province of KwaZulu-Natal, South Africa. Liquid-liquid extraction was used to extract the analytes from water and pore water samples and soxhlet extraction was used to extract sediment samples with subsequent florisil clean-up and gas chromatography-mass spectrometry (GC-MS) analysis. Twelve selected OCPs were analysed and their total concentrations were found to range from 8.04–21.06 ng/mL, 36.06–188.43 ng/mL and 148.17–554.73 ng/g in unfiltered surface water, unfiltered pore water and surface sediment (dry weight (dw)), respectively. The results indicated that the concentrations of these selected pesticides were far higher in sediment (72%) than in pore water (25%) and water (3%). The most polluted sites were Northern Wastewater Treatment influent (NWTI) for water (Σ12 OCP = 19.41 ± 1.43 ng/mL) and Northern Wastewater Treatment effluent (NWTE) for pore water (Σ12 OCP = 166.23 ± 7.16 ng/mL) and sediment (Σ12 OCP = 495.21 ± 32.38 ng/g). The most abundant individual OCPs and their average concentrations in general in the river were p,p′-DDE in unfiltered water (1.62 ±0.22 ng/mL) and unfiltered sediment pore water (17.09 ±7.96 ng/mL), and endrin in surface sediment (55.57 ± 19.01 ng/g, dw).

Profiles and removal efficiency of organochlorine pesticides with emphasis on DDTs and HCHs by two different sewage treatment works

Abstract The removal efficiencies of nine organochlorine pesticides (OCPs) were investigated in two sewage treatment works (STWs; Stonecutter Island [SCI] and Shatin [ST]). The levels of OCPs in sewage samples collected from SCI (chemically enhanced primary treatment) and ST (secondary treatment) were determined with gas chromatography–mass spectrometry. The crude sewage in the two STWs generally had low levels of total hexachlorocyclohexane (HCHs; total of alpha-, beta- and gamma-HCH; SCI, 19.4 ± 4.62 ng/L; ST, 12.1 ± 4.27 ng/L) and total dichloro-diphenyl-trichloroethane (DDTs; total of p,p’ and o,p’-DDE, -DDD and -DDT; SCI, 6.31 ± 2.83 ng/L; ST, 6.09 ± 1.67 ng/L). High total removal efficiencies for total HCHs (SCI, 79.9 ± 7.03%; ST, 82.5 ± 2.51%) and total DDTs (SCI, 96.1% ± 3.37%; ST, 99 ± 0.501%) were observed. In particular, ST achieved outstanding performance in the removal of heptachlor (100% ± 0.00%), heptachlor epoxide (94.8 ± 3.96%), hexachlorobenzene (99.7 ± 0.387%), gamma-HCH (100 ± 0.00%) and total DDTs (99.2 ± 0.644%). There was no observable correlation between the removal efficiencies and the log K o w values of individual OCPs, which suggests that the removal mechanisms may not be related to sorption by particulate matter. Removal of OCPs seems to rely more on other mechanisms such as volatilisation, advection and biotransformation. This study is the first to investigate the fate and distribution of OCPs throughout the entire sewage treatment process. The results provide valuable reference for potential modification of sewage treatment processes with regard to OCPs.

Organochlorine pesticides in sediments from Gulfs of Naples and Salerno, Southern Italy

Organochlorine pesticides (OCPs) have the potential to concentrate in the marine environment and threaten the local marine life. Here, we present the results of a study of the contamination profiles, spatial distribution, possible sources, and potential ecological risk of OCPs in marine sediments from Gulfs of Naples and Salerno, Southern Italy. The total concentrations of OCPs ranged from 0.54 to 99.6ng/g (average mean: AM=7.80±16.3ng/g). The concentration of OCPs from gulf of Salerno (AM=9.20±20.7ng/g) was higher than Naples (AM=7.49±15.3ng/g). The sediment levels of individual OCPs were (in sequence of concentration) dichlorodiphenyltrichloroethanes (DDTs, including p,p'-DDD, p,p'-DDE, o,p'-DDT and p,p'-DDT)>CHLs (heptachlor, heptachlor epoxide, trans-chlordane, and cis-chlordane)>hexachlorocyclohexanes (HCHs, including α-β-γ-and δ-HCH)>DRINs (aldrin, dieldrin, and endrin)>hexachlorobenzene (HCB)>SULPHs (α-endosulfan, β-endosulfan, and endosulfan sulfate). DDTs and heptachlor were the highest in proportion among the OCPs. High concentrations of OCPs were observed in the coastal area especially near the cities of Naples and Salerno as a result of terrigenous supply. The occurrence of high residual levels of OCPs found in this study may be attributed to their historical application. Marine dynamics influence the distribution of OCPs, in particular the HCHs, as they are less lipophilic and more soluble. According to established sediment quality guidelines, DDTs may cause ecological risk.

Evaluation of Genotoxic and Mutagenic Activity of Organic Extracts from Drinking Water Sources

An increasing number of industrial, agricultural and commercial chemicals in the aquatic environment lead to various deleterious effects on organisms, which is becoming a serious global health concern. In this study, the Ames test and SOS/umu test were conducted to investigate the potential genotoxicity and mutagenicity caused by organic extracts from drinking water sources. Organic content of source water was extracted with XAD-2 resin column and organic solvents. Four doses of the extract equivalent to 0.25, 0.5, 1 and 2L of source water were tested for toxicity. All the water samples were collected from six different locations in Guangdong province. The results of the Ames test and SOS/umu test showed that all the organic extracts from the water samples could induce different levels of DNA damage and mutagenic potentials at the dose of 2 L in the absence of S9 mix, which demonstrated the existence of genotoxicity and mutagenicity. Additionally, we found that Salmonella typhimurium strain TA98 was more sensitive for the mutagen. Correlation analysis between genotoxicity, Organochlorine Pesticides (OCPs) and Polycyclic Aromatic Hydrocarbons (PAHs) showed that most individual OCPs were frame shift toxicants in drinking water sources, and there was no correlation with total OCPs and PAHs.