Residual levels, tissue distribution and risk assessment of organochlorine pesticides (OCPs) in edible fishes from Taihu Lake, China

Tissue distribution and bioaccumulation of organochlorine pesticides (OCPs) in edible fishes collected from Taihu Lake, Cyprinus carpio (C. carpio) and Ctenopharyngodon idellus (C. idellus), were studied. OCPs were detected in all samples with hexachlorocyclohexanes (HCHs), aldrins (including aldrin, dieldrin, endrin, endrin aldehyde, and endrin ketone), heptachlors (heptachlor and heptachlor epoxide) and dichlorodiphenyltrichloroethanes (DDTs) being the predominant compounds for both fish species. Gill and gonad were found to be the dominant tissues for OCP bioaccumulation followed by liver, while muscle showed the least affinity of OCPs for both fishes. Tissue distribution indicated the exchange of contaminants between water and gill, as well as the food intake from environment were the dominant pathways for OCP bioaccumulation in gill-breathing fish, and the following tissue distribution was affected by both the physiological properties of target tissues and physicochemical characteristics of pesticides. OCP residues in fish were species-specific (45.63–1575.26 ng/g dry weight (dw) for C. idellus; 8.40–60.23 ng/g dw for C. carpio) mainly due to the growth rate of individuals as well as the metabolic capacity difference among species. HCHs and DDTs observed in fishes from Taihu Lake were comparable and moderate with other reported places in China. Human exposure risk assessment performed with the estimated daily intake values demonstrated the consumption of target fish species in Taihu Lake at present was safe.     

Residues and ecological risks of organochlorine pesticides in Lake Small Baiyangdian, North China

The levels of hexachlorocyclohexane (HCH) and dichloro-diphenyl-trichloroethane (DDT) in the water, suspended particulate matter (SPM), and sediments from Lake Small Baiyangdian were measured by gas chromatograph with a ⁶³Ni microelectron capture detector. The residual levels of the total HCHs in the water, SPM, and sediments were 1.59?±?2.24 ng L^?1, 25.42?±?1.72 ng g^?1 dw (dry weight), and 0.86?±?1.44 ng g^?1 dw, respectively. DDTs were not detected in the water samples. The concentrations of total DDTs were 158.79?±?1.67 ng g^?1 dw in SPM and 0.46?±?1.97 ng g^?1 dw in the sediments. Compared to other areas in China and abroad, the levels of residual HCH and DDT were relatively low in the water and sediments, but they were moderate to high in the SPM. Organic carbon partition coefficient values for HCH in this study were higher than previously published values and may reflect new input in this area. The residual HCHs in this area could be derived from a mixture of technical HCH and lindane because ongoing lindane use may be occurring. DDT in the majority of the study area was primarily attributed to historical discharge, but some regions may be receiving new input. The ecological risks of γ-HCH in the water were very low according to species sensitivity distribution models. The concentrations of HCH and DDT in the sediments from the study area did not exceed the sediment quality guidelines, which indicate little risk for benthic organisms.     

Organochlorine pesticide contamination in marine organisms of Yantai coast,northern Yellow Sea of China

To evaluate the contamination of organochlorine pesticides (OCPs) in marine organisms and their potential health risk on consumers in the northern Yellow Sea of China, mollusks, wild shrimps, and crabs were collected from the Yantai coast, and the OCP contents in the samples were analyzed and compared. The results indicate that all the samples have been contaminated by OCPs, and OCP concentrations varied in individual species and in sampling sites. Among the studied OCPs, ∑HCH and ∑DDT concentrations ranged from 0.91 to 13.92 ng g^?1 and from 10.16 to 411.19 ng g^?1, respectively. Meretrix was highly enriched with HCHs, while the highest DDT concentration was found in Crassostrea. For the OCP isomers, β-HCH was the predominant isomer of HCHs, and p,p′-DDE concentration was much higher than other isomers of DDTs. The concentrations of other OCPs (HCB, t-CHL, endrin, and mirex) were relatively low. For the shrimp and crab samples, Alpheus distinguendus samples accumulated a higher level of HCHs but lower DDTs than Oratosquilla aratoria and Carcinoplax vestitus in all sampling areas. HCHs in the samples of contrast area were not significantly lower than that of the sewage outfall area and port area, whereas DDTs in the samples of contrast area were relatively lower than that of the other two areas. Generally, all the OCP contents in the samples are in the range of the edible hygienic criteria except the total concentration of DDTs in Crassostrea.     

Occurrence and distribution of organochlorine pesticides (DDT and HCH) in sediments from the middle and lower reaches of the Yellow River, China

Sediments used in this study were selected from 23 stations in the middle and lower reaches of the Yellow River and its tributaries in November 2005. The levels and distribution patterns of selected organochlorine pesticides (OCPs = p,p ^′-DDT, o,p ^′-DDT, p,p ^′-DDE, p,p ^′-DDD, α-, β-, γ-, and δ-HCH) in samples were investigated by analysis of gas chromatography coupled with micro-electronic capture detector. Concentration of OCPs in the sediments from the Yellow River ranged from 0.05 to 5.03 ng g^???1 (mean, 1.02 ng g^???1) for ∑DDT, 0.09–12.89 ng g^???1 (mean, 1.08 ng g^???1) for ∑HCH. The concentration distribution of ∑DDT and ∑HCH varied significantly with different sampling station, indicating their different contamination sources. Composition analyses demonstrated that residues of DDTs in sediments came from the previous inputs of organochlorine pesticides, while β-HCH and γ-HCH significantly dominated in the sediments for HCHs.     

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Bizerte Lagoon,Tunisia: levels,sources, and toxicological significance

To assess the status of polycyclic aromatic hydrocarbon (PAH) contamination in sediments from the Bizerte Lagoon (northern Tunisia), 18 surface sediment samples were collected in March 2011 and analyzed for 14 US Environmental Protection Agency priority PAHs by high-performance liquid chromatography. The total concentrations of the 14 PAHs (ΣPAHs) ranged from 16.9 to 394.1 ng g^?1 dry weight (dw) with a mean concentration of 85.5 ng g^?1 dw. Compared with other lagoons, coasts, and bays in the world, the concentrations of PAHs in surface sediments of the Bizerte Lagoon are low to moderate. The PAHs’ composition pattern was dominated by the presence of four-ring PAHs (45.8 %) followed by five-ring (26.8 %) and three-ring PAHs (12.7 %). The PAH source analysis suggested that the main origin of PAHs in the sediments of the lagoon was mainly from pyrolytic sources. According to the numerical effect-based sediment quality guidelines of the USA, the levels of PAHs in the Bizerte Lagoon should not exert adverse biological effects. The total benzo[a]pyrene toxicity equivalent values calculated for the samples varied from 3.1 to 53.7 ng g^?1 dw with an average of 10.6 ng g^?1 dw.     

Organochlorine pesticides in the surface water and sediments from the Peacock River Drainage Basin in Xinjiang, China: a study of an arid zone in Central Asia

Fourteen surface water and nine surface sediment samples were collected from the Peacock River and analyzed for organochlorine pesticides (OCPs) by gas chromatograph?Celectron capture detector (GC-ECD). All the analyzed organochlorine pesticides, except o,p ^??-DDT, were detected in sediments from the Peacock River; but in the water samples, only ??-HCH, HCB, p,p ^??-DDD, and p,p ^??-DDT were detected at some sites. The ranges for total OCPs in the water and sediments were from N.D. to 195 ng l^???1 and from 1.36 to 24.60 ng g^???1, respectively. The only existing HCH isomer in the water, ??-HCH, suggested that the contamination by HCHs could be attributed to erosion of the weathered agricultural soils containing HCHs compounds. Composition analyses showed that no technical HCH, technical DDT, technical chlordanes, endosulfans, and HCB had been recently used in this region. However, there was new input of ??-HCH (lindane) into the Peacock River. The most probable source was water flowing from Bosten Lake and/or agricultural tailing water that was returned directly into the Peacock River. DDT compounds in the sediments may be derived mainly from DDT-treated aged and weathered agricultural soils, the degradation condition was aerobic and the main product was DDE. HCB in the sediment might be due to the input from Bosten Lake and the lake may act as an atmospheric deposition zone. There was no significant correlation between the concentrations of OCPs (including ??HCH, ??DDT, chlordanes, endosulfans, HCB and total OCPs) and the content of fine particles (<63 ??m). The concentrations of OCPs were affected by salinity.     

Multi-year monitoring of estuarine sediments as ultimate sink for DDT, HCH, and other organochlorinated pesticides in Argentina

Forty-nine superficial sediment samples used in this study were collected from eight sites in the Bahia Blanca Estuary, located in the Buenos Aires Province southwest, Argentina, in a period between April 2005 and March 2009, to assess the concentration levels, spatial and seasonal distribution, and putative input sources of 18 selected organochlorine pesticides (OCs), following UNEP-IAEA procedures. Average concentration levels in sediments ranged between 3.54 and 63.79 ng g^???1, d.w. (mean = 15.99 ng g^???1, d.w.), for ??OCs, and from nondetectable to 8.03 ng g^???1, d.w. (mean = 2.16 ng g^???1, d.w.), and from nondetectable to 3.20 ng g^???1 (mean = 0.97 ng g^???1, d.w.) for hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs), respectively. Principal component analysis allowed the classification of sampling sites according to the main OCs inputs over the estuary. In comparison to other worldwide locations and to the world coastal sediment concentrations range, sediment DDTs and HCHs levels were in the low range; on the opposite, ??OCs average was in the medium range. OCs seasonal distribution was found to be highly correlated with the precipitations seasonality and sowing seasons in the adjacent agriculture fields. In addition, an ecotoxicological risk assessment pointed industrial and agriculture catchment zones with intermediate probability of adverse effects to biota, while the city sewage outfall was classified with none indication of an immediate threat. Data indicated that the estuary sediments were functioning as a sink for persistent OC pesticides (either in use or banned), however, it was found a declining trend on their environmental burden.     

Distribution and sources of organochlorine pesticides in sediments of the Xiangjiang River, south-central China

The Xiangjiang River (XR), the second largest tributary of the Yangtze River, is mainly located in Hunan province in south-central China. Nineteen surface sediment samples (the top 3-cm layer) collected from XR were analyzed to determine the concentrations, distribution, sources, and ecological risk of organochlorine pesticides (OCPs). The concentrations of OCPs were 3.0–29.8 ng/g (dry weight) with a mean of 12.6?±?7.7 ng/g. The widely detected compounds included HCHs, DDTs, HCB, and dieldrin. Overall, the dominant OCPs in the sediments were mainly composed of residual and degradation products, e.g., β-HCH with a mean of 42.2 % in HCHs and p,p′-DDE with a mean of 43.5 % in DDTs, implying that OCPs in the sediments had suffered from long-term aging without fresh inputs in XR. However, there was a high proportion of p,p′-DDT to DDTs in three sites, suggesting that there was use of technical DDT from their surrounding areas at present. The ratios of α-HCH/γ-HCH and p,p′-DDD?+?p,p′-DDE/DDTs increase from the upper reaches to the lower reaches of XR, suggesting sediments enriched with α-HCH and metabolites DDD and DDE during sediment transport process and could be attributed to the transformation of γ-HCH to α-HCH and DDT to DDE or DDD. The assessment of the ecological risk indicates that the OCPs in the sediments of XR have a moderate adverse biological effect on organisms.     

Assessment of bioavailable fraction of POPS in surface water bodies in Johannesburg City,South Africa,using passive samplers: an initial assessment

In this study, the semipermeable membrane device (SPMD) passive samplers were used to determine freely dissolved concentrations of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in selected water bodies situated in and around Johannesburg City, South Africa. The devices were deployed for 14 days at each sampling site in spring and summer of 2011. Time weighted average (TWA) concentrations of the water-borne contaminants were calculated from the amounts of analytes accumulated in the passive samplers. In the area of interest, concentrations of analytes in water ranged from 33.5 to 126.8 ng l^?1 for PAHs, from 20.9 to 120.9 pg l^?1 for PCBs and from 0.2 to 36.9 ng l^?1 for OCPs. Chlorinated pesticides were mainly composed of hexachlorocyclohexanes (HCHs) (0.15–36.9 ng l^?1) and dichlorodiphenyltrichloromethane (DDT) with its metabolites (0.03–0.55 ng l^?1). By applying diagnostic ratios of certain PAHs, identification of possible sources of the contaminants in the various sampling sites was performed. These ratios were generally inclined towards pyrogenic sources of pollution by PAHs in all study sites except in the Centurion River (CR), Centurion Lake (CL) and Airport River (AUP) that indicated petrogenic origins. This study highlights further need to map up the temporal and spatial variations of these POPs using passive samplers.     

Impacts of climate-induced changes on the distribution of pesticides residues in water and sediment of Lake Naivasha, Kenya

This study reports evidence of increased chlorpyrifos contamination in sediment and water in Lake Naivasha following its intensive application in the horticultural farms in the catchment area. Analytical results show that levels of chlorpyrifos residues were influenced by climate-induced rainfall pattern with higher levels reported during period of heavy precipitation with significant decrease during low rainfall. On average, the levels ranged between 14.8 and 32.8 ng g^?1 in sediment during rainy season compared to a range of 8.5–16.6 ng g^?1 in the dry season. Additionally, the mean concentration of chlorpyrifos in water ranged between 8.61 and 22.4 μg L^?1 during rainy season and below detection limit (bdl) ?13.6 μg L^?1 in dry season as quantified by enzyme-linked immunosorbent assay. Meanwhile, independent t test analysis indicated that there was significant difference in concentration at p?≤?0.05 between the seasons with respect to sediment and water samples. This demonstrated that climate-induced variations had considerable influence on contamination. While diazinon and carbofuran were equally applied intensively, their levels were below the detection limit in the all the samples analyzed. ELISA results were validated by the capillary-HPLC photodiode-array detector instrument analysis, and statistical comparison showed no significant difference between them. It was evident that chlorpyrifos residues determination in water and sediment by ELISA can be a useful strategy in environmental management and monitoring program, and a complimentary analytical tool to high performance liquid chromatography. Levels of chlorpyrifos detected in sediment and water were found to exceed recommended criteria for protection of aquatic life and preservation of water quality and may be hazardous if not regularly monitored.     

Levels and distribution of PCDD/Fs, dl-PCBs, and organochlorine pesticides in sediments from the lower reaches of the Haihe River basin, China

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), and organochlorine pesticides (OCPs) in surface sediments from the lower reaches of the Haihe River basin, northern China, were determined by high-resolution gas chromatograph–high-resolution mass spectrometer. The concentrations of 2,3,7,8-substituted PCDD/Fs, dl-PCBs, and total OCPs [sum of hexachlorobenzene, hexachlorocyclohexanes, and dichlorodiphenyltrichloroethane (DDTs)] in 17 sediment samples were in the ranges of 11.6–1,180,924 pg/g dry weight (dw), 18.7–50,017 pg/g dw, and 1.7–35,280 ng/g dw, respectively. The contamination levels in the samples varied significantly between the different sites. Abnormally high concentrations of PCDD/Fs, dl-PCBs, and some OCPs were found in sediments from the lower reaches of the main channel of the Haihe River and the Dagu Drainage River, which were attributed to the historical production of pentachlorophenol and other pesticides near these locations. High levels of DDTs were detected in the Yongding New River sediment, which were likely to have originated from the discharge of wastewater from a dicofol factory upstream. In samples taken from other sites, the concentrations of these pollutants were at levels comparable to those documented in other areas of China. This preliminary investigation suggests that historical pesticide production in the Haihe River basin has contributed significantly to the contamination of this aquatic ecosystem and that further attention to this issue is warranted.     

Anthropogenic nexus on organochlorine pesticide pollution: a case study with Tamiraparani river basin,South India

The levels of 17 organochlorine pesticides residues (OCPs) in surface water and sediments from Tamiraparani river basin, South India were investigated to evaluate their potential pollution and risk impacts. A total of 96 surface water and sediment samples at 12 sampling stations were collected along the river in four seasons during 2008–2009. The ΣOCP concentrations in surface water and sediments were in the range of 0.1 to 79.9 ng l⁻¹ and 0.12 to 3,938.7 ng g⁻¹ dry weight (dw), respectively. Among the OCPs, the levels of dichlorodiphenyltrichloroethanes (DDTs), aldrin, dieldrin, cis-chlordane, trans-chlordane, and mirex were dominant in the sediments. The dominant OCPs in water samples are heptachlor, o,p′-DDE, dieldrin, o,p′-DDD, and mirex, which show different source of contamination pattern among sampling seasons. The distribution pattern of DDTs, hexachlorocyclohexane, and other OCPs in the present study shows heterogenic nature of nonpoint source of pollution. Notable contamination of water and sediment sample that was observed in upstream (S2) 58 ng l⁻¹ and downstream (S11) 1,693 ng g⁻¹ dw explains agricultural and municipal outfalls, whereas frequent damming effect reduces the concentration level in the midstream. The overall spatial–temporal distribution pattern of ΣOCP residues are illustrated by GIS package.     

Polycyclic aromatic hydrocarbon levels in European catfish from the upper Po River basin

Polycyclic aromatic hydrocarbons (PAHs) are a major concern in environmental studies as many of them have been labeled as probable carcinogens by the International Agency for Research on Cancer (IARC 1983). Due to their lipophilic properties and resistance to degradation, PAHs can accumulate in organic tissue. As a consequence, alarming concentrations of these compounds have been found in many aquatic species. The European catfish (Silurus glanis) is a top food chain predator that is considered to be a reliable bio-indicator of environmental pollution. From 2009 to 2011, 54 specimens of S. glanis were captured from four different sites covering the area of the Po River basin (Northern Italy). Fish muscles were analyzed in the laboratory to determine the levels of nine PAHs, namely naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, pyrene, benz[a]anthracene, chrysene, and benz[a]pyrene (BaP), which were detected by high-performance liquid chromatography (HPLC). The total average concentration of PAHs was 26.90?±?49.50 ng g^?1 (min 0.60, max 275.75 ng g^?1). Analysis showed that 9.20 % of the fish muscles exceeded the maximum levels of 2 ng g^?1 set for BaP by European regulations (Commission Regulation (EC), 2006). Values measured for benz[a]pyrene ranged from 0.05 to 8.20 ng g^?1 (mean 1.07?±?1.58 ng g^?1). Chrysene and benz[a]anthracene, both considered potential human carcinogens (PAH2), were found at levels of 4.40 and 0.05 ng g^?1 (mean values), respectively. The highest mean concentration was recorded for anthracene (12.92 ng g^?1), which has been recently included in the list of substances of very high concern (SVHC) as reported by the European Chemicals Agency (ECHA 1–9, 2009).     

Polycyclic aromatic hydrocarbons in water, sediment and soil of the Songhua River Basin, China

The Songhua River is the third largest river in China and the primary source of drinking and irrigation water for northeastern China. The distribution of 16 priority polycyclic aromatic hydrocarbons (PAHs) in water [dissolved water (DW) and suspended particulate matter (SPM)], sediment, and soil in the river basin was investigated, and the associated risk of cancer from these PAHs was also assessed. The total concentration of PAHs ranged from 13.9 to 161 ng L^?1 in DW, 9.21 to 83.1 ng L^?1 in SPM, 20.5 to 632 ng g^?1 dw (dry weight) in sediment, and from 30.1 to 870 ng g^?1 dw in soil. The compositional pattern of PAHs indicated that three-ring PAHs were predominant in DW and SPM samples, while four-ring PAHs dominated in sediment and soil samples. The spatial distribution of PAHs revealed some site-specific sources along the river, with principal component analysis indicating that these were from pyrogenic sources (such as coal and biomass combustion, and vehicle emissions) and coke oven emission distinguished as the main source of PAHs in the Songhua River Basin. Based on the ingestion of PAH-contaminated drinking water from the Songhua River, cancer risk was quantitatively estimated by combining the Incremental Lifetime Cancer Risk assessment model and BaP-equivalent concentration for five age groups of people (adults, teenagers, children, toddlers, and infants). Overall, the results suggest that the estimated integrated lifetime cancer risk for all groups was in acceptable levels. This study is the first attempt to provide information on the cancer risk of PAHs in drinking water from the Songhua River.     

Selected organochlorine pesticides (OCPs) in surface soils from three major states from the northeastern part of India

Eighty-two surface soil samples were collected from forest, grassland, tea estate, wildlife sanctuary, wetland, and roadside areas from the northeastern states of India, viz., Tripura, Manipur, and Assam. Thirteen different organochlorine pesticides (OCPs) were detected from background soils using gas chromatography electron capture detector. Manipur soils were found to be with higher concentration of dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and endosulfan followed by Tripura and Assam. The spearman correlation coefficient shows significant correlation between HCHs, DDTs, and endosulfan isomers (r ²?>?0.5 and p?<?0.05). Additionally, α-HCH, δ-HCH, o,p′-DDE, and endosulfan-sulfate shows good correlation with total organic carbon in soil (r ²?=?0.5, p?=?0.05), indicating that the soil organic matter could enhance adsorption of these compounds, also demonstrating that the present OCPs in the background soil were from similar source. Further principal component analysis evaluates that most of the higher volatile compounds where clustered together in soil. However, after comparing with different states of Indian soil samples, the concentrations of OCPs in the present study areas are much lower and comparable with background soil across the globe.     

Imposex and butyltin concentrations in Bolinus brandaris (Gastropoda: Muricidae) from the northern Tunisian coast

The imposex incidence and butyltin concentration i.e. tributyltin with its di- and mono-substituted metabolites were investigated in the muricid Bolinus brandaris sampled from two sites on the northern Tunisian coast (the Lagoon of Bizerta and the small Gulf of Tunis). Both populations had imposex, with stages of imposex development varying between VDS 1 and VDS 4.3. All imposex indices (imposex frequency (I %), female penis length, female vas deferens length, vas deferens sequence index, relative penis length index, and vas deferens length index) were significantly higher in snails from the Bizerta lagoon. Butyltins were detected in the whole tissues of both sexes from the two sites. TBT levels were higher in gastropods collected from the lagoon of Bizerta (12.65 ±1.48 ng Sn g^???1 dw in female and 15.21 ±1.13 ng Sn g^???1 dw in male) than in individuals from the Gulf of Tunis (10.71 ±1.26 ng Sn g^???1 dw in female and 11.65 ±1.63 ng Sn g^???1 dw in male), corroborating the data of imposex analysis. These results confirmed that B. brandaris could be used as a bioindicator species of butyltin pollution in the studied areas. In addition, this study provided baseline data that could serve for long-term monitoring of TBT pollution in Tunisia, since legislation to reduce the use of TBT-based antifouling paints has not been introduced yet.     

Determination of organochlorine pesticide concentrations in flathead mullet (Mugil cephalus) caught from the western Black Sea coast of Turkey

The objective of this study was to determine the levels of 14 organochlorine pesticides (OCPs) in flathead mullet (Mugil cephalus) caught from the western Black Sea coast of Turkey. The fish samples were caught from five different locations of the western Black Sea coast of Turkey in August 2009. Organochlorine pesticides were extracted from the liver tissues, and then the levels of OCPs were measured using gas chromatography with an electron capture detector. Organochlorine pesticides were detected in all locations. The levels of total OCPs in fish samples ranged between 0.224 and 1.103 μg g^?1 dry weight in the western Black Sea coast of Turkey. DDT, beta-HCH, and endosulfan I were the dominant OCPs in the fish samples. The levels of DDT in fish samples ranged between 0.081 and 0.186 μg g^?1 dry weight. The levels of total HCH in fish samples ranged between 0.007 and 0.376 μg g^?1 dry weight in the western Black Sea coast of Turkey. Although the usage of OCPs was banned in Turkey, the results of this study clearly indicated the presence of OCPs in the western Black Sea coast of Turkey and exposure of living organisms to these chemicals.     

Organochlorine contaminants in the Vistula Lagoon sedimentation zone as possible source of lagoon recontamination

The presented results include decade of monitoring of the Vistula Lagoon waters and have been supplemented by the determination of chlorinated compounds, as well as on concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the sedimentation zone. Monitoring of river waters entering the Polish part of the lagoon and the lagoon waters confirmed the presence of plant protection chemical; the largest contributors has lindane (34%) and DDT_total (21%); the same as for sediments were dominate lindane (19%) and DDT_total (14%) within pp-DDT isomer dominate (13%). In the lagoon water, PCDD/Fs were determined within a range of 1.5–5.6 ng dm^?3, leading to average toxicity of 0.18?±?0.13 ng TEQ·dm^?3. In sediments, their concentrations fell within a range of 22.7–405.7 ng kg^?1 dw and the average toxicity of the lagoon sediments was set at 5.00?±?1.98 ng TEQ·kg^?1 dw. Both in water and sediments, the greatest share among PCDD/Fs has octa-chlorodibenzodioxin. Due to the hydromorphological conditions of the lagoon, the waters are mixed to the bottom causing the surface layer of sediment to become remobilized—this is suggested as the key factor when it comes to water recontamination and increased access of POPs to marine organisms.     

Distributions, sources, and ecological risks of DDT-related contaminants in water, suspended particulate matter, and sediments from Haihe Plain, Northern China

The residual levels of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including p,p′-DDT, DDD, and DDE) in water, suspended particulate matter (SPM), and sediments from major rivers, lakes, and reservoirs in Haihe Plain were measured with a gas chromatograph equipped with a ⁶³Ni microelectron capture detector. In the fall of 2004, the contents of the total DDXs in the water and SPM were 0.29?±?0.69 ng L^?1 and 423.13?±?577.85 ng g^?1 dry wt., respectively. In the spring of 2005, the total DDXs were 0.36?±?0.91 ng L^?1 for water and 35.93?±?62.65 ng g^?1 dry wt. for SPM. The average concentration of DDXs for sediments was 7.10?±?7.57 ng g^?1 dry wt. during the two seasons. The Eastern-Hebei-Province Coastland River System was the most polluted, which was mainly attributable to the extensive use of DDT pesticide and dicofol in that system. Recent DDT inputs still occur in some regions, as indicated by DDT/(DDD + DDE) > 1 at 29–36 % of the sites for water and 55–61 % of the sites for SPM. The potential ecological risks of DDT in the water were assessed using a species sensitivity distribution model. Only shrimp and crabs were found to have potentially affected fraction values of 1.63?×?10^?3 to 2.27?×?10^?4, with probabilities beyond the hazardous concentration for 5 % of species (HC5) values of 1.90–2.56 %, suggesting only slight risks. DDXs in the sediments of some sites were also of potential risk to benthic organism based on consensus-based sediment quality guidelines.     

珠江三角洲城市群及高海拔地区表层土中有机氯农药的空间分布特征

利用GC-ECD方法测定了珠江三角洲城市群及高海拔地区表层土壤中的有机氯农药。有机氯农药变幅为2.4~78.7 ng/g,平均15.9 ng/g。最高值出现在江门。总HCHs变幅为ND~19.2 ng/g,平均2.91 ng/g, 最高值出现在佛山。总DDTs变幅为ND~74.6 ng/g,平均值为9.91 ng/g。最高值出现在东莞。六氯苯在佛山较高。灭蚁灵在深圳的污染较其它地区严重。总体来说,HCHs污染程度较低,但部分地区有林丹的使用;有些采样点DDTs的污染程度超过了国家土壤环境质量标准的一级自然背景值,且有些区域可能有非三氯杀螨醇的DDTs外源输入。