HCH and DDT residues in molluscs from Chinese Bohai coastal sites

Species-specific accumulation and temporal trends of bisphenols and benzophenones in mollusks from the Chinese Bohai Sea during 2006-2015

Information on the occurrence and bioaccumulation of bisphenols and benzophenones in coastal marine invertebrates is limited. In this study, concentrations of eight bisphenol and five benzophenone analogues were determined in 186 mollusks collected from coastal areas of the Chinese Bohai Sea during the period 2006-2015. Total concentrations of bisphenols and benzophenones were in range of not detected (nd)-58 (geometric mean: 13.0 ng/g) and nd-59.1 (2.06 ng/g) on a dry-weight basis, respectively. BPA and BPF were the major bisphenols, collectively accounting for >90% of the total concentrations. BP-3 was the predominant benzophenone, representing 74% of the total concentrations. The mollusk species, Meretrix meretrix, accumulated high concentrations of both bisphenols and benzophenones. A steady increase in bisphenol concentrations in mollusks was observed in recent years, whereas no obvious temporal trend was found for benzophenones. The estimated daily intakes of bisphenols through consumption of mollusks were lower than the current reference dose. This study establishes a baseline concentration for bisphenols and benzophenones in mollusks in Chinese coastal waters.

Distribution of methylsiloxanes in benthic mollusks from the Chinese Bohai Sea

Methylsiloxanes are a class of silicone compounds that have been widely used in various industrial processes and personal care products for several decades. This study investigated the spatial distribution of three cyclic methylsiloxanes (D4-D6) and twelve linear methylsiloxanes (L5-L16) in mollusks collected from seven cities along the Bohai Sea. D4-D6 (df = 71%-81%) and L8-L16 (df = 32%-40%) were frequently detectable in the mollusk samples, while L5-L7 were not found in any mollusk samples. Cyclic methylsiloxanes (D4-D6) were found in mollusks with the mean concentrations of 15.7 ± 12.3 ng/g ww for D4, 24.6 ± 15.8 ng/g ww for D5 and 34.0 ± 23.0 ng/g ww for D6. Among the seven sampling cities, the cyclic methylsiloxanes were predominant in mollusks, with the total cyclic methylsiloxanes (sum of D4-D6, ∑CMS) accounting for 74.2%-80.7% of the total methylsiloxanes. ∑CMS along the coastline demonstrated a clear gradient, with the highest concentrations in mollusks at the sampling sites located in the western part of the Bohai Sea and the lowest concentrations in mollusks from cities located in the eastern part of the Bohai Sea. The biota-sediment accumulation factors for cyclic methylsiloxanes (D4-D6) and linear methylsiloxanes (L8-L16) were estimated as 0.42 ± 0.06-0.53 ± 0.06 and 0.13 ± 0.03-0.19 ± 0.05, respectively.

Temporal Trends of Parabens and Their Metabolites in Mollusks from the Chinese Bohai Sea during 2006-2015: Species-Specific Accumulation and Implications for Human Exposure

Parabens are used as preservatives in many consumer products, and human exposure to these chemicals has been a public concern. In this study, mollusks ( n = 186), collected from the Chinese Bohai Sea during 2006-2015, were analyzed for six parabens and their five metabolites. The total concentration of parabens was in the range of 2.66-299 ng/g dw (geometric mean: 24.1). Methyl paraben and 4-hydroxybenzoic acid were the predominant parent and metabolic parabens, respectively found in mollusks. Mollusk species, Mactra veneriformis, Mytilus edulis, and Cyclina sinensis contained elevated concentrations of both parent and metabolic parabens. A gradual increase in paraben concentrations was found in mollusks collected between 2006 and 2012. Principal component analysis suggested the existence of a common source for these chemicals in mollusks. Consumption of mollusks can contribute to human exposures and we estimated daily intakes of parabens through the consumption of mollusks. This is the first study to report temporal trends and accumulation of parabens and their metabolites in a variety of invertebrate species from coastal marine environments.

Human health risk assessment of pesticide residues in market-sold vegetables and fish in a northern metropolis of China

With growing concerns about food safety and stricter national standards in China, attention has focused on vegetables and fish as they are an important part of the Chinese daily diet, and pesticide residues can accumulate in these foodstuffs. The local consumption habits of vegetables and fish were determined using questionnaires distributed in the major regions of the northern metropolis. Then, the samples of fruit-like vegetables, leafy and root vegetables, and five species of fish (freshwater and marine) were collected from supermarkets and traditional farmers' markets in the city. The concentrations and profiles of pesticide residues (hexachlorocyclohexane (HCH), dichlorodiphenyl trichloroethane (DDT), and endosulfan) in the samples were determined and compared. For the vegetables, the concentration ranges of ΣDDT, ΣHCH, and Σendosulfan were not detectable (ND) to 10.4 ng/g fresh weight (f.w.), ND to 58.8 ng/g f.w., and ND to 63.9 ng/g f.w., respectively. For the fish samples, the corresponding values were 0.77-25.0 ng/g f.w., 0.02-1.42 ng/g f.w., and 1.22-22.1 ng/g f.w., respectively. Only one celery sample exceeded the maximum residue limits (MRLs) of HCH residues set by Chinese regulations (GB2763-2014). The estimated daily intakes (EDIs) and hazard ratios (HRs) were calculated using data from the recently published Exposure Factors Handbook for the Chinese Population. The EDIs and HRs showed that the levels of organochlorine pesticide (OCP) residues in vegetables and fish in this area are safe.

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.

Emerging persistent organic pollutants in Chinese Bohai Sea and its coastal regions

Emerging persistent organic pollutants (POPs) have widely aroused public concern in recent years. Polybrominated diphenyl ethers (PBDEs) and perfluorooctane sulfonyl fluoride/perfluorooctane sulfonic acid (POSF/PFOS) had been newly listed in Stockholm Convention in 2009, and short chain chlorinated paraffins (SCCPs) and hexabromocyclododecanes (HBCDs) were listed as candidate POPs. Bohai Sea is located in the arms of numbers of industrial cities, the semienclosed location of which makes it an ideal sink of emerging pollutants. In the present paper, latest contamination status of emerging POPs in Bohai Sea was reviewed. According to the literature data, Bohai Sea areas are not heavily contaminated by emerging POPs (PBDE: 0.01–720 ng/g; perfluorinated compounds: 0.1–304 ng/g; SCCPs: 64.9–5510 ng/g; HBCDs: nd-634 ng/g). Therefore, humans are not likely to be under serious risk of emerging POPs exposure through consuming seafood from Bohai Sea. However, the ubiquitous occurrence of emerging POPs in Bohai Sea region might indicate that more work should be done to expand the knowledge about potential risk of emerging POPs pollution.

Polybrominated diphenyl ethers contamination in marine organisms of Yantai coast, northern Yellow Sea of China

To evaluate the contamination of polybrominated diphenyl ethers (PBDEs) in marine organisms of the northern Yellow Sea of China, mollusks, wild shrimps and crabs were collected from the Yantai coast and ten PBDE congeners levels in the samples were analyzed and compared. The results indicate all the samples have been contaminated by PBDEs and PBDEs concentrations varied in individual species and in sampling sites. The concentration range of ΣPBDEs in the samples was 0.23-10.56 ng/g d.w. below the national edible criteria 40 ng/g d.w.. Congener compositions were mainly dominated by BDE 209.

Short chain chlorinated paraffins in mollusks from coastal waters in the Chinese Bohai Sea

As an extremely complex group of persistent organic pollutants (POPs) candidates in the Stockholm Convention, short chain chlorinated paraffins (SCCPs) have been of extensive concern in recent years. In this study, nine bivalve and two gastropod species were collected in 2009 to evaluate the spatial distributions and potential factors influencing the bioaccumulation of SCCPs in mollusks in the Chinese Bohai Sea. The concentrations of ∑ SCCPs in the mollusks were in the range 64.9-5510 ng/g (dry weight) with an average chlorine content of 61.1%. C(10) and C(11) were the predominant homologue groups of SCCPs, which accounted for about 29.7% and 34.9% of ∑ SCCPs, respectively. Six and seven chlorinated substituents were the main congener groups. Mya arenaria (Mya), Mactra veneriformis (Mac), and Crassostrea talienwhanensis (Oyster, Ost) had higher average concentrations of SCCPs than other species, implying that these bivalves could be used as sentinels to indicate SCCPs contamination in this coastal region. A significant positive linear relationship was found between SCCP concentrations and lipid content of the mollusks, whereas the lipid-normalized SCCP concentrations were negatively linear-related to the trophic levels (TL), which implied that SCCPs did not show biomagnification in mollusks in this region.

Probabilistic ecological risk assessment of DDTs in the Bohai Bay based on a food web bioaccumulation model

The fugacity-based food web model was developed to simulate the bioaccumulation of dichloro-diphenyl-trichloroethanes (DDTs) in the aquatic ecosystem in the Bohai Bay. The internal exposure levels (IELs) of DDTs in various organism categories were calculated. Monte Carlo-based uncertainty analysis was performed to get the of IEL distributions of DDTs in organisms. Probabilistic ecological risk assessment (ERA) was performed based on IEL distributions and internal species sensitivity distributions (SSDs). The results show that fugacities and bioaccumulation factors (BAFs) generally increased with increasing trophic level in the food web. Octanol-water partition coefficient (K(ow)), DDT levels in water and the lipid contents had the greatest influences on IELs in the organism bodies. The ecological risks of DDTs were relatively high. The risk order was p,p'-DDT>p,p'-DDE>p,p'-DDD. At an internal hazard quotient (HQ(int)) criterion of 1/5, the risk probabilities were 0.10 (0.055-0.17), 0.079 (0.045-0.13) and 0.053 (0.028-0.092) for p,p'-DDT, p,p'-DDE and p,p'-DDD, respectively. The results from ERA based on the internal exposure approximated those based on external exposure. The food web model is a feasible method to predict the extent of bioaccumulation and IELs of hydrophobic organic pollutants in organisms as a step to evaluate their risk posed on aquatic ecosystems.

Dietary intake and potential health risk of DDTs and PBDEs via seafood consumption in South China

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

Bioavailability of organochlorine compounds in aqueous suspensions of fullerene: evaluated with medaka (Oryzias latipes) and negligible depletion solid-phase microextraction

The wide application of engineered nanomaterials, such as fullerene (C(60)), will inevitably lead to their release into the aqueous environment, which may alter the bioavailability of organic compounds to aquatic organisms. Negligible depletion solid-phase microextraction (nd-SPME) together with medaka (Oryzias latipes) bioaccumulation were used to study the effects of aqueous suspensions of fullerene (nC(60)) on the bioavailability of eight organochlorine compounds (OCCs) (logK(OW) 3.76-6.96). Freely dissolved concentrations of OCCs decreased by 11.5-88.4% at addition of 5mgL(-1)nC(60) as indicated by reduced equilibrium concentrations in the SPME fiber coating, the highest reduction being observed for the most hydrophobic OCCs. Medaka bioaccumulation study demonstrated that at the kinetic uptake regime, nC(60) significantly decreased the bioaccumulation of the high hydrophobic OCCs (logK(OW)>6), but slightly enhanced the bioaccumulation of the less hydrophobic OCCs (logK(OW)<6). The OCC concentrations in medaka (C(fish)) at the kinetic uptake regime linearly correlated with that in nd-SPME fiber (C(fiber)) without nC(60) (p=0.007-0.013, R(2)=0.666-0.723), but this correlation deteriorated with the presence of nC(60) (p=0.073-0.081, R(2)=0.423-0.440). These results suggest that in nC(60) the uptake mechanism of OCCs to medaka is different from that to nd-SPME fiber. While only the freely dissolved OCCs are available to nd-SPME fiber, both the freely dissolved and the nC(60) associated OCCs contributed to the accumulation of OCCs to medaka.

Organochlorine pesticide and heavy metal residues in some edible biota collected from Quanzhou Bay and Xinghua Bay, southeast China

In order to assess the contamination of edible marine organisms in Quanzhou and Xinghua Bays, Fujian Province, China, concentrations of organochlorine pesticides (hexachlorocyclohexane isomers or HCHs and dichlorodiphenyltrichloroethane isomers/derivatives or DDTs) and heavy metals (Cu, Pb, Zn, As, Cr, Cd, Ni and Hg) in 13 species collected from different sites in the bays were analyzed by GC-ECD and ICP-MS. The concentration of the sum of DDTs exceeded that the sum of HCHs in the samples. Most of the organisms showed higher levels of DDTs than the first level criterion (10 ng/g) for marine biological quality in China (GB 18421-2001) but conformed to the first level criterion (20 ng/g) for HCHs. The estimated mean daily uptake of pesticides was below the level for minimal risk to the consumers. The levels of Cd, As and Pb in most organisms from both bays were markedly elevated and above the recommended legal limits for human consumption. Our results showed the need for routine monitoring of marine species contamination to ensure public and environmental health.

Persistent organic pollutant residues in the sediments and mollusks from the Bohai Sea coastal areas, North China: an overview

The Bohai Sea costal area is one of the most developed zones of China and the sewage water from populous and developed cities, including Beijing, Tianjin, Qinhuangdao and Dalian is discharged into the Bohai Sea. Additionally, its semi-enclosed characteristic restricts water exchange, which leads to high accumulation of pollutants in the environment. This overview presents the residues of 6 classes of Persistent Organic Pollutants (POPs), including PAHs, DDTs, HCHs, PCBs and PCDD/Fs, in the sediments and mollusks of the Bohai Sea through analyzing previous literatures. In the sediments, the highest PAH concentrations were detected in the vicinities of Qinhuangdao, while the northeast corner of the Bohai Bay possessed the highest levels of DDTs and PCBs. The investigations on HCHs and PCDD/Fs distributions on the whole sea scale have not been reported. In mollusks, PAH concentrations were in the same order of magnitude in the whole Bohai Sea, so were DDTs, HCHs and PCBs, while the outlier maximum values of PCDDs and PCDFs occurred in Yingkou. In general, the POPs residues in mollusks collected from Shandong Province were higher than the other areas. The compositions of DDTs, HCHs and PCBs in sediments indicated their recent usage. By comparing POP concentrations in sediments with the recommended criterions, it was shown that some individual PAH compounds occasionally associated with adverse biological effects in the vicinities of the Liaodong Bay and Qinhuangdao, and the Liaohe River Estuary were heavily contaminated with DDTs, but PCBs were all below the thresholds. In order to reveal the transference and transformation of POPs in the environment, further studies concerning with their behavior, fate and bioaccumulation in the different trophic levels should be programmed. Moreover, laws and regulations should be enforced to ban the illegal usage of POPs-containing pesticides to guarantee health of the environment and human.

HCH and DDT Residues in Bivalves Anodonta woodiana from the Taihu Lake, China

The present article attempts to use freshwater bivalves Anodonta woodiana for monitoring the pollution of hexachlorocyclohexane isomers (alpha-, beta-, gamma-, delta-HCH), dichlorodiphenyltrichloroethanes (o, p', p, p'-DDT) and metabolites (p, p'-DDE, p, p'-DDD) in the Taihu Lake, China. A total of 36 bivalves were sampled from 4 sites of Huzhou city, Dapu of Yixing city, Xueyan of Changzhou city, and Wulihu of Wuxi city around the lake in August-October 2004. The organochlorines were detected in all bivalves, and the mean concentration of SigmaDDTs (7.07 ng/g wet weight) was significantly higher than that of SigmaHCHs (2.37 ng/g wet weight). Overall, SigmaHCHs are at the highest concentrations in the bivalves from the Dapu and Huzhou site, whereas SigmaDDTs are at highest concentrations in the bivalves from the Wulihu site. Compositions of SigmaHCHs were predominated by alpha- and gamma-HCH isomers in the bivalves from all four study sites. Among these sampling sites, p, p'-DDT exhibited the highest percentage in the bivalves from Huzhou site. Furthermore, significant regional variations in compositions of both SigmaDDTs and SigmaHCHs had been identified. The residue levels of SigmaDDTs and SigmaHCHs in the bivalves of the present study were much lower than the corresponding residue limits for aquatic products of Ministry of Agriculture of China, FDA, and FAO/WHO. These findings suggest that Anodonta woodiana could serve as a unique bioindicator to monitor the HCH and DDT pollutions in the freshwater environment.

Tissue distribution of organochlorine pesticides in fish collected from the Pearl River Delta, China: implications for fishery input source and bioaccumulation

Fish tissues from different fishery types (freshwater farmed, seawater farmed and seawater wild) were analyzed for organochlorine pesticides (OCPs), with the aim to further our understanding of bioaccumulation, and reflect the state of different fishery environments. Significantly higher SigmaOCP levels were found in seawater farmed fish than others, and among three freshwater farmed species, the lowest levels occurred in filter-feeding fish (bighead carp). Liver contained the highest SigmaOCP levels, while no significant differences were found among other tissues. Among DDT components, p,p'-DDT was abundant in seawater fish, while for freshwater fish, p,p'-DDE was the predominant congeners, except for northern snakehead (34% for p,p'-DDE and 30% for p,p'-DDT). The new source of DDTs to freshwater fish ponds was partly attributed to dicofol, whereas sewage discharged from the Pearl River Delta and anti-fouling paint were likely the DDTs sources to seawater farmed fish.

Agrochemical and polychlorobyphenyl (PCB) residues in the Mekong River delta, Vietnam

An environmental survey on pesticide residues and polychlorobyphenyl compounds (PCBs), encompassing more than 70 polar and non-polar compounds quantifiable by the techniques used, was performed in the Mekong River delta based on analyses of water, sediment and bivalve mollusc samples. Few polar compounds, such as diazinon and fenotrothion, were detected in water but a high number of non-polar chlorinated compounds, such as DDT, HCH, endosulfan and PCBs, were detected in sediments and biota. The highest concentrations measured were of DDT with an average 6.3 ng g(-1) dry weight (range 0.32-67 ng g(-1)) in sediments and 38.6 ng g(-1) (range 5.5-123 ng g(-1)) in molluscs' soft tissues. Amongst chlorinated compounds, DDT concentrations were followed in decreasing order by those of PCB, endosulfan, hexachlorocyclohexane and chlordane. Residues of organochlorine compounds originate from local usage of agrochemicals although with a likely contribution also of atmospheric deposition of residues (not measured) originated elsewhere. Concentrations of PCB and pesticide residues in the aquatic environment of the Mekong River delta are lower than values reported for other regions of Vietnam and Asia. Nevertheless, current concerns about the effects of chlorinated compounds on public health advise improved control of chemical residue discharges in order to abate environmental contamination.

Distribution of organochlorine pesticides (OCPs) in conifer needles in the southeast Tibetan Plateau

Twenty-nine conifer needles in mountain-valley areas from the southeastern Tibet were collected with altitude span from 1520 to 4340m above sea level (m.a.s.l.). They were analyzed for organochlorine pesticides (OCPs), including hexachlorocyclohexanes (alpha-, beta-, gamma- and delta-HCH), dichlorodiphenyltrichloroethane (p,p'-DDE, p,p'-DDD, o,p'-DDT and p,p'-DDT) and hexachlorobenzene (HCB). Concentrations of OCPs in samples ranged from 0.69 to 4.3 ng/g, from 0.39 to 4.9 ng/g and from 1.9 to 20.5 ng/g (dry weight) for HCB, total HCHs and DDTs, respectively. The levels of DDTs found here were noticeably higher than those from other high mountainous regions. Composition of HCH isomers and DDTs was analyzed, and it was found that the high ratio of o,p'-DDT/p,p'-DDT might be caused by the application of dicofol in adjacent regions. A number of environmental factors controlling the distribution of OCPs in regional scale were also discussed in this paper.

Levels and bioaccumulation of organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in fishes from the Pearl River estuary and Daya Bay, South China

Fifty fish samples were collected from the Pearl River estuary (PRE) and Daya Bay, South China and were analyzed for DDTs, HCHs, chlordanes and polybrominated biphenyl ethers (PBDEs). Except the high concentrations of DDT observed in fishes, the concentrations of HCHs, chlordanes and PBDEs were low when compared to other regions. BDE-47 was the predominant PBDE congener and the BDE-209 concentrations were relatively low, despite its high concentration in surface sediments. The absence of significant increase of DDT, HCH, chlordane and PBDE concentrations towards higher delta15N values, as well as the lack of a significant correlation (p<0.1) between log concentrations (lipid normalized) and delta15N, may indicate a weak biomagnification of these chemicals in the food webs. Good agreement was observed between their concentrations and lipid contents of the organisms. Bioconcentration was suggested to be responsible for the accumulation of OCPs and PBDEs in the lower trophic organisms in the studied subtropical waters.

Monitoring of toxic substances in the Hong Kong marine environment

A long-term programme for monitoring toxic substances in the marine environment was established in Hong Kong in 2004, focusing on chemicals of potential ecological and health concern. The programme ran on 3-year cycles, with the first two years monitoring marine water, sediment, biota, and the third year monitoring pollution sources. Twenty-four priority chemicals were measured, including dioxins/furans, dioxin-like PCBs, total PCBs, PAHs, DDTs, HCHs, TBTs, phenol, nonylphenol (NP), NP ethoxylates, PBDEs and metals. Results from the first three years of monitoring indicate that toxic substances in the Hong Kong marine environment were within the range reported for the coastal waters in China and other regions, but generally lower than in the Pearl River Estuary. The levels met the standards for protecting aquatic life and human consumption. Sewage effluent, stormwater and river water were possible sources of phenolic compounds; whereas air deposition or regional pollution, rather than local discharges, may contribute to the dioxins/furans, PAHs and PCBs found in the marine environment.

Concentrations and characteristics of organochlorine pesticides in aquatic biota from Qiantang River in China

The Qiantang River is a typical river flowing through an agricultural area in China. It was studied in 2006 for its aquatic biota quality by determining 13 organochlorine pesticides (OCPs) in the edible parts of crabs, clams, shrimp, fish, aquatic plants, as well as water and sediments collected from seven sites along its upper reaches all the way downstream. The levels of all insecticides were in the range of 17+/-13 (water plants), 35+/-36 (shrimp), 32+/-14 (crabs), 39+/-21 (clams), 47+/-35 (fish) ng/g wet weight (ww) and in the range of 2936+/-2356 (water plants), 5827+/-6013 (shrimp), 2102+/-966 (crabs), 1859+/-1018 (clams), 3624+/-11331 (fish) ng/g lipid. DDT and its metabolites were the predominant contaminants in most biota. A linear relationship was observed between the log bio-concentration factor (BCF) and log octanol-water partition coefficients (Kow) for fish, clams and shrimp. Composition analyses in various environmental media indicated a recent usage of lindane and dicofol into the river.

Polybrominated diphenyl ethers and organochlorine pesticides in sewage sludge of wastewater treatment plants in China

The concentrations of chemicals in sewage sludge from wastewater treatment plants (WWTPs) may relate to their levels of use and environmental pollution in the region. In this work, sludge samples were collected from 31 WWTPs in 26 cities in China and analyzed for polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs). The concentrations of SigmaPBDE (sum of congeners 17, 28, 47, 66, 71, 85, 99, 100, 138, 153, 154, and 183) ranged from 6.2 to 57ng/g (dw). The concentration of decabromodiphenyl ether (BDE-209) ranged from below limit of detection (LOD) to 1109ng/g (dw) (with a median of 27ng/g (dw)), and averaged 55% (median 69%) of the total PBDEs. These levels are about 10-100 times lower than those found in Europe and North America. PBDE levels in sludge were not found to depend on the location and capacity of the WWTPs. Concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane (DDTs) and its major degradation products, and hexachlorobenzene (HCB) ranged from below detection limit to 167ng/g (dw), 11 to 1065ng/g (dw), and 7.5 to 319ng/g (dw), respectively. The major DDT degradation products were p,p'-DDE and p,p'-DDD. The major hexachlorocyclohexane (HCH) isomer in sludge is beta-HCH, reflecting its higher affinity to solids and resistance to degradation than other isomers.

Organochlorine pesticides in seafood products from southern China and health risk assessment

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

Investigation of organochlorine pesticides (OCPs) in mollusks collected from coastal sites along the Chinese Bohai Sea from 2002 to 2004

Mollusks living in seas can accumulate organochlorine pesticides (OCPs). The residue levels of selected OCPs: dichlorodiphenyltrichloroethane (p,p'-DDT, o,p'-DDT, p,p'-DDE, p,p'-DDD), hexachlorocyclohexanes (alpha-, beta-, gamma- and delta-HCH) in gastropod and bivalve species collected from ten coastal cites along the Chinese Bohai Sea were investigated from 2002 to 2004. The species included nine kinds of mollusks: Rapana venosa, Neverita didyma, Scapharca subcrenata, Mytilus edulis, Amusium, Crassostrea talienwhanensis, Meretix meretrix, Sinonovacula constricta, Ruditapes philippinarum, Mactra veneriformis. The results showed that OCPs widely existed in the mollusks organisms. p,p'-DDT, p,p'-DDE, beta-HCH were the major compounds. Statistical analysis (One-way ANOVA) showed that the contents of OCPs in these mollusks did not change obviously from 2002 to 2004. Principal component analysis (PCA) was also used for determining the polluting characters existing in this selected field.

Residual concentrations of micropollutants in benthic mussels in the coastal areas of Bohai Sea, North China

Studies of heavy metals and organic pollutants in different benthic mussel species from Bohai Sea show that concentrations of Cd in mussels commonly exceed national biological quality standards. In addition, a site located in Laizhou Bay exhibits higher average concentrations of As, Hg and Pb with respect to the other sites. Residual levels of petroleum hydrocarbons at several sites in Liaodong Bay also exceed quality guidelines. Contents and compositional characteristics of DDT and its metabolites in mussels suggest the probability of recent inputs and potential ecological risks to the local benthic environment.

Accumulation features of organochlorine pesticides and heavy metals in fish from high mountain lakes and Lhasa River in the Tibetan Plateau

Organochlorine pesticides and heavy metals were analyzed in fish from remote mountain lakes and Lhasa River in Tibetan Plateau. Concentrations of summation operatorHCH, summation operatorDDT and HCB in fish muscles were in the range of 0.13-2.6 ng/g, 0.78-23 ng/g, 0.31-3.2 ng/g based on wet weight, respectively. Heavy metals were routinely found with different levels in fish. The Cu and Zn levels were relatively high with the maximum concentrations reaching 2.0 and 6.9 microg/g, respectively. Accumulation of OCPs and heavy metals are quite different in tissues and organs. Gill seems to accumulate more OCPs due to absorption by its larger surface per tissue. Heavy metal levels were generally high in liver, eggs and gill, and low in brain and muscle. Results from this study demonstrate that the Tibetan Plateau functions as a regional contaminant convergence zone by long-range atmospheric transport and orographic cold trapping.

Distribution and characteristics of organic micropollutants in surface sediments from Bohai Sea

Spatial distribution and compositional characteristics of PAHs, DDTs and PCBs in surface sediments from Bohai Sea were investigated. Proportion of LMW PAHs at Jinzhou Bay was significant, due probably to the petrogenic sources from neighboring oil wells and plants, while HMW PAHs were dominant in the other sea areas, inferred pyrogenic origins mainly from coal or petroleum combustion. The average ERL quotient for the PAH species in Qinhuangdao and Liaodong Bay indicated relatively stronger potential ecological risk. The concentration ratios of DDT to metabolites (DDD + DDE) exceeded 1.0 in the coastal areas of Qinhuangdao, Liaodong Bay and Bohai Bay, demonstrated some recent inputs of DDT nearby, and DDD as the major degradation product. The concentrations of PCBs were generally low, however, the contents of DDTs were greater than the ERL guidelines in the coastal areas of Qinhuangdao, Liaodong Bay and Bohai Bay, and suggested the potential ecological risk.

The levels and distribution of organochlorine pesticides (OCPs) in sediments from the Haihe River, China

The levels and distribution patterns of the selected organochlorine pesticides (OCPs=p,p'-DDT, o,p'-DDT, p,p'-DDE, p,p'-DDD, alpha-, beta-, gamma- and delta-HCH) in surficial sediments from the Haihe River and Dagu Drainage River of Tianjin were investigated by means of gas chromatography coupled with micro-electronic capture detector (GC-microECD). Concentrations of OCPs in the sediments from the Haihe River ranged from 1.88 to 18.76ng g(-1) (mean 7.33ng g(-1)) for sum HCH, 0.32-80.18ng g(-1) (mean 15.94ng g(-1)) for sum DDT. Compared with the Haihe River, the Dagu Drainage River was much more contaminated by HCHs and DDTs, wherein sum HCH ranged from 33.24 to 141.03ng g(-1) (mean 87.74ng g(-1)) and sum DDT ranged from 3.60 to 83.49ng g(-1) with a mean value of 35.52ng g(-1). The concentration distribution of sum DDT and sum HCH was different indicated their different contamination sources. Composition analyses indicated that a recent usage or discharge of HCH and DDT into the Dagu Drainage River.