Heavy metal contamination along the China coastline: A comprehensive study using Artificial Mussels and native mussels.

A comprehensive study was carried out to assess metal contamination in five cities spanning from temperate to tropical environment along the coastal line of China with different hydrographical conditions. At each of the five cities, Artificial Mussels (AM) were deployed together with a native species of mussel at a control site and a polluted site. High levels of Cr, Cu and Hg were found in Qingdao, high level of Cd, Hg and Pb was found in Shanghai, and high level of Zn was found in Dalian. Furthermore, level of Cu contamination in all the five cities was consistently much higher than those reported in similar studies in other countries (e.g., Australia, Portugal, Scotland, Iceland, Korea, South Africa and Bangladesh). Levels of individual metal species in the AM showed a highly significant correlation with that in the native mussels (except for Zn in Mytilus edulis and Cd in Perna viridis), while no significant difference can be found between the regression relationships of metal in the AM and each of the two native mussel species. The results demonstrated that AM can provide a reliable time-integrated estimate of metal concentration in contrasting environments over large biogeographic areas and different hydrographic conditions, and overcome the shortcomings of monitoring metals in water, sediment and the use of biomonitors.

OCPs and PCBs in marine edible fish and human health risk assessment in the eastern Guangdong, China.

Marine edible fish samples were collected from two important nearshore fishing sites in the eastern Guangdong Province, China: Shantou Harbor and Haimen Bay. In the mixed edible muscle tissues of marine fish samples, the concentrations of polychlorinated biphenyls, dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), chlordanes, and hexachlorobenzene ranged from 1.12 to 53.87, ND (not detected) to 84.01, 0.22 to 7.09, ND to 4.74, and ND to 1.49 ng/g wet weight (ww) in Haimen Bay, respectively, and from ND to 70.35, ND to 164.83, ND to 8.68, ND to 25.61, and ND to 1.76 ng/g ww in Shantou Harbor, respectively. The concentrations of PCBs, DDTs, and HCHs in all samples did not exceed maximum residue limits (China and United States Food and Drug Administration). However, a few fish samples exceed the maximum levels established by the European Union. Daily fish consumption from this region can be of serious concern, and lifetime cancer risk remains a possibility in the studied area.

Polychlorinated dibenzo-p-dioxins and dibenzofurans pollution in China: sources, environmental levels and potential human health impacts.

This review represents an assessment of the pollution status of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in China (the mainland, Hong Kong and Taiwan). During the past decades, seven PCDD/Fs pollution hotspots have been found: (a). Ya-er Lake, Hubei Province, with 'total PCDD/Fs' level reaching 177,427 pg g(-1) (dry weight) in lake sediments; (b). Chinese Schistosomiasis affected areas of Jiangxi Province with 33,660 pg g(-1) in soil; (c). e-waste recycling area of Yangtze River Delta, with 2726 pg g(-1) in paddy soil; (d). e-waste recycling area of Guiyu (eastern part of Guangdong Province), with 967,500 pg g(-1) in mixture of burnt residue and soil (the highest level among all hotspots); (e). Pearl River Delta with 2630 pg g(-1) in coastal sediment. (f). Kwun Tong, Victoria Harbour, Hong Kong with 10,999 pg g(-1) in coastal sediment; and (g). southern Taiwan with 606,000 pg g(-1) in soil near the vicinity of a pentachlorophenol manufacturing factory. The main sources of PCDD/Fs in China were formed from impurities during the production of polychlorophenol, hexachlorobenzene, polychlorinated biphenyls, organic chlorinated pesticide and triclosan. In addition, sources of PCDD/Fs included municipal waste incineration, mineral fuel usage, open burning of electronic waste and crop residues, industrial waste discharge and vehicle exhaust emission. Due to potential human health risks from long-term exposure to PCDD/Fs at these hotspots, body loadings of these contaminants should be monitored.

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.

Use of the clam Asaphis deflorata as a potential indicator of organochlorine bioaccumulation in Hong Kong coastal sediments.

In order to test its ability as a bioaccumulator, the deposit feeding clam Asaphis deflorata, collected from a clean coastal area in Hong Kong (Ding Chau, Ma On Shan), was exposed to field-collected sediments representing a gradient of contamination. Sediments were collected from four sites, namely Shek O in the southeast of Hong Kong Island, Ap Lei Chau in Aberdeen district, Tai Kok Tsui in the Mong Kok waterfront, and To Kwa Wan near Kowloon City pier. Shek O was the cleanest and To Kwa Wan was the most polluted site. Replicate 30L fiberglass tanks containing equal numbers of organisms were maintained for 28 days, with equal quantities of sediment and filtered seawater. Prior to this the animals were depurated for 10 days in clean sediment. During the 28-day holding period, sampling of both sediment and clams was performed on days 0, 10 and 28, along with condition index measurements. Concentrations of organochlorine pesticides and PCBs in sediments showed that Shek O was the cleanest of the sites, followed by Ap Lei Chau, Tai Kok Tsui and To Kwa Wan. There were marked differences among the sites, especially in PAH concentrations, with To Kwa Wan showing extremely high sediment concentrations. Following exposure, the biota concentrations of various organochlorine pesticides and PCBs suggested that there was sediment concentration-dependent accumulation by A. deflorata on day 10 of the experiment. However, there was no significant increase on day 28 for any of the compounds tested. Contaminant concentrations in clams feeding on Shek O sediments were minimal and almost the same on all sampling days, indicating the presence of only baseline contaminant concentrations. The condition indices (CI) of the clams on various sampling days showed that the animals were relatively more stable in sediment from Shek O. There were some deaths in all the test tanks (including those containing Shek O sediments). In addition, clams appeared to bury faster in the cleaner Shek O sediment and remained buried, unlike those in the sediment from the other locations, where some remained predominantly on the surface. Nevertheless, despite not completely burying, the clams in other test sediments still exhibited sediment concentration-dependent tissue accumulation. The results of the investigation indicate the possibility of developing a standard test protocol for bioaccumulation by sediment dwelling invertebrates, for practical use in Hong Kong, using A. deflorata.

Historical trends of organic pollutants in sediment cores from Hong Kong.

Recent studies have indicated the occurrence of a wide range of trace organic contaminants, including polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the Hong Kong environment. These contaminants are potentially harmful to ecological systems, particularly in coastal areas. In this study, two sediment cores (4m) were collected from southern waters of Hong Kong in 2004 to study the historical trends, distribution patterns, and potential sources of trace organic contaminants. DDTs (p,p'-DDT, o,p'-DDT, p,p'-DDD, o,p'-DDD and p,p'-DDE), hexachlorohexanes (HCHs) (alpha and gamma), hexachlorobenzene (HCB), and PCBs were detected in the samples, whereas other target compounds were all below detection limits. Many OCPs have not been produced or used for many years due to toxicological or environmental concerns and PCB use is prohibited in Hong Kong. However, some compounds were still detectable in recent years, and were found to be widely distributed in the environment, likely because of pollutant inputs from the highly industrialized Pearl River Delta region. These results provide important information on current and historical contamination in Hong Kong, and help to reconstruct the pollution history of these trace organic pollutants in Hong Kong coastal waters.

The legacy of organochlorinated pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in Chinese coastal seawater monitored by semi-permeable membrane devices (SPMDs).

Semi-permeable membrane devices (SPMDs) were applied to sample some Organochlorinated Pesticides (OCPs), Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) from the seawater of 14 Chinese coastal areas. The total concentrations of OCPs (∑16OCPs), PAHs (∑15PAHs) and PCBs (∑35PCBs) were in the ranges of 489.2-2174, 589.4-53,160, and 133.2-3658 ng/g lipid, respectively. The ∑15PAHs varied significantly with the sampling locations, which were far higher in north Chinese coastal areas than in south areas, whereas ∑16OCPs and ∑35PCBs only slightly fluctuated along the entire coast line. Comparing SPMD to grab sampler, it was found that the distribution patterns of the PCBs and OCPs in seawater were generally similar. However, the compositional profiles of the PAHs, PCBs, DDTs and HCHs in SPMDs were slightly different to grab samplers and organisms. The SPMDs accumulated less lipotropic compounds, which are inclined to dissolve in water rather than in organisms.

Distribution and transportability of hexabromocyclododecane (HBCD) in the Asia-Pacific region using skipjack tuna as a bioindicator.

The geographical distribution of hexabromocyclododecane (HBCD) was investigated through analysis of muscle tissue of skipjack tuna (Katsuwonus pelamis) collected from offshore waters of Asia-Pacific region (Japan, Taiwan, Philippines, Indonesia, Seychelles, Brazil, Japan Sea, East China Sea, South China Sea, Indian Ocean and North Pacific Ocean). HBCD was detected in almost all samples analyzed (<0.1 to 45 ng/g lipid weight basis), indicating widespread presence of this compound in the marine environment. Elevated concentrations of HBCD were found in skipjack tuna from areas around Japan, which have the larger modern industrial/urban societies, and implicated these areas as primary regional sources. All three individual HBCD isomers (alpha-, gamma- and beta-HBCD) were detected in almost all samples; the percentage contribution of the alpha-isomer to total HBCD increased with increasing latitude. The estimated empirical 1/2 distance for alpha-HBCD was 8500 km, which is one of the highest atmospheric transportability among various halogenated persistent organic pollutants (POPs).

Ecological risk assessments of endocrine disrupting organotin compounds using marine neogastropods in Hong Kong.

As active ingredients of anti-fouling paints that are widely used on ship hulls, organotin compounds, in particular tributyltin (TBT), are well-known endocrine disruptors causing sex changes in marine organisms and widespread in coastal waters and sediments worldwide. In this study, a comprehensive ecological risk assessment (ERA) of organotins was conducted in Hong Kong waters through determining the imposex status, sex ratio and tissue burdens of these compounds in the neogastropods, Thais clavigera and Thais luteostoma collected from 29 coastal sites. We also investigated the historical trend of organotin effects on these gastropods, and performed a probabilistic ERA based on tissue burden of TBT in the animals. Our results demonstrated that imposex indices were positively correlated with the body burden of organotins in the gastropods. Across all sites, the sex ratio (female:male) decreased significantly with increasing imposex levels or tissue burden of organotins, implying that such pollutants can result in a male-biased population, potentially leading to local extinction in extreme cases. Based on the ERA, 5.4% of all populations of T. clavigera are at risk due to exposure to TBT; the risks include growth inhibition, impairment of immune functions and reduced fitness. Seriously impacted areas included Aberdeen, Repulse Bay, Butterfly Beach, Mui Wo and Ha Mei Wan. A comparison with historical data revealed that there had been some improvement in the areas with low marine traffic, and distant from the major harbour/port. This could partly be due to the restriction on the use of TBT on small vessels (<25m in length) since 1992. Nevertheless, the organotin contamination still remains severe in areas with high marine traffic or adjacent to large harbours/ports. In particular, the situation in the northeastern waters of Hong Kong has been getting worst since 1996 that is probably associated with the rapid development of the cargo container port at Yantian in China.

A novel approach for estimating the removal efficiencies of endocrine disrupting chemicals and heavy metals in wastewater treatment processes.

The wide occurrence of endocrine disrupting chemicals (EDCs) and heavy metals in coastal waters has drawn global concern, and thus their removal efficiencies in sewage treatment processes should be estimated. However, low concentrations coupled with high temporal fluctuations of these pollutants present a monitoring challenge. Using semi-permeable membrane devices (SPMDs) and Artificial Mussels (AMs), this study investigates a novel approach to evaluating the removal efficiency of five EDCs and six heavy metals in primary treatment, secondary treatment and chemically enhanced primary treatment (CEPT) processes. In general, the small difference between maximum and minimum values of individual EDCs and heavy metals measured from influents/effluents of the same sewage treatment plant suggests that passive sampling devices can smooth and integrate temporal fluctuations, and therefore have the potential to serve as cost-effective monitoring devices for the estimation of the removal efficiencies of EDCs and heavy metals in sewage treatment works.

Global pollution monitoring of polychlorinated dibenzo-p-dioxins (PCDDs), furans (PCDFs) and coplanar polychlorinated biphenyls (coplanar PCBs) using skipjack tuna as bioindicator.

In order to elucidate the global distribution of dioxins and related compounds, such as PCDDs, PCDFs and coplanar PCBs, levels of these compounds were determined in the muscle of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters and open seas near Japan, Taiwan, Philippines, Indonesia, Seychelles and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Indian Ocean and the North Pacific Ocean. PCDDs, PCDFs and coplanar PCBs were detected in almost all the specimens collected from all the locations surveyed, indicating widespread contamination by these compounds in the marine environment. Higher concentrations of dioxins and coplanar PCBs were detected in the samples from temperate Asian regions, plausibly due to larger usage and anthropogenic generation in highly industrialized countries around the East China Sea and the South China Sea, such as Japan, Korea, Taiwan, Hong Kong and coastal China.

Field validation of antioxidant enzyme biomarkers in mussels (Perna viridis) and clams (Ruditapes philippinarum) transplanted in Hong Kong coastal waters.

Green-lipped mussels, Perna viridis, and Manila clams, Ruditapes philippinarum were sourced from "clean" sites in the Hong Kong region, depurated in a laboratory using uncontaminated filtered seawater for 8 days, and transplanted to a suspected gradient of chemically polluted sites in Hong Kong. After 14- and 28-days of field exposure, several antioxidant parameters including glutathione S transferase (GST), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) were quantified in gill and hepatopancreas tissues. Whole body tissue concentrations of polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (PHCs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) were determined in pooled site samples. Chemical analyses indicated that: (a) clams had higher levels of PAHs, PHCs, DDTs and PCBs, whereas mussels had higher hexachlorocyclohexane (HCHs) and there was no difference between species for dieldrin and remaining OCs; (b) Kat O should not be continued as a "clean" reference site for Hong Kong, because of the levels of contaminants measured and (c) PAH concentrations in the current survey were similar to those previously measured. Toxicological conclusions were: (a) antioxidant responses were different between species; (b) CAT and GST have highest utility in clams for field use in Hong Kong, whereas CAT in both gill and hepatopancreas tissue showed most potential in mussels; (c) significant induction of antioxidant responses over day 0 (excluding GPx in both tissues, and GST in mussel hepatic tissue); (d) groups of contaminants do not consistently induce antioxidant responses and (e) organochlorines and PCBs correlated significantly with CAT and GST in clam hepatopancreas and with CAT in mussel gill and hepatic tissue. Multivariate statistical techniques indicated little relationship between the site patterns for antioxidant responses and the contaminant gradients identified in body burden analysis.

Polybrominated diphenyl ethers (PBDEs) in sediments and mussel tissues from Hong Kong marine waters.

Sediments and green-lipped mussels, Perna viridis, were used to investigate concentrations of polybrominated diphenyl ethers (PBDEs) in Hong Kong's marine environment. PBDEs have been used extensively over the past two decades as flame retardants in polymer additives for a variety of plastics, computers, furniture, building materials, and fabrics. Many measurements of PBDEs in various environmental matrices have been reported from Belgium, Holland, Japan, Europe and North America, but few measurements are available for the southeast Asian region and Hong Kong. PBDE congeners (n=15) were measured in 13 sediments and nine mussel samples, taken from Hong Kong marine waters. The Sigma15PBDEs in sediments ranged between 1.7 and 53.6 ng g(-1) dry wt, with the highest concentrations located around the most heavily populated areas of Victoria Harbour and Sai Kung, while the lowest concentrations of Sigma15PBDEs were found at more remote locations of Sha Tau Kok, Wong Chuk Bay, Castle Peak Bay, and Gold Coast. Sigma15PBDEs ranged from 27.0 to 83.7 ng g(-1) dry wt of mussel tissues. Although not identical, most of the congeners in sediments were found in mussel tissues, with BDE-47, BDE-99, BDE-153 and BDE-183 being the most prominent in both matrices. On the basis of a literature survey, the concentrations of PBDEs reported in Hong Kong sediments and mussel tissues are amongst the highest in the world.

Distribution and sources of polycyclic aromatic hydrocarbons in the sediment of a sub-tropical coastal wetland.

Sediment cores (0-35cm below surface) from twelve sampling stations in the Mai Po and Inner Deep Bay Ramsar Site of Hong Kong were retrieved in the period March-December 1999. Vertical profiles of 15 priority polycyclic aromatic hydrocarbons (PAHs) in each sediment core were determined. Ranges of total PAH concentration, [sigmaPAH], in the wetland sediment were 0.18-0.83 (N = 0.36) microg/g dried sediment (mudflats) and 0.63-0.96 (x = 0.77) microg/g dried sediment (mangroves). A decreasing trend in depth averaged [sigmaPAH] was observed from the landward end towards the seaward end of the Marshes. On the mudflats, vertical profiles of the PAHs were quite uniform. At the fringe of the Mai Po mangroves, significantly higher concentration of all PAHs was observed at the upper 0 to -8 cm layer. No significant difference in the distribution patterns of the 15 priority PAHs in summer and winter was observed. This indicates that distribution of PAHs in the sediment of the Mai Po Marshes is not very sensitive to sub-tropical climatic changes of the region. Two PAH isomer ratios, [Phen]/([Phen] + [Anthra]) and [Pyrene]/([Pyrene] + [Fluoran]), were used to identify potential sources of PAH contamination in the wetland. Results revealed that local deposition is a more important source than long-range atmospheric transportation.

A comparison of polycyclic aromatic hydrocarbon and petroleum hydrocarbon uptake by mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) in Hong Kong coastal waters.

The ability of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) to accumulate polycyclic aromatic hydrocarbons (PAHs) and petroleum hydrocarbons (PHCs) from five sites in Hong Kong's coastal waters was compared. Mussels consistently had higher levels of contaminants, but their utility was limited at one highly polluted site due to mortality. Mussels and SPMDs ranked sites differently in terms of individual contaminant levels. Although SPMDs overcome many of the disadvantages of using living organisms to measure contaminants in marine waters, they cannot be used as "mimics" due to different PAH and PHC accumulation patterns.

Evaluation of biomarkers of exposure and effect in juvenile areolated grouper (Epinephelus areolatus) on foodborne exposure to benzo[a]pyrene.

Food-borne benzo[a]pyrene (B[a]P) was administered daily to juvenile grouper (Epinephelus areolatus) at two environmentally realistic concentrations (a low dose of 0.25 microg B[a]P/g body wt/d and a high dose of 12.5 microg B[a]P/g body wt/d) to investigate and relate temporal changes in body burden of B[a]P, hepatic ethoxyresorufin-O-deethylase (EROD) activities, growth, RNA:DNA ratio, estradiol, testosterone, and triiodothyronine (T3). After feeding with B[a]P diets for four weeks, fish were fed with normal diet for another four weeks to study recovery of the various biomarkers during the depuration period. After one week of exposure, both body muscle B[a]P burdens and hepatic EROD activities significantly increased. Body burdens were stable in tissues until the fourth week of exposure, when concentrations in the high-dose group increased markedly, at which time a concomitant decrease in EROD was found. During the depuration period, body burdens decreased in the second week, and EROD declined in the first week. Growth and RNA:DNA ratio were unaltered. Despite large variations found in sex steroid levels, elevation of testosterone was clearly evident in the fourth week, showing that B[a]P may disrupt the balance of sex steroids in fish. Significantly, increases in plasma-free T3 concentrations were found in the fourth week of exposure and the first week of depuration, suggesting that development and reproduction may potentially be at risk during chronic exposures. Our data also suggest that these hormonal disturbances are not persistent and that normal hormonal levels can be restored soon after contamination is abated.

Biofouling confounds the uptake of trace organic contaminants by semi-permeable membrane devices (SPMDs).

The outer layers of layflat, low density polyethylene plastic tubing (the principal component of semi-permeable membrane devices, SPMDs) were biofouled at a clean site in Hong Kong coastal waters for periods of 1-4 weeks. Following pre-fouling, triolein was added to the SPMDs and, along with control (unfouled) devices, they were exposed to a range of organochlorine pesticides (alpha-HCH, aldrin, p,p'-DDT) and PAHs (anthracene, fluoranthene and benzo(a)pyrene) under laboratory conditions. Results showed that the uptake of contaminants by SPMDs was severely reduced by as much as 50% under fouling conditions in comparison to unfouled controls. The ultimate utility of SPMDs as passive monitors is thus reduced, although alternative measures, such as the use of permeability reference compounds may compensate, and allow for realistic evaluations of dissolved environmental concentrations in aquatic environments. However, due to the complexities involved in such procedures--especially as they need to be conducted on a case-by-case basis-the utility of SPMDs appears to be limited for estimates of bioavailability unless necessary calibrations are undertaken within each environment that the sampler is used.

The occurrence and ecological risks of endocrine disrupting chemicals in sewage effluents from three different sewage treatment plants, and in natural seawater from a marine reserve of Hong Kong.

We determined the concentrations of 12 endocrine disrupting chemicals (EDCs) in sewage effluents collected from three different sewage treatment plants (STPs) in Hong Kong, and found 4-nonylphenol (NP) and bisphenol A (BPA) were the most abundant EDCs. Effluent concentrations of NP and BPA were higher in dry season than in wet season, but opposite seasonal changes of NP were observed in receiving waters, probably due to the surface runoff. The two secondary STPs showed higher removal efficiency for these compounds than the preliminary STP, while having higher removal efficiency in wet season. Therefore, it is necessary to upgrade the preliminary STP and improve the EDC removal efficiency in dry season. Seawaters from the Cape D' Aguilar Marine Reserve adjacent to these STPs also exhibited elevated NP levels with a hazard quotient >1. Furthermore, diluted effluents from the STPs elicited significant transcriptional responses of EDC-related genes in the marine medaka fish.

Evaluation of organochlorine contamination in Indo-Pacific humpback dolphins (Sousa chinensis) from the Pearl River Estuary, China.

Organochlorine compounds, including polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane (DDTs), hexachlorocyclohexane (HCHs), chlordanes (CHLs) and hexachlorobenzene (HCB) were analyzed in blubber samples collected from fifteen Indo-Pacific humpback dolphins (Sousa chinensis) stranded in the Pearl River Delta during the period from 2004 to 2009. In general, the magnitude of the mean concentrations is: ∑DDTs>∑PCBs>∑HCHs>∑CHLs>HCB. DDT levels found in this study were very high, with the ΣDDT ranging from 845 to 179,000 ng/g wet weight. Of particular importance is the fact that new inputs from diverse sources still exist in the Pearl River Delta. ∑PCBs ranged from 123 to 10,200 ng/g wet weight. More studies are necessary for a better understanding of these organochlorine contaminants and their impact on the conservation of humpback dolphins residing in the Pearl River Estuary waters.