Bioaccumulation and human health risk assessment of DDT and its metabolites (DDTs) in yellowfin tuna (Thunnus albacares) and their prey from the South China Sea.

DDTs were detected in yellowfin tuna (Thunnus albacares, 92.1-221.8 ng‧g-1 lipid weight) and their prey (54.9-93.5 ng‧g-1 lipid weight) from the South China Sea (SCS). DDT levels reported in this study were lower than those of the previous studies indicated the recent mitigation of DDT contamination in the SCS. Higher DDT levels were observed in fat abdominal muscle than lean dorsal muscle in adult yellowfin tuna. Meanwhile, DDT levels in adult yellowfin tuna were higher than the young ones. The composition profiles of DDT and its metabolites suggested DDTs in fish in the SCS were mainly derived from the historical use of technical DDTs. DDTs were biomagnified through food chains with the trophic magnification factor of 2.5. Risk assessment results indicated that dietary exposure to DDTs through lifetime fish consumption from the SCS would pose little cancer and noncarcinogenic risk to coastal residents.

Stereoselective bioaccumulation of syn- and anti-Dechlorane plus isomers in different tissues of common carp (Cyprinus carpio).

Common carps (Cyprinus carpio) were exposed to syn- and anti-Dechlorane Plus (DP) isomers to investigate absorption, tissue distribution, and stereoselective bioaccumulation of DP isomers. The absorption efficiencies of anti-DP in the gastrointestinal system were higher than those of syn-DP. A linear accumulation was found for both isomers in all fish tissues except for serum; and the liver and gill exhibited the highest and lowest DP assimilation efficiency, respectively. The elimination of DP isomers in all tissues followed first-order kinetics, with the fastest depuration rate occurring in the liver and serum. The biomagnification factors (BMFs) of both isomers were less than one in all tissues, except for serum. Anti-DP was preferably accumulated in the liver, gill, and serum, whereas syn-DP was selectively accumulated in the carcass and gastrointestinal tract. As a whole, fish did not show selective accumulation of the syn- or anti-DP isomer in the uptake stage, whereas a selective accumulation of syn-DP in fish was observed during the depuration period, which could be due to a selective excretion of anti-DP. Metabolism cannot be ruled out as a possible reason considering the high fanti values and the high elimination rate of DPs in the liver.

Tracing the biotransformation of polychlorinated biphenyls (PCBs) in common carp (Cryprinus carpio): Enantiomeric fraction and compound-specific stable carbon isotope analyses.

Metabolites of polychlorinated biphenyls (PCBs) in fish are difficult to detect in vivo due to the complexity of biometabolism. In the present study, atropisomeric fraction analysis of chiral PCB congeners and compound-specific isotopic analysis (CSIA) were applied to trace the biotransformation of PCBs in fish by exposure of common carp (Cryprinus carpio) to the commercial PCB mixture Aroclor 1242. Stereoselective elimination of the chiral PCB congeners 91, 95, and 136 was observed, indicating a stereoselective biotransformation process. The δ(13)C values of PCBs 5/8, 18, and 20/33 in fish were increased compared with those in the spiked food, while PCBs 47/48 and 49 showed significant heavy isotope depletion. These results suggested a significant biotransformation of the corresponding individual PCB congeners although the potential PCB metabolites, hydroxylated PCBs (OH-PCBs) and methylsulfone PCBs (MeSO2-PCBs), were not detected in the fish tissue samples throughout this experiment. The results of the present study demonstrated that a combination of chiral analysis and CSIA is a promising new approach for investigating the biotransformation of PCBs in biota.

Spatial-temporal trend and health implications of polycyclic aromatic hydrocarbons (PAHs) in resident oysters, South China Sea: A case study of Eastern Guangdong coast.

Spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) were investigated in Eastern Guangdong coast, China. Total PAH concentrations in oysters ranged from 231 to 1178ng/g with a mean concentration of 622ng/g dry weight. Compared with other bays and estuaries, PAH levels in oysters were moderate. Spatial distribution of PAHs was site specific, with relatively high PAH concentrations observed in Zhelin Bay and Kaozhouyang Bay. Based on the Spearman test analysis, only PAH concentration in oysters from Jiazi Harbor showed a significant increasing trend (P<0.05). Three-ring PAHs were the most abundant, accounting for 54.2%-88.4% of total PAHs. Diagnostic ratios suggested that PAHs were derived mainly from petroleum origin. BaP and ∑4PAH concentrations were well within the European Union limits (5ng/g and 30ng/g wet weight, respectively). The incremental lifetime cancer risks (ILCR) for PAHs were <10(-5), indicating that the adverse health risks associated with oyster consumption in this area were minimal.

Polycyclic aromatic hydrocarbons in surface sediments and marine organisms from the Daya Bay, South China.

Polycyclic aromatic hydrocarbons (PAHs) were investigated in the marine ecosystem of the Daya Bay, South China. The PAH concentrations ranged from 340 to 710 ng/g dry weight in the sediments and from 110 to 520 ng/g wet weight in marine organisms, respectively. The dominant compounds were three- and four-ring PAHs in the sediments (53%-89%) and two- and three-ring PAHs in the marine species (67%-94%), respectively. PAHs mainly originated from both pyrolytic and petrogenic sources. Comparison with the effects-based sediment quality guideline values suggested that the ecological risk caused by the total PAHs was relatively low (less than 25% incidence of adverse effects) in the sedimentary environment. The median cancer risk level via seafood consumption (1.6 × 10(-5) for urban residents and 1.2 × 10(-5) for rural residents, respectively) was slightly higher than the maximum admissible level (10(-5)) set by US EPA, but lower than the priority risk level (10(-4)).

Distribution of organophosphorus flame retardants in sediments from the Pearl River Delta in South China.

Twelve organophosphorus flame retardants (PFRs) were identified in the sediments and the sediment core collected from the rivers and the estuary in the Pearl River Delta, with the aim of investigating their spatial and vertical distributions. The concentrations of PFRs ranged from 8.3 to 470 ng/g dry weight with high levels of PFRs in the urban area and the e-waste recycling region. Generally, TPhP, TCPP, TEHP, TCEP, and TBEP were the dominant compounds of the PFRs, the composition of which varied across the different regions, reflecting the different sources of PFRs. In the estuary, the PFRs mainly derived from the Xijiang River and the Shunde sections. Increased concentrations of halogen-containing PFRs have been observed in the upper layers of the sediment core. Conversely, relatively high concentrations of halogen-free PFRs were observed in the lower layers of the sediment core, indicating different usage patterns or environmental behaviors between the halogen and the non-halogen PFRs in the study area.

Legacy and emerging halogenated organic pollutants in marine organisms from the Pearl River Estuary, South China.

A suite of legacy and emerging halogenated organic pollutants (HOPs) were measured in marine organisms (coastal fish and invertebrates) from the Pearl River Estuary, South China, to investigate the current contamination status after the Stockholm Convention was implemented in China. Dichlorodiphenyltrichloroethane and its metabolites (DDTs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were detected in all samples at concentrations of 54-1500, 16-700, and 0.56-59ng/g lipid weight, respectively. Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), 2,3,5,6-tetrabromo-p-xylene (pTBX), and pentabromotoluene (PBT) were also found at concentrations of ND (non-detectable) to 37ng/g lipid weight. The concentrations of these investigated contaminants in the present study were at moderate levels, as compared with those reported in other regions. Significant interspecies differences were found in the levels of DDTs, PCBs, PBDEs and the alternative halogenated flame retardants (AHFRs). DDTs were the predominant HOPs in those species and represented >50% of the total HOPs, followed by PCBs, PBDEs, and AHFRs. The total estimated daily intakes (EDIs) of DDTs, PCBs, PBDEs, and AHFRs were 28, 12, 1.0, and 0.18 (ng/kg)/d, respectively, via seafood consumption. These concentrations are not expected to pose health risks to humans.

An eight year (2005-2013) temporal trend of halogenated organic pollutants in fish from the Pearl River Estuary, South China.

Dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), 2,3,5,6-tetrabromo-p-xylene (pTBX) and pentabromotoluene (PBT) were measured in baby croaker (Collichthys lucidus) and mullet (Osteomugil ophuyseni) collected in 2005 and 2013 from the Pearl River Estuary. DDTs, HCHs, PCBs, and PBDEs were detected in two fish species at concentrations of 150-8100, 1.4-120, 22-560, 2.2-280 ng/g lipid wt., respectively. The levels of these chemicals were significantly lower in 2013 than in 2005. The compositions for DDTs, HCHs, and PBDEs in 2013 differed from those in 2005, indicating source changes between the two sampling periods. DP, pTBX and PBT were detected at concentrations of ND-130 ng/g lipid wt. No clear temporal trends were found for these contaminants. Overall, these results indicated the effectiveness of regulations and source controls in substantively reducing inputs of these contaminants to the Pearl River Estuary.

[Residues and risk assessment of polycyclic aromatic hydrocarbons in the surface sediments and marine organisms from Dapeng Bay, Shenzhen].

In order to assess contamination by polycyclic aromatic hydrocarbons (PAHs), surface sediments and marine organism samples of fish, shrimp and shellfish were collected from the Dapeng Bay, Shenzhen in October 2011. Concentrations fof sixteen priority PAHs were determined by gas chromatography and mass spectrometry (GC-MS). The total concentrations of PAHs (Sigma PAHs ) ranged from 216. 56 ng.g-1 to 1 314. 92 ng.g-1 dry weight in sediment samples and from 70. 88 ng.g-1 to 251.90 ng.g-1 wet weight in biological samples, respectively. The mean concentration was the highest in fish (171.52 ng.g-1 ), followed by mussel (134.75 ng.g-1) and shrimp (123.35 ng.g-1) in the studied marine organisms. Compared with those in other water bodies around the world, PAHs pollution in the studied area was at medium level. The dominant fraction in the surface sediments was the 4-ring PAHs. Identification of PAH sources suggested that PAHs in Dapeng Bay were likely originated from both pyrolytic and petrogenic sources. The most abundant PAHs were 3-ring PAHs in the tissues of organisms, which may be governed by their feeding behaviors, habitats, and bioavailability of PAHs. Ecological risk assessment indicated that PAHs in surface sediments might have adverse impacts on local ecosystem. Health risk analysis revealed that the potency equivalent concentrations of BaP to the total PAHs in marine organisms from Dapeng Bay were relatively high and may cause some concerns on human health by consumption.

Levels, composition profiles and sources of polycyclic aromatic hydrocarbons in surface sediments from Nan'ao Island, a representative mariculture base in South China.

Levels, composition profiles and sources of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Nan'ao Island, one of the largest mariculture bases in South China were investigated. The total PAHs concentrations ranged from 265.49 to 951.27 ng/g (dry weight) with a mean of 515.90 ng/g, and seven possible carcinogenic PAHs accounted for 76.94% of total PAHs. Among various mariculture sections, the highest PAHs level was found in the large seaweed culture; while the lowest concentration was detected in the abandoned culture. The composition of PAHs was characterized by low molecular weight PAHs, and Phe Ant and Pyr were the dominant constituent. PAHs may be mainly originated from petroleum and combustion of biomass and coal. Risk assessments suggested that the probability of adverse effect was lower than 25% and PAHs exposure was moderately carcinogenic.