Jiamo Fu

Occurrence, compositional profiles and possible sources of polybrominated diphenyl ethers in urban soils of Shanghai, China.

By a long-term field investigation, occurrence, compositional profiles and possible sources of polybrominated diphenyl ethers (PBDE) were analyzed with 55 samples collected from surface soil at the urban areas of Shanghai. The results showed that 29 PBDE were detected among 44 target PBDEs. The concentrations of summation operator(29)PBDE ranged from 23.6 to 3797 ng kg(-1) with a mean value of 735 ng kg(-1). BDE209 was the predominant congener in a range of 0.291-2910 ng kg(-1) with a mean of 477 ng kg(-1) in agreement with the fact that commercial decabromodiphenyl ether (DeBDE) mixtures were dominant technical PBDEs mixtures used in China. Meanwhile, PBDE congeners and homologues analysis and principal component analysis (PCA) also revealed that the major source of PBDE in the soil samples was associated with the prevalent use of technical DePBDE. The correlation analysis proved that there was a significant correlation between total organic carbon (TOC) and individual PBDEs excluding BDE209, suggesting the significant influence of TOC on PBDE contamination in soil.

Polychlorinated biphenyls contamination in urban soil of Shanghai: level, compositional profiles and source identification.

Surface soil samples taken from 55 sampling sites at the urban areas of Shanghai were collected and analyzed for the occurrence of 144 polychlorinated biphenyls (PCBs) by GC-μECD. The results showed that totally 74 PCB congeners were identified and the mean concentration of total PCBs was 3057 ng kg(-1) with a range of 232 to 1,1325 ng kg(-1). Compared with the related reports, the level of PCBs contamination in this study was approximately equal to the global background value in soils, but higher than Chinese background for rural and urban soils. According to the compositional profiles of PCBs homologues, a higher proportion of low chlorinated (from tri-CBs to hexa-CBs) was observed. The results indicated that PCB15+13, PCB18, PCB28, PCB104+47 and PCB153 were the most dominant congeners among the identified PCBs. Through homologues analysis, cluster analysis and principal component analysis (PCA), it was found that PCBs were stretched from mixed local sources, and appeared to be mostly originated by Aroclor 1260- and 1254-like mixtures as well as some samples influenced by Aroclor 1232 and 1242. The correlation analysis showed the relatively good correlation among the PCB homologues and soil total organic carbon (TOC), suggesting important influence of soil TOC on PCBs contamination in soil matrix in Shanghai region. The toxic equivalency (TEQ) concentrations of these six dioxin-like PCBs detected in urban soil samples range from 2.71 to 24.9 pg kg(-1)-PCDDeq with a mean 8.18 pg kg(-1)-PCDDeq.

Polycyclic aromatic hydrocarbons in animal-based foods from Shanghai: bioaccessibility and dietary exposure

A total of 175 samples of 18 types of food were collected from markets in Shanghai, China, and the concentrations and bioaccessibility of 15 priority-controlled polycyclic aromatic hydrocarbons (PAHs) in these samples were determined. The mean concentrations of PAHs varied between 2.4 and 47.1u2009ngu2009g−1 wet weight, with the highest being observed in snail and lowest in chicken. The concentrations were lower than the maximum levels of PAH allowed for food per EU regulations. Among the PAHs measured, phenanthrene was the predominant one. Most of the PAHs originated from pyrogenic sources, analysed using molecular indices. The mean bioaccessibility of PAHs varied from 29.0% to 61.2% as measured by simulating the human gastrointestinal digestion process. Linear relationships between the bioaccessibility and lipid contents were observed for most PAH congeners. The daily intake of PAHs by an average Shanghai resident was 848u2009ngu2009day−1 and decreased to 297u2009ngu2009day−1 when the bioaccessibility of PAHs were considered, demonstrating that most intake might have been overestimated. According to the potency equivalent concentrations and screening values of PAHs, consumption of snail and clam, especially snail, should be limited.

Musks and organochlorine pesticides in breast milk from Shanghai, China: Levels, temporal trends and exposure assessment

The concentrations of musks (polycyclic musks and nitro musks) and traditional organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane and its metabolites (DDT, DDE, DDD, and total DDTs), hexachlorobenzene (HCB), and hexachlorocyclohexanes (HCHs) in breast milk collected in Shanghai, China during the period 2006-2010, were determined. The total concentrations ranged from 4.7 to 276.2 (median: 58.4) ng/glipid weight (lw) for musks and from 88.3 to 2532.9 (median: 1003.8) ng/glw for OCPs. 4,4-DDE (median: 655.4 ng/glw) was the predominant OCP, followed by β-HCH (median: 172.5 ng/g lw), and HHCB (1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[γ]-2-benzopyran) (median: 17.7 ng/g lw) was the dominant musk. There was no statistical correlation between total musk concentrations, and HCB, HCHs, DDTs or total OCP concentrations, indicating their different exposure routes and metabolism in humans (p=0.182-0.325). Clear reductions in temporal trends in the levels of DDTs and HCB, especially HCHs (p<0.01) were observed during the sampling period, and the high DDE/DDT ratios in the samples indicated past exposure to DDTs. The relatively high median concentrations of HHCB and HHCB-lactone in 2010 suggested a probably increasing tendency. There were statistically significant influences regarding maternal age and parity on OCP accumulation (p=0.001-0.002), but no significant effect on musks was found (p=0.542-0.919). Musk exposure in neonates via breast milk was 2-3 orders of magnitude lower than suggested provisional tolerable daily intakes (PTDI). The estimated daily intakes for HCB and DDTs were below the PTDI in Canada, however, 56% of those for HCHs exceeded the Canadian PTDI. OCP contamination of breast milk requires further attention.

Ozone sensitivity analysis with the MM5-CMAQ modeling system for Shanghai.

Ozone has become one of the most important air pollution issues around the world. This article applied both O3/(NO(y)-NO(x)) and H2O2/HNO3 indicators to analyze the ozone sensitivity in urban and rural areas of Shanghai, with implementation of the MM5-CMAQ modeling system in July, 2007. The meteorological parameters were obtained by using the MM5 model. A regional emission inventory with spatial and temporal allocation based on the statistical data has been developed to provide input emission data to the MM5-CMAQ modeling system. Results showed that the ozone concentrations in Shanghai show clear regional differences. The ozone concentration in rural areas was much higher than that in the urban area. Two indicators showed that ozone was more sensitive to VOCs in urban areas, while it tended to be NO(x) sensitive in rural areas of Shanghai.

Occurrence, compositional patterns, and possible sources of polybrominated diphenyl ethers in agricultural soil of Shanghai, China

The present study analyzed surface soil collected from agricultural region of Shanghai to determine the occurrence, compositional patterns and possible sources of polybrominated diphenyl ethers (PBDEs). The results showed that 32 PBDEs were detected among 44 target PBDEs. Total PBDE concentrations ranged from 129 to 1245 ng kg(-1) with a mean of 429 ng kg(-1). BDE209 was the predominant congener in a range of 33.2-796 ng kg(-1) with a mean of 254 ng kg(-1). Meanwhile, BDE47, BDE49, BDE153, BDE190, and BDE99 have the most abundant with high concentrations and detectable frequencies. PBDE congeners and homologues analysis and principal component analysis (PCA) also revealed that the major source of PBDE in the soil samples was associated with the prevalent use of technical decabromodiphenyl ether (Deca-BDE) and pentabromodiphenyl ether (Penta-BDE). The correlation analysis proved that there was a significant correlation between total organic carbon (TOC) and lower brominated PBDEs, indicating the significant diffuse nature of the sources of these congeners.

Factors Affecting the Bioaccessibility of Polychlorinated Biphenyls Using In Vitro Test

Factors affecting the bioaccessibility of PCBs in food matrix during digestion were investigated using a static in vitro digestion model simulating human gastrointestinal (GI) tract. The results showed that the ratios of digestive juice to the mass of food (L/M), the pH values of the digestive juice and the ageing time of PCBs in food matrix had significant effect on it. The PCBs bioaccessibility increased with the L/M ratio and the pH values increasing, while it decreased with the ageing time prolong. The present study provides basic information for advanced in vitro studies on the bioaccessibility of PCBs in human body.

Digestion Mechanism of Polychlorinated Biphenyls in Gastrointestinal Tract Using In Vitro Test

A static in vitro digestion model simulating human gastrointestinal tract was used to investigate digestion mechanism of polychlorinated biphenyls (PCBs) in food during digestion. The results showed that the release process of PCBs from food matrix conformed by the pseudo-second-order kinetic model at non-equilibrium condition and reached equilibrium after 2h in small intestine, while the adsorption and release processes at equilibrium were follow Langmuir isotherm equation (R 2 > 0.99). The study results also demonstrated that the relationship between the released PCBs and their levels in food is a partitioning-based model, and has nothing to do with their contamination levels. The present study provides basic information for advanced in vitro and in vivo studies on the mechanism or uptake of PCBs or other chemicals in human body.