Assessment of exposure to polybrominated diphenyl ethers associated with consumption of market hens in Guangzhou.

To evaluate contamination by polybrominated diphenyl ethers (PBDEs) in market hens and human PBDE exposure via hen consumption in Guangzhou, hens were collected and their muscle, liver, fat, blood, yolk, and ingluvies tissues were analyzed for 13 PBDE congeners. The median highest concentration of ∑PBDEs was found in the ingluvies (5.30 ng/g lw), followed by the muscle (2.53 ng/g lw), with the lowest located in the yolk (0.09 ng/g lw). The concentrations of PBDEs in the muscle tissue of market hens in Guangzhou were at medium levels compared to others reported around the world. BDE-47, -153, -99, and -183 were the predominant congeners. The daily intake concentrations of PBDEs from hen muscle were estimated to range from 0.08 to 0.31 ng/kg/day in this study, with a Hazard Quotient (HQ) below 1.0. These results suggest that the health risk of PBDEs for the general population, through the consumption of market hens in Guangzhou, was generally low. However, the intake of PBDEs via food consumption may be one major exposure pathway for the general population of Guangzhou.

Levels and distribution of synthetic musks and polycyclic aromatic hydrocarbons in sludge collected from Guangdong Province.

The levels and distribution of six polycyclic musks, three nitromusks and 15 polycyclic aromatic hydrocarbons (PAHs) were investigated in sludge collected from 19 municipal wastewater treatment plants (WWTPs) in six cities in Guangdong Province, China. PAHs were detected in all of the sludge samples, and the levels of the total 15 PAHs ranged from 177.2-4421.8 µg/kg dry weight (dw). Four polycyclic musks, 4-acetyl-1,1-dimethyl-6-tert-butylindan (ADBI), 6-acetyl-1,1,2,3,3,5-hexamethylindan (AHMI), 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta (g) -2-benzopyran (HHCB) and 7-acetyl -1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydro naphthalene (AHTN), were found in these samples. The total concentrations of polycyclic musks varied from 794.4-12960.3 µg/kg dw, with HHCB and AHTN being the main components. Of the three nitromusks, 2,6-dinitro-3-methoxy-4-tert- butyl - toluene (MA) was only found in one sludge sample at the limit of detection (LOD) level, while 1-tert-butyl-3,5-dimethyl-2,4,6-trinitrobenzene (Musk xylene, MX) and 4-acetyl-1-tert-butyl-3,5-dimethyl-2,6-dinitrobenzene (Musk ketone, MK) were found at levels ranging from the LOD to 65.8 µg/kg dw and LOD to 172.7 µg/kg dw, respectively, in most of the sludge samples. The PAHs, polycyclic musks and nitro musks were also shown to have various distribution patterns, possibly due to their different wastewater sources and wastewater treatment technology.

Diepoxybutane induces the formation of DNA-DNA rather than DNA-protein cross-links, and single-strand breaks and alkali-labile sites in human hepatocyte L02 cells.

1,3-Butadiene (BD) is an air pollutant and a known carcinogen. 1,2,3,4-Diepoxybutane (DEB), one of the major in vivo metabolites of BD, is considered the ultimate culprit of BD mutagenicity/carcinogenicity. DEB is a bifunctional alkylating agent, being capable of inducing the formation of monoalkylated DNA adducts and DNA cross-links, including DNA-DNA and DNA-protein cross-links (DPC). In the present study, we investigated DEB-caused DNA cross-links and breaks in human hepatocyte L02 cells using comet assay. With alkaline comet assay, it was observed that DNA migration increased with the increase of DEB concentration at lower concentrations (10-200µM); however, at higher concentrations (200-1000µM), DNA migration decreased with the increase of DEB concentration. This result indicated the presence of cross-links at >200µM, which was confirmed by the co-treatment experiments using the second genotoxic agents, tert-butyl hydroperoxide and methyl methanesulfonate. At 200µM, which appeared as a threshold, the DNA migration-retarding effect of cross-links was just observable by the co-treatment experiments. At <200µM, the effect of cross-links was too weak to be detected. The DEB-induced cross-links were determined to be DNA-DNA ones rather than DPC through incubating the liberated DNA with proteinase K prior to unwinding and electrophoresis. However, at the highest DEB concentration tested (1000µM), a small proportion of DPC could be formed. In addition, the experiments using neutral and weakly alkaline comet assays showed that DEB did not cause double-strand breaks, but did induce single-strand breaks (SSB) and alkali-labile sites (ALS). Since SSB and ALS are repaired more rapidly than cross-links, the results suggested that DNA-DNA cross-links, rather than DPC, were probably responsible for mutagenicity/carcinogenicity of DEB.

Gas chromatography/combustion/isotope ratio mass spectrometric analysis of the stable carbon composition of tetrols.

The stable carbon isotope compositions of tetrols, erythritol and threitol were determined by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Using four tetrols with various delta(13)C values derivatized by methylboronic acid, the carbon isotope analysis method achieved excellent reproducibility and high accuracy. There was no carbon isotopic fractionation during the derivatization processes. The differences in the carbon isotopic compositions of methylboronates between the measured and calculated ranged from -0.20 to 0.12 per thousand, within the specification of the GC/C/IRMS system. It was demonstrated that delta(13)C values of tetrols could be calculated by a simple mass balance equation between tetrols, methylboronic acid, and methylboronates. The analogous 2-methyltetrols, marker compounds of photooxidation products of atmospheric isoprene, should have similar behavior using the same derivatization reagent. This method may provide insight on sources and sinks of atmospheric isoprene.

Distribution, source apportionment, and transport of PAHs in sediments from the Pearl River Delta and the Northern South China Sea.

Polycyclic aromatic hydrocarbons (PAHs) were measured in 59 surface sediments from rivers in the Pearl River Delta and the northern continental shelf of the South China Sea. Total PAH concentrations varied from 138 to 6,793 ng/g dry weight. The sources of PAH inputs to sediments in the Pearl River Delta were qualitatively and quantitatively determined by diagnostic ratios and principal components analysis with multiple linear regression. The results showed that on average coal and wood combustion, petroleum spills, vehicle emissions, and nature sources contributed 36%, 27%, 25%, and 12% of total PAHs, respectively. Coal and biomass combustion was the main source of PAHs in sediments of the South China Sea, whereas petroleum combustion was the main source of pyrolytic PAHs in riverine and estuarine sediments of the Pearl River Delta. Perylene was formed in situ in river sediments and then transported to coastal areas along with other PAHs. The relative abundance of perylene from five-ring PAHs can be used to estimate the contribution of riverine-discharged PAHs to coastal sediments.

Polycyclic aromatic hydrocarbons in suspended particulate matter and sediments from the Pearl River Estuary and adjacent coastal areas, China.

The spatial distribution, composition, and sources of polycyclic aromatic hydrocarbons (PAHs) in sediments and suspended particulate matter (SPM) from the Pearl River Estuary and adjacent coastal areas were examined. Total PAH concentrations varied from 189 to 637 ng/g in sediments and 422 to 1,850 ng/g in SPM. PAHs were dominated by 5,6-ring compounds in sediments and by 2,3-ring compounds in SPM samples. Assessment of PAH sources suggested that biomass and coal combustion is the major PAH source to the outer part of the estuary sediments and that petroleum combustion is the major PAH source to the inner part of estuary sediments. As for SPM samples, PAH isomer pair ratios indicated multiple (petroleum, petroleum combustion, and biomass and coal combustion) PAH sources, and significant temporal variations could exist for the sources of water column PAHs in the study area. The distribution of perylene in SPM samples indicated that the river was the dominant source of perylene in SPM and that perylene could be taken as an index to assess the contribution of river inflow to the total PAHs in SPM samples. The high concentration of perylene in the sediment was indicative of an in situ biogenic origin.

Polybrominated diphenyl ethers in surface sediments of the Yangtze River Delta: Levels, distribution and potential hydrodynamic influence.

A total of 32 surface sediments collected from the Yangtze River Estuary, Hangzhou Bay and the Qiantang River were analyzed for polybrominated diphenyl ethers (PBDEs). The concentrations of summation operatorPBDEs (sum of 12 PBDE congeners without BDE 209) and BDE 209 varied from n.d. to 0.55 and from 0.16 to 94.6 ng/g, respectively. The spatial variability of summation operatorPBDEs concentrations indicated that waste discharge from the urban areas might been the main source of PBDEs in the Yangtze River Delta. BDE 209 was the predominant congener (approximately 90-100%) detected among the 13 congeners, consistent with the fact that technical deca-BDE mixtures are presently the dominant technical PBDE mixtures used in China. Compared to published data acquired from other locales, PBDE congeners with less than four bromines were more abundant in the present study area. The hydrodynamic conditions may likely be a significant factor in dictating the observed levels and congener distribution patterns of PBDEs.

Distribution of alkylphenols in the Pearl River Delta and adjacent northern South China Sea, China.

The occurrence of alkylphenols (APs) was investigated in surface water and sediments from the Pearl River Delta and adjacent northern South China Sea. Most of the water samples contained detectable amounts of APs, ranging up to 0.628 microg l(-1) for nonylphenol (NP) and 0.068 microg l(-1) for octylphenol (OP). APs were found in all of the sediment samples with concentrations ranging from 59 to 7808 microg kg(-1) for NP and from 1 to 93 microg kg(-1) for OP. The Zhujiang River showed the highest concentrations of APs in both water and sediments. Significant decrease of APs concentrations going from the Zhujiang River to the Shiziyang River was observed. The Xijiang River contained concentrations of APs slightly higher in water but relatively lower in sediments than the Lingding Bay, which might be attributed to their different hydrodynamic and sedimentary characteristics. There was a decreasing trend of APs in water from the rivers to the estuary and further to the sea on the whole. In the Lingding Bay and its outer waters, concentrations of APs in sediments increased to a maximum and then decrease seaward, which was consistent with the distribution trend of the sediment organic carbon contents. Linear regression analyses showed the concentrations of APs were markedly correlated with the sediment organic carbon contents, indicating that the sediment organic carbon is an important factor controlling the levels of APs in sediments.

[Light Absorption Properties of Water-Soluble Organic Carbon (WSOC ) Associated with Particles in Autumn and Winter in the Urban Area of Guangzhou].

Light absorption properties of water-soluble organic carbon (WSOC) were investigated in the urban area of Guangzhou. The fine particulate matter (PM2.5) and size-segregated samples were collected in September and December of 2014 and January of 2015. The variation of absorption with wavelength of WSOC was characterized by the absorption Angström exponent (AAEabs). The AAE values of WSOC in PM2.5 were 3.72 ± 0.41 in autumn and 3.91 ± 0.70 in winter, which were lower than those in Beijing and north America. The mass absorption efficiency (MAE) of WSOC at 365 nm wavelength was 0.52 m² · g⁻¹ in autumn and 0.92 m² · g⁻¹ in winter, exhibiting distinct variations between autumn and winter. In winter, the MAEwsoc values exhibited a decreasing trend with increasing particle size, and all size-segregated MAE(WSOC) values in autumn were lower than those in winter, particularly for the particles < 0.95 µm, suggesting more contribution of the secondary formation to WSOC. Comparing the MAE values of elemental carbon (EC) and WSOC, it could be found that the contribution of WSOC to the light extinction of particles couldn't be ignored when the particles were mainly emitted from primary sources.

Chlorinated and polycyclic aromatic hydrocarbons in riverine and estuarine sediments from Pearl River Delta, China.

Spatial distribution of chlorinated hydrocarbons [chlorinated pesticides (CPs) and polychlorinated biphenyls (PCBs)] and polycyclic aromatic hydrocarbons (PAHs) was measured in riverine and estuarine sediment samples from Pearl River Delta, China, collected in 1997. Concentrations of CPs of the riverine sediment samples range from 12 to 158 ng/g, dry weight, while those of PCBs range from 11 to 486 ng/g. The CPs concentrations of the estuarine sediment samples are in the range 6-1658 ng/g, while concentrations of PCBs are in the range 10-339 ng/g. Total PAH concentration ranges from 1168 to 21,329 ng/g in the riverine sediment samples, whereas the PAH concentration ranges from 323 to 14,812 ng/g in the sediment samples of the Estuary. Sediment samples of the Zhujiang River and Macao harbor around the Estuary show the highest concentrations of CPs, PCBs, and PAHs. Possible factors affecting the distribution patterns are also discussed based on the usage history of the chemicals, hydrologic condition, and land erosion due to urbanization processes. The composition of PAHs is investigated and used to assess petrogenic, combustion and naturally derived PAHs of the sediment samples of the Pearl River Delta. In addition, the concentrations of a number of organic compounds of the Pearl River Delta samples indicate that sediments of the Zhujiang river and Macao harbor are most likely to pose biological impairment.

[Level, distribution, and source identification of polychlorinated naphthalenes in surface agricultural soils from an electronic waste recycling area].

The concentration of 46 polychlorinated naphthalenes (PCNs) in the agricultural soils from Luqiao was analyzed by GC-NCI-MS. The objectives of this study were to investigate the contents, spatial distribution and sources of PCNs. The total concentrations of PCNs (sigma PCNs) in soil samples were in the range of 0.062 to 2.92 ng x g(-1), with a mean of 0.630 ng x g(-1). Tetra-CNs and penta-CNs were the predominant homologues in most of the samples, accounting for 18.4% - 88.8% and 8.40% - 53.1%, with average values of 46.7% and 30.7%, respectively, followed by tri-CNs, accounting for 0 - 47.3%, with a mean of 10.6%. Cluster analysis and combustion marker analysis showed that the sampling sites were mainly polluted by Halowax 1014 and Halowax 1013, also possibly polluted by PCBs mixtures and e-waste combustion process. Compared to other studies, the PCNs concentration in this study was at a medium level.

[Characteristics of polychlorinated biphenyls in soils from an electronic waste recycling area].

The concentrations of 144 polychlorinated biphenyls (PCBs) in the soils from Luqiao were analyzed by GC-microECD. The objectives of this study were to understand the contents, spatial distribution and sources. The sigma PCBs concentrations in soils samples were in the range of 0.779 ng x g(-1) to 937 ng x g(-1), with a mean of 75.7 ng x g(-1), and the relatively high level of PCBs were mainly distributed in the south central area. Penta-CBs, hexa-CBs and tetra-CBs were the primary homologues in 38 samples, with the range of 13.0% - 61.1%, 4.59% - 48.8% and 10.1% - 31.5%, respectively. Di-CBs was the most predominant homologues in other samples, with the range of 47.1% - 75.2%. The hierarchical cluster analysis (HCA) showed that most of samples were mainly polluted by Ar1254, few samples were polluted by Ar1221. Significant correlations were observed between sigma PCBs and TOC, which suggested PCBs were affected by TOC in soils. The correlation analysis also showed significant correlation among the PCBs homologues (except di-CBs and nona-CBs), which suggested PCBs might have the similar sources. Compared to other studies from different countries and regions, the PCBs concentrations in the present study were at an upper-middle level.

[Levels, distribution and possible sources of polychlorinated biphenyls in river sediments from an electronic waste recycling area].

The concentrations of 144 polychlorinated biphenyls (PCBs) in the river sediments from Luqiao were analyzed by GC-muECD. The objectives of this study were to understand the contents, spatial distribution and possible sources of PCBs. The Sigma PCBs concentrations detected in the river sediments were in the range of 1.66 to 5 930 ng x g(-1), with a mean of 763 ng x g(-1). Tri-CBs, tetra-CBs and penta-CBs were the primary PCB congeners in all samples, accounting for 2.63%-57.6%, 10.4%-54.6% and 7.82%-46.1%, respectively. Octa-CBs and deca-CBs were the minor PCB congeners in all samples, with the percentages of 0-8.57% and 0-11.0%, respectively. The hierarchical cluster analysis (HCA) showed that 22 samples were mainly polluted by Ar1248, 9 samples were polluted by Ar1254, and 6 samples were contaminated by Ar1016, Ar1232 and Ar1242. The PCBs concentrations found in the present study were at an upper-middle level compared with those in other studies in the world. The PCBs pollution in the present area had a high ecological risk.

Concentrations and seasonal variations of polybrominated diphenyl ethers (PBDEs) in in- and out-house dust and human daily intake via dust ingestion corrected with bioaccessibility of PBDEs.

The objective of this study was to investigate the concentrations, seasonal variations, bioaccessibility, and associated human daily intake of polybrominated diphenyl ethers (PBDEs) in in- and out-house dust collected in Shanghai, China. The PBDE concentrations varied from 131.6 to 3,886.7 ng g(-1) (with an average of 948.2 ng g(-1)) in in-house dust and from 8.7 to 3,116.3 ng g(-1) (with an average of 290.8 ng g(-1)) in out-house dust during four seasons. The PBDE concentrations in the autumn were the lowest for both in- and out-house dust. Among the detected PBDEs, BDE209 was the predominant congener, accounting for more than 80% of the total PBDE amounts. The bioaccessibility of PBDEs, measured using a simulation system of human gastrointestinal tract, was determined as 14.2-66.4% depending on individual PBDE congeners and showed significant negative correlations with organic matter in dust. After corrected with the bioaccessibility of PBDEs, the human daily intake of PBDEs via dust ingestion was calculated to be 0.4-21.4 and 4.3-40.6 ng day(-1) for an average adult and child in Shanghai, respectively. The values were much lower than most estimates in the literature, in which the bioaccessibility of PBDEs were not taken into account, suggesting that the intake of PBDEs may have been overestimated.

[Levels, distribution and possible sources of polybrominated diphenyl ethers in river sediments from an electronic waste recycling area].

The concentrations of 41 polybrominated diphenyl ethers (PBDEs) in the river sediments from Luqiao were analyzed by GC-NCI-MS. The objectives of this study were to understand the contents, spatial distribution and sources. The Sigma40 PBDEs (excluding BDE209) concentrations in sediments sampled were in the range of 0.177 to 161 ng x g(-1), with a mean of 22.5 ng x g(-1), and the concentrations of BDE209 were from 0.36 to 958 ng x g(-1), with a mean of 148 ng x g(-1). Deca-BDE was the most predominant in 9 PBDE homologues in most of samples, accounting for 38.4%-96.0%, with an average of 74.4% nona-BDEs and hepta-BDEs, accounting for 3.3%-25.8% and 0.01%-14.1%, respectively. Significant correlations were observed among all of PBDEs congeners, which suggested these PBDEs might have the similar sources. The homologue composition of PBDEs and hierarchical cluster analysis (HCA) showed that most of sampling sites were mainly polluted by deca-BDE formulation, and others polluted by deca-BDE and octa-BDE formulations. Compared to other studies from different countries and regions, the PBDEs concentrations in the present study were at a medium-to-low level. But it should be concerned that a few of sampling sites were highly contaminated by point sources.

Polybrominated diphenyl ethers in food and associated human daily intake assessment considering bioaccessibility measured by simulated gastrointestinal digestion.

The concentrations of PBDEs in 299 vegetable and animal-based food samples of 31 species, collected in Shanghai, China, and the bioaccessibility of PBDEs in part of the samples were determined. The PBDE concentrations ranged from 0 to 1245.4pgg(-1) with animal-based food containing more PBDEs than vegetables. The bioaccessibility of PBDEs, determined by a method simulating human gastrointestinal digestion process, were from 2.6% to 39.9% in vegetables, and from 5.2% to 105.3% in animal-based food. For animal-based food, good correlations were observed between the bioaccessibility of PBDEs and the fat content, thus the fat content in animal-based food was able to be used to estimate the bioaccessibility of PBDEs. The total daily intake of PBDEs via ingestion of vegetables and animal-based food for an average Shanghai resident was estimated as 13235.7 and 13668.0pg d(-1), respectively, but the amounts available for human absorption were reduced to 2674.4 and 4316.6pgd(-1) after the PBDE bioaccessibility was considered. Finally, the contributions of different food groups to the total daily intake of PBDEs were evaluated. The results revealed that, when not considering the bioaccessibility of PBDEs, vegetables were the leading contributor (49.2%), followed by fish (34.0%). However, the sequence was reversed after the PBDE bioaccessibility was taken into account. The results indicated that human exposure to PBDEs via food ingestion might have been significantly overestimated and the exposure assessment could be misleading if the bioaccessibility of PBDEs was not considered.

[Residues of organochlorine pesticides in urban soil of Shanghai].

The 55 soil samples were collected from Shanghai urban areas in March 2007. The residues and distribution characteristics of organochlorine pesticides (OCPs) in the soil samples were investigated with gas chromatography. The results showed that HCHs, DDTs, and HCB were in the ranges of nd-38.58 microg x kg(-1), 1.81-79.61 microg x kg(-1) and 0.16-40.25 microg x kg(-1), respectively. The total OCPs concentrations in urban soil of Shanghai ranged from 3.12 microg x kg(-1) to 91.07 microg x kg(-1) with a mean of 22.33 microg x kg(-1), and the p,p'-DDE took over 60% of the total OCPs. The main contaminated areas were distributed in the park and greenbelts. The composition of OCPs indicated that OCPs in soil samples mainly came from historical application. Compared to the reference data, the pollution burden in soil of Shanghai was lower than those in other areas of China and in German, Argentina and Poland.

[Distribution, possible source and ecological risk assessment of polycyclic aromatic hydrocarbons in river sediments from a typical contaminated area].

The concentrations of 16 US EPA PAHs in 37 sediment samples collected from Luqiao were analyzed by isotope dilution gas chromatograph/mass spectrometer (GC/MS), and their distribution characters,sources and ecological risk were further investigated. Each of the 16 PAHs could be detected in all of the sediment samples, the total concentrations of the 16 PAHs in the sediments ranged from 59.3 microg/kg to 3 180 microg/kg,with a mean of 722 microg/kg. The pollution level of PAHs can be categorized as low to moderate when compared with other studies around the world. SigmaPAHs were significantly correlated with TOC (r = 0.699, p < 0.001), indicating that TOC was a key soil property affecting the level and fate of PAHs in sediments. The isomeric ratios and factor analysis revealed that PAHs in the Luqiao sediments were originated from mixed sources, and combustion source was dominant. Six sampling sites had the mean PAH ERL quotient > 1, indicating that some sediments in Luqiao may have potential ecological risk. The toxic benzo[a]pyrene equivalents (TEQ(BaP)) of the 16 PAHs ranged from 3.41 microg/kg to 485 microg/kg, 98.4% of which was contributed by 7 carcinogenic PAHs, indicating that 7 PAHs were the main influential factors to the ecological risk.

Assessment of the bioaccessibility of polybrominated diphenyl ethers in foods and the correlations of the bioaccessibility with nutrient contents.

Bioaccessibility of a contaminant in foods is the fraction of the contaminant mobilized from the food matrices during gastrointestinal digestion. In the present paper, the bioaccessibility of polybrominated diphenyl ethers (PBDEs) in 13 types of foods, including fish, meat, rice, flour, and vegetables, was determined using an in vitro digestion method. The bioaccessibility obtained ranged from 2.6% to 41.3%. It was found that the bioaccessibility of PBDEs exhibited positive correlations with fat and carbohydrate contents and negative correlations with protein and dietary fiber contents in the foods. Fat was the most important factor affecting the bioaccessibility of PBDEs. The mechanism underlying the correlations was discussed in view of partition of PBDEs between liquid and solid phases. To our knowledge, this is the first article systematically investigating the bioaccessibility of PBDEs in foods and demonstrating the influence of the food constituents on the bioaccessibility of PBDEs.