Pollution characteristics and underlying ecological risks of primary semi-volatile organic compounds (SVOCs) in urban watersheds of Shanghai, China.

We investigated the pollution characteristics of ninety semi-volatile organic compounds (SVOCs) in the rivers and lakes of Shanghai. Total concentrations of Σ90SVOCs in water and sediment samples from 30 sites ranged from 1.47 to 19.5 µg/L and 2.38 to 9.48 mg/kg, respectively. PAEs and PAHs were the major contaminant compounds found in all samples. OCPs accounted for less than 3% of the total concentrations of Σ90SVOCs and other SVOCs were either not detected or only detected in trace amounts. Our results indicated that domestic swage, industrial wastewater, petroleum products, and other human activities were the pollutant sources to the water and sediment. It is noteworthy that products that contain the banned chemicals HCH and DDT are still under use within the studied areas. Ecological and health risk assessment results showed that dieldrin and BBP have the potential to cause adverse effects on the environment, while B(a)p and DBP have high carcinogenic risks to humans.

Occurrence, sources and health risk assessment of polycyclic aromatic hydrocarbons in urban (Pudong) and suburban soils from Shanghai in China.

A comprehensive investigation was conducted to the urban (Pudong) and suburban soils in Shanghai. A total of 154 soil samples were analyzed for 26 PAHs including highly carcinogenic dibenzopyrenes (DBPs). The total concentrations ranged from 25.8 to 7380 µg kg(-1) for Σ26PAHs and 18.8 to 6320 µg kg(-1) for 16 USEPA priority PAHs (Σ16PAHs), respectively. The BaP toxic equivalent (BaPeq) concentrations were between 6.41 and 2880 µg kg(-1) for Σ24PAHs, 1.11 and 620 µg kg(-1) for Σ16PAHs and 2.72 and 2250 µg kg(-1) for Σ4DBPs. The high PAH contamination in green land soils might originate mainly from local road traffic and industrial activities, and sewage sludge application or waste water irrigation for soil. Seven sources of soil PAHs in Shanghai were identified by positive matrix factorization (PMF) model. The mean risk quotient (m-RQ) values indicated that there were medium to high ecological risks in 9.10% of soil samples, pyrene (Pyr), benzo[b]fluoranthene (BbF) and benz[a]anthracene (BaA) were the major ecological risk drivers under agricultural use. The cancer risk (CR) values were within the acceptable range at 35.7%, 35.1% and 31.2% of sampling sites for children, youths and adults, respectively. The total lifetime carcinogenic risk (TLCR) values at 57.8% of sampling sites were within the acceptable range. Overall, cancer risks of soil PAHs in all sampling sites in the studied area were below the highest acceptable risk, suggesting that soil PAHs are unlikely to pose a significant cancer risk for population based on ingestion, dermal contact and inhalation exposure pathways.

Phthalate diesters in airborne PM(2.5) and PM(10) in a suburban area of Shanghai: seasonal distribution and risk assessment.

Concentrations of nine phthalate diesters in 24-h airborne PM2.5 and PM10 were determined from October 2011 to August 2012 in a suburban area in Shanghai, China. Dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), di-iso-butyl phthalate (DIBP), benzyl butyl phthalate (BzBP), and di(2-ethylhexyl) phthalate (DEHP) were frequently detected in airborne particulate matter at sum concentrations of these six compounds ranging from 13.3 to 186 ng/m(3), with an average value of 59.8 ng/m(3) in PM2.5, and from 10.1 to 445 ng/m(3), with an average value of 132 ng/m(3) in PM10. DEHP, DBP, and DIBP were the major phthalate diesters found in PM samples. DEHP was found predominantly in coarse (size fraction of between PM2.5 and PM10) particles, whereas DMP, DEP, DBP, DIBP, and BzBP were found predominantly in fine (PM2.5) particles. The concentrations of phthalates in PM during warm months (207 ng/m(3) for PM10 and 71.9 ng/m(3) for PM2.5, on average) were significantly higher than those during cold months (76.9 ng/m(3) for PM10 and 50.4 ng/m(3) for PM2.5). Significant positive correlations were found between concentrations of total phthalates, DEHP, and BzBP, with the total mass and organic carbon content of PM. Based on the concentrations of DEHP, incremental lifetime cancer risks (ILCR) from inhalation exposure were estimated using a Monte Carlo simulation. Although the 95% probabilities for the ILCR values for the general population were below the U.S. Environmental Protection Agency (EPA) threshold of 10(-6), our result is an underestimate of the actual health risk because we only considered the outdoor inhalation exposure to DEHP in this study.

Polycyclic aromatic hydrocarbons (PAHs) in urban soils of the megacity Shanghai: occurrence, source apportionment and potential human health risk.

A comprehensive investigation was conducted to the urban soil in the megacity Shanghai in order to assess the levels of PAHs and potential risks to human health, to identify and quantitatively assess source contributions to the soil PAHs. A total of 57 soil samples collected in main urban areas of Shanghai, China were analyzed for 26 PAHs including highly carcinogenic dibenzopyrene isomers. The total concentrations ranged from 133 to 8,650 ng g for ΣPAHs and 83.3 to 7,220 ng g for ΣPAHs, with mean values of 2420 and 1,970 ng g, respectively. DBalP and DBaeP may serve as markers for diesel vehicle emission, while DBahP is a probable marker of coke tar as distinct from diesel emissions. Six sources in Shanghai urban area were identified by PMF model; their relative contributions to the total soil PAH burden were 6% for petrogenic sources, 21% for coal combustion, 13% for biomass burning, 16% for creosote, 23% for coke tar related sources and 21% for vehicular emissions, respectively. The benzo[a]pyrene equivalent (BaP) concentrations ranged from 48.9-2,580 ng g for ΣPAHs, 7.02-869 ng g for ΣPAHs and 35.7-1,990 ng g for ΣDBPs. The BaP concentrations of ΣDBPs made up 72% of ΣPAHs. Nearly half of the soil samples showed concentrations above the safe BaP value of 600 ng g. Exposure to these soils through direct contact probably poses a significant risk to human health from carcinogenic effects of soil PAHs. The index of additive cancer risk (IACR) values in almost one third of urban soil samples were more than the safe value of 1.0, indicating these urban soil PAHs in the study area may pose a potential threat to potable groundwater water quality from leaching of carcinogenic PAH mixtures from soil.

Interaction mechanism between berberine and the enzyme lysozyme.

In the present paper, the interaction between model protein lysozyme (Lys) and antitumorigenic berberine (BBR) was investigated by spectroscopic methods, for finding an efficient and safe photosensitizer with highly active transient products using in photodynamic therapy study. The fluorescence data shows that the binding of BBR could change the environment of the tryptophan (Trp) residues of Lys, and form a new complex. Static quenching is the main fluorescence quenching mechanism between Lys and BBR, and there is one binding site in Lys for BBR and the type of binding force between them was determined to be hydrophobic interaction. Furthermore, the possible interaction mechanism between BBR and Lys under the photoexcitation was studied by laser flash photolysis method, the results demonstrated that BBR neutral radicals (BBR(-H)) react with Trp (K=3.4×10(9)M(-1)s(-1)) via electron transfer to give the radical cation (Trp/NH(+)) and neutral radical of Trp (TrpN). Additionally BBR selectively oxidize the Trp residues of Lys was also observed by comparing the transient absorption spectra of their reaction products. Through thermodynamic calculation, the reaction mechanisms between (3)BBR and Trp or Lys were determined to be electron transfer process.

Tissue-specific distribution of fatty acids, polychlorinated biphenyls and polybrominated diphenyl ethers in fish from Taihu Lake, China, and the benefit-risk assessment of their co-ingestion.

The fish tissues from four species collected from Taihu Lake, China, were analyzed including dorsal, ventral, and tail muscles, heart, liver, and kidney. The highest and lowest concentrations of fatty acids were respectively observed in livers and muscles. There were significant intraspecies and interspecies differences in the compositions of most fatty acids among muscle, heart, liver, and kidney. All the tissues were generally beneficial for consumption considering fatty acids. People mainly consume the muscle. Hence, the benefits from two polyunsaturated fatty acids, i.e., eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and risks from PCBs and PBDEs via fish consumption were evaluated by calculating the benefit-risk quotient (BFQ) for the intake of fish muscle containing EPA+DHA vs. PCBs or PBDEs. The BFQ values considering carcinogenic and noncarcinogenic effects for PCBs were ∼3000 and 10 times higher than those of PBDEs via fish consumption to achieve the recommended EPA+DHA intake of 250 mg d(-1), respectively. The results also suggested that the risk consuming the dorsal muscle was generally lower than the ventral and tail muscles.

Polycyclic aromatic hydrocarbons and organochlorine pesticides in fish from Taihu Lake: their levels, sources, and biomagnification.

The investigation of biomagnification of polycyclic aromatic hydrocarbons (PAHs) and endosulfan, an organochlorine pesticide (OCP) and a new persistent organic pollutant, has been limited in freshwater food chains. The objective of the present study was to investigate the levels with focus on the sources and biomagnification of PAHs and OCPs in fish from Taihu Lake, China. In 193 samples of 24 species investigated, the concentrations ranged from 289 to 9 500 ng/g lipid weight (lw) for PAHs, and from 121 to 904 ng/g lw for OCPs, indicating that the fish in the lake was moderately contaminated. The PAHs mainly originated from both unburned petroleum and combustion of fossil fuels, and the OCPs from aged residues. It was unlikely that most of the PAHs and OCPs were biodiluted through the food chain because their trophic magnification factors were higher than one nevertheless the P-values >0.05. Aldrin, dieldrin, p,p'-DDE, p,p'-DDD, and endosulfan sulfate were significantly biomagnified through the food chain.

DNA damage induced by three major metabolites of 1,3-butadiene in human hepatocyte L02 cells.

1,3-Butadiene (BD) is a carcinogenic air pollutant. Its bioactivation produces four major metabolites, i.e., 3,4-epoxy-1-butene (EB), 3,4-epoxy-1,2-butanediol (EBD), 1,2,3,4-diepoxybutane (DEB), and 3-butene-1,2-diol (BDD). Studies have been mostly focused on DEB due to its strong mutagenicity/carcinogenicity. In contrast, studies of genotoxicity of EB, EBD, and BDD have been limited. In particular, genotoxicity of EBD and BDD using strand breaks as the endpoint has not been investigated. To obtain a more complete understanding of BD toxicity, in the present study, we used comet assay to investigate DNA damage induced by EB, EBD, and BDD in human hepatocyte L02 cells, with the aim to determine their relative potencies, the types of DNA damage, and the possible pathway to form strand breaks. Using alkaline comet assay (pH>13), it was observed that EB and EBD caused similar concentration-dependent increases in DNA migration from 50 to 1000µM. However, BDD induced a statistically significant increase only at 1000µM, and the increase itself was very small. EBD was as potent as EB at lower concentrations (≤200µM), and was slightly less potent than EB at higher concentrations. The results indicated that these metabolites could generate strand breaks in cells with the rank order of the potencies being EB>≈EBD≫BDD. All three compounds failed to cause statistically significant increases in DNA migration in pre-lysed cells, suggesting that they did not produce strand breaks through chemical pathways under our experimental conditions. By using comet assays at pH 11.9 and pH 9, it was demonstrated that EB and EBD generated both single-strand breaks (SSB) and alkali-labile sites, but BDD produced only SSB. To our knowledge, this is the first report to investigate EBD- and BDD-induced strand breaks in cells. The results implied that EBD could play an important role in toxicity of BD.

[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.

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.

[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.

[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.

[Indoor deposition flux and congener profiles of polybrominated diphenyl ethers (PBDEs) in Shanghai, China].

Indoor dry deposition of eight homes and offices in the urban area of Shanghai, China were sampled with clean glass plate during July to August of 2008 to study the indoor deposition flux and congener profiles of polybrominated diphenyl ethers (PBDEs). 16 PBDEs congeners which including BDE-17, -28, -71, 47, -66, -77, -100, -99, -85, -118, -154, -153, -138, -183, -190 and BDE-209 were measured by GC-MS with negative chemical ionization (NCI) in selected ion monitoring (SIM) mode. The particulate deposition flux of PBDEs in homes and offices were (10.9 +/- 8.2) and (14.2 +/- 11.9) ng x (m2 x d)(-1) respectively. Deca-BDE (BDE-209) was the major compound, accounting for 88.2% -99.2% of the quantified PBDEs. The particulate deposition flux in the offices [(3.1 +/- 2.0) mg x (m2 x d)(-1)] was relatively lower than that of homes, but the concentration of PBDEs in the particles [(3361.6 +/- 1987.4) ng x g(-1)] was significantly higher than that of homes [(1169.1 +/- 647.1) ng x g(-1)]. The concentration of PBDEs in the indoor dry deposition of Shanghai ranked in the middle level comparing with other cities around the world. The indoor deposition flux of PBDEs was mainly correlated with the flux of particle deposition and the usage of electrical and electronic products, but not the interior decoration and the amount of furniture.

[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.

Occurrence, distribution and possible sources of organochlorine pesticides in agricultural soil of Shanghai, China.

Surface soil samples from agricultural soil of Shanghai were collected and analyzed for 24 organochlorine pesticides (OCPs). The concentrations were in the ranges of nd-10.38 n gg(-1) for HCHs (sum of alpha-, beta-, gamma- and delta-HCH), 0.77-247.45 ng g(-1) for DDTs (sum of p,p'-DDT, p,p'-DDD, p,p'-DDE, and o,p'-DDT), 0.84-10.08 ng g(-1) for CHLs (sum of heptachlor, heptachlor epoxide, cis-chlordane, trans-chlordane, and trans-nonachlor), nd-3.68 ng g(-1) for endosulfan (sum of alpha- and beta-endosulfan), 0.10-3.62 ng g(-1) for HCB and nd-5.69 ng g(-1) for other OCPs (sum of aldrin, dieldrin and endrin). The total OCPs concentrations ranged from 3.16 to 265.24 ng g(-1) and the main contaminated areas were distributed in the south regions of Shanghai (including Fengxian, Nanhui and Jinshan districts). According to the measured concentrations and detection frequencies, HCHs, DDTs, HCB and heptachlor epoxide were the most dominant compounds among the 24 OCPs. The different compositions of DDT, HCH, chlordane and endosulfan indicated that the residues of these compounds in most soil samples originated from historical application, besides slight recent introduction at some sampling locations. The correlation analysis showed no significant relationship between TOC and OCPs. The quality of Shanghai agricultural soil was classified as low pollution by OCPs.

Determination of gaseous carbonyl compounds by their pentafluorophenyl hydrazones with gas chromatography/mass spectrometry.

A sensitive and reliable method has been developed for the simultaneous determination of 20 airborne carbonyl compounds in the C(1)-C(10) range. The carbonyls were collected onto solid sorbent coated with pentafluorophenyl hydrazine (PFPH), followed by solvent extraction and gas chromatographic (GC)/mass spectrometric (MS) analysis of the PFPH derivatives. The sorbent is packed into two separate sections in a glass sampling tube. The two-section design allows convenient checking of collection efficiency and breakthrough. The sampling tube, with a coating amount of 971 nmol PFPH per 100 mg Tenax TA and operated at a sampling flow rate of 80 mL min(-1), collects the 20 carbonyls with efficiencies above 95%. Hexane extracts the collected carbonyls in their PFPH derivatives in the sampling tube with better than 95% extraction efficiency. It is necessary to let the sampling tube sit at ambient temperature for 3 days before solvent extraction to ensure complete derivatization of the carbonyls. The limits of detection (LODs) of the tested carbonyls are in the range of 3.7-11.6 ng per sample. The method has been field-tested both in ambient environment and in an indoor environment from burning mosquito-repellent incense. Eighteen carbonyls were detected in the ambient air samples with the exception of o-tolualdehyde and m-tolualdehyde, while all the 20 target carbonyls were found in the incense smoke. Compare field test with classical DNPH-HPLC/UV method, good agreement exited between the two methods for lower molecular carbonyls but PFPH method is found to be a better analytical method for determination of high molecular weight carbonyls.

Levels, composition profiles and sources of polycyclic aromatic hydrocarbons in urban soil of Shanghai, China.

Levels, composition profiles and sources of polycyclic aromatic hydrocarbons (PAHs) were analyzed in 55 surface soil samples collected from Shanghai urban districts. The total concentrations of 22 PAHs (SigmaPAHs) ranged from 442 to 19,700 microgkg(-1), with a mean of 3780 microgkg(-1), and the sum of 16 priority PAHs (Sigma16PAHs) varied from 347 to 17,900 microgkg(-1), with a mean of 3290 microgkg(-1), and the seven possible carcinogenic PAHs (Sigma7CarPAHs) accounted for 36-58% of Sigma16PAHs. Among different functional areas, the higher level of PAHs was found in the roadside, followed by greenbelt, commercial district, park, and residential district. The composition of PAHs was characterized by the high molecular weight PAHs, among which fluoranthene, pyrene, benzo[b]fluoranthene and chrysene were most dominant components. A correlation analysis showed that there was relatively good correlation among the individual PAHs, but the contents of PAHs were poorly correlated with soil total organic carbon (TOC). A principal component analysis and PAHs isomeric ratios indicate that PAHs in Shanghai urban soil mainly originated from combustion. The toxic assessment suggested that soil PAHs exposure is medium carcinogenic at present level.