[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.

Distribution of polybrominated diphenyl ethers and HBCD in sediments of the Hunhe River in Northeast China.

Forty surface sediment samples from the Hunhe River in Northeast China were evaluated for contamination by polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). The results showed that decabromodiphenyl ether (BDE-209) was the predominant congener, accounting for >98 % of PBDEs in all sediment. The concentrations of BDE-209 and HBCD ranged from 3.96 to 327 ng/g dry weight and 0.05 to 25.8 ng/g dry weight, respectively, suggesting that BDE-209 was more widely applied in the study area. The mean concentrations of BDE-209 and HBCD in the downstream portion of the Hunhe River (BDE-209 148 ng/g dry weight and HBCD 3.74 ng/g dry weight) were found to be relatively higher than those in the upstream portion of the Hunhe River and the Dahuofang Reservoir, revealing an association with municipal sewage and industrial effluent received from the cities of Fushun and Shenyang. γ-HBCD was the most abundant diastereoisomer of all three analyzed HBCD isomers; however, marked elevations of α-HBCD were also found in most sediment samples. Surprisingly, the relative abundance (mean 38%) of α-HBCD in sediment from the upstream portion of the Hunhe River was significantly higher (p < 0.006, t test) than those in Dahuofang Reservoir (mean 24%). Moreover, the severe heavy metal contamination associated with the frequent mining activities in this region was tentatively suggested as being responsible for the increased levels of α-HBCD.

Spatial distribution of heavy metal contamination in soils near a primitive e-waste recycling site.

The total concentrations of 12 heavy metals in surface soils (SS, 0-20 cm), middle soils (MS, 30-50 cm) and deep soils (DS, 60-80 cm) from an acid-leaching area, a deserted paddy field and a deserted area of Guiyu were measured. The results showed that the acid-leaching area was heavily contaminated with heavy metals, especially in SS. The mean concentrations of Ni, Cu, Zn, Cd, Sn, Sb and Pb in SS from the acid-leaching area were 278.4, 684.1, 572.8, 1.36, 3,472, 1,706 and 222.8 mg/kg, respectively. Heavy metal pollution in the deserted paddy field was mainly concentrated in SS and MS. The average values of Sb in SS and MS from the deserted paddy field were 16.3 and 20.2 mg/kg, respectively. However, heavy metal contamination of the deserted area was principally found in the DS. Extremely high concentrations of heavy metals were also observed at some special research sites, further confirming that the level of heavy metal pollution was very serious. The geoaccumulation index (Igeo) values revealed that the acid-leaching area was severely polluted with heavy metals in the order of Sb > Sn > Cu > Cd > Ni > Zn > Pb, while deserted paddy field was contaminated predominately by metals in the order of Sb > Sn > Cu. It was obvious that the concentrations of some uncommon contaminants, such as Sb and Sn, were higher than principal contaminants, such as Ni, Cu, Zn and Pb, suggesting that particular attention should be directed to Sn and Sb contamination in the future research of heavy metals in soils from e-waste-processing areas. Correlation analysis suggested that Li and Be in soils from the acid-leaching area and its surrounding environment might have originated from other industrial activities and from batteries, whereas Ni, Cu, Zn, Cd, Pb, Sn and Sb contamination was most likely caused by uncontrolled electronic waste (e-waste) processing. These results indicate the significant need for optimisation of e-waste-dismantling technologies and remediation of polluted soil environment.

Distribution of heavy metal pollution in sediments from an acid leaching site of e-waste.

The spatial distribution, bioavailability, potential risks and emission sources of 12 heavy metals in sediments from an acid leaching site of e-waste were investigated. The results showed that the sediments from the acid leaching site were significantly contaminated with Cu, Zn, Cd, Sn, Sb and Pb, especially in the middle sediments (30-50 cm), with average concentrations of 4820, 1260, 10.7, 2660, 5690 and 2570 mg/kg, respectively. Cu, Cd and Pb were mainly present in the non-residual fractions, suggesting that the sediments from the acid leaching site may exert considerable risks. Mn, Ni, Zn, Sn and Sb were predominantly associated with the residual fraction. Despite their low reactivity and bioavailability, uncommon pollutants, such as Sn and Sb, may exert environmental risks due to their extremely elevated total concentrations. All of these results indicate that there is an urgent need to control the sources of heavy metal emission and to remediate contaminated sediments. CAPTURE ABSTRACT: In addition to Ni, Cu, Zn, Cd and Pb, the sediments from an acid leaching site in Guiyu were heavily polluted with uncommon heavy metal pollutants, such as Sn and Sb.

[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.

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 47.1 ng g(-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 848 ng day(-1) and decreased to 297 ng day(-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.

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.

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.

[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.

[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.

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.

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.

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.

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.

[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.

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.

[Ambient levels of carbonyl compounds in Shanghai, China].

A ternary-mobile phase program with acetonitrile, water and tetrahydrofuran was developed to identify and quantify 22 carbonyl compounds species by HPLC-UV. The analytical method succeeded in separating acrolein from acetone. Two sampling sites (industrial district and business district) were chosen to study carbonyl compounds levels in ambient air of Shanghai. The results indicated that formaldehyde, acetaldehyde, acetone and 2-butanone (C1-C4 carbonyl compounds) were the most abundant carbonyl compounds in ambient air of Shanghai. The four carbonyls together accounted for 78.95% (industrial district) and 77.63% (business district) of the total carbonyl compounds, respectively. In industrial district, the mean concentrations of formaldehyde, acetaldehyde, acetone and 2-butanone were 10.36, 15.32, 9.95 and 4.56 microg/m3, respectively; in business district, their mean levels were 10.00, 10.04, 7.80 and 2.81 microg/m3, respectively. So the mean levels of C1-C4 carbonyl compounds in industrial district were higher than in business district. The higher concentrations of the total carbonyls were also found in industrial district (53.64 microg/m3) than in business district (41.96 microg/m3). A similar diel variation occurred to the two districts that higher carbonyl concentrations were shown in morning peak and nighttime than in other three periods.