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Inhalation exposure to flame retardants used as additives to minimize fire risk and plasticizers is ubiquitous in human daily activities, but has not been adequately assessed. To address this research gap, the present study conducted an assessment of human health risk for four age groups through inhalation exposure to size fractionated particle-bound and gaseous halogenated flame retardants (polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs)) and organophosphate esters (OPEs) at indoor and outdoor environments (school, office, and residence) in three districts of a megacity (Guangzhou, China). Results demonstrated that OPEs were the dominant components among all targets. Indoor daily intakes of PBDEs and OPEs were 13–16 times greater than outdoor levels for all age groups. Gaseous OPEs contributed significantly greater than particle-bound compounds to daily intakes of all target compounds. Based on the different life scenarios, hazard quotient (HQ) and incremental life cancer risk (ILCR) from adults exposure to PBDEs and OPEs in indoor and outdoor settings were the greatest, followed by adolescents, children, and seniors. The estimated HQ and ILCR for all age groups both indoors and outdoors were lower than the safe level (HQ = 1 and ILCR = 10−6), indicating that the potential health risk for local residents in Guangzhou via inhalation exposure to atmospheric halogenated flame retardants and OPEs was low. Image 1 • Indoor daily intakes of PBDEs and OPEs were 13–16 times greater than outdoor levels. • Daily intakes of gaseous OPEs were greater than particle-bound OPEs. • Inhalation exposure health risk for residents in Guangzhou to PBDEs and OPEs was low. Comprehensive investigation of indoor and outdoor polybrominated diphenyl ethers and organophosphate esters are conducted to provide new insight in risk assessment of human inhalation exposure to atmospheric halogenated flame retardants and plasticizers in an urban zone. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) sized between 0.33 and 5 mm were collected using Manta trawls from ten surface seawater sites in Bohai and Huanghai Seas, China. A total of 1024 (Bohai Sea) and 132 (Huanghai Sea) microplastic pieces were classified, including polystyrene foams, polyethylene films and lines, and other plastic pellets, with concentrations of MPs ranging from 3 to 162 particles per 100 m 3 (0.012–2.96 mg m −3 ). A pretreatment of MPs with 30% H 2 O 2 in water did not significantly lower polycyclic aromatic hydrocarbon (PAH) concentrations on MPs compared to no H 2 O 2 pretreatment. Measurements of PAHs carried on the collected MPs indicated that the concentrations of the sum of 16 PAHs were in the range of 3400−119,000 ng g −1 . The sources of PAHs in Bohai and Huanghai Seas were highly similar, with petroleum and gasoline probably as the dominant sources. The present study shows the relative importance of MPs in regards to chemical transport in the marine environment. The combination of high concentrations of PAHs affiliated with MPs and the increasing magnitude of plastic pollution in the world's oceans demonstrates the considerable importance of MPs to the fate of PAHs in marine environments. [ABSTRACT FROM AUTHOR]

Although a number of studies have assessed the occurrence of atmospheric polycyclic aromatic hydrocarbons (PAHs) in indoor environment, few studies have systemically examined the indoor-outdoor interplay of size-dependent particulate PAHs and potential health risk based on daily lifestyles. In the present study, size-dependent particle and gaseous samples were collected both indoors and outdoors within selected schools, offices and residences located in three districts of Guangzhou, China with different urbanization levels during the dry and wet weather seasons. Results from measurements of PAHs showed that higher total PAH concentrations occurred in residential areas than in other settings and in indoor than in outdoor environments. Compositional profiles and size distribution patterns of particle-bound PAHs were similar indoors and outdoors, predominated by 4-and 5-ring PAHs and the 0.56–1.0 μm particle fraction. Statistical analyses indicated that outdoor sources may have contributed to 38–99% and 62–100% of the variations for indoor particle-bound and gaseous PAH concentrations, respectively. Incremental life cancer risk ( ILCR ) from human exposure to indoor and outdoor PAHs based on different lifestyles followed the order of adults > children > adolescents > seniors. All average ILCR values for four age groups were below the lower limit of the Safe Acceptable Range (10 −6 ). In addition, the ILCR value for adults (average: 7.2 × 10 −7 ; 95% CI: 5.4 × 10 −8 ‒2.5 × 10 −6 ), estimated from outdoor air PAH levels with 24-h exposure time, was significantly higher than our assessment results (average: 5.9 × 10 −7 ; 95% CI: 6.3 × 10 −8 ‒1.9 × 10 −6 ), suggesting the significance of assessing human inhalation exposure risks of indoor and outdoor PAHs in urban air based on daily lifestyles. [ABSTRACT FROM AUTHOR]

Diet is considered as the most important human exposure pathway for polybrominated diphenyl ethers (PBDEs). Metabolism and accumulation patterns of PBDEs in different growth periods of chickens are helpful for evaluating human dietary exposure, but such information is scarce. In this study, female chickens were fed with food spiked with BDE-209 at 85 mg kg −1 , and the intake, accumulation, and excretion of BDE-209 and its main metabolites in various tissues were examined. Concentrations of BDE-209 in chicken tissues increased over time in a tissue-specific manner; they were the greatest in liver and generally the lowest in breast meat during the entire exposure period. The kinetic patterns were dependent on both growth-dilution effects and accumulated concentrations of BDE-209. Tissue concentrations of ∑ 8 PBDE (sum of BDE-28, 47, 99, 100, 153, 154, 183, and 209) followed the sequence of liver > blood > skin > intestine > stomach > leg meat > breast meat. Different tissue partition coefficients and perfusion rates for blood may have resulted in different PBDE concentrations in tissues. The absorption efficiency of BDE-209 in chicken tissues followed the sequence of liver (0.15 ± 0.032%) > skin (0.14 ± 0.038%) > intestine (0.071 ± 0.021%) > breast meat (0.062 ± 0.020%) > leg meat (0.059 ± 0.016%) > stomach (0.021 ± 0.0095%), likely due in part to facilitated absorption of BDE-209 by transport proteins (P-glycoproteins). On average, 9.3 ± 1.7% of BDE-209 was excreted in feces. Estimated human average dietary intake via the consumption of chicken tissues of ∑ 8 PBDE for adults and children was 319 and 1380 ng day −1 for liver, 211 and 632 ng day −1 for leg meat, and 104 and 311 ng day −1 for breast meat from the contaminated group. Liver clearly poses the highest exposure risk for human consumption, particularly if chickens are fed with contaminated feed. [ABSTRACT FROM AUTHOR]

Human and ecological risks of BDE-209 have drawn much attention, particularly with growing e-waste recycling activities in developing countries. To further address the issue of BDE-209 biotransformation, a laboratory-controlled study was conducted. Female Sprague-Dawley rats were dosed orally by gavage at a daily dose of 1 mg kg −1 body weight for 7 d and a depuration period of 22 d, to characterize absorption, distribution, metabolism, and elimination dynamics of BDE-209 during multi-dose exposures simulating short-term oral exposure of e-waste workers. The concentrations of BDE-209 in all tissues increased exponentially during the 7-d exposure period, indicating that multi-dose exposure could lead to increased accumulation of BDE-209 in rats. The liver accumulated the greatest amount of BDE-209 on a wet-weight basis, while adipose tissue had the highest concentration by the end of the 22-d depuration period. Half-lives of BDE-209, 207, and 197 during depuration were 1.1 ± 0.1, 2.7 ± 0.3, and 10.5 ± 3.1 d in serum and 0.9 ± 0.1, 2.2 ± 0.2, and 11.8 ± 2.3 d in liver, i.e., the half-life increased with decreasing level of bromination from deca- to octa-BDEs and was similar in both serum and liver. By contrast, the half-life of the debromination metabolite BDE-207 (21.7 ± 7.7 d) was longer in small intestine than in serum and liver, suggesting slower depletion of BDE-209 metabolites in small intestine. The metabolism of BDE-209 was not responsible for the occurrence of low brominated BDE congeners and OH and MeO-PBDEs in human tissues. [ABSTRACT FROM AUTHOR]

Plastic pellets and microbes are important constitutes in sediment, but the significance of microbes colonizing on plastic pellets to the environmental fate and transport of organic contaminants has not been adequately recognized and assessed. To address this issue, low-density polyethylene (LDPE), polyoxymethylene (POM) and polypropylene (PP) slices were preloaded with dichlorodiphenyltrichloroethanes (DDTs), polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) and incubated in abiotic and biotic sediment microcosms. Images from scanning electron microscope, Lysogeny Broth agar plates and confocal laser scanning microscope indicated that all polymer slices incubated in biotic sediments were colonized by microorganisms, particularly the LDPE slices. The occurrence of biofilms induced higher dissipation rates of DDTs and PAHs from the LDPE slice surfaces incubated in the biotic sediments than in the abiotic sediments. Plastic colonization on LDPE slice surfaces enhanced the biotransformation of DDT and some PAHs in both marine and river sediments, but had little impact on PCBs. By comparison, PP and POM with unique properties were shown to exert different impacts on the physical and microbial activities as compared to LDPE. These results clearly demonstrated that the significance of polymer surface affiliated microbes to the environmental fate and behavior of organic contaminants should be recognized. [ABSTRACT FROM AUTHOR]

Wet deposition is not only a mechanism for removing atmospheric pollutants, but also a process which reflects loadings of atmospheric pollutants. Our previous study on wet deposition examined the effectiveness of short-term control measures on atmospheric particulate pollution, which were partly effective for organic pollutants of current input sources. In the present study, dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs), representative of legacy contaminants, were measured in the same samples collected throughout the entire year of 2010 in Guangzhou, a large urban center in South China. Concentrations of ∑DDT (sum of o,p ′ and p,p ′-DDT, o,p ′ and p,p ′-DDE, o,p ′ and p,p ′-DDD, and p , p ′-DDMU) and ∑HCH (sum of α -, β -, γ -, and δ -HCH) in wet deposition were in the ranges of nd–69 (average: 1.8 ng L −1 ) and nd–150 ng L −1 (average: 5.1 ng L −1 ), respectively. In addition, the results of source diagnostics and backward air mass trajectories appeared to suggest the transport of antifouling paint derived DDTs from the coastal region off South China to Guangzhou. The combined wet and dry deposition flux of ∑HCH in the first quarter (January to March) was greater than that in the fourth quarter (October to December), while those of ∑DDT were comparable in the first and fourth quarters. Similar trends were also observed for the concentrations of ∑HCH and ∑DDT in aerosol samples. These results suggested the short-term pollution control measures implemented during the 16th Asian Games and 10th Asian Para Games (held in November and December 2010, respectively) did not work well for DDTs. The reduced input of HCHs during the fourth quarter was probably associated with the strict ban on lindane for food safety, which also exposed the weakness of control measures focusing mainly on the removal of atmospheric particulate matter. [ABSTRACT FROM AUTHOR]

The fate of hydrophobic organic compounds in aquatic environment are largely determined by their exchange at sediment-water interface, which is highly dynamic and subject to rapidly evolving environmental conditions. In turn, environmental conditions may be governed by both physicochemical parameters and anthropogenic events. To examine the importance of various impact factors, passive sampling devices were deployed at the seafloor of Hailing Bay, an urbanized estuarine bay in Guangdong Province of South China to measure the sediment-water diffusion fluxes of several metabolites of dichlorodiphenyltrichloroethane (DDT), p,p ′-DDE, p,p ′-DDD and o,p ′-DDD. The physicochemical properties of water (temperature, pH, salinity and dissolved oxygen) and surface sediment (sediment organic matter, physical composition, pH, water content, colony forming unit and catalase activity) were also measured. The results showed that the diffusion fluxes of o,p ′-DDD, p,p ′-DDD and p,p ′-DDE at sites A1 and A2 near a fishing boat maintenance facility ranged from 0.42 to 4.73 ng m −2 d −1 (from sediment to overlying water), whereas those at offshore sites varied between −0.03 and −3.02 ng m −2 d −1 (from overlying water to sediment), implicating A1 and A2 as the sources of the target compounds. The distribution patterns of the diffusion fluxes of the target compounds were different from those of water and sediment parameters (water temperature, salinity, sediment texture, pH, colony forming unit and catalase activity) at six sampling sites. This finding suggested that none of these parameters were critical in dictating the sediment-water diffusion fluxes. Besides, decreases in the contents of kerogen and black carbon by 6.7% and 11% would enhance the diffusion fluxes of the target compounds by 11–14% and 12–23%, respectively, at site A1, indicating that kerogen and black carbon were the key factors in mediating the sediment–water diffusion fluxes of DDT-related compounds in field environments. [ABSTRACT FROM AUTHOR]

Mass transfer of hydrophobic organic contaminants (HOCs) across the air-water interface is an important geochemical process controlling the fate and transport of HOCs at the regional and global scales. However, few studies have characterized concentration or fugacity profiles of HOCs near both sides of the air-water interface, which is the driving force for the inter-compartmental mass transfer of HOCs. Herein, we introduce a novel passive sampling device which is capable of measuring concentration (and therefore fugacity) gradients of HOCs across the air-water interface. Laboratory studies indicated that the escaping fugacity values of polycyclic aromatic hydrocarbons (PAHs) from water to air were negatively correlated to their volatilization half-lives. Results for field deployment were consistent between the passive sampler and an active method, i.e., a combination of grab sampling and liquid-liquid extraction. In general, the fugacity profiles of detected PAHs were indicative of an accumulation mechanism in the surface microlayer of the study regions (Haizhu Lake and Hailing Bay of Guangdong Province, China), while p,p '-DDD tended to volatilize from water to the atmosphere in Hailing Bay. Furthermore, the fugacity profiles of the target analytes increased towards the air-water interface, reflecting the complexity of environmental behavior of the target analytes near the air-water interface. Overall, the passive sampling device provides a novel means to better characterize the air-water diffusive transfer of HOCs, facilitating the understanding of the global cycling of HOCs. [ABSTRACT FROM AUTHOR]

Natural organic matter and grain size are considered as important parameters dictating the transport and fate of organic compounds in sediment. However, increasing evidence suggested that manufactured debris may alter the underlying mechanisms for biogeochemical cycling of organic compounds. To examine this assumption, estuarine sediment and embedded debris were collected from a fishery base in Guangdong Province of South China and analyzed for organophosphorus flame retardants (OPFRs), phthalates (PAEs), organotin compounds (OTs) and dichlorodiphenyltrichloroethanes (DDTs). Coarse-size debris (> 200 μm) were heterogeneously distributed in sediment, and most abundant near the boat maintenance facilities, aquaculture zone and shipping channel. The median concentrations of OPFRs, OTs, PAEs and DDTs in debris were 11 , 0.2, 11 and 3.9 μg g −1 dry sample weight −1 , respectively, 1 to 3 orders of magnitude greater than those in bulk sediment (19, 60, 240 and 570 ng g −1 dry sample weight −1 , respectively). Furthermore, OPFRs, OTs and PAEs were mostly (> 99%) enriched in coarse-size (63–2000 μm) sediment, and there was no significant correlation ( p > 0.05) between the concentrations of OPFRs, OTs and PAEs in bulk and size-fractioned sediment samples and total organic carbon or grain size, similar to the distribution pattern of DDTs reported previously. When distinct debris were removed from the light-density (< 1.7 g cm −3 ) fraction of coarse-size (200–2000 μm) sediment, the concentration levels of OPFRs, OTs, PAEs and DDTs declined by 84%, 59%, 55% and 7%, respectively. Obviously, debris irregularly distributed in sediment can alter the sediment sorption capacity for OPFRs, OTs and PAEs, and thus may undermine the significance of organic matter and grain size to the distribution of organic chemicals in sediment. Finally, commonly used procedures for preparing sediment samples and screening of debris may disturb the grain size distribution or underestimate the abundance of heavy-density debris, resulting in flawed sediment quality assessment. [ABSTRACT FROM AUTHOR]

An overlooked issue for field application of in situ performance reference compound (PRC) calibration methods is the validity of the assumption that both the sorption of a target compound and desorption of its corresponding PRC follow the first-order kinetics with the same rate constants under stagnant conditions. In the present study, disposable polydimethylsiloxane fibers of 2 sizes (7 and 35 µm) impregnated with 8 13C-labeled or deuterated PRCs were statically deployed into different marine sediments, from which the kinetics for sorption of the target compounds and desorption of the PRCs were characterized. Nonsymmetrical profiles were observed for exchange of the target analytes and their corresponding PRCs in sediment under stagnant conditions. The hysteretic desorption of PRCs in the kinetic regime may be ascribed to the low chemical potential between the fiber and sediment porewater, which reflects the inability of water molecules to rapidly diffuse through sediment to solvate the PRCs in the aqueous layer around the fiber surface. A moderate correlation ( r = 0.77 and r = 0.57, p < 0.05 for both regressions) between the PRC-calibrated equilibrium concentrations of 1,1-dichloro-2,2-bis-(chlorophenyl) ethylene ( p, p′-DDE) and polychlorinated biphenyl (PCB)-153 and the lipid normalized levels in worms ( Neanthes arenaceodentata) was obtained in co-exposure tests under simulating field conditions, probably resulting from slightly overestimated bioavailability because of the hysteretic desorption of PRCs and toxic effects. Environ Toxicol Chem 2016;35:1978-1985. © 2015 SETAC [ABSTRACT FROM AUTHOR]

Anthropogenic impacts have continuously intensified in mega urban centers with increasing urbanization and growing population. The spatial distribution pattern of such impacts can be assessed with soil halogenated flame retardants (HFRs) as HFRs are mostly derived from the production and use of various consumer products. In the present study, soil samples were collected from the Pearl River Delta (PRD), a large urbanized region in southern China, and its surrounding areas and analyzed for a group of HFRs, i.e., polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane, bis(hexachlorocyclopentadieno)cyclooctane (DP) and hexabromobenzene. The sum concentrations of HFRs and PBDEs were in the ranges of 0.66–6500 and 0.37–5700 (mean: 290 and 250) ng g −1 dry weight, respectively, around the middle level of the global range. BDE-209 was the predominant compound likely due to the huge amounts of usage and its persistence. The concentrations of HFRs were greater in the land-use types of residency, industry and landfill than in agriculture, forestry and drinking water source, and were also greater in the central PRD than in its surrounding areas. The concentrations of HFRs were moderately significantly ( r 2 = 0.32–0.57; p < 0.05) correlated with urbanization levels, population densities and gross domestic productions in fifteen administrative districts. The spatial distribution of DP isomers appeared to be stereoselective as indicated by the similarity in the spatial patterns for the ratio of anti -DP versus the sum of DP isomers ( f anti -DP ) and DP concentrations. Finally, the concentrations of HFRs sharply decreased with increasing distance from an e-waste recycling site, indicating that e-waste derived HFRs largely remained in local soil. [ABSTRACT FROM AUTHOR]

Freely dissolved polycyclic aromatic hydrocarbons (PAHs) were monitored in seven inland lakes of Antarctica by a polyethylene (PE)-based passive sampling technique, with the objective of tracking human footprints. The measured concentrations of PAHs were in the range of 14–360 ng L −1 with the highest values concentrated around the Russian Progress II Station, indicating the significance of human activities to the loading of PAHs in Antarctica. The concentrations of PAHs in the inland lakes were in the upper part of the PAHs levels in aquatic environments from remote and background regions across the globe. The composition profiles of PAHs indicated that PAHs in the inland lakes were derived mainly from local oil spills, which was corroborated by a large number of fuel spillage reports from ship and plane crash incidents in Antarctica during recent years. Clearly, local human activities, rather than long-range transport, are the dominant sources of PAH contamination to the inland lakes. Finally, the present study demonstrates the efficacy of PE-based passive samplers for investigating PAHs in the aquatic environment of Antarctica under complex field conditions. [ABSTRACT FROM AUTHOR]

Antifouling paint applied to fishing vessels is the primary source of dichloro-diphenyl-trichloroethane (DDT) to the coastal marine environments of China. With the aim to provide science-based support of potential regulations on DDT use in antifouling paint, we utilized a fugacity-based model to evaluate the fate and impact of p , p ′-DDT, the dominant component of DDT mixture, in Daya Bay and Hailing Bay, two typical estuarine bays in South China. The emissions of p , p ′-DDT from fishing vessels to the aquatic environments of Hailing Bay and Daya Bay were estimated as 9.3 and 7.7 kg yr −1 , respectively. Uncertainty analysis indicated that the temporal variability of p , p ′-DDT was well described by the model if fishing vessels were considered as the only direct source, i.e., fishing vessels should be the dominant source of p , p ′-DDT in coastal bay areas of China. Estimated hazard quotients indicated that sediment in Hailing Bay posed high risk to the aquatic system, and it would take at least 21 years to reduce the hazards to a safe level. Moreover, p , p ′-DDT tends to migrate from water to sediment in the entire Hailing Bay and Daya Bay. On the other hand, our previous research indicated that p , p ′-DDT was more likely to migrate from sediment to water in the maricultured zones located in shallow waters of these two bays, where fishing vessels frequently remain. These findings suggest that relocating mariculture zones to deeper waters would reduce the likelihood of farmed fish contamination by p , p ′-DDT. [ABSTRACT FROM AUTHOR]

Fish is one of the most important nutrition sources for humanity. Contaminant exposure risk in fish farming will eventually deliver to the crowd through diet. China is the largest fish producing as well as exporting country, where mariculture plays an important role in fish production, especially in South China. Previous investigations indicated that a variety of compartments in farming areas of South China Sea were polluted by persistent organic pollutants, including DDT (dichlorodiphenyltrichloroethane) and its derivatives, some of which is designated as DDTs. In the present study, Hailing Bay and Daya Bay of Guangdong Province, China, were selected as the study sites and DDTs as the target compounds. A fish enrichment model was developed to assess the relative contributions of various pathways to the mass loadings of DDTs in the fish. Average concentrations (and concentration ranges) of DDTs in various environmental compartments of Hailing Bay and Daya Bay were included in modeling and analysis. Modeling results indicated that fish food and seawater contributed approximately the same proportions for the DDTs in maricultured fish. Antifouling paint was supposed to be the primary source of water DDTs in mariculture zone of Hailing Bay and Daya Bay, which contributed 69 % of the total DDTs to the mariculture water. We suggest that in order to protect people from consuming highly contaminated maricuture zone fish, the most effective and feasible methods are using environment-friendly antifouling paint and applying less polluted fish food in the fish reproduction process. [ABSTRACT FROM AUTHOR]

Recently published literature indicated that dichlorodiphenyltrichloroethane (DDT)-containing antifouling paint flakes were heterogeneously distributed within estuarine sediments. However, the significance of antifouling paint flakes in the fate and transport of DDT compounds and other organic pollutants in estuarine sediment is yet to be adequately addressed. To fill this knowledge gap, estuarine sediment and paint flakes from cabin and boat surfaces were collected from a fishery base in Guangdong Province of South China and analyzed for DDT compounds. Coarse fractioned samples collected from the vicinity of boat maintenance facilities contained appreciable amounts of colorful particles, which were identified as paint flakes by Fourier transform infrared spectroscopy. The highest concentrations of DDXs (sum of DDTs and its metabolites) occurred in the heavy-density (>1.7 g cm −3 ) fraction of coarse-size (200–2000 μm) sediments from near the boat maintenance facilities, suggesting the importance of paint flakes in the distribution pattern of “hot spots” in estuarine sediment. Moreover, the desorption rates of DDT compounds from paint flakes and the heavy-density fraction of coarse-size sediment were both extremely slow. Apparently, unevenly distributed paint flakes in sediment can artificially inflate the sorption capacity of heavy-density sediment for DDT compounds, and therefore can substantially change the environmental fate and behavior of hydrophobic organic chemicals in estuarine sediment. Finally, commonly used source diagnostic indices of DDT compounds were mostly grain-size and density dependent in sediment, as a result of the occurrence of paint flakes, which may strongly compromise the outcome of any source diagnostics efforts. [ABSTRACT FROM AUTHOR]