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Plastics are crucial constituents in electronic waste (e-waste) and part of the issue in e-waste recycling and environmental protection. However, previous studies have mostly focused on plastic recovery or thermal behavior of flame retardants, but not both simultaneously. The present study simulated the process of e-waste thermal treatment to explore tetrabromobisphenol A (TBBPA) pyrolysis at various temperatures using polystyrene (PS), polyvinyl chloride (PVC), and e-waste plastics as polymer matrices. Pyrolysis of TBBPA produced bromophenol, bromoacetophenone, bromobenzaldehyde, and bromobisphenol A. Co-pyrolysis with the polymer matrices increased emission factors by 1 − 2 orders of magnitude. The pyrolytic products of TBBPA, TBBPA+PS, and TBBPA+PVC were mainly low-brominated bisphenol A, while that of TBBPA in e-waste plastics was consistently bromophenol. Increasing temperature drove up the proportions of gaseous and particulate products, but lowered the relative abundances of inner wall adsorbed and residual products in pyrolysis of pure TBBPA. In co-pyrolysis of TBBPA with polymer matrix, the proportions of products in different phases were no longer governed solely by temperature, but also by polymer matrix. Co-pyrolysis of TBBPA with PS generated various bromophenols, while that with PVC produced chlorophenols and chlorobrominated bisphenol A. Transformation pathways, deduced by ab initio calculations, include hydrogenation-debromination, isopropylphenyl bond cleavage, oxidation, and chlorination. [Display omitted] • Co-pyrolysis of TBBPA with PS and PVC produces numerous aldehyde and ketone compounds. • Temperature enhances the emission of particulated products from prolysis of TBBPA. • Hydroxylation, methylation, and addition reaction occur in pyrolysis of TBBPA+PS. • Radical Cl• from PVC plays an important role in the co-pyrolysis of TBBPA. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Crude e-waste recycling was simulated in closed chamber. • Emissions of OPFRs were large in both thermal treatment and open burning. • OPFRs were probably emitted in association with particles. • The abundances of OPFRs were lower in coarse particles than in fine particles. Abstract Organophosphate flame retardants (OPFRs) have been increasingly produced and consumed since the gradual phase-out of polybrominated diphenyl ethers. Primitive recycling of e-waste can be a significant input source of OPFRs to the environment. Thermal treatment and open burning of typical e-wastes were conducted in a closed chamber to examine the emissions and the size distribution patterns of particle-bound OPFRs from these processes. The sum emission factors of OPFRs were 3.70 × 104–3.65 × 105 ng g−1 by thermal treatment and 5.22 × 103–9.27 × 104 ng g−1 by open burning. The output-input mass ratios of OPFRs for plastic casings were 0.030–116 and 0.012–7.1 by thermal treatment and open burning, respectively, and were 0.11–40 and 0.0014–6.7 for printed circuit boards. The size distribution patterns of OPFRs were characterized by one unimodal peak (0.56–1.0 μm) for thermal treatment and bimodal peaks (0.56–1.0 or 1.0–1.8 and 10–18 μm) for open burning. Particle-bound OPFRs appeared to form in affiliation with particles rather than by adsorption or deposition from the gaseous phase to particulate organic matter. With increasing amounts of OPFRs used in a variety of consumer products, the emissions of OPFRs to the environment are expected to increase continuously in the future. [ABSTRACT FROM AUTHOR]

Abstract Urban residents spend the majority of time in indoor environments, which, however, may not be a safe haven for staying away from outdoor air pollution, especially in China. To examine this hypothesis, the particle mass concentrations (0.056–18 μm) and number concentrations (14–660 nm) were simultaneously measured in and outside of three typical urban indoor settings (n = 9), i.e., school, office and residence in Guangzhou, China from October–November 2014 (dry weather season) and June–August 2015 (wet weather season). The indoor and outdoor particle number concentrations were positively correlated with each other at all three sampling settings for both dry and wet weather seasons (r 2 = 0.13–0.65, p < 0.001). The infiltration factors and indoor/outdoor ratios of particles (14–660 nm) were estimated at 0.30–0.75 and 0.85–1.5, respectively, which were comparable to or higher than those (0.12–0.76 and 0.03–1.1) found in cites of other countries under infiltration conditions. Furthermore, the average infiltration factor of fine particle numbers (50–660 nm) in an office was 0.61 during a severe haze episode, indicating that approximately 60% of outdoor particles penetrated indoors. All findings suggested an efficient transport of outdoor particle sources into indoor environment, confirming that exposure of the general public to indoor particles in China should not be overlooked due to effective infiltration of outdoor particles and frequent heavy haze episodes. Graphical abstract Image 1 Highlights • Indoor and outdoor particle number concentrations were significantly correlated. • Particle infiltration factors in Guangzhou were greater than those in other cities. • Indoor microenvironments with great infiltration of outdoor particles is not safe. [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]

Health risk of residents dwelling around e-waste recycling zones has been a global concern, but has not been adequately examined. The present study was intended to evaluate the potential health risk of residents through inhalation exposure to size-fractionated particle-bound heavy metals in a typical e-waste recycling zone, South China. Anthropogenic metals (Zn, Se, Pb, Sb, As, and Cd) were predominantly enriched in fine particles ( D p < 1.8 μm), whereas the crustal elements (Ti, Fe, and Co) tended to accumulate in coarse particles ( D p > 1.8 μm). Although the daily inhalation intakes of the target metals were significantly lower than those through food consumption and ingestion of house dust, the hazard quotients of total metals for adults (95% CI: 1.0–5.5) and children (95% CI: 3.0–17) were greater than 1. Moreover, the incremental lifetime cancer risks of five carcinogenic metals (Cr, Co, Ni, As, and Cd) for adults and children were 1.3 × 10 −3 (95% CI: 4.1 × 10 −4 –3.0 × 10 −3 ) and 3.9 × 10 −3 (95% CI: 1.3 × 10 −3 –8.6 × 10 −3 ), respectively, substantially higher than the acceptable cancer risk range of 10 −6 –10 −4 . All these findings suggested that health risks were high for local residents dwelling around the e-waste recycling zone through inhalation exposure to particle-bound heavy metals, for both adults and children. [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]

Atmospheric size-fractionated particles were collected at different heights in an e-waste recycling zone (QY) and urban Guangzhou (GZ), China and analyzed for organophosphate flame retardants (OPFRs). The total air concentrations of eight OPFRs were 130 ± 130 and 138 ± 127 ng m −3 in QY and GZ, respectively. Compositional profiles of chlorinated OPFRs were different between QY and GZ, but the size distribution patterns of all OPFRs were not significantly different at different heights. Estimated atmospheric deposition fluxes of OPFRs were 51 ± 67 and 55 ± 13 μg m −2 d −1 in QY and GZ, respectively, and the coarse particles ( D p > 1.8 μm) dominated both the dry and wet deposition fluxes. Moreover, not all particle-bound OPFRs were inhalable and deposited in the human respiratory tract. The calculated inhalation doses of OPFRs were much lower than the reference doses, suggesting that potential health risk due to inhalation exposure to particle-bound OPFRs in the e-waste recycling zone and urban site was low. [ABSTRACT FROM AUTHOR]

To evaluate the impacts of anthropogenic events on the rapid urbanized environment, the levels of legacy organochlorine pesticides (OCPs) and current-use insecticides (CUPs), i.e., dichlorodiphenyltrichloroethane and its metabolites (DDTs), hexachlorocyclohexanes (HCHs), pyrethroids and organophosphates in soil of the Pearl River Delta (PRD) and surrounding areas were examined. Spatial concentration distributions of legacy OCPs and CUPs shared similar patterns, with higher concentrations occurred in the central PRD with more urbanization level than that in the PRD's surrounding areas. Furthermore, relatively higher concentrations of OCPs and CUPs were found in the residency land than in other land-use types, which may be attributed to land-use change under rapid urbanization. Moderate correlations between gross domestic production or population density and insecticide levels in fifteen administrative districts indicated that insecticide spatial distributions may be driven by economic prosperity. The soil–air diffusive exchanges of DDTs and HCHs demonstrated that soil was a sink of atmospheric o , p ′-DDE, o , p ′-DDD, p , p ′-DDD and o , p ′-DDT, and was a secondary source of HCHs and p , p ′-DDT to atmosphere. The soil inventories of DDTs and HCHs (100 ± 134 and 83 ± 70 tons) were expected to decrease to half of their current values after 18 and 13 years, respectively, whereas the amounts of pyrethroids and organophosphates (39 and 6.2 tons) in soil were estimated to decrease after 4 and 2 years and then increase to 87 and 1.0 tons after 100 years. In this scenario, local residents in the PRD and surrounding areas will expose to the high health risk for pyrethroids by 2109. Strict ban on the use of technical DDTs and HCHs and proper training of famers to use insecticides may be the most effective ways to alleviate the health effect of soil contamination. [ABSTRACT FROM AUTHOR]

Abstract: Tracing regional anthropogenic influences is important for assessing the magnitude of human interferences with the environment. In the present study, the utility of soil linear alkylbenzenes (LABs) as indicators of anthropogenic influences was examined, with the emphasis on the role of atmospheric transport in dissipating LABs from input sources to remote areas. The Pearl River Delta, South China, which has experienced rapid economic growth and urbanization, was selected as the study region. The concentrations of LABs (mean: 8.6ng/g and median: 5.7ng/g, with an outlier of 2020ng/g excluded) suggested that sewage contamination throughout the entire study region was generally light. The spatial variation of sewage pollution was significantly positively correlated with population density and per capita gross domestic product, with hot spots concentrated in the central PRD. Atmospheric deposition was hypothesized as an important input route for soil LABs in forestry and drinking water source areas with little impact of irrigation or direct wastewater discharge. This proposition could explain the opposite spatial patterns of LAB concentrations and values of a biodegradation index (5-C12 +5-C13)/(5-C11 +5-C10), where i-C n defines a specific LAB congener with i and n indicating the position of the phenyl group and the number of carbon atoms on the alkyl chain, respectively. These findings somewhat validated LABs as tracers of regional anthropogenically derived contamination, with atmospheric transport of LABs as a viable dissipating mechanism. [Copyright &y& Elsevier]

Abstract: The occurrence of polycyclic aromatic hydrocarbons (PAHs) in soil of the Pearl River Delta (PRD) and surrounding areas was examined on a basis of six land-use types and four geographic regions, from which the impacts of anthropogenic events on the terrestrial environment were evaluated. No significant difference in the concentrations of Σ28PAH and Σ15PAH (sums of 28 and 15 PAHs, respectively) was found among the land-use types of industry, landfill and residency. On the other hand, higher soil PAH concentrations occurred in the central PRD characterized by dense population and high urbanization level, compared to other geographic regions. Source diagnostics implicated the combustions of coal and refined petroleum as the major input sources of anthropogenic PAHs. Furthermore, low molecular weight PAHs tended to volatilize from soil to air while the opposite was prevailing for high molecular weight PAHs. The mean annual diffusive flux of Σ15PAH (852μgm−2 yr−1) from the soil to the atmosphere in the central PRD was greater than those in the PRD's periphery (195μgm−2 yr−1), West region (322μgm−2 yr−1) and East region (84.9μgm−2 yr−1), suggesting that the central PRD may have become a secondary source of PAHs to the surrounding areas. Finally, ecological risk assessment based on the classification from Maliszewska-Kordybach showed that 3.5% of soil within the central PRD was heavily contaminated by PAHs and 5.2million residents may be subjected to high health risk. [Copyright &y& Elsevier]

Abstract: Rainwater samples were simultaneously collected from three locations in Guangzhou, a mega metropolitan center in South China, during the entire year of 2010, and analyzed for particulate matter (PM), total organic carbon and polycyclic aromatic hydrocarbons (PAHs), with the objectives of assessing the seasonality of washout effects and efficiency for removal of pollutants from the atmosphere by wet deposition. The contents of PM, particulate organic carbon, and dissolved organic carbon were in the ranges of 0.74–420 (average: 8.1 mg L−1), 0.16–40 (average: 1.3 mg L−1), and 0.34–6.9 mg L−1 (average: 1.4 mg L−1), respectively. Concentrations of Σ15PAH (sum of the 16 priority PAH compounds defined by the United States Environmental Protection Agency minus naphthalene) in wet deposition samples ranged from 39 to 1580 ng L−1 with an average of 170 ng L−1. The PAH concentration levels were slightly abated compared to those acquired previously in Guangzhou during the year of 2005, probably indicating a favorable change of energy consumption patterns in the region. There were moderately significant negative correlations between washout ratios and rainfall intensities (0–4.3 mm h−1). The total annual fluxes of wet and dry depositions combined for PM and PAHs in the urban area of Guangzhou were 34 g m−2 yr−1 and 6.0 × 102 μg m−2 yr−1 with 50 and 57% being contributed from wet deposition, respectively. The monthly capacity for removal (CR) of PM and PAHs (calculated as the wet deposition flux dividing the total flux) varied widely with different months, and was lower during the dry weather season (January–March and October–December) than during the wet weather season (April–September). Finally, the air quality index related to PM10 was negatively correlated to CR values of PM and PAHs, indicating the need to control the emissions of anthropogenically derived pollutants during the dry weather season. [Copyright &y& Elsevier]

Highlights: [•] Two-point measurement approach enhanced by adoption of passive sampling techniques. [•] Benthic chamber stops assumption that chemical-concentration gradient is linear. [•] Passive sampling device increases flux-measurement accuracy and is a powerful tool. [ABSTRACT FROM AUTHOR]

Solid-phase microextraction (SPME) has often been used to estimate the freely dissolved concentration ( Cfree) of organic contaminants in sediments. A significant limitation in the application of SPME for Cfree measurement is the requirement for attaining equilibrium partition, which is often difficult for strongly hydrophobic compounds such as DDT. A method was developed using SPME with stable isotope-labeled analogues as performance reference compounds (PRCs) to measure Cfree of DDT and metabolites (DDTs) in marine sediments. Six 13C-labeled or deuterated PRCs were impregnated into polydimethylsiloxane (PDMS) fiber before use. Desorption of PRCs from PDMS fibers and absorption of DDTs from sediment were isotropic in a range of sediments evaluated ex situ under well-mixed conditions. When applied to a historically contaminated marine sediment from a Superfund site, the PRC-SPME method yielded Cfree values identical to those found by using a conventional equilibrium SPME approach (Eq-SPME), wherease the time for mixing was reduced from 9 d to only 9 h. The PRC-SPME method was further evaluated against bioaccumulation of DDTs by Neanthes arenaceodentata in the contaminated sediment with or without amendment of activated carbon or sand. Strong correlations were consistently found between the derived equilibrium concentrations on the fiber and lipid-normalized tissue residues for DDTs in the worms. Results from the present study clearly demonstrated the feasibility of coupling PRCs with SPME sampling to greatly shorten sampling time, thus affording much improved flexibility in the use of SPME for bioavailability evaluation. Environ Toxicol Chem 2013;32:1946-1953. © 2013 SETAC [ABSTRACT FROM AUTHOR]

A passive water sampler with low-density polyethylene (LDPE) as the sorbent phase was built and field-tested for sensing freely dissolved concentrations of hydrophobic organic compounds (HOCs) in fresh and coastal water. Based on the measured LDPE-water partition coefficients ( Kpew) of 12 polycyclic aromatic hydrocarbons (PAHs) and dichlorodiphenyltrichloroethane (DDT) and its seven metabolites, the detection limits with the passive sampler containing 10-g LDPE ranged from 0.04 to 56.9 pg/L in the equilibrium sampling mode. Furthermore, the utility of the passive sampler in measuring dissolved HOC concentrations in open waters was examined through a comparison with solid-phase extraction combined with liquid-liquid extraction (SPE-LLE) and poly(dimethyl)siloxane (PDMS) coated fiber samplers. The total concentrations of PAHs (3.8-16 ng/L) obtained by the passive sampler were lower than those (87.7-115.5 ng/L) obtained through SPE-LLE. This large difference was probably attributable to slower water exchange in and out of the passive sampler as time progressed because of blockage by algae in eutrophia reservoirs and high dissolved organic carbon contents resulting in higher-than-expected PAH concentrations by SPE-LLE. Furthermore, the concentrations and compositional profiles of DDXs (sum of p,p′-DDT, p,p′-DDD, p,p′-DDE, o,p′-DDT, o,p′-DDD, o,p′-DDE, and p,p′-DDMU) at site A obtained by the passive sampler agreed with the results obtained with the PDMS-coated fibers, suggesting that the passive sampler was able to reasonably quantify dissolved HOCs in seawater. Environ. Toxicol. Chem. 2012; 31: 1012-1018. © 2012 SETAC [ABSTRACT FROM AUTHOR]

Abstract: With compiled and analyzed information about recent advances in passive sampling techniques for sediment porewater, we discuss common quantitation methods (equilibrium and kinetic diffusion-controlled sampling), effects of temperature and salinity on passive sampling, and benefits and drawbacks of currently available passive samplers based on the principles of solid-phase microextraction. The results show that the in-fiber standardization technique, which is kinetic diffusion-controlled, could shorten sampling time and obtain accurate results using isotopically-labeled reference compounds. Another quantitative method, time-weighted average sampling, may be viable for simultaneously measuring all analytes in sediment porewater, as it is more effective with respect to cost and time. In addition, the effects of temperature and salinity on passive sampling should be quantified in field applications. Currently available passive samplers (e.g., employing polymer-coated fibers and low-density polyethylene sheets) can sense hydrophobic organic chemicals (HOCs) in sediment porewater, but the small capacity and the inflexibility of polymer-coated fibers need to be further improved, while better physical protection of polyethylene devices, particularly when they are deployed under rough conditions, should be carefully considered. In conclusion, passive samplers for in-situ measurement of dissolved HOCs in sediment porewater should be combined with a suitable quantitative method and calibration for the effects of temperature and salinity. [Copyright &y& Elsevier]

The coefficients of partitioning (Kpew) between low-density polyethylene (LDPE) film (50-mm thickness) and water for 23 polybrominated diphenyl ether (PBDE) congeners were determined based on a regression analysis of sorption kinetics over an extended exposure period (up to 365 d). A curvilinear relationship between log Kpew and log KOW (octanol–water partition coefficient) was obtained for the target BDE congeners with the turning point at log KOW approximately 8. Previously obtained dietary uptake efficiencies of BDE congeners in common carp (Cyprinus carpio) were also found to relate curvilinearly to log KOW. In addition, fieldmeasured relative abundances of BDE-209 compiled from previous investigations conducted in the Pearl River Delta of South China were significantly (p<0.001) higher in abiotic samples (n¼79 from 11 matrices) than in biotic samples (n¼73 from 12 matrices), suggesting the likelihood for reduced bioavailability of BDE-209 in certain biota. Finally, a molecular-scale analysis indicated that the curvilinear relationship between log Kpew and log KOW can be attributed to the energy barrier that a molecule has to overcome as it attempts to diffuse into the LDPE structure, which can become significant for larger molecules. Similarly, the reduced bioavailability of BDE-209 in many biological species can be regarded as a reflection of the magnitude of molecular interactions between cell membranes and BDE-209. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fabric-air distribution coefficients and particle deposition fluxes are used to assess the accumulation of target analytes. • Normalized fabric-air distribution coefficients of gaseous compounds are dictated by Specific surface area and porosity. • Sorption capacity of fabrics is greatly influenced by particle-bound compounds on clothing surfaces. Abstract Vapor-phase constituents of tobacco smoke are known to accumulate on clothing surfaces; however, the significance of texture properties, such as specific surface area, porosity, and surface roughness, and airborne particles to the sorption capacity of fabrics has not been adequately addressed. In the present study, cotton (t-shirt) and polyester (pajama and lab coat) fabrics were exposed to cigarette smoke containing gaseous and particulate tobacco-derived compounds (e.g., N-nitrosamines). Fabric-air distribution coefficients and particle deposition fluxes were then determined to evaluate the accumulation of the target analytes. Appreciable amounts of N'-nitrosoanabasine (NAB) and 4′-(nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK) were detected in all three fabric types although particle-bound NAB and NNK were found only in cigarette smoke. In addition, the root mean square surface roughness heights for three types of clothes were within the same order of magnitude. As such, the deposition fluxes of particle-bound N'-nitrosonornicotine (NNN) and NNK to fabric surface may have contributed to 6–20% and 56–100% of total NNN and NNK in fabrics, respectively, estimated based on the assumed deposition velocity of 0.65 m h−1. Apparently, the sorption capacity of fabrics can be greatly influenced by particle-bound compounds on clothing surfaces, resulting in either over- or under-estimation of fabric-air distribution/partitioning coefficients. [ABSTRACT FROM AUTHOR]

Barbecue (BBQ) is one of the most popular cooking activities with charcoal worldwide and produces abundant polycyclic aromatic hydrocarbons (PAHs) and particulate matter. Size distribution and clothing-air partitioning of particle-bound PAHs are significant for assessing potential health hazards to humans due to exposure to BBQ fumes, but have not been examined adequately. To address this issue, particle and gaseous samples were collected at 2-m and 10-m distances from a cluster of four BBQ stoves. Personal samplers and cotton clothes were carried by volunteers sitting near the BBQ stoves. Particle-bound PAHs (especially 4–6 rings) derived from BBQ fumes were mostly affiliated with fine particles in the size range of 0.18–1.8 μm. High molecular-weight PAHs were mostly unimodal peaking in fine particles and consequently had small geometric mean diameters and standard deviations. Source diagnostics indicated that particle-bound PAHs in BBQ fumes were generated primarily by combustion of charcoal, fat content in food, and oil. The influences of BBQ fumes on the occurrence of particle-bound PAHs decreased with increasing distance from BBQ stoves, due to increased impacts of ambient sources, especially by petrogenic sources and to a lesser extent by wind speed and direction. Octanol-air and clothing-air partition coefficients of PAHs obtained from personal air samples were significantly correlated to each other. High molecular-weight PAHs had higher area-normalized clothing-air partition coefficients in cotton clothes, i.e., cotton fabrics may be a significant reservoir of higher molecular-weight PAHs. Capsule Particle-bound PAHs from barbecue fumes are generated largely from charcoal combustion and food-charred emissions and mainly affiliated with fine particles. [ABSTRACT FROM AUTHOR]

Biomass fuels remain main energy sources in many remote rural regions, but potential health hazards from exposure to biomass combustion fumes have not been adequately assessed. Combustion of biomass fuels generates abundant polycyclic aromatic hydrocarbons (PAHs); hence residential exposure to PAHs can be used to evaluate the potential health risk to remote rural populations. The present study selected rural Tibetans to address the above-mentioned issue. Samples of indoor air and dust, human urine and local foods (Tsampa flour and buttered tea) were collected from five rural households in Langkazi County, an agricultural and pasturing region in Tibet of China in the summer season, which represented the best-case scenario as no heating was required. Residential exposure to PAHs by adults amounted to benzo[ a ]pyrene equivalent (BaP eq ) dosages of 110–760, 1.2–50 and 0.5–23 ng d −1 for ingestion, inhalation and dermal contact, respectively. Daily intakes of naphthalene, fluorene, phenanthrene and pyrene estimated from urinary monohydroxy PAH metabolites and from diet and inhalation exposure to PAHs were comparable (3.9, 1.9, 12 and 3.3 μg d −1 versus 9.5, 2.5, 5.1 and 1.1 μg d −1 ), indicating the utility of external exposure in assessing daily intake of PAHs. The median incremental lifetime cancer risk was 32 × 10 −6 (95% confidence interval: 0.7–73 × 10 −6 ) for ingestion and 2.4 × 10 −6 (95% confidence interval: 0.02–12 × 10 −6 ) for inhalation and dermal contact combined, indicating moderate to slight potential cancer risk. Diet is the dominant source of health hazards for rural Tibetans, but cooking fumes also present a meaningful concern. The present study demonstrates that the pristine lifestyles of remote rural residents may be of global health concern, and merit further investigations. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented that comments on the article “Global Aquatic Passive Sampling (AQUA-GAPS): Using Passive Samplers to Monitor POPs in the Waters of the World,” by R. Lohmann and D. Muir in a 2010 issue.

Abstract: A conventional solid-phase microextraction (SPME) method combined with liquid–liquid extraction was applied under equilibrium and nonequilibrium conditions to determine the partition coefficients (K doc) of 25 polychlorinated biphenyl congeners (PCBs) between Sigma–Aldrich humic acid (HA) and water. The values of log K doc determined with equilibrium SPME were linearly correlated with the logarithm of the octanol–water partition coefficients (K ow) for PCB congeners at log K ow <∼7.2, but the trends were disrupted for log K ow from ∼7.2 to 8.18. In addition, short-term (5min to 4 days) and long-term (5–44 days) uptake profiles of PCBs were established, from which a pseudo-equilibrium for sorption of PCBs was revealed at ∼4 days of extraction. To understand this phenomenon, the uptake profiles were fitted with two equations (one equation is often used for pure water samples and the other one is applicable for samples containing complex matrices) derived from a first-order kinetics model. Subsequently, K doc values obtained through kinetic approaches were compared with those acquired from equilibrium SPME. The comparison of K doc values indicated that the pseudo-equilibrium was caused by the slow desorption of PCBs from HA rather than the biphasic desorption mechanism. [Copyright &y& Elsevier]

[Display omitted] • Particles release from erasers and pen grips upon dermal contact. • Particles derived from erasers and pen grips are mainly smaller than 1 μm. • Migrated particles mediate dermal contact of plasticizers to erasers and pen grips. Dermal exposure to chemicals released from daily consumer products is a rising concern, particularly for children who are susceptible to unintentional hand-to-mouth transfer and related chemical exposure risk. However, chemical transfer induced by tiny particles of intact products has yet to be adequately addressed. The objective of the present study was to determine the potentiality of particles release from intact erasers and pen grips upon dermal contact by measuring the migration rates of the embedded plasticizers (phthalates and its alternatives). The results showed that billions of particles were released from erasers (0.6–1.2 × 109) and pen grips (0.2–1.6 × 108) upon dermal contact at ambient temperature, with sizes mainly smaller than 1 μm. The composition of eraser leachates was identical to that of the corresponding bulk eraser, as confirmed by Fourier-transform infrared spectroscopy and pyrolysis. Migrated hydrophobic plasticizers may be used as indicators of particle release from erasers and pen grips. The potentiality of particle release was negatively correlated with the total plasticizer contents (r = −0.51; p < 0.05) for both erasers and pen grips. These findings indicated that particles directly released from school supplies and accessories could be a non-negligible source of human exposure to plasticizers. [ABSTRACT FROM AUTHOR]

Abstract Bioaccessibility of particle-bound hydrophobic organic contaminants and related particle size effects are significant for assessing the potential human health risk via inhalation exposure, but have not been clearly evaluated. To fill this knowledge gap, the present study developed an in vitro method to estimate the inhalation bioaccessibility of particulate polycyclic aromatic hydrocarbons (PAHs) using simulated human lung fluids, i.e. , a modified Gamble's solution (MGS) and artificial lysosomal fluid (ALF) with Tenax as the absorption media. Assay parameters, namely incubation time (10 d) and influence of filter use, were optimized for establishing the in vitro method. The results showed that the bioaccessibility of PAHs increased with increasing particle size, but other factors, such as total organic carbon and chemical hydrophobicity, also played a large role in the fate of these compounds. The results from this portion of the present study were then used to evaluate human health risk, which showed that the risk of these particle-bound PAHs by incorporating size-dependent PAHs bioaccessibility and deposition efficiency in the human respiratory tract into inhalation exposure risk calculations was reduced by >90% when compared to using total concentration. This suggested that the inhalation bioaccessibility and deposition efficiency of hydrophobic organic chemicals should be included in human health risk assessment. Graphical abstract Unlabelled Image Highlights • An in vitro method was developed for evaluating the IBAF of particle-bound HOCs. • The inhalation bioaccessibility of PAHs decreased with increasing hydrophobicity. • The IBAF of particle-bound HOCs is significant to human health risk assessment. [ABSTRACT FROM AUTHOR]

Cultivation of microalgae in anaerobically digested effluent is beneficial for removal of nutrients, such as nitrogen and phosphorus, and heavy metals at reduced cost and generation of biomass to produce biofuels. In the present study, four strains of oleaginous microalgae, separated from fresh water in South China, were evaluated for their ability to remove nitrogen and phosphorus. The results showed that Scenedesmus sp. (GN 171) was capable of removing nitrogen and phosphorous in BG-11 medium at the rates of 97% and 99%. Two types of anaerobically digested effluents, i.e., grass anaerobically digested effluent and molasses wastewater anaerobically digested effluent, were chosen as the nutrient sources. These anaerobically digested effluents diluted in BG-11 medium or with tap water were used as the substitute medium to cultivate GN 171; other pretreatment methods, such as sterilization and dilution ratio, were also taken into consideration. A ratio of 1/3 for unsterilized grass anaerobically digested effluent/tap water mixture (designated as G4) was the optimal proportion for growth of GN 171 and removal of nitrogen and phosphorus at a large scale. The dry weight of GN 171 reached 3.2 g L −1 , and the total lipid, carbohydrate and protein contents were 34%, 30% and 16% in G4. The efficacies for removal of total nitrogen, ammonia nitrogen, phosphorus and selected heavy metals were generally satisfactory. It seems possible to use ADE, rather than any artificial medium, as the sole nutrient source for microalgae production. [ABSTRACT FROM AUTHOR]

• Dissolved PBDEs and OPFRs were concentrated in porewater and overlying water. • Sediment is interchanged with sink and source for riverine transport of OPFRs. • Sediment-water diffusion of PBDEs and OPFRs was not significant compared to riverine transport. Despite ample evidence on spreading of e-waste derived hazardous materials, riverine transport of organic contaminants from e-waste recycling zones to surrounding areas has not been evaluated. To address this issue, passive and grab sampling methods were used to assess sediment-water diffusion and horizontal transport of polybrominated diphenyl ethers (PBDEs) and organophosphorus flame retardant (OPFRs) at upstream and downstream sites of two rivers in a typical e-waste recycling zone. Sediment acted as a source of BDE-17 with fluxes of 0.007−0.04 ng m−2 d−1 at all sampling sites. BDE-47 and BDE-99 reached equilibrium between overlying water and sediment porewater. Sediment interconverted from a sink at the upstream site to a source of OPFRs at the downstream site with a flux varying between −7.3 and 234 ng m−2 d−1. The amounts of OPFRs (11−45 g d−1) via horizontal riverine transport were greater than those of PBDEs (0.68−2 g d−1). The vertical sediment-water diffusion of PBDEs and OPFRs was not significant compared to horizontal riverine transport. The annual riverine outputs of PBDEs and OPFRs from the downstream sites were 250–330 g and 12,000–16,500 g, respectively, indicating the significance of riverine transport of organic contaminants from e-waste recycling zones to surrounding areas. [Display omitted] [ABSTRACT FROM AUTHOR]

The partition coefficient (K pew) of an analyte between low-density polyethylene (LDPE) film and water is a critical parameter for measuring freely dissolved concentrations of the analyte with PE passive sampling devices. Measuring log K pew for super hydrophobic organic chemicals (HOCs) have been proven extremely difficult. The present study developed a large volume model for measuring log K pew of super HOCs, i.e., novel halogenated flame retardants (NHFRs). Results showed that the measured log K pew values of selected PAHs and PCBs obtained by the large volume model were in line with those from the co-solvent model and the literature data within less 0.3 log units of difference, while those of NHFRs (6.27–7.34) except for hexachlorocyclopentadienyldibromocyclooctane (HCDBCO) and Decabromodiphenyl ethane (DBDPE) were significantly lower than those (6.51–8.89) from the co-solvent model. A curvilinear relationship was observed between log K pew and log K ow of all target compounds, with the turning point at log K ow = ∼8.0 in the large volume model, but that was not found for the co-solvent model. These can be attributed to the large molecular volumes (> 450 Å3) for NHFRs, which require high Gibbs free energy to penetrate into the inside structures of LDPE in the large volume model. However, the solvent swelling effects in the co-solvent model needs to be investigated. Therefore, the large volume model is robust to determine the K pew values of super HOCs for facilitating the application of aquatic passive sampling techniques. • The large volume model is feasible to measure the K pew values of super HOCs. • The K pew values of HOCs from the co-solvent model were greater than other models. • The K pew values of NHFRs decreased with increasing molecular volumes. [ABSTRACT FROM AUTHOR]

• Polystyrene-nanoplastics (PS-NPs) enhance antioxidant activity and activate carbon metabolism. • The difference in root-related gene expressions is induced by PS-NPs. • Jasmonate and lignin biosynthesis are inhibited by PS-NPs treatments. • Exogenous JA application alleviates potential adverse effects of PS-NPs on rice seedlings. Potential adverse effects of nanoplastics (NPs) on marine organisms have received increased attention in recent years. In contrast, few data are available on terrestrial plants, especially on the mechanisms for transport of NPs in plants and phytotoxicity (at both phenotypic and molecular levels) of plants induced by NPs. To address this knowledge gap, we conducted a microcosm study in which hydroponically-cultured rice (Oryza sativa L.) seedlings were exposed to polystyrene (PS)-NPs at 0, 10, 50, and 100 mg L−1 for 16 d and examined for morphological and physiological phenotypes and transcriptomics. Laser confocal scanning micrographs confirmed PS-NPs were uptaken by rice roots, greatly benefitted from the transport activity of aquaporin in rice roots. The significant enhancement (p < 0.05) of antioxidant enzyme activities reflected the oxidative stress response of rice roots upon exposure to PS-NPs. Treatment by PS-NPs decreased root length and increased lateral root numbers. Carbon metabolism was activated (e.g., increased carbon and soluble sugar contents) whereas jasmonic acid and lignin biosynthesis were inhibited. The present study demonstrated the likelihood for transport of PS-NPs in rice roots and induced phytotoxicity by PS-NPs, which should inspire further investigations into the potential human health risks from rice consumption. [ABSTRACT FROM AUTHOR]

Human health concerns are rising with polybrominated diphenyl ethers' (PBDEs) analogues, methoxylated and hydroxylated PBDEs (MeO-PBDEs and OH-PBDEs), due to their occurrences in foods and greater potential toxicological effects than PBDEs. While the oral bioaccessibilities (BA%) of PBDEs in foods are available, such information on MeO-PBDEs and OH-PBDEs, and the effects of cooking on them have not been adequately addressed. The present study was conducted with fish and chicken egg as typical foods to assess the bioaccessibility (BA%) of PBDEs, MeO-PBDEs, and OH-PBDEs using the colon extended physiologically based extraction test and examine the effects of cooking processes (boiling, frying, and steaming) on them. The results showed that thermal degradation or transformation of the target compounds did not occur during boiling and frying of fish. The BA% of individual PBDEs, MeO-PBDEs, and OH-PBDEs were 20–51% for boiled fish, 11–20% for pan-fried fish, 15–77% for steamed egg, and 42–68% for pan-fried egg. Cooking decreased the BA% of all target compounds in fish due to protein denaturation. However, the BA% of OH-PBDEs in pan-fried egg were greater than those in steamed egg. In addition, the substituent groups of CH 3 O- and OH- did not pose any effects on the BA% of BDE-47 in fish, but OH-group decreased its BA% in egg. These findings suggested that MeO-PBDEs and OH-PBDEs exhibited the similar oral BA% in fish to PBDEs, but the underlying mechanism for the effects of cooking on BA% of OH-PBDEs in egg needs to be further investigated. Unlabelled Image • MeO- and OH-PBDEs exhibited the similar bioaccessibility in fish and egg to PBDEs. • Cooking decreased the bioaccessibility of PBDEs, MeO-PBDEs, and OH-PBDEs in fish. • PBDEs and MeO- and OH-PBDEs were more bioaccessible in fried egg than fried fish. [ABSTRACT FROM AUTHOR]

Antibiotics and current-use pesticides are ubiquitous in the environment. It is important to figure out their spatial distribution under the influences of anthropogenic activities and transport from rivers to coastal oceans. To address this knowledge gap, the present study conducted quarterly sampling in eight main runoff outlets of the Pearl River, South China, and obtained total concentrations of antibiotics and current-use pesticides at 24–296 ng L−1. Higher total concentrations of these chemicals occurred in summer, attributed to seasonal consumption patterns and washout by rainfalls, respectively. The spatial distributions of target analytes were not significantly different between the eastern and western outlets with high and moderate urbanization levels, respectively. Approximately 16.4, 17.7, and 12.5 tons of antibiotics, organophosphorus pesticides, and neonicotinoids were discharged annually from the outlets to the South China Sea. These results suggested that usage amount and hydrology exhibited positive effects on the riverine inputs of the target chemicals. In addition, most target chemicals exhibited low risks to green algae, but erythromycin and parathion posed high ecological risks to aquatic organism (Daphnid and fish). Unlabelled Image • Higher concentrations of current-use pesticides occurred in summer and autumn. • Urbanization level did not affect spatial patterns of antibiotics and pesticides. • There was none significant difference on seasonal distribution of antibiotics. • Great amount of neonicotinoids from urban regions was loaded from the Pearl River. [ABSTRACT FROM AUTHOR]

Passive sampling techniques have been widely used to determine the dissolved concentration profiles of hydrophobic organic compounds (HOCs) in sediment porewater. However, the effects of having a protection for the passive sampler on profiling HOCs concentrations in sediment porewater, especially in deep sediment, have remained unclear. To address this issue, low density polyethylene passive samplers with and without protectors, which consisted of glass fiber filter and porous stainless steel shield, were simultaneously deployed in sediment of the Dongjiang River, South China. The results showed that the protectors retarded the dissipation of performance reference compounds (PRCs) from the sampler by a factor of 2–9. The protectors seemed to exert a negligible effect on the measured concentrations of PAHs, BDE-47, and BDE-99 in surficial sediment porewater (0–14 cm depth) from both samplers. However, the sediment porewater concentration profiles of PAHs and BDE-47 from the sampler with protectors were in agreement with those normalized by dry weight in deep sediment (16–34 cm depth), indicating that a diffusion layer established by the protectors may minimize the probability of local depletion of the target analytes in deep sediment. In addition, the log K oc values of PAHs, BDE-47, and BDE-99 exhibited a slight increasing trend with sediment depth. This finding suggested that in situ passive sampling techniques could be a feasible tool in determining the site-specific log K oc values of HOCs at different sediment depths. Image 1 • Protectors significantly retarded the dissipation of PRCs. • Protectors did not affect the measured concentrations of PAHs in surficial porewater. • PAHs profile from the sampler with protectors was similar to that in deep sediment. [ABSTRACT FROM AUTHOR]