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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]

Understanding particle size distribution and size-resolved gas-particle partitioning of semi-volatile organic compounds (SVOCs) is important for characterizing their fate in atmosphere. However, the size-resolved gas-particle partitioning characteristics of SVOCs has not been adequately considered. To address this issue, the present study collected gaseous and size-fractioned particulate samples both in and outside of schools, offices, and residences in three districts of different urbanization levels in a megacity, Guangzhou, South China during two seasons. Typical SVOCs, including 15 polycyclic aromatic hydrocarbons (PAHs), six organophosphate esters and seven phthalic acid esters were measured. Emission sources, physicochemical properties, and environmental conditions at the sampling sites considerably impacted the spatiotemporal distribution patterns and particle size distribution of target SVOCs. Not all observed gas-particle partition coefficients (K p) of target SVOCs were negatively correlated with subcooled liquid-vapor pressures (P L 0), probably because certain factors, such as the non-exchangeable part of the particle-bound SVOCs, were not considered in traditional gas-particle partition theories. Particle size was an important factor affecting gas-particle partitioning. Adsorption was the dominant mechanism for PAHs with high molecular weight in different particle modes. A new model was established to predict size-resolved K p of PAHs with high molecular weight based on P L 0 and particle size. [Display omitted] • Observed log K p of PAEs and OPEs were not well correlated with log P L 0. • Observed log K p of 3- and 4-rings PAHs were negatively related with log P L 0. • Adsorption was the dominant gas-particle partition mechanism of 3- and 4-rings PAHs. • Particle size affects gas-particle partitioning of semi-volatile organic compounds. • The established model greatly predicted size-resolved K p of 3- and 4-rings PAHs. [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]

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]

Tire-derived particles and polyethylene (PE) debris co-exist in estuaries and potentially deteriorate water quality. Chemicals can be emitted from tire-derived particles and resorb to PE debris. However, there was lack of information about the interaction (e.g., sorption and desorption) between tire-derived chemicals and PE debris. By combining batch sorption and desorption experiments along with in situ field deployment of PE sheets, we examined the utility of benzothiazoles (BTZs) sorbed in PE as suitable markers of tire-derived inputs. The sorptive characteristics and PE-water partition coefficients (often designated as K pew) of selected tire-derived marker candidates, i.e., polycyclic aromatic hydrocarbons (PAHs), benzothiophenes (BTPs) and BTZs, were measured. Moderately polar BTPs and BTZs (except for 2-(4-morpholinyl) benzothiazole) reached equilibrium within 2–8 days, compared to 20 days for nonpolar PAHs. The measure K pew values and octanol-water partition coefficients of PAHs and BTZs were linearly correlated with each other (r 2 > 0.80; p < 0.05). The desorption potentiality of PAHs and BTZs from tire particles is consistent with the hydrophilic properties of the target chemicals, while desorption ratios of BTZs and PAHs are 25–87% and <20%, respectively. Samplers with PE sheets as the sorbent phase were deployed in Hailing Bay, an urbanized estuary in South China, to measure concentrations of PAHs, BTPs and BTZs. Benzothiazoles sorbed in PE samples were associated with the massive utilization of automobile tires, while PAHs were linked to the boat maintenance facilities and BTPs were not detected in any tire particle and field PE samples. Therefore sorbed BTZs in PE can potentially serve as chemical markers of tire-derived inputs to estuaries. [Display omitted] • Benzothiazoles reach equilibrium between polyethylene and water within 2–8 days. • Benzothiazoles are weakly attracted to tire rubber matrices. • Benzothiazoles sorbed in polyethylene are related to utilization of tires. • Sorbed benzothiazoles are suitable markers of tire-derived leachate inputs. [ABSTRACT FROM AUTHOR]

Available data were reviewed to assess the status of contamination by persistent organic pollutants (POPs), including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), in drinking water sources and coastal waters of China. The levels of POPs in China's waters were generally at the high end of the global range. A comparison of China's regulatory limits indicated that PCBs in rivers and coastal water may pose potential human health risk. Occurrence of DDTs in some rivers of China may also pose health risk to humans using the regulatory limits of DDTs recommended by the European Union. Future monitoring of POPs in China's waters should be directed towards analytes of concern (e.g. PCBs and PCDD/Fs) and to fill data gaps for analytes (e.g. PBDEs, PCDD/Fs, and chlordane) and in watersheds/regions (e.g. West China) where data are scarce. [Copyright &y& Elsevier]

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]

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]

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., (Copyright © 2019 Elsevier Ltd. All rights reserved.)