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Abstract Marine organisms are naturally exposed to different environmental pollutants including organic pollutants and nanoparticles. The interactive effects between nanoparticles and other chemicals on aquatic organisms have raised concerns regarding the potential of nanomaterials as the vector for other chemicals. In the present study, the effect of nano zinc oxide (nZnO) on the bioavailability of triphenyltin chloride (TPTCl) was studied, and their combined acute and reproductive toxicity to the marine copepod Tigriopus japonicus were evaluated. At experimental concentration ranges of nZnO in this study, the percentage of dissolution of Zn2+ was relative stable (from 62% to 66%), and nZnO did not affect the bioavailability of TPTCl to the copepods. The acute toxicity of binary mixtures of nZnO/TPT was equivalent to that of the mixture of Zn2+/TPT. In agreement with the decrease in TPTCl's LC 50 values at the presence of nZnO, their interacting effect was synergistic based on response addition response surface model, and the interacting parameter was modelled to be −1.43. In addition to acute toxicity test, reproductive toxicity tests revealed that exposure to nZnO and TPTCl didn't affect the successful mating rate and the number of nauplii in the 1st brood, but they extended the time for the eggs to hatch from 2.53 days to 3.94 and 3.64 days, respectively. The exposure to nZnO/TPTCl mixture delayed the time to hatch to 5.78 days. Graphical abstract Image 1 Highlights • LC 50 values of TPT decreased at the presence of nZnO. • Interaction between TPT and nZnO was equivalent to TPT and Zn2+. • NZnO did not affect the bioavailability of TPT. • The interaction of TPT and nZnO was synergistic according to RARS model. • RARS model better fitted the data than CARS model. This study observed synergistic effect between nZnO and TPTCl on the marine copepod Tigriopus japonicus by applying response addition response surface model. [ABSTRACT FROM AUTHOR]

Highway toll station workers' occupational exposure levels and health effects of polycyclic aromatic hydrocarbons (PAHs) have been analyzed through personal particulate sampling and urinary biomonitoring during March-May, 2014 in Tianjin, China. Personal particulate samples were collected during highway toll station workers' day shift working time (from 9:00 a.m. to 5:00 p.m.). Pre-shift and post-shift spot urine samples were collected on each participant. In personal particulate samples, 16 priority PAHs suggested by USEPA were measured, and in the urine samples oxidative stress biomarker (8-OHdG) was analyzed. The measured mean occupational exposed concentration of PM2.5 was 230.73 μg m−3, and the mean p-PAHs exposed concentration was 319.90 ng m−3 for the selected workers. Urinary concentrations of 8-OHdG increased by two times following an 8-h work shift in participants. Significant positive associations were found between post-work shift urinary 8-OHdG and p-PAH concentrations. Our finding indicated that personal air exposures to PAHs originating from traffic emissions are important in increasing oxidative burdens in human body. [ABSTRACT FROM AUTHOR]

Triphenyltin (TPT) often coexists with tributyltin (TBT) and Cu in coastal waters worldwide. The combined toxic effect of TPT and TBT has always been assumed to be additive without any scientific proof, and the combined effect of Cu and TPT on marine organisms has not been vigorously studied. This study, therefore, investigated the acute toxicity of binary mixture of TPT/Cu and TPT/TBT to five selected marine species including Thalassiosira pseudonana , Skeletonema costatum , Tigriopus japonicus , Brachionus koreanus and Oryzias melastigma . The interaction between TPT and TBT or Cu was modeled antagonistic based on concentration addition (CA) model, while it was synergistic according to response addition (RA) model. Both model well predicted the toxicity of binary mixtures to the five organisms. As for the environmental risk assessment, CA overestimated the toxicity in most cases and thus is a more conservative model than RA model for assessing the toxicity of these chemical mixtures. [ABSTRACT FROM AUTHOR]

Toxic effects of triphenyltin (TPT) to different life stages of the marine medaka Oryzias melastigma were investigated through a series of life-cycle based exposure experiments. In embryo stage, TPT exposure could elevate the heartbeat rate at Day 6–8 post-fertilization and increase the expression levels of five heart development related genes (i.e., ATPase , COX2 , BMP4 , GATA4 and NKX2.5 ). In larval stage, TPT shortened the body length at ≥ 10 μg/L and suppressed the swimming activity of the fish larvae at Day 1 post-hatching at 50 μg/L. In reproductive stage, TPT exposure resulted in a male-biased sex ratio (2 μg/L) and reduced the gonadosomatic index (GSI) in females (≥ 0.1 μg/L), which might in turn lead to a decline in their population fitness. The reproductive stage of O. melastigma was more sensitive to TPT than other stages, while the GSI of female medaka was the most sensitive endpoint. [ABSTRACT FROM AUTHOR]

Boosting the low catalytic activity of bacteriogenic Ag/AgCl nanoparticles (NPs) by adding Co2+ in a model reaction, i.e. p-nitrophenol (PNP) reduction, was observed. Under optimal conditions, Co–Ag/AgCl NPs show an apparent rate constant (kapp) of 0.0837 s−1 upon PNP reduction. Considering the trace amount of Co–Ag/AgCl NPs used in catalysis (about 1.2 μg), the activity parameter κ (which is the ratio of kapp and catalyst mass) can reach more than 6.97 × 104 s−1 g−1, which is 214-fold higher than that of pristine Ag/AgCl NPs. Meanwhile, this κ value is also the highest value reported to date. In addition, the biogenic Co–Ag/AgCl NPs exhibit superior catalytic activities over other substrates, such as m-nitrophenol, o-nitrophenol, methyl orange and rhodamine B. The activity enhancement mechanism is supposed to be that Co2+ acts as a Lewis acid, and coordinates with the surface peptides to affect the electric field distribution at the Ag/AgCl NP interface. [ABSTRACT FROM AUTHOR]

The bioavailability and toxicity of metals to aquatic organisms are highly dependent on water quality parameters in freshwaters. The biotic ligand model (BLM) for copper is an approach to generate the water quality criteria (WQC) with water chemistry in the ambient environment. However, few studies were carried out on the WQCs for copper based on the BLM approach in China. In the present study, the toxicity for copper to native Chinese aquatic organisms was conducted and the published toxicity data with water quality parameters to Chinese aquatic species were collected to derive the WQCs for copper by the BLM approach. The BLM-based WQCs (the criterion maximum criteria (CMC) and the criterion continuous concentration (CCC)) for copper in the freshwater for the nation and in the Taihu Lake were obtained. The CMC and CCC values for copper in China were derived to be 1.391 μg/L and 0.495 μg/L, respectively, and the CMC and CCC in the Taihu Lake were 32.194 μg/L and 9.697 μg/L. The high concentration of dissolved organic carbon might be a main reason which resulted in the higher WQC values in the Taihu Lake. The WQC of copper in the freshwater would provide a scientific foundation for water quality standards and the environment risk assessment in China. [ABSTRACT FROM AUTHOR]

Pentachlorophenol (PCP) has been reported toxic to aquatic organisms, and it frequently occurs at relatively high concentrations in most Chinese waters due to the re-emergence of schistosomiasis since 2003. Several studies about Water Quality Criteria (WQC) for PCP had been performed to protect the aquatic ecosystem, but in most of these studies the toxicity data were not properly analyzed (e.g. screening and processing methods). Moreover, little study was carried out on the ecological risk assessment (ERA) based on environmental factors. In this study, through collecting published native toxicity data of PCP along with relationships between toxicity and pH, pH-dependent WQC was established using a standardized scientific statistical method in China. The Criterion Maximum Concentration (CMC) and Criterion Continuous Concentration (CCC) were expressed as a function of pH. These were (1) CMC = exp(1.361×pH-8.034) and (2) CCC = exp(1.361×pH-10.434). At pH 7.8, the derived CMC and CCC were 13.21 and 1.20 μg/L, respectively. In addition, four tiers of the ERA were conducted based on pH for different waterbodies at different seasons. In tiered 1, 2, 3 and 4 ERA, PCP exposure concentrations were standardized to that at pH 7.8. Results showed that all levels of ERA method in the tiered framework were consistent with each other, and the risks of PCP in Liaohe river of wet season, Taihu lake and Liaohe river of dry season increased successively. The Hazard quotient (HQ) method indicated that small fluctuations in pH would lead to misleading hazard results. PCP concentrations of 8.66 μg/L at pH 7.37 in one site posed more risk than PCP of 9.57 μg/L at pH 7.93 in another site. The joint probability suggested that ecological risks may exist 11.84% in the dry season and 1.51% in the wet season in Liaohe River, and 4.98% in Taihu Lake, respectively while 5% thresholds (HC 5 ) were set up to protect aquatic organisms. We hope this work could provide more information to manage and control PCP pollution in Taihe Lake and Liaohe River. [ABSTRACT FROM AUTHOR]

There has been a growing concern about plastic pollution, both from a health and ecological perspective. One of the major concerns with plastic debris, especially microplastics (MPs) relates to their strong potential for releasing additives and chemicals. Di-2-ethylhexyl phthalate (DEHP) is a common plastic additive widely used as plasticizer in plastic products, and is of global concern due to its widespread contamination in the environment. In this study, two conventional nondegradable plastics (polyethylene (PE) bags and PE mulch) and two biodegradable plastics (poly(butylene adipate co-terephtalate)-starch-based-polylactic acid bags (PBAT/PLA bags) and PLA mulch) were selected to investigate the release of DEHP to seawater. The results showed that leaching potentials of DEHP from different types of MPs varied. Among the four selected MPs, PE mulch had the highest leaching potential (6.88 μg/g), followed by PE bags (4.24 μg/g), PLA mulch (1.10 μg/g) and PBAT/PLA bags (0.89 μg/g). The DEHP leaching kinetic curves of the four MPs were all in line with the pseudo first order model. The potential risk of environmental and human exposure to the leached DEHP was assessed using the average Phthalate Pollution Index (PPI). The calculated PPI indicated low pollution risks of DEHP released by the four MPs in seawater. [Display omitted] • DEHP can be released into seawater from biodegradable and conventional microplastics. • Release of DEHP from microplastics is associated with plastic type. • The pseudo first order model effectively describes the DEHP leaching kinetic process. • The PPI indicated low pollution risks of DEHP released by the MPs in seawater. [ABSTRACT FROM AUTHOR]

Tire wear particles (TWPs), which are among the microplastic pollutants in the environment, can inevitably accumulate in coastal sediments. The present study comprehensively investigated the effect of pristine TWPs on bacterial community structure in coastal sediments and compared the effect of pristine TWPs and aged TWPs on nine strains of bacteria in sediments. In addition, the effect of the TWP leachate was studied with all the nine bacterial strains and the toxicity-causing substances in the leachate was investigated using Bacillus subtilis. Exposure to TWPs could lead to a shift in bacteria community and affect nitrogen metabolism in marine sediments. Aged TWPs were more toxic than pristine TWPs due to changes in particle surface characteristics. The leachate exhibited greater toxicity than TWPs as well, and Zn was identified to be the major toxicity-causing substance. The overall results of this study are important for understanding the effects of TWPs and the leachates on microorganisms in marine sediments. [Display omitted] • TWPs could alter the bacteria community in marine sediments. • Aged TWPs showed slightly higher inhibitory effects on bacteria. • The TWP leachate was toxic to three of the bacteria species. • Zn was the major toxicity-causing substance in the TWP leachate. [ABSTRACT FROM AUTHOR]

In order to understand the sources and potential formation processes of atmospheric carbonaceous aerosols in South China, fine particle samples were collected at a high-elevation mountain site-Mount Lu (29°35′ N, 115°59′ E, 1165 m A.S.L.) during August-September, 2011. Eight carbonaceous fractions from particles were resolved following the IMPROVE thermal/optical reflectance protocol. During the observation campaign, the daily concentrations of PM at Mount Lu ranged from 7.69 to 116.39 μg/m, with an average of 58.76 μg/m. The observed average organic carbon (OC) and elemental carbon (EC) concentrations in PM were 3.78 and 1.28 μg/m, respectively. Secondary organic carbon (SOC) concentration, estimated by EC-tracer method, was 2.07 μg/m on average, accounting for 45.0 % of the total OC. The enhancement of secondary organic aerosol (SOA) formation was observed during cloud/fog processing, and heterogeneous acid-catalyzed reactions may have contributed to SOA formation as well. Back trajectory analysis indicated that air masses were mainly sourced from southern China during observation period, and this air mass source was featured by highest values of OC and effective carbon ratio (ECR). Relation of carbonaceous species and principal component analysis indicated that multiple sources contributed to the carbonaceous aerosols at Mount Lu. [ABSTRACT FROM AUTHOR]

To understand the deposition and transport of PAHs in southern China, a measurement campaign was conducted at a high-elevation site (the summit of Mount Heng, 1269 m A.S.L.) from April 4 to May 31, 2009, and a total of 39 total suspended particulate samples were collected for measurement of PAH concentrations. The observed particulate-bound PAHs concentrations ranged from 1.63 to 29.83 ng/m3, with a mean concentration of 6.03 ng/m3. BbF, FLA, and PYR were the predominant compounds. Good correlations were found between individual PAHs and meteorological parameters such as atmospheric pressure, relative humidity, and ambient temperature. The backward trajectory analysis suggested that particulate samples measured at the Mount Heng region were predominantly associated with the air masses from southern China, while the air masses transported over northern and northwestern China had relative higher PAHs concentrations. Based on the diagnostic ratios and factor analysis, vehicular emission, coal combustion, industry emission, and unburned fossil fuels were suggested to be the PAHs sources at Mount Heng site. However, the reactivity and degradation of individual PAHs could influence the results of PAH source profiles, which deserves further investigations in the future. [ABSTRACT FROM AUTHOR]

Species sensitivity distribution (SSD) method has been widely used to derive water quality criteria (WQC). However, the toxicity data of some environmental pollutants are not easily accessible, especially for endangered and threatened species. Thus, it would be very desirable and economical to predict the toxicity of those species not subjected to toxicity test with the aid of a mathematical model. The interspecies correlation estimation (ICE) model (developed by the US Environmental Protection Agency (USEPA)) uses the initial toxicity estimate for one species to produce correlated toxicity values for multiple species, and it can be utilized to develop SSD and HC (hazardous concentration, 5th percentile). In this study, we explored the applicability of ICE to predict toxicity of phenanthrene to various species. ICE-based SSDs were generated using three surrogate species ( Oncorhynchus mykiss, Lepomis macrochirus, and Daphnia magna) and compared with the metrical-based SSD. The corresponding HC of both models were also compared. The results showed there were no significant differences between HC derived from measured acute and ICE-based predicted values. The ICE model was verified as a valid approach for generating SSDs with limited toxicity data and deriving WQC for phenanthrene. [ABSTRACT FROM AUTHOR]

In this study, toxicity of effluents in a wastewater treatment plant and of receiving water in an adjacent stream was periodically monitored from November 2007 to June 2008, in order to trace and reduce sources of toxicants. The results showed that toxicity of final effluent (FE) changed greatly over different sampling events, and appeared to have impacts on toxicity of downstream water with a significant correlation (r 2 =0.87, p<0.05). In particular, FE toxicity was always higher than that of secondary effluent (SE). Toxicity identification evaluation (TIE) for the FE sample collected in March 2008 showed that FE toxicity was attributed to low quality of Fenton reagent with Zn contamination used for SE treatment. Furthermore, Zn concentrations in FE samples significantly correlated with FE toxicity during the sampling period (r 2 =0.95, p<0.05). After changing the Fenton reagent to one containing low Zn, Zn concentration and toxicity of FE greatly decreased in the following months. [Copyright &y& Elsevier]