The Antarctic continent is among the most pristine regions; yet various organic contaminants have been measured there routinely. Air and snow samples were collected during the austral spring (October–November, 2010) along the western Antarctic Peninsula and analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) to assess the relative importance of long-range transport versus local primary or secondary emissions. Highest concentrations of PCBs, PBDEs and DDTs were observed in the glacier’s snow sample, highlighting the importance of melting glaciers as a possible secondary source of legacy pollutants to the Antarctic. In the atmosphere, contaminants were mainly found in the vapor phase (>65%). Hexachlorobenzene (33.6 pg/m3), PCBs (11.6 pg/m3), heptachlor (5.64 pg/m3), PBDEs (4.22 pg/m3) and cis-chlordane (2.43 pg/m3) were the most abundant contaminants. In contrast to other compounds, PBDEs seem to have originated from local sources, possibly the research station itself. Gas-particle partitioning for analytes were better predicted using the adsorption partitioning model than an octanol-based absorption approach. Diffusive flux calculations indicated that net deposition is the dominant pathway for PBDEs and chlordanes, whereas re-volatilization from snow (during melting or metamorphosis) was observed for PCBs and some OCPs.

Diethylhexyl phthalate (DEHP) is considered to be an endocrine disruptor, which unlike other chemicals that have either non-specific (e.g., narcotics) or more generalized reactive modes of action, affect the Hypothalamic-pituitary-gonadal (HPG) axis and tend to have specific interactions with particular molecular targets within biochemical pathways. Responding to this challenge, a novel method for deriving predicted no-effect concentration (PNEC) and probabilistic ecological risk assessment (PERAs) for DEHP based on long-term exposure to potentially sensitive species with appropriate apical endpoints was development for protection of Chinese surface waters. PNECs based on potencies to cause lesions in reproductive tissues of fishes, which ranged from 0.04 to 0.20 μg DEHP L−1, were significantly less than those derived based on other endpoints or other taxa, such as invertebrates. An assessment of risks posed by DEHP to aquatic organisms in surface waters of China showed that 88.17% and 78.85% of surface waters in China were predicted to pose risks to reproductive fitness of fishes with thresholds of protection for aquatic organisms based on 5% (HC5) and 10% (HC10), respectively. Assessment of risks of effects based on effects mediated by the HPG-axis should consider effects on chronic, non-lethal endpoints for specific taxa, especially for reproductive fitness of fishes.

Plastics are common and pervasive anthropogenic debris in marine environments. Floating plastics provide opportunities to alter the abundance, distribution and invasion potential of sessile organisms that colonize them. We selected plastics from seven recycle categories and quantified settlement of (i) bryozoans Bugula neritina (Linnaeus, 1758) in the lab and in the field, and of (ii) barnacles Amphibalanus (= Balanus) amphitrite (Darwin, 1854) in the field. In the laboratory we cultured barnacles on the plastics for 8 weeks and quantified growth, mortality, and breaking strength of the side plates. In the field all recyclable plastics were settlement substrata for bryozoans and barnacles. Settlement depended on the type of plastic. Fewer barnacles settled on plastic surfaces compared to glass. In the lab and in the field, bryozoan settlement was higher on plastics than on glass. In static laboratory rearing, barnacles growing on plastics were initially significantly smaller than on glass. This suggested juvenile barnacles were adversely impacted by materials leaching from the plastics. Barnacle mortality was not significantly different between plastic and glass surfaces, but breaking strength of side plates of barnacles on polyvinyl chloride (PVC) and polycarbonate (PC) were significantly lower than breakage strength on glass. Plastics impact marine ecosystems directly by providing new surfaces for colonization with fouling organisms and by contaminants shown previously to leach out of plastics and impact biological processes.

Recent studies indicate that while unfunctionalized carbon nanomaterials (CNMs) exhibit very low decomposition rates in soils, even minor surface functionalization (e.g., as a result of photochemical weathering) may accelerate microbial decay. We present results from a C60 fullerene-soil incubation study designed to investigate the potential links between photochemical and microbial degradation of photo-irradiated C60. Irradiating aqueous ¹³C-labeled C60 with solar-wavelength light resulted in a complex mixture of intermediate products with decreased aromaticity. Although addition of irradiated C60 to soil microcosms had little effect on net soil respiration, excess ¹³C in the respired CO2 demonstrates that photo-irradiating C60 enhanced its degradation in soil, with ∼0.78% of 60 day photo-irradiated C60 mineralized. Community analysis by DGGE found that soil microbial community structure was altered and depended on the photo-treatment duration. These findings demonstrate how abiotic and biotic transformation processes can couple to influence degradation of CNMs in the natural environment.

Thallium (Tl) is a toxic and non-essential heavy metal. Raw Pb–Zn ores and solid smelting wastes from a large Pb–Zn smelting plant – a typical thallium (Tl) pollution source in South China, were investigated in terms of Tl distribution and fractionation. A modified IRMM (Institute for Reference Materials and Measurement, Europe) sequential extraction scheme was applied on the samples, in order to uncover the geochemical behavior and transformation of Tl during Pb–Zn smelting and to assess the potential environmental risk of Tl arising from this plant. Results showed that the Pb–Zn ore materials were relatively enriched with Tl (15.1–87.7 mg kg−1), while even higher accumulation existed in the electrostatic dust (3280–4050 mg kg−1) and acidic waste (13,300 mg kg−1). A comparison of Tl concentration and fraction distribution in different samples clearly demonstrated the significant role of the ore roasting in Tl transformation and mobilization, probably as a result of alteration/decomposition of related minerals followed by Tl release and subsequent deposition/co-precipitation on fine surface particles of the electrostatic dust and acidic waste. While only 10–30% of total Tl amounts was associated with the exchangeable/acid-extractable fraction of the Pb–Zn ore materials, up to 90% of total Tl was found in this fraction of the electrostatic dust and acidic waste. Taking into account the mobility and bioavailability of this fraction, these waste forms may pose significant environmental risk.

Heavy metals (Cr, Co, Ni, As, Cd, and Pb) can be bound to PM adversely affecting human health. Quantifying the source impacts on heavy metals can provide source-specific estimates of the heavy metal health risk (HMHR) to guide effective development of strategies to reduce such risks from exposure to heavy metals in PM2.5 (particulate matter (PM) with aerodynamic diameter less than or equal to 2.5 μm). In this study, a method combining Multilinear Engine 2 (ME2) and a risk assessment model is developed to more effectively quantify source contributions to HMHR, including heavy metal non-cancer risk (non-HMCR) and cancer risk (HMCR). The combined model (called ME2-HMHR) has two steps: step1, source contributions to heavy metals are estimated by employing the ME2 model; step2, the source contributions in step 1 are introduced into the risk assessment model to calculate the source contributions to HMHR. The approach was applied to Huzou, China and five significant sources were identified. Soil dust is the largest source of non-HMCR. For HMCR, the source contributions of soil dust, coal combustion, cement dust, vehicle, and secondary sources are 1.0 × 10−4, 3.7 × 10−5, 2.7 × 10−6, 1.6 × 10−6 and 1.9 × 10−9, respectively. The soil dust is the largest contributor to HMCR, being driven by the high impact of soil dust on PM2.5 and the abundance of heavy metals in soil dust.

Ecological communities are increasingly exposed to natural and anthropogenic stressors. While the effects of individual stressors have been broadly investigated, there is growing evidence that multiple stressors are frequently encountered underscoring the need to examine interactive effects. Pesticides and infectious diseases are two common stressors that regularly occur together in nature. Given the documented lethal and sublethal effects of each stressor on individuals, there is the potential for interactive effects that alter disease outcomes and pesticide toxicity. Using larval wood frogs (Lithobates sylvaticus), we examined the reciprocal interaction between insecticides (carbaryl and thiamethoxam) and the viral pathogen ranavirus by testing whether: (1) prior ranavirus infection influences pesticide toxicity and (2) sublethal pesticide exposure increases susceptibility to and transmission of ranavirus. We found that prior infection with ranavirus increased pesticide toxicity; median lethal concentration (LC50) estimates were reduced by 72 and 55% for carbaryl and thiamethoxam, respectively. Importantly, LC50 estimates were reduced to concentrations found in natural systems. This is the first demonstration that an infection can alter pesticide toxicity. We also found that prior pesticide exposure exacerbated disease-induced mortality by increasing mortality rates, but effects on infection prevalence and transmission of the pathogen were minimal. Collectively, our results underscore the importance of incorporating complexity (i.e. order and timing of exposures) into research examining the interactions between natural and anthropogenic stressors. Given the environmental heterogeneity present in nature, such research will provide a more comprehensive understanding of how stressors affect wildlife.

For the first time in the current literature, the effect of titanium dioxide (TiO2) nanoparticles on the community structure of macroinvertebrates has been investigated in situ. Macroinvertebrates were exposed for 100 days to an environmentally relevant concentration of TiO2 nanoparticles, 25 mg kg−1 in sediment. Czekanowski's index was 0.61, meaning 39% of the macroinvertebrate community structure was affected by the TiO2 treatment. Non-metric multidimensional scaling (NMDS) visualized the qualitative and quantitative variability of macroinvertebrates at the community level among all samples. A distance-based permutational multivariate analysis of variance (PERMANOVA) revealed the significant effect of TiO2 on the macroinvertebrate community structure. The indicator value analysis showed that the relative frequency and abundance of Planorbarius corneus and Radix labiata were significantly lower in the TiO2 treatment than in the control. Meanwhile, Ceratopogonidae, showed a significantly higher relative frequency and abundance in the TiO2 treatment than in the control.

This study investigated the effect of fulvic acid (FA) on the colloidal stability and reactivity of nano zero-valent iron (nZVI) at pH 5, 7 and 9. The sedimentation behavior of nZVI differed at different pH. A biphasic model was used to describe the two time-dependent settling processes (i.e., a rapid settling followed by a slower settling) and the settling rates were calculated. Generally, the settling of nZVI was more significant at the point of zero charge (pHpzc), which could be varied in the presence of FA due to the adsorption of FA on the nZVI surface. More FA was adsorbed on the nZVI surface at pH 5–7 than pH 9, resulting in the varying sedimentation behavior of nZVI via influencing the electrostatic repulsion among particles. Moreover, it was found that there was a tradeoff between the stabilization and the reactivity of nZVI as affected by the presence of FA. When FA concentration was at a low level, the adsorption of FA on the nZVI surface could enhance the particle stabilization, and thus facilitating the Cr(VI) reduction by providing more available surface sites. However, when the FA concentrations were too high to occupy the active surface sites of nZVI, the Cr(VI) reduction could be decreased even though the FA enhanced the dispersion of nZVI particles. At pH 9, the FA improved the Cr(VI) reduction by nZVI. Given the adsorption of FA on the nZVI surface was insignificant and its effect on the settling behavior of nZVI particles was minimal, it was proposed that the FA formed soluble complexes with the produced Fe(III)/Cr(III) ions, and thus reducing the degree of passivation on the nZVI surface and facilitating the Cr(VI) reduction.

To reveal the emission patterns of brominated flame retardants (BFRs) in the Beijiang River, South China, concentrations of polybrominated diphenyl ethers (PBDEs) and phenolic BFRs (2,4,6-tribromophenol (TBP), pentabromophenol (PeBP), tetrabromobisphenol A (TBBPA)), and bisphenol A (BPA) in water and sediments were simultaneously measured, and the geographic information system (GIS) were applied to analyse their emission patterns. Results showed that PBDEs, TBP, PeBP, TBBPA and BPA were ubiquitous in the water and sediment samples collected from the Beijiang River. However, most of the concentrations were very low or below the detection limits (DL). In water, Σ20PBDEs (sum of all 20 PBDEs congeners) levels ranged from < DL to 232 pg L−1, with the predominant congeners containing low bromine contents. The levels of TBP, PeBP, TBBPA and BPA in water were lower than 810 pg L−1. In sediments, Σ20PBDEs varied from 260 to 5640 pg g−1 dry weight (d.w.), with the predominant congeners containing high bromine contents. The levels of TBP, PeBP, TBBPA and BPA were lower than 600 pg g−1 d.w.. Risk assessments indicated that the water and sediments at the sampling locations imposed no estrogenic risk (E2EQ < 1.0 ng E2 L−1), and the eco-toxicity assessment at three trophic levels also showed no risk at all sampling sites in water (RQTotal < 1.0), but with a potential eco-toxicity at some sampling points in sediments (1.0<RQTotal < 10.0).