The aim of this study was to evaluate the influence of a shrimp farm cultivation cycle in the composition of sediments and on the structure of macrobenthic assemblages. Concentrations of nutrients, Zn and Cu were significantly higher in impact than control areas. In general, the level of contaminants was highest during the harvesting period and in sites closest to the discharge of effluents. Abundances and number of taxa of benthic invertebrates were at least one order of magnitude smaller in impacted areas than in controls. The structure of the benthic assemblages was significantly different at these two treatments. The combined use of biological and chemical data showed to be efficient to provide precise answers regarding the extent of impacts caused by shrimp cultivation. The results provide the basis for a better understanding of impacts of this activity and can subsidize the development of better management practices for coastal areas.

Tetrabromobisphenol A (TBBPA) exists widely in river and lake sediments; it has raised growing attention in recent years as emerging contaminant due to its possible threats to the aquatic environment and human health. Using a specialized simulator, the relationships between hydrodynamic disturbances and resuspension characteristics were simulated, with an emphasis on microscopic characteristics. Furthermore, TBBPA release from sediment was studied in relation to hydrodynamic disturbances and resuspension characteristics. The results show that stronger water disturbances caused an increase in suspended solids concentration (SSC) and produced different behaviors of particle size distribution (PSD) and media diameter (D50) in the slight and large-scale resuspension situations. As for microscopic resuspension characteristics, the specific surface area (SSA) of suspended particulate matter (SPM) was very different from that of smooth particles. This difference may result from the fractal nature of the SPM. The fractal dimension (FD) of SPM was found to have a significant correlation with turbulent kinetic energy. TBBPA release into overlying water and adsorption onto SPM both increased with hydrodynamic disturbances; but the release into overlying water is more dominant. The TBBPA concentrations in SPM under different hydrodynamic conditions were significant related to SSA, indicating that SSA is a key factor affecting the TBBPA adsorption capacity of SPM. TBBPA concentrations in sediment decreased slightly with the increased hydrodynamic dispersion. Findings from this research show the importance of considering the hydrodynamic disturbance and resuspension characteristics in understanding TBBPA release behavior in aquatic environment.

Material flow analysis (MFA) is a useful tool to predict the flows of engineered nanomaterials (ENM) to the environment. The quantification of release factors is a crucial part of MFA modeling. In the last years an increasing amount of literature on release of ENM from materials and products has been published. The purpose of this review is to analyze the strategies implemented by MFA models to include these release data, in particular to derive transfer coefficients (TC). Our scope was focused on those articles that analyzed the release from applications readily available in the market in settings that resemble average use conditions. Current MFA studies rely to a large extent on extrapolations, authors’ assumptions, expert opinions and other informal sources of data to parameterize the models. We were able to qualitatively assess the following aspects of the release literature: (i) the initial characterization of ENM provided, (ii) quantitative information on the mass of ENM released and its characterization, (iii) description of transformation reactions and (iv) assessment of the factors determining release. Although the literature on ENM release is growing, coverage of exposure scenarios is still limited; only 20% of the ENMs used industrially and 36% of the product categories involved have been investigated in release studies and only few relevant release scenarios have been described. Furthermore, the information provided is rather incomplete concerning descriptions and characterizations of ENMs and the released materials. Our results show that both the development of methods to define the TCs and of protocols to enhance assessment of ENM release from nano-applications will contribute to increase the exploitability of the data provided for MFA models. The suggestions we provide in this article will likely contribute to an improved exposure modeling by providing ENM release estimates closer to reality.

This study for the first time reported the occurrence, distribution and concentrations of organophosphate esters (OPEs) in soils caused by plastic waste treatment, as well as their influence on OPE accumulation in wheat (Triticum aestivum L.). Eight OPEs were detected with the total concentrations of 38–1250 ng/g dry weight in the soils from the treatment sites, and tributoxyethyl phosphate and tri(2-chloroethyl) phosphate present as the dominant OPEs. There were similar distribution patterns of OPEs and significant correlations between the total OPE concentrations in the soils from the plastic waste treatment sites with those in the nearby farmlands (P < 0.005), indicating that plastic waste treatment caused the OPE contamination of farmland soils. The uptake and translocation of OPEs by wheat were determined, with OPEs of high hydrophobicity more easily taken up from soils and OPEs with low hydrophobicity more liable to be translocated acropetally.

Whereas air pollution in many Chinese cities has reached epidemic levels in recent years, limited research has explored the spatial and temporal patterns of fine air particles such as PM2.5, or particulate matter with diameter smaller than 2.5 μm, using nationally representative data. This article applied spatial statistical approaches including spatial interpolation and spatial regression to the analysis of ground-level PM2.5 observations for 190 Chinese cities in 2014 obtained from the Chinese Air Quality Online Monitoring Platform. Results of this article suggest that most Chinese cities included in the dataset recorded severe levels of PM2.5 in excess of the WHO’s interim target and cities in the North China Plain had the highest levels of PM2.5 regardless of city size. Spatially interpolated maps of PM2.5 and population-weighted PM2.5 indicate vast majority of China’s land and population was exposed to disastrous levels of PM2.5 concentrations. The regression results suggest that PM2.5 in a city was positively related to its population size, amount of atmospheric pollutants, and emissions from nearby cities, but inversely related to precipitation and wind speed. Findings from this research can shed new light on the complex spatiotemporal patterns of PM2.5 throughout China and provide insights into policies aiming to mitigate air pollution in China.

Organohalogen pollutants are of concern in many river and estuarine environments, such as the New York-New Jersey Harbor estuary and its tributaries. The Hackensack River is contaminated with various metals, hydrocarbons and halogenated organics, including polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins. In order to examine the potential for microbial reductive dechlorination by indigenous microorganisms, sediment samples were collected from five different estuarine locations along the Hackensack River. Hexachlorobenzene (HCB), hexabromobenzene (HBB), and pentachloroaniline (PCA) were selected as model organohalogen pollutants to assess anaerobic dehalogenating potential. Dechlorinating activity of HCB and PCA was observed in sediment microcosms for all sampling sites. HCB was dechlorinated via pentachlorobenzene (PeCB) and trichlorobenzene (TriCB) to dichlorobenzene (DCB). PCA was dechlorinated via tetrachloroaniline (TeCA), trichloroanilines (TriCA), and dichloroanilines (DCA) to monochloroaniline (MCA). No HBB debromination was observed over 12 months of incubation. However, with HCB as a co-substrate slow HBB debromination was observed with production of tetrabromobenzene (TeBB) and tribromobenzene (TriBB). Chloroflexi specific 16S rRNA gene PCR-DGGE followed by sequence analysis detected Dehalococcoides species in sediments of the freshwater location, but not in the estuarine site. Analysis targeting 12 putative reductive dehalogenase (rdh) genes showed that these were enriched concomitant with HCB or PCA dechlorination in freshwater sediment microcosms.

Nickel bioavailability is reduced in the presence of dissolved organic carbon (DOC), suspended solids (TSS), and other complexing ligands; however, no studies have examined the relative importance of Ni exposure through different compartments (water, sediment, food). Hyalella azteca and Lymnaea stagnalis were exposed to Ni-amended water, sediment, and food, either separately or in combination. Both organisms experienced survival and growth effects in several Ni compartment tests. The DOC amendments attenuated L. stagnalis Ni effects (survival, growth, and ⁶²Ni bioaccumulation), and presence of TSS exposures demonstrated both protective and synergistic effects on H. azteca and L. stagnalis. ⁶²Ni trophic transfer from food to H. azteca and L. stagnalis was negligible; however, bioaccumulating ⁶²Ni was attributed to ⁶²Ni-water (⁶²Ni flux from food), ⁶²Ni-TSS, and ⁶²Ni-food. Overall, H. azteca and L. stagnalis Ni compartment toxicity increased in the following order: Ni-water >> Ni-sediment >> Ni-all (water, sediment, food) >> Ni-food.

Increasing production of rare earth elements (REE) might lead to future contamination of the environment. REE have been shown to accumulate in high concentrations in roots of plants. Plant experiments with Zea mays exposed to a nutrient solution containing gadolinium (Gd) or yttrium (Y) with 10 mg L−1 Gd or Y were carried out to investigate this accumulation behaviour. Total concentrations of 3.17 g kg−1 and 8.43 g kg−1 of Gd and Y were measured in treated plant roots. Using a novel combination of laser ablation mass spectrometry and time-of-flight secondary ion mass spectrometry, imaging of location and concentration of Gd and Y was carried out in root thin sections of treated roots. Single spots of elevated REE concentration were found at the epidermis, while inside the cortex, weak signals of Gd+ and Y+ were aligning with the root cell structures. The composition of Gd-containing secondary ions proves an REE-oxide phase accumulated at the epidermis, limiting REE availability for further uptake.

Heavy metal pollution, as well as greenhouse effect, has become a serious threat today. Both heavy metal and heat stresses can arrest seed germination. What response can be expected for seed germination under both stress conditions? Here, the effects of heavy metals (Cu2+, Cd2+ and Hg2+) on maize seed germination were investigated at 20 °C and 40 °C. Compared with 20 °C, heat stress induced thermodormancy. However, this thermodormancy could be significantly alleviated by the addition of a low concentration of heavy metals. Heavy metals, as well as heat stress induced H2O2 accumulation in germinating seeds. Interestingly, this low concentration of heavy metal that promoted seed germination could be partly blocked by DMTU (a specific ROS scavenger), irrespective of temperature. Accordingly, H2O2 addition reinforced this promoting effect on seed germination, which was induced by a low concentration of heavy metal. Furthermore, we found that the NADPH oxidase derived ROS was required for seed germination promoted by the heavy metals. Subsequently, treatment of seeds with fluridone (a specific inhibitor of ABA) or ABA significantly alleviated or aggravated thermodormancy, respectively. However, this alleviation or aggravation could be partly attenuated by a low concentration of heavy metals. In addition, germination that was inhibited by high concentrations of heavy metals was also partly reversed by fluridone. The obtained results support the idea that heavy metal-mediated ROS and hormone interaction can finally affect the thermodormancy release or not.

The extensive use of antibiotics in human and veterinary medicine and their subsequent release into the environment may have direct consequences for autochthonous bacterial communities, especially in freshwater ecosystems. In small streams and rivers, local inputs of wastewater treatment plants (WWTPs) may become important sources of organic matter, nutrients and emerging pollutants, such as antibiotic resistance genes (ARGs). In this study, we evaluated the effect of WWTP effluents as a source of ARGs in river biofilms. The prevalence of genes conferring resistance to main antibiotic families, such as beta-lactams (blaCTX-M), fluoroquinolones (qnrS), sulfonamides (sul I), and macrolides (ermB), was determined using quantitative PCR (qPCR) in biofilm samples collected upstream and downstream WWTPs discharge points in four low-order streams. Our results showed that the WWTP effluents strongly modified the hydrology, physico-chemistry and biological characteristics of the receiving streams and favoured the persistence and spread of antibiotic resistance in microbial benthic communities. It was also shown that the magnitude of effects depended on the relative contribution of each WWTP to the receiving system. Specifically, low concentrations of ARGs were detected at sites located upstream of the WWTPs, while a significant increase of their concentrations was observed in biofilms collected downstream of the WWTP discharge points (particularly ermB and sul I genes). These findings suggest that WWTP discharges may favour the increase and spread of antibiotic resistance among streambed biofilms. The present study also showed that the presence of ARGs in biofilms was noticeable far downstream of the WWTP discharge (up to 1 km). It is therefore reasonable to assume that biofilms may represent an ideal setting for the acquisition and spread of antibiotic resistance determinants and thus be considered suitable biological indicators of anthropogenic pollution by active pharmaceutical compounds.