This report presents an exhaustive literature review on the toxicity of manufactured ZnO nanoparticles (NPs) to ecological receptors across different taxa: bacteria, algae and plants, aquatic and terrestrial invertebrates and vertebrates. Ecotoxicity studies on ZnO NPs are most abundant in bacteria, and are relatively lacking in other species. These studies suggest relative high acute toxicity of ZnO NPs (in the low mg/l levels) to environmental species, although this toxicity is highly dependent on test species, physico-chemical properties of the material, and test methods. Particle dissolution to ionic zinc and particle-induced generation of reactive oxygen species (ROS) represent the primary modes of action for ZnO NP toxicity across all species tested, and photo-induced toxicity associated with its photocatalytic property may be another important mechanism of toxicity under environmentally relevant UV radiation. Finally, current knowledge gaps within this area are briefly discussed and recommendations for future research are made.

Biochar plays an important role in the behaviors of organic pollutants in the soil environment. The role of humic acid (HA) and metal cations on the adsorption affinity of polychlorinated biphenyls (PCBs) to the biochars in an aqueous medium and an extracted solution from a PCBs-contaminated soil was studied using batch experiments. Biochars were produced with pine needles and wheat straw at 350 °C and 550 °C under anaerobic condition. The results showed that the biochars had high adsorption affinity for PCBs. Pine needle chars adsorbed less nonplanar PCBs than planar ones due to dispersive interactions and separation. Coexistence of HA and metal cations increased PCBs sorption on the biochars accounted for HA adsorption and cation complexation. The results will aid in a better understanding of biochar sorption mechanism of contaminants in the environment.

The Moderate Resolution Imaging Spectroradiometer (MODIS) provides daily global coverage, but the 10 km resolution of its aerosol optical depth (AOD) product is not adequate for studying spatial variability of aerosols in urban areas. Recently, a new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm was developed for MODIS which provides AOD at 1 km resolution. Using MAIAC data, the relationship between MAIAC AOD and PM2.5 as measured by the EPA ground monitoring stations was investigated at varying spatial scales. Our analysis suggested that the correlation between PM2.5 and AOD decreased significantly as AOD resolution was degraded. This is so despite the intrinsic mismatch between PM2.5 ground level measurements and AOD vertically integrated measurements. Furthermore, the fine resolution results indicated spatial variability in particle concentration at a sub-10 km scale. Finally, this spatial variability of AOD within the urban domain was shown to depend on PM2.5 levels and wind speed.

Experiments were conducted to analyze processes impacting arsenic transport in irrigation water flowing over bare rice-field soils in Bangladesh. Dissolved concentrations of As, Fe, P, and Si varied over space and time, according to whether irrigation water was flowing or static. Initially, under flowing conditions, arsenic concentrations in irrigation water were below well-water levels and showed little spatial variability across fields. As flowing-water levels rose, arsenic concentrations were elevated at field inlets and decreased with distance across fields, but under subsequent static conditions, concentrations dropped and were less variable. Laboratory experiments revealed that over half of the initial well-water arsenic was removed from solution by oxidative interaction with other water-column components. Introduction of small quantities of soil further decreased arsenic concentrations in solution. At higher soil-solution ratios, however, soil contributed arsenic to solution via abiotic and biotic desorption. Collectively, these results suggest careful design is required for land-based arsenic-removal schemes.

Four organophosphorus esters (OPEs) were detected in aerosol samples collected in the West Pacific, the Indian Ocean and the Southern Ocean from 2009 to 2010, suggesting their circumpolar and global distribution. In general, the highest concentrations were detected near populated regions in China, Australia and New Zealand. OPE concentrations in the Southern Ocean were about two orders of magnitude lower than those near major continents. Additionally, relatively high OPE concentrations were detected at the Antarctic Peninsula, where several scientific survey stations are located. The four OPEs investigated here are significantly correlated with each other, suggesting they may derive from the same source. In the circumpolar transect, OPE concentrations were associated with ocean gyres in the open ocean. Their concentrations were positively related with average vorticity in the sampling area suggesting that a major source of OPEs may be found in ocean gyres where plastic debris is known to accumulate.

A steady state Level III fate model was established and applied to quantify source–receptor relationship in a coking industry city in Northern China. The local emission inventory of PAHs, as the model input, was acquired based on energy consumption and emission factors. The model estimations were validated by measured data and indicated remarkable variations in the paired isomeric ratios. When a rectification factor, based on the receptor-to-source ratio, was calculated by the fate model, the quantitatively verified molecular diagnostic ratios provided reasonable results of local PAH emission sources. Due to the local ban and measures on small scale coking activities implemented from the beginning of 2004, the model calculations indicated that the local emission amount of PAHs in 2009 decreased considerably compared to that in 2003.

This study assessed concentrations and investigated potential source regions for PCBs, PBDEs, and organochlorine pesticides in Acadia National Park, Maine, USA. Back-trajectories and potential source contribution function (PSCF) values were used to map potential source areas for total-PCBs, BDE-47, and 10 organochlorine pesticides. The constructed PSCF maps showed that ANP receives high pollutant concentrations in air masses that travel along four main pathways: (1) from the SW along the eastern Atlantic seaboard, (2) from the WSW over St. Louis, and Columbus regions, (3) from the west over Chicago, and Toronto regions, and (4) from WNW to NNW over the Great Lakes, and Quebec regions. Transport of all studied pollutants were equally distributed between the first three pathways, with only minor contributions from the last pathway. This study concludes that the high-pollutant concentrations arriving at ANP do not exclusively originate from the major urban centers along the eastern Atlantic seaboard.

Halocarbons including chloroform (CHCl3), trichloroethylene (C2HCl3), tetrachloroethylene (C2Cl4), chlorodibromomethane (CHBr2Cl) and bromoform (CHBr3) were measured in the Yellow Sea (YS) and the East China Sea (ECS) during spring 2011. The influences of chlorophyll a, salinity and nutrients on the distributions of these gases were examined. Elevated levels of these gases in the coastal waters were attributed to anthropogenic inputs and biological release by phytoplankton. The vertical distributions of these gases in the water column were controlled by different source strengths and water masses. Using atmospheric concentrations measured in spring 2012 and seawater concentrations obtained from this study, the sea-to-air fluxes of these gases were estimated. Our results showed that the emissions of C2HCl3, C2Cl4, CHBr2Cl, and CHBr3 from the study area could account for 16.5%, 10.5%, 14.6%, and 3.5% of global oceanic emissions, respectively, indicating that the coastal shelf may contribute significantly to the global oceanic emissions of these gases.

Lignin derived macromolecular compounds are the main constituents responsible for the hazardous effects of discharged effluents from the pulp and paper industry in receiving waters. It was shown by ultraviolet–visible (UV–vis) and fluorescence spectroscopies that a selective photodegradation of these structures occurred upon irradiation of fulvic acids (FA) from a kraft pulp mill effluent. Though photodegradation was not remarkably affected by the presence of the natural photosensitizer nitrate, it was inhibited under the presence of chloride. These results indicate that the fate of macromolecular organic matter from kraft pulp mill effluents may be different depending on the type of receiving waters, having a higher persistence when effluents are discharged in estuarine or marine waters than when they are discharged in fresh water.