GeoChip, a comprehensive gene microarray, was used to examine changes in microbial functional gene structure throughout the 4-year life cycle of a pilot-scale ethanol blend plume, including 2-year continuous released followed by plume disappearance after source removal. Canonical correlation analysis (CCA) and Mantel tests showed that dissolved O2 (which was depleted within 5 days of initiating the release and rebounded 194 days after source removal) was the most influential environmental factor on community structure. Initially, the abundance of anaerobic BTEX degradation genes increased significantly while that of aerobic BTEX degradation genes decreased. Gene abundance for N fixation, nitrification, P utilization, sulfate reduction and S oxidation also increased, potentially changing associated biogeochemical cycle dynamics. After plume disappearance, most genes returned to pre-release abundance levels, but the final functional structure significantly differed from pre-release conditions. Overall, observed successions of functional structure reflected adaptive responses that were conducive to biodegradation of ethanol-blend releases.

The mercury (Hg) pollution of sediments is the main carrier of Hg for the biota and, subsequently, for the local fish consumers in Augusta Bay area (SE Sicily, Italy), a coastal marine system affected by relevant sewage from an important chlor-alkali factory. This relationship was revealed by the determination of Mass Dependent (MDF) and Mass Independent Fractionation (MIF) of Hg isotopes in sediment, fish and human hair samples. Sediments showed MDF but no MIF, while fish showed MIF, possibly due to photochemical reduction in the water column and depending on the feeding habitat of the species. Benthic and demersal fish exhibited MDF similar to that of sediments in which anthropogenic Hg was deposited, while pelagic organisms evidenced higher MDF and MIF due to photoreduction. Human hair showed high values of δ202Hg (offset of +2.2‰ with respect to the consumed fish) and Δ199Hg, both associated to fish consumption.

The presence of polycyclic aromatic hydrocarbons (PAHs) has been postulated as a mechanism by which biochar might mitigate N2O emissions. We studied whether and to what extent N2O emissions were influenced by the three most abundant PAHs in biochar: naphthalene, phenanthrene and pyrene. We hypothesised that biochars contaminated with PAHs would show a larger N2O mitigation capacity and that increasing PAH concentrations in biochar would lead to higher mitigation potentials. Our results demonstrate that the high-temperature biochar (550 °C) had a higher capacity to mitigate soil N2O emissions than the low-temperature biochar (350 °C). At low PAH concentrations, PAHs do not significantly contribute to the reductions in soil N2O emissions; while biochar stimulated soil N2O emissions when it was spiked with high concentrations of PAHs. This study suggests that the impact of biochar on soil N2O emissions is due to other compositional and/or structural properties of biochar rather than to PAH concentration.

The effects of chloride on dissolution and toxicity of silver nanoparticles (AgNPs) have been well studied. However, their intermediate shapes during the transition have not been illustrated to-date. Herein, the chloride-induced shape transformation process of AgNPs under long-term, low-concentration conditions is explored. A unique triangular Ag–AgCl heterostructure is observed. The structure then evolves into a symmetric hexapod and finally into a smaller AgNP. This transformation process could be affected by other environmental conditions, such as 0.4 mg/mL humic acid, 5% surfactants and 1 mg/mL bovine serum albumin protein. Our results offer new knowledge regarding the shape transformation process of AgNPs in the presence of chloride, which can be valuable in relevant studies concerning the effect of water chemistry on the behavior of AgNPs.

This study investigates the potential health risk from urban gardening. The concentrations of the trace elements arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) in five common garden crops from three garden sites in Copenhagen were measured. Concentrations (mg/kg dw) of As were 0.002–0.21, Cd 0.03–0.25, Cr < 0.09–0.38, Cu 1.8–8.7, Ni < 0.23–0.62, Pb 0.05–1.56, and Zn 10–86. Generally, elemental concentrations in the crops do not reflect soil concentrations, nor exceed legal standards for Cd and Pb in food. Hazard quotients (HQs) were calculated from soil ingestion, vegetable consumption, measured trace element concentrations and tolerable intake levels. The HQs for As, Cd, Cr, Cu, Ni, and Zn do not indicate a health risk through urban gardening in Copenhagen. Exposure to Pb contaminated sites may lead to unacceptable risk not caused by vegetable consumption but by unintentional soil ingestion.

The European Union authorization procedure for pesticides includes an assessment of the leaching risk posed by pesticides and their degradation products (DP) with the aim of avoiding any unacceptable influence on groundwater. Twelve-year's results of the Danish Pesticide Leaching Assessment Programme reveal shortcomings to the procedure by having assessed leaching into groundwater of 43 pesticides applied in accordance with current regulations on agricultural fields, and 47 of their DP. Three types of leaching scenario were not fully captured by the procedure: long-term leaching of DP of pesticides applied on potato crops cultivated in sand, leaching of strongly sorbing pesticides after autumn application on loam, and leaching of various pesticides and their DP following early summer application on loam. Rapid preferential transport that bypasses the retardation of the plow layer primarily in autumn, but also during early summer, seems to dominate leaching in a number of those scenarios.

LSER models for organic compounds adsorption by single and multi-walled carbon nanotubes and activated carbon were successfully developed. The cavity formation and dispersion interactions (vV), hydrogen bond acidity interactions (bB) and π-/n-electron interactions (eE) are the most influential adsorption mechanisms. SWCNTs is more polarizable, less polar, more hydrophobic, and has weaker hydrogen bond accepting and donating abilities than MWCNTs and AC. Compared with SWCNTs and MWCNTs, AC has much less hydrophobic and less hydrophilic adsorption sites. The regression coefficients (e, s, a, b, v) vary in different ways with increasing chemical saturation. Nonspecific interactions (represented by eE and vV) have great positive contribution to organic compounds adsorption, and follow the order of SWCNTs > MWCNTs > AC, while hydrogen bond interactions (represented by aA and bB) demonstrate negative contribution. These models will be valuable for understanding adsorption mechanisms, comparing adsorbent characteristics, and selecting the proper adsorbents for certain organic compounds.

Environmental risks of polybrominated diphenyl ethers (PBDEs) in sewage sludge are assessed based on the concentration by exhaustive extraction, which is a likely overestimation of the pool available to exposed organisms. This study evaluated the bioaccessibility of PBDEs in sewage sludge from Shanghai using a 3-compartment model and a 6-d Tenax extraction. The very slowly fraction contributed 56–88% of total PBDEs in spiked sludge, whereas the rapidly desorbing fraction contributed only 1.1–10%. For the same PBDE congener, the rapidly desorbing fractions for sewage sludge measured in the present study were lower than those for sediment. The bioaccessible concentrations of PBDEs were 2.3–56 ng/g dry weight in sewage sludge from Shanghai, which represented 5.2% of the concentration determined by exhaustive (Soxhlet) extraction. BDE-209 was the predominant congener in sludge, contributing to 63% of the total. Moreover, the Ratio between 6-h Tenax and Soxhlet concentrations (T/S Ratio, indicating bioaccessibility) was lower in sludge generated from industrial wastewater treatment compared to sludge from facilities that treated mostly domestic wastewater. The T/S Ratio of PBDE congeners was related to KOW, specifically as KOW increases, the T/S Ratio decreased. These results will improve understanding of the fate and potential toxicity of PBDEs during land and/or landfill application of sewage sludge.

Actual measure-based studies have estimated ingestion rate of moderate and high daily use to female college students and career women in northeast of China. Sequential extraction analyses showed that total bioaccessible metals concentration in lipstick ranged from 2.103 to 31.103 μg/g and in lip balm ranged from 0.100 to 3.716 μg/g. The relationship between total bioaccessible metal concentrations and the cost of lip cosmetics showed a negative correlation. Lead was detected in all 30 products (100%), with an average concentration of 0.346 for lip balm and 0.407 μg/g for lipstick. With the exception of chromium content in three lipsticks, the estimated exposure in female college students and career women to target metals via lipstick and lip balm ingestion (calculated for moderate and high use) were much lower than the acceptable reference limits. The findings strongly emphasize the need to focus on the health risk of lip balm.

Since 1969, northern gannet (Morus bassanus) eggs from Bonaventure Island, Québec, have been collected to monitor concentrations of contaminants. Levels of p,p′-DDE, which caused low breeding success of Bonaventure gannets in the 1960s, decreased by 99.4% from 1969 to 2009 (17.1–0.1 mg/kg ww), with concomitant improvement of hatching success. PCBs, most organochlorines and mercury also showed decreasing trends. Stable isotopes of carbon (δ13C) and nitrogen (δ15N) were measured to track the possible influence of diet changes on concentrations of contaminants over time. The confounding effect of the combustion of fossil fuels on baseline values of δ13C (the Suess effect) was taken into account. No temporal trends were observed in δ13C and δ15N values in gannet eggs. Hence trophic level or foraging area had a negligible influence on temporal trends of contaminants.