Between 1950 and 1963 approximately 11 million kilograms of mercury (Hg) were used at the Oak Ridge Y-12 National Security Complex (Y-12 NSC) for lithium isotope separation processes. About 3% of the Hg was lost to the air, soil and rock under facilities, and East Fork Poplar Creek (EFPC) which originates in the plant site. Smaller amounts of Hg were used at other Oak Ridge facilities with similar results. Although the primary Hg discharges from Y-12 NSC stopped in 1963, small amounts of Hg continue to be released into the creek from point sources and diffuse contaminated soil and groundwater sources within Y-12 NSC. Mercury concentration in EFPC has decreased 85% from ∼2000ng/L in the 1980s. In general, methylmercury concentrations in water and in fish have not declined in response to improvements in water quality and exhibit trends of increasing concentration in some cases.

Soil acidification was assessed in the Eastern Sudetes Mountains (Czech Republic) between 1941 and 2003, i.e. before and after the period of major industrial pollution (1950s–1990s). The twenty sites included in our study were distributed along a gradient of altitude ranging 1000m. Values of pH have decreased in 80–90% of the pairs of samples after the six decades, on average by 0.7 for pH-H₂O and 0.6 for pH-KCl. Organic matter increased in the topsoil, probably reflecting a change in decomposition conditions. The most important finding is that the acidification varies along the joint gradient of altitude/tree layer composition, and displays a changing pattern in three soil horizons (A, B and C). Contrary to expectations, most acidified were soils in beech forests at lower elevations.

The toxicity of commercially-available CuO and ZnO nanoparticles (NPs) to pathogenic bacteria was compared for a beneficial rhizosphere isolate, Pseudomonas chlororaphis O6. The NPs aggregated, released ions to different extents under the conditions used for bacterial exposure, and associated with bacterial cell surface. Bacterial surface charge was neutralized by NPs, dependent on pH. The CuO NPs were more toxic than the ZnO NPs. The negative surface charge on colloids of extracellular polymeric substances (EPS) was reduced by Cu ions but not by CuO NPs; the EPS protected cells from CuO NPs-toxicity. CuO NPs-toxicity was eliminated by a Cu ion chelator, suggesting that ion release was involved. Neither NPs released alkaline phosphatase from the cells’ periplasm, indicating minimal outer membrane damage. Accumulation of intracellular reactive oxygen species was correlated with CuO NPs lethality. Environmental deposition of NPs could create niches for ion release, with impacts on susceptible soil microbes.

This study provides information on the current status of contamination by DDT in agricultural soils in south-western Spain. A recent use of technical DDT in at least 17% of the soils was found based on the values (<1) of the ratio [Formula: see text] . According to the ratio [Formula: see text] , a dicofol type contamination was detected in about 27% of the soils. A wide range of concentrations was observed (0.08–11.1 ng/g d.w.) regardless of the type of crop soil. Enantiomeric fractions (EFs), based on the chiral analysis of o,p′-DDT residues differed from the racemic value (0.500) in most soils but they were not correlated with the study variables [DDTs], SOM, [Formula: see text] and [Formula: see text] . Given the health risks posed by DDT, our findings support how the environmental control of legacy pollutants such as DDT cannot be neglected.

Tetracycline antibiotics including tetracycline (TTC), oxytetracycline (OTC) and chlorotetracycline (CTC) undergo rapid transformation to yield various products in the presence of MnO₂ at mild conditions (pH 4–9 and 22 °C). Reaction rates follow the trend of CTC > TTC > OTC, and are affected by pH and complexation of TCs with Mg²⁺ or Ca²⁺. Experimental results of TTC indicate that MnO₂ promotes isomerization at the C ring to form iso-TTC and oxidizes the phenolic-diketone and tricarbonylamide groups, leading to insertion of up to 2 O most likely at the C9 and C2 positions. In contrast, reactions of OTC with MnO₂ generate little iso-OTC, but occur mainly at the A ring’s dimethylamine group to yield N-demethylated products. CTC yields the most complicated products upon reactions with MnO₂, encompassing transformation patterns observed with both TTC and OTC. The identified product structures suggest lower antibacterial activity than that of the parent tetracyclines.

An urban soil chronosequence in downtown Detroit, MI was studied to determine the effects of time on pedogenesis and heavy metal sequestration. The soils developed in fill derived from mixed sandy and clayey diamicton parent materials on a level late Pleistocene lakebed plain under grass vegetation in a humid-temperate (mesic) climate. The chronosequence is comprised of soils in vacant lots (12 and 44 years old) and parks (96 and 120 years old), all located within 100m of a roadway. An A-horizon 16cm thick with 2% organic matter has developed after only 12 years of pedogenesis. The 12 year-old soil shows accelerated weathering of iron (e.g. nails) and cement artifacts attributed to corrosion by excess soluble salts of uncertain origin. Carbonate and Fe-oxide are immobilizing agents for heavy metals, hence it is recommended that drywall, plaster, cement and iron artifacts be left in soils at brownfield sites for their ameliorating effects.

Parks with various types of vegetations played an important role in ameliorating air quality in urban areas. However, the attenuation effect of urban vegetation on levels of air pollution was rarely been experimentally estimated. This study, using seasonal monitoring data of total suspended particles (TSP), sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) from six parks in Pudong District, Shanghai, China, demonstrated vegetations in parks can remove large amount of airborne pollutants. In addition, crown volume coverage (CVC) was introduced to characterize vegetation conditions in parks and a mixed-effects model indicated that CVC and the pollution diffusion distance were key predictors influencing pollutants removal rate. Therefore, it could be estimated by regression analysis that in summer, urban vegetations in Pudong District could contribute to 9.1% of TSP removal, 5.3% of SO₂ and 2.6% of NO₂. The results could be considered for a better park planning and improving air quality.

Atmospheric deposition of trace metals and metalloids from anthropogenic sources has led to the contamination of many European peatlands. To assess the fate and behaviour of previously deposited arsenic and lead, we constructed catchment-scale mass budgets for a degraded peatland in Northern England. Our results show a large net export of both lead and arsenic via runoff (282 ± 21.3 gPb ha⁻¹ y⁻¹ and 60.4 ± 10.5 gAs ha⁻¹ y⁻¹), but contrasting controls on this release. Suspended particulates account for the majority of lead export, whereas the aqueous phase dominates arsenic export. Lead release is driven by geomorphological processes and is a primary effect of erosion. Arsenic release is driven by the formation of a redox-dynamic zone in the peat associated with water table drawdown, a secondary effect of gully erosion. Degradation of peatland environments by natural and anthropogenic processes has the potential to release the accumulated pool of legacy contaminants to surface waters.

Monitoring soil pollution is a key aspect in sustainable management of contaminated land but there is often debate over what should be monitored to assess ecological risk. Soil pore water, containing the most labile pollutant fraction in soils, can be easily collected in situ offering a routine way to monitor this risk. We present a compilation of data on concentration of trace elements (As, Cd, Cu, Pb, and Zn) in soil pore water collected in field conditions from a range of polluted and non-polluted soils in Spain and the UK during single and repeated monitoring, and propose a simple eco-toxicity test using this media. Sufficient pore water could be extracted for analysis both under semi-arid and temperate conditions, and eco-toxicity comparisons could be effectively made between polluted and non-polluted soils. We propose that in-situ pore water extraction could enhance the realism of risk assessment at some contaminated sites.

Reactive nitrogen can travel far from emission sources and impact sensitive ecosystems. From 2002 to 2006, policy actions have led to decreases in NOₓ emissions from power plants and motor vehicles. In this study, atmospheric chemical transport modeling demonstrates that these emissions reductions have led to a downward trend in ambient measurements of transported reactive nitrogen, especially atmospheric concentrations and wet deposition of nitrate. The trend in reduced nitrogen, namely ammonium, is ambiguous. As reduced nitrogen becomes a larger fraction of the reactive nitrogen budget, wide-spread NH₃ measurements and improved NH₃ emissions assessments are a critical need.