A novel non-dsrAB (without dissimilatory sulfite reductase genes) sulfate-reducing bacterium (SRB) Clostridium sp. BXM was isolated from a paddy soil. Incubation experiments were then performed to investigate the formation of reduced sulfur compounds (RSC) by Clostridium sp. BXM, and RSC-induced dechlorination of p,p′-DDT in culture medium and soil solution. The RSCs produced were 5.8mM and 4.5mM in 28mM sulfate amended medium and soil solution respectively after 28-day cultivation. The p,p′-DDT dechlorination ratios were 74% and 45.8% for 5.8mM and 4.5mM RSCs respectively at 6h. The metabolites of p,p′-DDT found in the two reaction systems were identified as p,p′-DDD and p,p′-DDE. The dechlorination pathways of p,p′-DDT to p,p′-DDD and p,p′-DDE were proposed, based on mass balance and dechlorination time-courses. The results indicated that RSC-induced natural dechlorination may play an important role in the fate of organochlorines.

Long-term fluxes of CO₂, and combined short-term fluxes of CH₄ and CO₂ were measured with the eddy covariance technique in the city centre of Florence. CO₂ long-term weekly fluxes exhibit a high seasonality, ranging from 39 to 172% of the mean annual value in summer and winter respectively, while CH₄ fluxes are relevant and don’t exhibit temporal variability. Contribution of road traffic and domestic heating has been estimated through multi-regression models combined with inventorial traffic and CH₄ consumption data, revealing that heating accounts for more than 80% of observed CO₂ fluxes. Those two components are instead responsible for only 14% of observed CH₄ fluxes, while the major residual part is likely dominated by gas network leakages. CH₄ fluxes expressed as CO₂ equivalent represent about 8% of CO₂ emissions, ranging from 16% in summer to 4% in winter, and cannot therefore be neglected when assessing greenhouse impact of cities.

The effects of ozone exposure during the cropping season on rice grain quality were investigated in chamber experiments employing four ozone treatments (charcoal filtered air, ambient, 2× ambient, and 2.5× ambient concentration) and six genotypes. The concentrations of protein and lipids in brown rice increased significantly in response to ozone, while starch concentration and thousand kernel mass decreased. Other parameters, including the concentrations of iron, zinc, phenolics, stickiness and geometrical traits did not exhibit significant treatment effects. Total brown rice yield, protein yield, and iron yield were negatively affected by ozone. Numerous genotypic differences occurred in the response to ozone, indicating the possibility of optimizing the grain quality in high ozone environments by breeding. It is concluded that although the concentrations of two important macronutrients, proteins and lipids, increased in ozone treated grains, the implications for human nutrition are negative due to losses in total grain, protein and iron yield.

Spatially explicit estimates of critical loads of nitrogen (N) deposition (CLNdₑₚ) for nutrient enrichment in aquatic ecosystems were developed for the Rocky Mountains, USA, using a geostatistical approach. The lowest CLNdₑₚ estimates (<1.5 ± 1 kg N ha⁻¹ yr⁻¹) occurred in high-elevation basins with steep slopes, sparse vegetation, and abundance of exposed bedrock and talus. These areas often correspond with areas of high N deposition (>3 kg N ha⁻¹ yr⁻¹), resulting in CLNdₑₚ exceedances ≥1.5 ± 1 kg N ha⁻¹ yr⁻¹. CLNdₑₚ and CLNdₑₚ exceedances exhibit substantial spatial variability related to basin characteristics and are highly sensitive to the NO₃ ⁻ threshold at which ecological effects are thought to occur. Based on an NO₃ ⁻ threshold of 0.5 μmol L⁻¹, N deposition exceeds CLNdₑₚ in 21 ± 8% of the study area; thus, broad areas of the Rocky Mountains may be impacted by excess N deposition, with greatest impacts at high elevations.

Mercury concentration ([Hg]), δ¹⁵N, and δ¹³C values were measured in eggs from common murres (Uria aalge), thick-billed murres (U. lomvia), glaucous gulls (Larus hyperboreus), and glaucous-winged gulls (L. glaucescens) collected in Alaska from 1999 to 2005. [Hg] was normalized to a common trophic level using egg δ¹⁵N values and published Hg trophic magnification factors. Egg [Hg] was higher in murres from Gulf of Alaska, Cook Inlet, and Norton Sound regions compared to Bering Sea and Bering Strait regions, independent of trophic level. We believe the Yukon River outflow and terrestrial Hg sources on the southern Seward Peninsula are responsible for the elevated [Hg] in Norton Sound eggs. Normalizing for trophic level generally diminished or eliminated differences in [Hg] among taxa, but temporal variability was unrelated to trophic level. Normalizing murre egg [Hg] by trophic level improves the confidence in regional comparisons of Hg sources and biogeochemical cycling in Alaska.

A comprehensive, weight-of-evidence based ecological risk assessment approach integrating laboratory and in situ bioaccumulation and toxicity testing, passive sampler devices, hydrological characterization tools, continuous water quality sensing, and multi-phase chemical analyses was evaluated. The test site used to demonstrate the approach was a shallow estuarine wetland where groundwater seepage and elevated organic and inorganic contaminants were of potential concern. Although groundwater was discharging into the surficial sediments, little to no chemical contamination was associated with the infiltrating groundwater. Results from bulk chemistry analysis, toxicity testing, and bioaccumulation, however, suggested possible PAH toxicity at one station, which might have been enhanced by UV photoactivation, explaining the differences between in situ and laboratory amphipod survival. Concurrently deployed PAH bioaccumulation on solid-phase micro-extraction fibers positively correlated (r² ≥ 0.977) with in situ PAH bioaccumulation in amphipods, attesting to their utility as biomimetics, and contributing to the overall improved linkage between exposure and effects demonstrated by this approach.

The spatial distribution of per- and polyfluoroalkyl compounds (PFCs) were investigated in coastal waters collected onboard research vessel Snow Dragon from the East to South China Sea in 2010. All samples were prepared by solid-phase extraction and analyzed using high performance liquid chromatography/negative electrospray ionization-tandem mass spectrometry (HPLC/(−)ESI-MS/MS). Concentrations of 9 PFCs, including C₄ and C₈ (PFBS, PFOS) perfluoroalkyl sulfonate (PFSAs), C₅–C₉ and C₁₃ (PFPA, PFHxA, PFHpA, PFOA, PFNA, PFTriDA) perfluoroalkyl carboxylates (PFCAs), and N-ethyl perfluorooctane sulfonamide (EtFOSA) were quantified. The ΣPFC concentrations ranged from 133 pg/L to 3320 pg/L, with PFOA (37.5–1541 pg/L), PFBS (23.0–941 pg/L) and PFHpA (0–422 pg/L) as dominant compounds. Concentrations of PFCs were greater in coastal waters along Shanghai, Ningbo, Taizhou, Xiamen and along coastal cities of the Guangdong province compared to less populated areas along the east Chinese coast. Additionally, the comparison with other seawater PFC measurements showed lower levels in this study.

Lichens are an excellent model to study the bioaccumulation of heavy metals but limited information is available on the molecular mechanisms occurring during bioaccumulation. We investigated the changes of the lichen proteome during exposure to constant concentrations of mercury. We found that most of changes involves proteins of the photosynthetic pathway, such as the chloroplastic photosystem I reaction center subunit II, the oxygen-evolving protein and the chloroplastic ATP synthase β-subunit. This suggests that photosynthesis is a target of the toxic effects of mercury. These findings are also supported by changes in the content of photosynthetic pigments (chlorophyll a and b, and β-carotene). Alterations to the photosynthetic machinery also reflect on the structure of thylakoid membranes of algal cells. Response of lichens to mercury also involves stress-related proteins (such as Hsp70) but not cytoskeletal proteins. Results suggest that lichens adapt to mercury exposure by changing the metabolic production of energy.