Global nitrogen (N) deposition has been enhanced with anthropogenic N emissions, and its impacts on mosses are receiving more and more attention. This study investigates how N deposition influence the biomass and stoichiometry of moss Rhytidium rugosum, using a 3-year N enrichment experiment with 0, 2, 5 and 10 g N m−2 yr−1 in a boreal forest in Northeast China. Low N additions caused an N redundancy and moderate to high N additions resulted in a biomass loss. N additions reduced biomass ratios of green to brown tissues and increased N and phosphorus (P) contents, suggesting changes in photosynthetic capacity and litter decomposition. Biomass N pools showed a unimodal response to the N additions, and P pools decreased under moderate and high N additions. Our findings indicate significant stoichiometric and biomass changes caused by N deposition may lead to a substantial carbon and nutrient loss in boreal moss carpets.

To determine the effects of ozone (O3) on the canopy carbon budget, we investigated photosynthesis and respiration of leaves of Siebold's beech saplings under free air O3 exposure (60 nmol mol−1, during daytime) in relation to the within-canopy light gradient; we then calculated the canopy-level photosynthetic carbon gain (PCG) and respiratory carbon loss (RCL) using a canopy photosynthesis model. Susceptibilities of photosynthesis and respiration to O3 were greater in leaves of upper canopy than in the lower canopy. The canopy net carbon gain (NCG) was reduced by O3 by 12.4% during one growing season. The increased RCL was the main factor for the O3-induced reduction in NCG in late summer, while contributions of the reduced PCG and the increased RCL to the NCG were almost the same in autumn. These results indicate contributions of changes in PCG and RCL under O3 to NCG were different between seasons.

Levels of total organic carbon (TOC) and black carbon (BC) were determined together with those of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in the selected eighteen coastal sites (n = 285) along the Arabian Sea from Pakistan. Results showed that the total concentration of TOC, BC, ∑OCPs and ∑26PCBs ranged between 0.3 and 2.9% dw, 0.1–0.2% dw, 0.9–110 ng g−1 dw and 6.2–1200 ng g−1 dw, respectively. Correlation analysis of BC (r = 0.26–0.89) and TOC (r = 0.06–0.69) revealed a stronger association with studied compounds. The sedimentary depositional fluxes (D) for ∑OCPs and ∑26PCBs were calculated as 1.7 and 4.9 tons yr−1, respectively. In the coastal belt of Pakistan, sedimentary mass inventories (I) indicated the presence of 13 and 37 metric tons of ∑OCPs and ∑26PCBs, respectively.

This study is the first comprehensive evaluation of total Hg and methylmercury (MeHg) concentrations in wild marine fish from an estuarine and a coastal ecosystem in southern China. A total of 571 fish from 54 different species were examined. Our results showed that the Hg levels were generally low in the fish, and the Hg levels were below 30 ng g−1 (wet weight) for 82% of the samples, which may be related to the reduced size of the fish and altered food web structure due to overfishing. Decreased coastal wetland coverage and different carbon sources may be responsible for the habitat-specific Hg concentrations. The degree of biomagnification was relatively low in the two systems.

In vitro tests using human adenocarcinomic alveolar epithelial cell line A549 and small mouse monocyte-macrophage cell line J774A.1 were conducted to test toxicity of six PM (particulate matter) samples from Beijing. The properties of the samples differ significantly. The production of inflammatory cytokine (TNF-α for J774A.1) and chemokine (IL-8 for A549) and the level of intracellular reactive oxygen species (ROS) were used as endpoints. There was a positive correlation between water soluble organic carbon and DTT-based redox activity. Both cell types produced increased levels of inflammatory mediators and had higher level of intracelllar ROS, indicating the presence of PM-induced inflammatory response and oxidative stress, which were dose-dependent and significantly different among the samples. The releases of IL-8 from A549 and TNF-α from J774A.1 were significantly correlated to PM size, Zeta potential, endotoxin, major metals, and polycyclic aromatic hydrocarbons. No correlation between ROS and these properties was identified.

Here, we provide Rock Eval and black carbon (BC) characteristics and polycyclic aromatic hydrocarbon (PAH) distribution coefficients (KD) for sediments from the Danube, Elbe, Ebro, and Meuse river basins. PAH desorption kinetic parameters were determined using sequential Tenax extractions. We show that residual carbon (RC) from Rock Eval analysis is an adequate predictor of fast, slow, and very slow desorbing fractions of 4-ring PAHs. RC correlated better than BC, the latter constituting only 7% of RC. A dual domain sorption model was statistically superior to a single domain model in explaining KD for low molecular weight PAHs, whereas the opposite was observed for high molecular weight PAHs. Because particularly the 4-ring PAHs are bioavailable and relevant from a risk assessment perspective and because their fast desorbing fractions correlate best with RC, we recommend RC as a relevant characteristic for river sediments.

The dissolution of Ag (citrate, gelatin, polyvinylpyrrolidone and chitosan coated), ZnO, CuO and carbon coated Cu nanoparticles (with two nominal sizes each) has been studied in artificial aqueous media, similar in chemistry to environmental waters, for up to 19 days. The dissolved fraction was determined using DGT (Diffusion Gradients in Thin films), dialysis membrane (DM) and ultrafiltration (UF). Relatively small fractions of Ag nanoparticles dissolved, whereas ZnO dissolved nearly completely within few hours. Cu and CuO dissolved as a function of pH. Using DGT, less dissolved Ag was measured compared to UF and DM, likely due to differences in diffusion of organic complexes. Similar dissolved metal concentrations of ZnO, Cu and CuO nanoparticles were determined using DGT and UF, but lower using DM. The results indicate that there is a need to apply complementary techniques to precisely determine dissolution of nanoparticles in aqueous media.

We analysed the variability of equivalent black carbon (BC) and ozone (O3) at the global WMO/GAW station Nepal Climate Observatory-Pyramid (NCO-P, 5079 m a.s.l.) in the southern Himalayas, for evaluating the possible contribution of open vegetation fires to the variability of these short-lived climate forcers/pollutants (SLCF/SLCP) in the Himalayan region.We found that 162 days (9% of the data-set) were characterised by acute pollution events with enhanced BC and O3 in respect to the climatological values. By using satellite observations (MODIS fire products and the USGS Land Use Cover Characterization) and air mass back-trajectories, we deduced that 56% of these events were likely to be affected by emissions from open fires along the Himalayas foothills, the Indian Subcontinent and the Northern Indo-Gangetic Plain.These results suggest that open fire emissions are likely to play an important role in modulating seasonal and inter-annual BC and O3 variability over south Himalayas.

The fate and lability of added soluble Ag in soils over time was examined by measurement of labile metal (E-value) by isotopic dilution using the 110mAg radioactive isotope and the solid-phase speciation of Ag by X-ray absorption near edge structure (XANES) spectroscopy. After two weeks of ageing the E-values for Ag decreased by 20–90% with a further decrease of 10–40% after six months. The overall decrease in labile Ag for all soils after the 6 month ageing period was 50–100%. The ageing was more rapid and pronounced in the alkaline soils. XANES results for Ag in soils indicated that for the majority of soils the added Ag+ was reduced to metallic Ag over time, and associations with Fe-oxohydroxides and reduced S groups in organic matter also decreased Ag lability. Strong positive correlations were found between metallic Ag and non-labile Ag and between organic carbon and Ag bonded with S species.

In Asia, the evaluation of black carbon (BC) using global aerosol-transport models has been incomplete due to a lack of available measurements. Recently, new measurements and datasets at various Asian sites have become available for use in model validation. In this study, we compared the BC mass concentrations obtained by an aerosol-coupled global nonhydrostatic model adopting a uniform-grid system with in-situ measurements and other models over Asia. The results revealed that our model, as well as other global models, was unable to reproduce the observed BC values at most sites in China and India, most likely due to strong local hotspots. To overcome the inconsistency between the models and measurements, we developed a new aerosol-transport model using a stretched-grid system for high-resolution simulations with up to approximately 10 km grids. Our model can be used as a global-to-regional seamless aerosol-transport model for low to high horizontal resolution simulations.