Estimates of non-point source (NPS) contribution to total water pollution in China range up to 81% for nitrogen and to 93% for phosphorus. We believe these values are too high, reflecting (a) misuse of estimation techniques that were developed in America under very different conditions and (b) lack of specificity on what is included as NPS. We compare primary methods used for NPS estimation in China with their use in America. Two observations are especially notable: empirical research is limited and does not provide an adequate basis for calibrating models nor for deriving export coefficients; the Chinese agricultural situation is so different than that of the United States that empirical data produced in America, as a basis for applying estimation techniques to rural NPS in China, often do not apply. We propose a set of national research and policy initiatives for future NPS research in China.

The use of passerine species as bioindicators of metal bioaccumulation is often underutilized when examining the wildlife habitat value of polluted sites. In this study we tested feathers of nestlings of two common bird species (house wren and American robin) for accumulation of Pb, Zn, As, Cr, Cu, Fe in comparison of a polluted, urban brownfield with a rural, unpolluted site. House wren nestlings at the study site accumulated significantly greater concentrations of all target metals except Zn. At the polluted site we found significant species differences of metal concentrations in feathers, with house wrens accumulating greater concentrations of Pb, Fe, and Zn but slightly lesser accumulations of Cr and Cu than American robins. Although house wren nestlings demonstrated significant accumulation of metals, these concentrations showed little effect on size metrics or fledge rates during the breeding season compared to nestlings from the control site.

Identification of mining-related contaminants is important in order to assess the spreading of contaminants from mining as well as for site remediation purposes. This study focuses on lead (Pb) contamination in biota near the abandoned ‘Black Angel Mine’ in West Greenland in the period 1988-2008. Stable Pb isotope ratios and total Pb concentrations were determined in lichens, seaweed and mussels as well as in marine sediments. The results show that natural background Pb (207Pb/206Pb: 0.704-0.767) and Pb originating from the mine ore (207Pb/206Pb: 0.955) have distinct isotopic fingerprints. Total Pb in lichens, seaweed, and mussels was measured at values up to 633, 19 and 1536 mg kg-1 dry weight, respectively, and is shown to be a mixture of natural Pb and ore-Pb. This enables quantification of mining-related Pb and shows that application of Pb isotope data is a valuable tool for monitoring mining pollution.

Pesticide transport models commonly assume first-order pesticide degradation kinetics for describing reactive transport in soil. This assumption was assessed in mini-column studies with associated batch degradation tests. Soil mini-columns were irrigated with atrazine in two intermittent steps of about 30 days separated by 161 days application of artificial rain water. Atrazine concentration in the effluent peaked to that of the influent concentration after initial break-through but sharply decreased while influx was sustained, suggesting a degradation lag phase. The same pattern was displayed in the second step but peak height and percentage of atrazine recovered in the effluent were lower. A Monod model with biomass decay was successfully calibrated to this data. The model was successfully evaluated against batch degradation data and mini-column experiments at lower flow rate. The study suggested that first-order degradation models may underestimate risk of pesticide leaching if the pesticide degradation potential needs amplification during degradation.

Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10–30, 35–55, 60–80 and 85–105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha−1 yr−1. Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen × ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation. Nitrogen alters threshold of ozone-induced senescence, but not below-ground resource allocation.

An agricultural ammonia (NH3) emission inventory in the North China Plain (NCP) on a prefecture level for the year 2004, and a 5 × 5 km2 resolution spatial distribution map, has been calculated for the first time. The census database from China's statistics datasets, and emission factors re-calculated by the RAINS model supported total emissions of 3071 kt NH3–N yr−1 for the NCP, accounting for 27% of the total emissions in China. NH3 emission from mineral fertilizer application contributed 1620 kt NH3–N yr−1, 54% of the total emission, while livestock emissions accounted for the remaining 46% of the total emissions, including 7%, 27%, 7% and 5% from cattle, pigs, sheep and goats, and poultry, respectively. A high-resolution spatial NH3 emissions map was developed based on 1 × 1 km land use database and aggregated to a 5 × 5 km grid resolution. The highest emission density value was 198 kg N ha−1 yr−1. The first high-resolution spatial distribution of ammonia emissions for the North China Plain showed rates up to 200 kg NH3–N ha−1 yr−1.

The distribution of total mercury (THg) within common deciduous trees and the applicability of tree cores as biomonitors of historical environmental THg trends were assessed for both contaminated and reference sites around Kingston, Ontario. Samples were collected from Acer spp., Quercus spp. Populus spp. and Salix spp. Bark and wood THg concentrations were found to be highly correlated whereas soil and wood THg concentrations were not. There were no temporal relationships for THg in dated tree rings corresponding with any other known environmental Hg trends. The shoreline speciess, Populus and Salix spp., had the greatest bark and wood Hg concentrations reaching 18 ng/g, significantly higher than for inland trees Quercus and Acer spp. with maximum values of 7 and 1.2 ng/g for bark and wood respectively. While tree cores cannot be reliably used as temporal THg biomonitors, there is promise for tree species such as Populus spp and Salix spp as spatial indicators of local long-term Hg contamination.

Earthworms were exposed to artificially contaminated soils of DE-71 and DE-79 to investigate the bioaccumulation and bioavailability of PBDEs in soil. All major congeners were bioavailable to earthworms. The uptake and elimination rate coefficients of PBDEs decreased with their logKows. The biota soil accumulation factors of PBDEs also declined with logKow. These may be due to the large molecular size and the high affinity of PBDEs to soil particles. The concentrations extracted by Tenax for 6 h correlated very well with those found in earthworms, suggesting that the bioavailability of PBDEs in soil is related to the fraction of rapid desorption from soil. This also indicates that 6 h Tenax extraction is a good proxy for the bioavailability of PBDEs to earthworms in soil. The BSAFs of PBDEs in aged soil decreased 22-84% compared to freshly spiked soil, indicating that aging may diminish the bioavailability of PBDEs in soil significantly.

Soil amendments previously shown to be effective in reducing metal bioavailability and/or mobility in calcareous metal-polluted soils were tested on a calcareous dredged sediment-derived soil with 26 mg Cd/kg dry soil, 2200 mg Cr/kg dry soil, 220 mg Pb/kg dry soil, and 3000 mg Zn/kg dry soil. The amendments were 5% modified aluminosilicate (AS), 10% w/w lignin, 1% w/w diammonium phosphate (DAP, (NH4)2HPO4), 1% w/w MnO, and 5% w/w CaSO4. In an additional treatment, the contaminated soil was submerged. Endpoints were metal uptake in Salix cinerea and Lumbricus terrestris, and effect on oxidation-reduction potential (ORP) in submerged soils. Results illustrated that the selected soil amendments were not effective in reducing ecological risk to vegetation or soil inhabiting invertebrates, as metal uptake in willows and earthworms did not significantly decrease following their application. Flooding the polluted soil resulted in metal uptake in S. cinerea comparable with concentrations for an uncontaminated soil.

Incubation and pot experiments using poplar (Populus nigra L. cv. Wolterson) were performed in order to evaluate the questionable efficiency of EDDS-enhanced phytoextraction of Cu from contaminated soils. Despite the promising conditions of the experiment (low contamination of soils with a single metal with a high affinity for EDDS, metal tolerant poplar species capable of producing high biomass yields, root colonization by mycorrhizal fungi), the phytoextraction efficiency was not sufficient. The EDDS concentrations used in this study (3 and 6 mmol kg-1) enhanced the mobility (up to a 100-fold increase) and plant uptake of Cu (up to a 65-fold increase). However, despite EDDS degradation and the competition of Fe and Al for the chelant, Cu leaching cannot be omitted during the process. Due to the low efficiency, further research should be focused on other environment-friendly methods of soil remediation.