Sorption of two herbicides, fluridone (FLUN) and norflurazon (NORO), by two types of biochars, whole sediment, and various soil/sediment organic matter (OM) fractions including nonhydrolyzable carbon (NHC), black carbon (BC) and humic acid (HA) was examined. The single-point organic carbon (OC)-normalized distribution coefficients (KOC) of FLUN and NORO at low solution concentration (Cₑ=0.01SW, solubility) for HA, NHC, and BC were about 3, 14, and 24 times and 3, 16, and 36 times larger than their bulk sediments, respectively, indicating the importance of different OM fractions in herbicide sorption. This study revealed that aliphatic moieties of the hydrothermal biochars and aromatic moieties of NHC samples, respectively, were possibly responsible for herbicide sorption. The hydrothermal biochar and condensed OM (i.e., NHC and BC) showed relatively high or similar herbicide sorption efficiency compared to the thermal biochar, suggesting that the hydrothermal biochar may serve as an amendment for minimizing off-site herbicide movement.

Available data were reviewed to assess the status of contamination by persistent organic pollutants (POPs), including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs), perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), in drinking water sources and coastal waters of China. The levels of POPs in China's waters were generally at the high end of the global range. A comparison of China's regulatory limits indicated that PCBs in rivers and coastal water may pose potential human health risk. Occurrence of DDTs in some rivers of China may also pose health risk to humans using the regulatory limits of DDTs recommended by the European Union. Future monitoring of POPs in China's waters should be directed towards analytes of concern (e.g. PCBs and PCDD/Fs) and to fill data gaps for analytes (e.g. PBDEs, PCDD/Fs, and chlordane) and in watersheds/regions (e.g. West China) where data are scarce.

High levels of polybrominated diphenyl ethers (PBDEs) have been extensively reported in urban areas and at e-waste recycling sites in coastal China. However, data are scarce in northern China and are not available in rural areas at all. In addition, it is often believed that air concentrations in rural areas are lower than those in urban areas without distinguishing rural residential areas and open fields. In this study, air samples were collected at 17 sites covering urban and rural (residential and open field) areas in northern China using active samplers. With BDE-209 dominated in all congeners, the average concentrations of BDE-209 (41 ± 72 pg/m³) and other 13 PBDEs (16 ± 12 pg/m³) were significantly lower than those found in south China, such as in Guangzhou or Hong Kong. On average, the total PBDE concentrations at the urban sites were 2.2 and 2.9 times of those at the rural residential and field sites, respectively.

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in sediments and benthic invertebrates near submarine municipal outfalls in Victoria and Vancouver, B.C., Canada, two areas with contrasting receiving environments. PBDE concentrations in wastewater exceeded those of the legacy PCBs by eight times at Vancouver and 35 times at Victoria. Total PBDE concentrations in benthic invertebrates were higher near Vancouver than Victoria, despite lower concentrations in sediments, and correlated with organic carbon-normalized concentrations in sediment. Principal Components Analysis indicated uptake of individual PBDE congeners was determined by sediment properties (organic carbon, grain size), while PCB congener uptake was governed by physico-chemical properties (octanol-water partitioning coefficient). Results suggest the utility of sediment quality guidelines for PBDEs and likely PCBs benefit if based on organic carbon-normalized concentrations. Also, where enhanced wastewater treatment increases the PBDEs to particulate organic carbon ratio in effluent, nearfield benthic invertebrates may face increased PBDE accumulation.

The rootless duckweed Wolffia globosa can accumulate and tolerate relatively large amounts of arsenic (As); however, the underlying mechanisms were unknown. W. globosa was exposed to different concentrations of arsenate with or without l-buthionine sulphoximine (BSO), a specific inhibitor of γ-glutamylcysteine synthetase. Free thiol compounds and As(III)–thiol complexes were identified and quantified using HPLC – high resolution ICP-MS – accurate mass ESI-MS. Without BSO, 74% of the As accumulated in the duckweed was complexed with phytochelatins (PCs), with As(III)–PC₄ and As(III)–PC₃ being the main species. BSO was taken up by the duckweed and partly deaminated. The BSO treatment completely suppressed the synthesis of PCs and the formation of As(III)–PC complexes, and also inhibited the reduction of arsenate to arsenite. BSO markedly decreased both As accumulation and As tolerance in W. globosa. The results demonstrate an important role of PCs in detoxifying As and enabling As accumulation in W. globosa.

Evidence from a multi-date regional-scale analysis of both high-flow and annual-average water quality data from Galloway, south-west Scotland, demonstrates that forest land cover continues to exacerbate freshwater acidification. This is in spite of significant reductions in airborne pollutants. The relationship between freshwater sulphate and forest cover has decreased from 1996 to 2006 indicating a decrease in pollutant scavenging. The relationship between forest cover and freshwater acidity (pH) is, however, still present over the same period, and does not show conclusive signs of having declined. Furthermore, evidence for forest cover contributing to a chlorine bias in marine ion capture suggests that forest scavenging of sea-salts may mean that the forest acidification effect may continue in the absence of anthropogenic pollutant inputs, particularly in coastal areas.

A complete accounting of net greenhouse gas balance (NGHGB) and greenhouse gas intensity (GHGI) affected by Fe(III) fertilizer application was examined in typical annual paddy rice-winter wheat rotation cropping systems in southeast China. Annual fluxes of soil carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) were measured using static chamber method, and the net ecosystem exchange of CO₂ (NEE) was determined by the difference between soil CO₂ emissions (RH) and net primary production (NPP). Fe(III) fertilizer application significantly decreased RH without adverse effects on NPP of rice and winter wheat. Fe(III) fertilizer application decreased seasonal CH₄ by 27–44%, but increased annual N₂O by 65–100%. Overall, Fe(III) fertilizer application decreased the annual NGHGB and GHGI by 35–47% and 30–36%, respectively. High grain yield and low greenhouse gas intensity can be reconciled by Fe(III) fertilizer applied at the local recommendation rate in rice-based cropping systems.

A multimedia fate model coupling dynamic water flow with a level IV fugacity model has been developed and applied to simulate the temporal and spatial fate of Polycyclic Aromatic Hydrocarbons (PAHs) in the Songhua River, China. The model has two components: in the first, the one-dimensional network kinematic wave equation is used to calculate varying water flow and depth. In the second, Fugacity IV equations are implemented to predict contaminant distributions in four environmental media. The estimated concentrations of eight PAHs in Songhua River are obtained, and all simulated results are in acceptable agreement with monitoring data, as verified with the Theil’s inequality coefficient test. The sensitivity of PAH concentration in each environmental phase to input parameters are also evaluated. Our results show the model predicts reasonably accurate contaminant concentrations in natural rivers, and that it can be used to supply necessary information for control and management of water pollution.

We investigated occurrence of selected compounds (4-t-octylphenol: 4-t-OP; 4-nonylphenols: 4-NP; bisphenol-A: BPA; estrone: E1; 17β-estradiol: E2; triclosan: TCS) and estrogenicity in surface water and sediment of the Yellow River in China by using combined chemical analysis and in vitro yeast screen bioassay. Estrogenic compounds 4-t-OP, 4-NP, BPA, E1, E2 and TCS were measured in the water samples, with their average concentrations of 4.7, 577.9, 46.7, 1.3, ND and 6.8 ng/L, respectively. In sediment, the average concentrations of 4-t-OP, 4-NP, BPA and TCS were 35.7, 0.5, 1.7 and 0.7 ng/g while E1 and E2 were not detected in the sediments of all selected sites. In general, the estrogenic compounds in surface water and sediment of the Yellow River were at relatively low levels, thus having medium to minimal estrogenic risks in most sites except for the site of east Lanzhou with high estrogenic risks.

The high wastewater volumes produced during citrus production at pre- and post-harvest level presents serious pesticide point-source pollution for groundwater bodies. Biobeds are used for preventing such point-source pollution occurring at farm level. We explored the potential of biobeds for the depuration of wastewaters produced through the citrus production chain following a lab-to-field experimentation. The dissipation of pesticides used pre- or post-harvest was studied in compost-based biomixtures, soil, and a straw-soil mixture. A biomixture of composted grape seeds and skins (GSS-1) showed the highest dissipation capacity. In subsequent column studies, GSS-1 restricted pesticides leaching even at the highest water load (462Lm⁻³). Ortho-phenylphenol was the most mobile compound. Studies in an on-farm biobed filled with GSS-1 showed that pesticides were fully retained and partially or fully dissipated. Overall biobeds could be a valuable solution for the depuration of wastewaters produced at pre- and post-harvest level by citrus fruit industries.