Natural events and anthropogenic activities are the reasons of undesirable resuspension of contaminated sediments in aquatic environment. Uncontrolled resuspension could remobilize weakly bound heavy metals into overlying water and pose a potential risk to aquatic ecosystem. Shallow harbours, with contaminated sediments are subjected to the risk of uncontrolled resuspension. Remediation of sediments in these areas cannot be performed by conventional in situ methods (e.g. capping with or without reactive amendment). Ex situ remediation also requires dredging of sediment, which could increase the risk of spreading contaminants. Alternatively, the resuspension technique was introduced to address these issues. The concept of the resuspension method is that finer sediments have a greater tendency to adsorb the contamination. Therefore, finer sediments, believed carry more concentration of contaminants, were targeted for removal from aquatic environment by a suspension mechanism in a confined water column. The objective of this study was to evaluate the feasibility of the resuspension technique as a new approach for remediation of contaminated sediment and a viable option to reduce the risk of remobilization of contaminants in harbours due to an undesirable resuspension event. Unlike the common in situ techniques, the resuspension method could successfully reduce the total concentration of contaminants in almost all samples below the probable effect level (PEL) with no significant change in the quality of overlying water. The results indicated that removal efficiency could be drastically enhanced for metals in sediment with a higher enrichment factor. Moreover, availability of metals (e.g. Cd and Pb) with a high concentration in labile fractions was higher in finer sediments with a high enrichment factor. Consequently, removal of contaminants from sediment through the resuspension method could reduce the risk of mobility and availability of metals under changing environmental conditions. Potential dredging in harbours could be performed safer and more cost-effective afterward.

Trace elements (TEs) transported by atmospheric fluxes can negatively impact isolated ecosystems. Modelling based on moss-borne TE accumulation makes tracking TE deposition in remote areas without monitoring stations possible. Using a single moss species from ombrotrophic hummock peatlands reinforces estimate quality. This study used a validated geomatic model of particulate matter dispersion to identify the origin of Cd, Zn, Pb and Cu accumulated in Sphagnum capillifolium and the distance transported from their emission sources. The residential and industrial sectors of particulate matter emissions showed the highest correlations with the TEs accumulated in S. capillifolium (0.28(Zn)-0.56(Cu)) and (0.27(Zn)-0.47(Cu), respectively). Distances of dispersion varied depending on the sector of emissions and the considered TE. The greatest transportation distances for mean emissions values were found in the industrial (10.6 km when correlating with all TEs) and roads sectors (13 km when correlating with Pb). The residential sector showed the shortest distances (3.6 km when correlating with Cu, Cd, and Zn). The model presented here is a new tool for evaluating the efficacy of air pollution abatement policies in non-monitored areas and provides high-resolution (200 × 200 m) maps of TE accumulation that make it possible to survey the potential impacts of TEs on isolated ecosystems.

Adsorption is an efficient method for removal of pharmaceuticals and personal care products (PPCPs). Magnetic resins are efficient adsorbents for water treatment and exhibit potential for PPCP removal. In this study, the magnetic hypercrosslinked resin Q100 was used for adsorption of PPCPs. The adsorption behavior of this resin was compared with those of two activated carbons, namely, Norit and F400D. Norit exhibited the fastest adsorption kinetics, followed by Q100. Norit featured a honeycomb shape and long-range ordered pore channels, which facilitated the diffusion of PPCPs. Moreover, the large average pore size of Q100 reduced diffusion resistance. The adsorbed amounts of 11 PPCPs on the three adsorbents increased with increasing adsorbate hydrophobicity. For Q100, a significant linear correlation was observed between the adsorption performance for PPCPs and hydrophobicity (logD value) of adsorbates (R2 = 0.8951); as such, PPCPs with high logD values (>1.69) could be efficiently removed. Compared with those of Norit and F400D, the adsorption performance of Q100 was less affected by humic acid because of the dominant hydrophobic interaction. Furthermore, Q100 showed improved regeneration performance, which renders it promising for PPCP removal in practical applications.

This study was aimed at investigating the detachment of fullerene nC60 nanoparticles (NPs) in saturated sand porous media under transient and static conditions. The nC60 NPs were first attached at primary minima of Derjaguin–Landau–Verwey–Overbeek (DLVO) interaction energy profiles in electrolyte solutions with different ionic strengths (ISs). The columns were then eluted with deionized water to initiate nC60 NP detachment by decreasing solution IS. Finally, the flow of the columns was periodically interrupted to investigate nC60 NP detachment under static condition. Our results show that the detachment of nC60 NPs occurred under both transient and static conditions. The detachment under transient conditions was attributed to the fact that the attractions acting on the nC60 NPs at primary minima were weakened by nanoscale physical heterogeneities and overcome by hydrodynamic drags at lower ISs. However, a fraction of nC60 NPs remained at shallow primary minima in low flow regions, and detached via Brownian diffusion during flow interruptions. Greater detachment of nC60 NPs occurred under both transient and static conditions if the NPs were initially retained in electrolyte solutions with lower valent cations due to lower attractions between the NPs and collectors. Decrease in collector surface chemical heterogeneities and addition of dissolved organic matter also increased the extent of detachment by increasing electrostatic and steric repulsions, respectively. While particle attachment in and subsequent detachment from secondary minima occur in the same electrolyte solution, our results indicate that perturbation in solution chemistry is necessary to lower the primary minimum depths to initiate spontaneous detachment from the primary minima. These findings have important implications for predicting the fate and transport of nC60 NPs in subsurface environments during multiple rainfall events and accordingly for accurately assessing their environmental risks.

Neutral Polyfluoroalkyl substances (PFASs) in the atmosphere were measured during a cruise campaign over the northern South China Sea (SCS) from September to October 2013. Four groups of PFASs, i.e., fluorotelomer alcohols (FTOHs), fluorotelomer acrylates (FTAs), fluorooctane sulfonamides (FOSAs) and fluorooctane sulfonamidoethanols (FASEs), were detected in gas samples. FTOHs was the predominant PFAS group, accounting for 95.2–99.3% of total PFASs (ΣPFASs), while the other PFASs accounted for a small fraction of ΣPFASs. The concentrations of ΣPFASs ranged from 18.0 to 109.9 pg m−3 with an average of 54.5 pg m−3. The concentrations are comparable to those reported in other marine atmosphere. Higher concentrations of ΣPFASs were observed in the continental-influenced samples than those in other samples, pointing to the substantial contribution of anthropogenic sources. Long-range transport is suggested to be a major pathway for introducing gaseous PFASs into the atmosphere over the northern SCS. In order to further understand the fate of gaseous PFASs during transport, the atmospheric decay of neutral PFASs under the influence of reaction with OH radicals and atmospheric physical processes were estimated. Concentrations of 8:2 FTOH, 6:2 FTOH and MeFBSE from selected source region to the atmosphere over the SCS after long-range transport were predicted and compared with the observed concentrations. It suggests that the reaction with OH radicals may play an important role in the atmospheric decay of PFAS during long-range transport, especially for shorted-lived species. Moreover, the influence of atmospheric physical processes on the decay of PFAS should be further considered.

With the increasing use of treated wastewater and biosolids in agriculture, residues of pharmaceutical and personal care products (PPCPs) in these reused resources may contaminate food produce via plant uptake, constituting a route for human exposure. Although various PPCPs have been reported to be taken up by plants in laboratories or under field conditions, at present little information is available on their metabolism in plants. In this study, we applied carrot cell cultures to investigate the plant metabolism of PPCPs. Five phase I metabolites of carbamazepine were identified and the potential metabolism pathways of carbamazepine were proposed. We also used the carrot cell cultures as a rapid screening tool to initially assess the metabolism potentials of 18 PPCPs. Eleven PPCPs, including acetaminophen, caffeine, meprobamate, primidone, atenolol, trimethoprim, DEET, carbamazepine, dilantin, diazepam, and triclocarban, were found to be recalcitrant to metabolism. The other 7 PPCPs, including triclosan, naproxen, diclofenac, ibuprofen, gemfibrozil, sulfamethoxazole, and atorvastatin, displayed rapid metabolism, with 0.4–47.3% remaining in the culture at the end of the experiment. Further investigation using glycosidase hydrolysis showed that 1.3–20.6% of initially spiked naproxen, diclofenac, ibuprofen, and gemfibrozil were transformed into glycoside conjugates. Results from this study showed that plant cell cultures may be a useful tool for initially exploring the potential metabolites of PPCPs in plants as well as for rapidly screening the metabolism potentials of a variety of PPCPs or other emerging contaminants, and therefore may be used for prioritizing compounds for further comprehensive evaluations.

Lead poisoning, through the ingestion of spent lead gunshot, is an established cause of morbidity and mortality in waterbirds globally, but the thresholds at which blood levels begin to affect the physiology of birds in the wild are less well known. Here we determine the prevalence of lead exposure in whooper swans and, for the first time, identify the level of blood lead associated with initial reductions in body condition. Blood lead elevated above background levels (i.e. >20 μg dL⁻¹) was found in 41.7% (125/300) of swans tested. Blood lead was significantly negatively associated with winter body condition when levels were ≥44 μg dL⁻¹ (27/260 = 10%). Our findings indicating that sub-lethal impacts of lead on body condition occur at the lower end of previously established clinical thresholds and that a relatively high proportion of individuals in this population may be affected, reaffirm the importance of reducing contamination of the environment with lead shot.

Evidence on the effects of long-term exposure to traffic pollution on health is inconsistent. In Greater London we examined associations between traffic pollution and emergency hospital admissions for cardio-respiratory diseases by applying linear and piecewise linear Poisson regression models in a small-area analysis. For both models the results for children and adults were close to unity. In the elderly, linear models found negative associations whereas piecewise models found non-linear associations characterized by positive risks in the lowest and negative risks in the highest exposure category. An increased risk was observed among those living in areas with the highest socioeconomic deprivation. Estimates were not affected by adjustment for traffic noise. The lack of convincing positive linear associations between primary traffic pollution and hospital admissions agrees with a number of other reports, but may reflect residual confounding. The relatively greater vulnerability of the most deprived populations has important implications for public health.

Though significant associations between particulate matter (PM) air pollution and cardiovascular diseases have been widely reported, it remains unclear what characteristics, such as particle size and chemical constituents, may be responsible for the effects. A time-series model was applied to examine the cardiovascular effects of particle size (for the period of 2009–2011) and chemical constituents (2007–2010) in Guangzhou, we controlled for potential confounders in the model, such as time trends, day of the week, public holidays, meteorological factors and influenza epidemic. We found significant associations of cardiovascular mortality with PM10, PM2.5 and PM1; the excess risk (ER) was 6.10% (95% CI: 1.76%, 10.64%), 6.11% (95% CI: 1.76%, 10.64%) and 6.48% (95% CI: 2.10%, 11.06%) for per IQR increase in PM10, PM2.5 and PM1 at moving averages for the current day and the previous 3 days (lag03), respectively. We did not find significant effects of PM2.5-10 and PM1-2.5. For PM2.5 constituents, we found that organic carbon, elemental carbon, sulfate, nitrate and ammonium were significantly associated with cardiovascular mortality, the corresponding ER for an IQR concentration increase at lag03 was 1.13% (95% CI: 0.10%, 2.17%), 2.77% (95% CI: 0.72%, 4.86%), 2.21% (95% CI: 1.05%, 3.38%), 1.98% (95% CI: 0.54%, 3.44%), and 3.38% (95% CI: 1.56%, 5.23%), respectively. These results were robust to adjustment of other air pollutants and they remained consistent in various sensitivity analyses by changing model parameters. Our study suggests that PM1 and constituents from combustion and secondary aerosols might be important characteristics of PM pollution associated with cardiovascular mortality in Guangzhou.

As a signatory of the Stockholm Convention and the largest developing country, China plays a very important role in implementation of the convention to reduce and finally eliminate persistent organic pollutants (POPs) in the world. In the past ten years after the enforcement in 2004, Chinese Government and scientists have made great progress on the study of POPs. The present work aims to provide an overview on recent studies on POPs in China, with particular focus on usage/emission inventory, residue inventory, and pollution status of POPs on national scale. Several legend (old) and new target POPs were comprehensively summarized with progress on inventory. Furthermore, several national scale monitoring programs have been selected for the occurrence, spatial and temporal trends of POPs in China, which are compared with Asian data and Global data. Based on the observed results, some important scientific issues, such as the primary and secondary distribution patterns, the primary and secondary fractionations, and air-soil exchange of POPs, are also discussed. It is proposed that more studies should be carried out for the new targeted POPs in future for both the national and global interests.