Branchial and intestinal osmoregulatory acclimation in the four-eyed sleeper, <Emphasis Type="Italic">Bostrychus sinensis</Emphasis> (Lacepède), exposed to seawater

Bostrychus sinensis is a facultative air breather that inhabits waters of a wide range of salinities. This study aimed to elucidate whether branchial and intestinal osmoregulatory acclimation occurred in B. sinensis transferred from 5‰ water through a progressive increase in salinities to seawater. Our results indicate that B. sinensis acted as a hyperosmotic regulator in 5‰ water, but exhibited hypoosmotic hypoionic regulation in seawater. During short- (1 day) and medium- (10 days) term acclimation to seawater, there were only minor perturbations in plasma osmolality and [Na⁺], which returned to control levels after 45 days of exposure to seawater. Branchial Na⁺/K⁺-ATPase activity was unaffected by 1, 10 or 45 days of exposure to seawater. However, prolonged (45 days) acclimation to seawater led to a significant increase in Na⁺/K⁺-ATPase α-subunit protein abundance. Taken together, these results indicate that there could be changes in the expression of Na⁺/K⁺-ATPase isoforms and/or post-translational modification of Na⁺/K⁺-ATPase in the gills of fish exposed to seawater. Immunofluorescence microscopy revealed that acclimation to seawater for 10 days only resulted in no change in branchial Na⁺/K⁺-ATPase protein expression, but there were increases in protein expression of cystic fibrosis transmembrane regulator (CFTR)-like chloride channel and Na⁺:K⁺:2Cl⁻ cotransporter (NKCC; probably NKCC1). Indeed, NKCC was undetectable in gills of fish kept in 5‰ water by Western blotting, but it became weakly detectable in fish exposed to seawater for 10 days and prominently expressed in fish exposed to seawater for 45 days. Therefore, our results indicate that branchial CFTR-like chloride channel and NKCC1 were the determining factors in the transition between hyperosmotic regulation and hypoosmotic hypoionic regulation in B. sinensis. Furthermore, the intestine of B. sinensis also served as an important osmoregulatory organ, since there were significant increases in both the activity and protein abundance of intestinal Na⁺/K⁺-ATPase in fish acclimated to seawater for 45 days. The effectiveness of branchial and intestinal osmoregulatory acclimation in B. sinensis during seawater acclimation led to only a minor increase in plasma osmolality, and thus resulted in relatively unchanged free amino acid contents in muscle and liver.     

Organic pollutants in compost and digestate. Part 2. Polychlorinated dibenzo-p-dioxins, and -furans, dioxin-like polychlorinated biphenyls, brominated flame retardants, perfluorinated alkyl substances, pesticides, and other compounds

Compost and digestate are important recycling fertilizers and have beneficial effects on soil parameters. However, they can contain significant amounts of organic pollutants. Here, the first comprehensive data set on dibenzo-p-dioxins and -furans (PCDD/F), dioxin-like polychlorinated biphenyls (DL-PCB), brominated flame retardants, perfluorinated alkyl substances (PFAS), pesticides, phthalates, nonylphenol and chlorinated paraffins (CP) in source-separated compost and digestate from Switzerland is presented (n = 3-18). The median summation 17PCDD/F and summation 12DL-PCB concentrations were at 3.2 ng I-TEQ kg(-1)dry weight (dw) and 3.0 ng WHO-TEQ kg(-1)dw, respectively. Brominated diphenyl ether 209 (BDE 209) accounted for 72% of the total polyBDE content (10 microg kg(-1)dw). Hexabromocyclododecane (HBCD) and tetrabromobisphenol A (TBBPA) levels were at 100 and 0.51 microg kg(-1)dw, respectively. PFAS were identified for the first time in compost and digestate (median concentration 6.3 microg kg(-1)dw, summation 21compounds). Out of 269 pesticides analysed, 30 fungicides, 14 herbicides, eight insecticides and one acaricide were detected. Di-(2-ethylhexyl)phthalate (DEHP) median concentration accounted for 280 microg kg(-1)dw and nonylphenol was below the detection limit of 1 mg kg(-1)dw. The sum of short and medium chain CP was between 90 and 390 microg kg(-1)dw. The concentrations observed were at or above the levels found in background soils, which are the main recipient of compost and digestate. Where actually applied, compost can contribute considerably to the total input of organic pollutants to the soil. However, on a total Swiss agricultural area base, inputs seem to be limited.     

Exploring the use of computer models in participatory integrated assessment – experiences and recommendations for further steps

Integrated assessment (IA) can be defined as a structured process of dealing with complex issues, using knowledge from various scientific disciplines and/or stakeholders, such that integrated insights are made available to decision makers (J. Rotmans, Enviromental Modelling and Assessment 3 (1998) 155). There is a growing recognition that the participation of stakeholders is a vital element of IA. However, only little is known about methodological requirements for such participatory IA and possible insights to be gained from these approaches. This paper summarizes some of the experiences gathered in the ULYSSES project, which aims at developing procedures that are able to bridge the gap between environmental science and democratic policy making for the issue of climate change. The discussion is based on a total of 52 IA focus groups with citizens, run in six European and one US city. In these groups, different computer models were used, ranging from complex and dynamic global models to simple accounting tools. The analysis in this paper focuses on the role of the computer models. The findings suggest that the computer models were successful at conveying to participants the temporal and spatial scale of climate change, the complexity of the system and the uncertainties in our understanding of it. However, most participants felt that the computer models were less instrumental for the exploration of policy options. Furthermore, both research teams and participants agreed that despite considerable efforts, most models were not sufficiently user-friendly and transparent for being accessed in an IA focus group. With that background, some methodological conclusions are drawn about the inclusion of the computer models in the deliberation process. Furthermore, some suggestions are made about how given models should be adapted and new ones developed in order to be helpful for participatory IA. This revised version was published online in July 2006 with corrections to the Cover Date.     

Estimating mercury emissions from a zinc smelter in relation to China’s mercury control policies

Mercury concentrations of flue gas at inlet/outlet of the flue gas cleaning, electrostatic demister, reclaiming tower, acid plant, and mercury contents in zinc concentrate and by-products were measured in a hydrometallurgical zinc smelter. The removal efficiency of flue gas cleaning, electrostatic demister, mercury reclaiming and acid plant was about 17.4%, 30.3%, 87.9% and 97.4% respectively. Flue gas cleaning and electrostatic demister captured 11.7% and 25.3% of the mercury in the zinc concentrate, respectively. The mercury reclaiming tower captured 58.3% of the mercury in the zinc concentrate. About 4.2% of the mercury in the zinc concentrate was captured by the acid plant. Consequently, only 0.8% of the mercury in the zinc concentrate was emitted to the atmosphere. The atmospheric mercury emission factor was 0.5 g t⁻¹ of zinc produced for the tested smelter, indicating that this process offers the potential to effectively reduce mercury emissions from zinc smelting.     

Physicochemical variations in atmospheric aerosols recorded at sea onboard the Atlantic–Mediterranean 2008 Scholar Ship cruise (Part II): Natural versus anthropogenic influences revealed by PM10 trace element geochemistry

The geochemistry of PM₁₀ filter samples collected at sea during the Scholar Ship Atlantic–Mediterranean 2008 research cruise reveals a constantly changing compositional mix of pollutants into the marine atmosphere. Source apportionment modelling using Positive Matrix Factorization identifies North African desert dust, sea spray, secondary inorganic aerosols, metalliferous carbon, and V–Ni-bearing combustion particles as the main PM₁₀ factors/sources. The least contaminated samples show an upper continental crust composition (UCC)-normalised geochemistry influenced by seawater chemistry, with marked depletions in Rb, Th and the lighter lanthanoid elements, whereas the arrival of desert dust intrusions imposes a more upper crustal signature enriched in “geological” elements such as Si, Al, Ti, Rb, Li and Sc. Superimposed on these natural background aerosol loadings are anthropogenic metal aerosols (e.g. Cu, Zn, Pb, V, and Mn) which allow identification of pollution sources such as fossil fuel combustion, biomass burning, metalliferous industries, and urban–industrial ports. A particularly sensitive tracer is La/Ce, which rises in response to contamination from coastal FCC oil refineries. The Scholar Ship database allows us to recognise seaborne pollution sourced from NW Africa, the Cape Verde and Canary islands, and European cities and industrial complexes, plumes which in extreme cases can produce a downwind deterioration in marine air quality comparable to that seen in many cities, and can persist hundreds of kilometres from land.     

Seasonal Variation of the Particle Size Distribution of n-Alkanes and Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Aerosol of Guangzhou, China

Seasonal aerosol samples have been collected by Andersen Hi-Vol pumping system equipped with a five stage cascade impactor and a backup filter (size range: 10–7.2 μ m, 7.2–3.0 μ m, 3.0–1.5 μ m, 1.5–0.95 μ m, 0.95–0.49 μ m, ≤0.49 μ m) in the Liwan district, Guangzhou. n-Alkanes were measured using gas chromatography and PAHs were measured using gas chromatography/mass spectrometry analysis. The bimodal log-normal distributions of n-alkanes and semi-volatile PAHs were found, while for non-volatile PAHs that was unimodal, so much as the mode of semi-volatile PAHs was similar with that of the particles. The n-alkanes and PAHs were preferably associated with fine particles. C _max (carbon number maximum) (C₂₂–C₂₆), CPI (carbon preference index) (1.12–1.21), U/R (unresolved to resolved components ratio) (7.42–10.7), wax% (0.9–3.12%) and the diagnostic ratios for PAHs revealed that vehicular emission was the major source of these organic compounds during the study periods, while the contribution of epicuticular waxes emitted by terrestrial plants was minor. CPI₂ (values for petrogenic hydrocarbons), CPI₃ (values for biogenic n-alkanes) and wax% revealed that the natural preferentially accumulated in the larger aerosol while the anthropogenic in the smaller. In addition, the different MMDs (mass median diameters) for n-alkanes and PAHs were observed in different seasons. The MMDs for n-alkanes and PAHs were higher in autumn/winter than those in spring/summer. The seasonal effect was related to the hydrocarbon content in the individual particulate fractions, showing a preferential association of n-alkanes and PAHs with larger particles in the autumn/winter season.     

Evaluation of analytical strategies for the determination of metal concentrations to assess landfill leachate contamination

Due to the complex nature of landfill leachates, metal and metalloid analyses prove to be tricky and suffer from a lack of standard protocols. A complete approach has been adopted to investigate the influence of the different steps during the sample processing of French landfill leachates. The validation of the entire protocol has been achieved using a laboratory reference material. This material, which is a real landfill leachate, is representative of real samples. Its evaluation has allowed a quality control for metal and metalloid analyses in landfill leachates. Precautions concerning storage temperature, aeration and filtration are proposed to perform accurate metal analyses in these complex matrices. The sample processing has been applied to the seasonal monitoring of a French landfill. The assessment of major leachate metallic contaminants such as As, Cr, Sb, Sn, has been performed by evaluating the relative enrichment of metals and metalloids in comparison with rain water and groundwater. In addition, hydrological data are useful and complementary information for pointing out the main factors affecting metal concentrations and thus their potential remobilisation pathways.     

Speciation and sources of atmospheric aerosols in a highly industrialised emerging mega-city in central China

Monitoring air quality in large urban agglomerations is the key to the prevention of air pollution-related problems in emerging mega-cities. The city of Wuhan is a highly industrialised city with >9 million inhabitants in Central China. Simultaneous PM10 sampling was performed during 1 year at one urban and one industrial site. Mean PM10 daily levels (156 microg m(-3) at the urban site and 197 microg m(-3) at the industrial hotspot) exceed the US-EPA or EU annual limit values by 3-4 times. A detailed study of daily speciation showed that the mean chemical composition of PM10 presents minimal differences between peak and low PM episodes. This implies that PM10 aerosols in the study area result from local emissions, and air quality management and abatement strategies in Wuhan should thus focus on local anthropogenic sources. The levels of some elements of environmental concern are relatively high (409-615 ngPb m(-3), 66-70 ngAs m(-3), 116-227 ngMn m(-3), 10-12 ngCd m(-3)) due to industrial, but also urban emissions. Principal component analysis identified a mineral source (probably cement and steel manufacture) and smelting as the main contributors to PM10 levels at the industrial site (34%), followed by a coal fired power plant (20%) and the anthropogenic regional background (16%). At the urban site the major PM10 source is a mixed coal combustion source (31%), followed by the anthropogenic regional background (28%) and traffic (16%).     

Study of boron behaviour in two Spanish coal combustion power plants

A full-scale field study was carried out at two Spanish coal-fired power plants equipped with electrostatic precipitator (ESP) and wet flue gas desulfurisation (FGD) systems to investigate the distribution of boron in coals, solid by-products, wastewater streams and flue gases. The results were obtained from the simultaneous sampling of solid, liquid and gaseous streams and their subsequent analysis in two different laboratories for purposes of comparison. Although the final aim of this study was to evaluate the partitioning of boron in a (co-)combustion power plant, special attention was paid to the analytical procedure for boron determination. A sample preparation procedure was optimised for coal and combustion by-products to overcome some specific shortcomings of the currently used acid digestion methods. In addition boron mass balances and removal efficiencies in ESP and FGD devices were calculated. Mass balance closures between 83 and 149% were obtained. During coal combustion, 95% of the incoming boron was collected in the fly ashes. The use of petroleum coke as co-combustible produced a decrease in the removal efficiency of the ESP (87%). Nevertheless, more than 90% of the remaining gaseous boron was eliminated via the FGD in the wastewater discharged from the scrubber, thereby causing environmental problems.     

Evaluating the environmental impacts of an urban wetland park based on emergy accounting and life cycle assessment: A case study in Beijing

In this paper, emergy accounting (EA) and life cycle assessment (LCA) methods are employed to investigate a typical urban wetland park, the Green Lake Urban Wetland Park (GLUWP) of Beijing, in terms of its environmental and capital inputs, ecosystem services and organic matter yields, environmental support, and sustainability. The LCA method is also used to obtain a quantitative estimation of the environmental impact of discharges during the entire life cycle of the GLUWP. Various emergy-based indices, such as emergy yield ratio (EYR), environmental load ratio (ELR), emergy sustainability index (ESI), net economic benefit (Np), and environmental impacts of process-based LCA, including global warming potential (GWP), eutrophication (EU), nonrenewable resource depletion (RU), energy consumption (EN), acidification potential (AP), photochemical oxidant creation potential (POCP), particulate matter (PM) and wastes (W), are calculated. The results show that the GLUWP has higher proportions of renewable resource input, less pressure on the environment, more environmental support and better ecological and economic benefits, which can be considered as an environment-friendly and long-term sustainable ecological practice, compared with another constructed wetland in Beijing. Meanwhile, the dominant environmental impact is induced by POCP with the construction phase contributing the most on the entire life cycle. It is expected that increasing green area, extensively using environment-friendly materials, optimizing construction techniques and reducing power consumption can promote the sustainability of the GLUWP.