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621.
Ohne Zusammenfassung 相似文献
622.
Bert Allard Mattias Bäckström Stefan Karlsson Anja Grawunder 《Environmental science and pollution research international》2014,21(11):6930-6938
A former open pit where black shale (alum shale) was excavated during 1942–1965 has been water filled since 1966. The water chemistry was dominated by calcium and sulphate and had a pH of 3.2–3.4 until 1997–1998, when pH was gradually increasing. This was due to the intrusion of leachates from alkaline cement waste deposited close to the lake. A stable pH of around 7.5 was obtained after 6–7 years. The chemistry of the pit lake has changed due to the neutralisation. Concentrations of some dissolved metals, notably zinc and nickel, have gone down, as a result of adsorption/co-precipitation on solid phases (most likely iron and aluminium hydroxides), while other metals, notably uranium and molybdenum, are present at elevated levels. Uranium concentration is reaching a minimum of around pH 6.5 and is increasing at higher pH, which may indicate a formation of neutral and anionic uranyl carbonate species at high pH (and total carbonate levels around 1 mM). Weathering of the water-exposed shale is still in progress. 相似文献
623.
Stefan Aerts Dirk Lips Stuart Spencer Eddy Decuypere Johan De Tavernier 《Journal of Agricultural and Environmental Ethics》2006,19(1):67-76
When making an assessment of animal welfare, it is important to take environmental (housing) or animal-based parameters into
account. An alternative approach is to focus on the behavior and appearance of the animal, without making actual measurements
or quantifying this. None of these tell the whole story. In this paper, we suggest that it is possible to find common ground
between these (seemingly) diametrically opposed positions and argue that this may be the way to deal with the complexity of
animal welfare. The model will have to be acceptable for the different parties that will be affected by it and real benefits
for the animal should result from it. This will be the basis of a practical ethical approach. All this can be condensed into
a model that essentially is made up out of three basic elements: the classical welfare analysis with an existing welfare assessment
tool, an assessment of the stockholder, and an implementation of the Free Choice Profiling technique. This new framework does
not pretend to be a different or better animal welfare matrix; it is intended to integrate existing knowledge and to provide
a practical tool to improve animal welfare. It identifies whether there are welfare problems on a farm, if present whether
these problems are caused by the housing system or the stockholder, and what can be done to improve the situation. 相似文献
624.
Two sets of experiments on typical Class G well cement were carried out in the laboratory to understand better the potential processes involved in well leakage in the presence of CO2. In the first set, good-quality cement samples of permeability in the order of 0.1 μD (10?19 m2) were subjected to 90 days of flow through with CO2-saturated brine at conditions of pressure, temperature and water salinity characteristic of a typical geological sequestration zone. Cement permeability dropped rapidly at the beginning of the experiment and remained almost constant thereafter, most likely mainly as a result of CO2 exsolution from the saturated brine due to the pressure drop along the flow path which led to multi-phase flow, relative-permeability effects and the observed reduction in permeability. These processes are identical to those which would occur in the field as well if the cement sheath in the wellbore annulus is of good quality. The second set of experiments, carried out also at in situ conditions and using ethane rather than CO2 to eliminate any possible geochemical effects, assessed the effect of annular spaces between wellbore casing and cement, and of radial cracks in cement on the effective permeability of the casing-cement assemblage. The results show that, if both the cement and the bond are of good quality, the effective permeability of the assemblage is extremely low (in the order of 1 nD, or 10?21 m2). The presence of an annular gap and/or cracks in the order of 0.01–0.3 mm in aperture leads to a significant increase in effective permeability, which reaches values in the range of 0.1–1 mD (10?15 m2). The results of both sets of experiments suggest that good cement and good bonding with casing and the surrounding rock will likely constitute a good and reliable barrier to the upward flow of CO2 and/or CO2-saturated brine. The presence of mechanical defects such as gaps in bonding between the casing or the formation, or cracks in the cement annulus itself, leads to flow paths with significant effective permeability. This indicates that the external and internal interfaces of cements in wells would most probably constitute the main flow pathways for fluids leakage in wellbores, including both gaseous/supercritical phase CO2 and CO2-saturated brine. 相似文献
625.
PAH and PCB in soils of Switzerland--status and critical review 总被引:1,自引:0,他引:1
Desaules A Ammann S Blum F Brändli RC Bucheli TD Keller A 《Journal of environmental monitoring : JEM》2008,10(11):1265-1277
The surface soil concentrations (0-20 cm) of the Swiss soil monitoring network (NABO) with 105 observation sites representing all major land use types ranged for the sum of 16 EPA PAH (PAH(16)) from 32 to 8465 microg kg(-1) (median 163 microg kg(-1)), for benzo[a]pyrene (BaP) from 0.5 to 1129 microg kg(-1) (median 13 microg kg(-1)) and for the sum of seven IRMM PCB (PCB(7)) from 0.5 to 12 microg kg(-1) (median 1.6 microg kg(-1)). The legal guide values of Switzerland were exceeded for PAH(16) at only three and for BaP at two sites. The PCB(7) concentrations were clearly below any assessment value. The concentration ranges were overlapping between all land use types. Tendencies for higher concentrations were observed at urban and viticulture sites. The overall measurement precision at repeatability conditions ranged from 1 to 37% RSD for PAH(16), BaP and PCB(7). The median bias for the chemical analysis was around zero for PAH(16), +5% for BaP and -5% for PCB(7) with spreads ranging from less than -20% up to more than +30%. The PAH profiles were clearly dominated by phenanthrene. Stratification by land use revealed a prevalence of benzo[a]pyrene at urban and naphthalene at conservation sites. For PCB, the general congener rank order was PCB no. 153 > 138 > 101 > 180. From a broad correlation screening only PAH(16)/BaP (r = 0.88**) were relevant for practical soil protection. The extensive comparison with other studies was severely biased by the lack of harmonisation, especially concerning sampling depth, sampling support, analytical method and the sum calculation procedure. 相似文献
626.
Yu Y Schleicher N Norra S Fricker M Dietze V Kaminski U Cen K Stüben D 《Journal of environmental monitoring : JEM》2011,13(2):334-346
Systematic sampling and analysis were performed to investigate the dynamics and the origin of suspended particulate matter smaller than 2.5 μm in diameter (PM(2.5)), in Beijing, China from 2005 to 2008. Identifying the source of PM(2.5) was the main goal of this project, which was funded by the German Research Foundation (DFG). The concentrations of 19 elements, black carbon (BC) and the total mass in 158 weekly PM(2.5) samples were measured. The statistical evaluation of the data from factor analysis (FA) identifies four main sources responsible for PM(2.5) in Beijing: (1) a combination of long-range transport geogenic soil particles, geogenic-like particles from construction sites and the anthropogenic emissions from steel factories; (2) road traffic, industry emissions and domestic heating; (3) local re-suspended soil particles; (4) re-suspended particles from refuse disposal/landfills and uncontrolled dumped waste. Special attention has been paid to seven high concentration "episodes", which were further analyzed by FA, enrichment factor analysis (EF), elemental signatures and backward-trajectory analysis. These results suggest that long-range transport soil particles contribute much to the high concentration of PM(2.5) during dust days. This is supported by mineral analysis which showed a clear imprint of component in PM(2.5). Furthermore, the ratios of Mg/Al have been proved to be a good signature to trace back different source areas. The Pb/Ti ratio allows the distinction between periods of predominant anthropogenic and geogenic sources during high concentration episodes. Backward-trajectory analysis clearly shows the origins of these episodes, which partly corroborate the FA and EF results. This study is only a small contribution to the understanding of the meteorological and source driven dynamics of PM(2.5) concentrations. 相似文献
627.
The goal of this work was to assess risk of chemical andbiological effects of metals in reacidified, limed water bodiesin Norway and Sweden. The risk assessment is based on aliterature review and evaluations of water chemical data fromthe 1995 Nordic Lake Survey. Compared to the pre-liming period,it us unlikely that enhanced remobilization of inorganicaluminium (Al) or other toxic metals (metal bomb hypothesis)from the catchment, the lake sediment and/or the streambed willoccur when limed waters reacidify. Rather, the concentrationsin surface waters are expected to be lower than before limingstarted, because of reduced atmospheric inputs of both strongacids and metals as Cd, Hg, Pb, and Zn during the last 10–20 yr. The concentrations in lakes relative to the biologicaleffect levels, as well as the chemical properties of thedifferent metals suggest that the potential biological risksassociated to reacidification of limed lakes decrease in theorder Al > Cd > Pb. The risks associated with Cr, Cu, Fe, Mn, Ni and Zn are very low and do not have to be consideredexcept in waters with known concentrations larger than the lowest biological risk level. Such waters are very rare (<2%). Aluminium is the metal that should be used to set the limit for judging the risk of biological damage due to reacidification of limed surface waters. 相似文献
628.
Thuyet D. Bui Jim Luong-Van Stefan W. Maier Chris M. Austin 《Environmental monitoring and assessment》2013,185(10):8715-8731
Coastal shrimp farming may lead to the contamination of sediments of surrounding estuarine and marine ecosystems as shrimp farm effluent often contains high levels of pollutants including a range of organic compounds (from uneaten feed, shrimp feces, and living and dead organisms) which can accumulate in the sediments of receiving waterways. The assessment and monitoring of sediment quality in tidal creeks receiving shrimp farm effluent can support environmental protection and decision making for sustainable development in coastal areas since sediment quality often shows essential information on long-term aquatic ecosystem health. Within this context, this paper investigates nutrient loadings in the sediments of tidal creeks receiving shrimp farm effluent in Quang Ninh, Vietnam, which now have a high concentration of intensive and semi-intensive shrimp farms. Sediment samples taken from inside creek sections directly receiving effluent from concentrated shrimp farms (IEC), from main creeks adjacent to points of effluent discharge outside concentrated shrimp farms (OEC), and few kilometers away from shrimp farms (ASF) as reference sites were collected and analyzed before and after shrimp crops to investigate spatial and temporal variation. The results showed that there were statistically significant differences in the concentrations of total nitrogen, total phosphorus, and total organic carbon among IEC, OEC, and ASF sites while the seasonal variation being limited over study times. A sediment nutrient index (SNI) computed from coefficient scores of the factor analysis efficiently summarizes sediment nutrient loads, which are high, albeit quite variable, in canals directly receiving effluents from farms but then decline sharply with distance from shrimp farms. The visualization and monitoring of sediment quality data including SNI on maps can strongly support managers to manage eutrophication at concentrated shrimp farming areas, contributing to sustainable development and management at coastal zones. 相似文献
629.
Wuytack T Wuyts K Van Dongen S Baeten L Kardel F Verheyen K Samson R 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2405-2411
We aimed at evaluating the effect of low-level air pollution on leaf area fluctuating asymmetry (FAA) and specific leaf area (SLA) of Salix alba L., taking into account other environmental factors. Cuttings were grown in standardized conditions in the near vicinity of air quality measuring stations in Belgium. Variability of SLA and FAA between measuring stations explained 83% and 7.26%, respectively, of the total variability. FAA was not influenced by air pollution or environmental factors such as shading, herbivory, air temperature and humidity. SLA was increased by an increase in shadow, while NOx and O3 concentrations had only a marginal influence. The influence of SO2 concentration was negligible. Although our data analysis suggests a relationship between SLA and NOx/O3 concentration, the absence of a straightforward relationship between FAA and SLA and air pollution still questions the usefulness of these bio-indicators for monitoring air pollution. 相似文献
630.
Toxicity of tributyltin to willow trees 总被引:1,自引:0,他引:1
Trapp S Ciucani G Sismilich M 《Environmental science and pollution research international》2004,11(5):327-330
BACKGROUND: Tributyltin is an organotin compound, used as an antifouling agent in ship paint, with heavy impact on the marine environment. Contaminated dredged harbor sludge is now dumped on land. The toxicity of tributyltin (TBT) to trees has not yet been quantified. Eventually, a vegetation cover on the dumped sludge could be established for the purpose of non-food cash crop production and phytoremediation. METHODS: The phytotoxicity of tributyltin chloride (TBTCl) and tributyltin hydride (TBTH) was measured at pH 4 and at pH 7 using the willow tree transpiration test. Different pH levels of the nutrient solutions were achieved by adding ammonium salt (low pH) or nitrate (high pH) as nitrogen source. RESULTS AND DISCUSSION: At low pH (pH 4), all trees showed symptoms of poor health. Transpiration decreased at concentrations above or equal to 0.1 mg TBTCl/l and 1 mg TBTH/L. The TBT toxicity was more pronounced at pH 7. The trees survived even the highest dose of 10 mg/l TBTCl or TBTH, although their growth and transpiration was strongly reduced. CONCLUSION: In contrast to other organisms, TBTCl and TBTH were less toxic to higher plants. RECOMMENDATIONS AND OUTLOOK: The toxicity of TBT is no hindrance for establishing vegetation on TBT-contaminated sludge. Phytoremediation and cash crop production could be possible with suitable plants. 相似文献