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11.
Assessment of phosphogypsum impact on the salt-marshes of the Tinto river (SW Spain): role of natural attenuation processes 总被引：2，自引：0，他引：2
About 120 Mton of phosphogypsum from the fertiliser industry were stack-piled on the salt-marshes of the Tinto river (Spain). This paper investigates the capacity of salt-marshes to attenuate contamination due to downward leaching from phosphogypsum. Solids and pore-waters were characterized at different depths of the pile to reach the marsh-ground. In superficial zones, metals were highly mobile, and no reduced sulphur was found. However, pollutant concentration decreased in the pore-water in deeper oxygen-restricted zones. Metal removal occurred by precipitation of newly formed sulphides, being this process main responsible for the contamination attenuation. Pyrite-S was the main sulphide component (up to 2528 mg/kg) and occurred as framboids, leading to high degrees of pyritization (up to 97%). The sulphidization reaction is Fe-limited; however, excess of acid-volatile sulphide over other metals cause precipitation of other sulphides, mainly of Cu and As. This decrease in metal mobility significantly minimises the impact of phosphogypsums on the salt-marshes. 相似文献
12.
Mogens H. Greve Markku Yli-Halla Aage A. Nyborg Ingrid Öborn 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):15-26
During the project “Nordic Reference Soils” 13 different soils from Denmark, Finland, Norway and Sweden were selected in order to represent i) soils covering the main areas of the Nordic area, ii) soils from the different climatic regions, and iii) environmental sensitive soils. The 13 Nordic Reference Soils provided an excellent basis for the evaluation of the WRB (World Reference Base for Soil Resources) performance under Nordic conditions. Classification according to the WRB poses considerable problems. These concern podzolized soils, cultivated soils, and the acid sulfate soils. Only three out of the seven podzolized soils are allocated in taxons reflecting that they were podzolized. Four out of the nine cultivated soils were exposed to substantial anthropogenic impact, resulting in man-made Mollic A-horizons, which is not reflected in the classification. The WRB-classification of the soils is compared with the FAO and Soil Taxonomy classification. This highlighted some of the classification problems. This paper will propose changes to the WRB in order to improve the performance of the system for Nordic soils. Geografisk Tidsskrift, Danish Journal of Geography 100: 15–26 相似文献
13.
Katrin Wendt-Potthoff Matthias KoschorreckMarta Diez Ercilla Javier Sánchez España 《Limnologica》2012,42(3):175-188
Microbial activity, abundance and biomass, and biogeochemical cycling of iron, sulphur and carbon were studied in the extremely acidic (pH 2.5-4.3), meromictic, nutrient-rich pit lake Cueva de la Mora in Spain. The goal was to find out (1) if the relatively high nutrient content influenced plankton abundance in the water column and alkalinity-producing microbial processes in the sediments compared to other acid pit lakes, and (2) if sediments in the shallow, mixed and the deep, stagnant parts of the lake exhibited differences in microbial activities and geochemical sediment composition related to meromixis. We hypothesised that redox cycling was more intense in the mixed part and higher amounts of reduced components would accumulate in the stagnant part. Especially phytoplankton biomass, CO2 production, and sulphate reduction were indeed higher than reported from typical acid pit lakes and were rather within the range of neutral or weakly acidic lakes, which can be attributed to the relatively high nutrient contents of Cueva de la Mora. Even in the monimolimnion, anaerobic processes occurred mainly in the sediments. Sediments from the mixed and stagnant parts of the lake differed markedly in their biogeochemistry. Mixolimnetic sediments showed high iron and sulphate reduction rates, and they appeared to undergo substantial recycling, as supported by reactive Fe, relation between gross sulphate reduction rate and net accumulation of reduced sulphur, and viable counts of iron and sulphur bacteria. Monimolimnetic sediments exhibited lower anaerobic microbial activities, and surprisingly they accumulated more Fe(II) than mixolimnetic sediments, but less reduced sulphur and carbon. This might be explained by a strong separation of the two water bodies, resulting in comparably less input of energy (light) and allochthonous matter into the monimolimnion. Regarding the total extent of alkalinity-generating microbial processes, their net effect is not sufficient to neutralise the lake within decades. 相似文献
14.
15.
Implications of EU-Water Framework Directive for the East German Postmining Landscape Lausitz: Coping with a sparse knowledge of the underground 总被引：1，自引：0，他引：1
Bastian Johannes Graupner Friedrich-Carl Benthaus Stephan Bürger Florian Werner 《Limnologica》2005,35(3):199-205
Mining dumps are major sources of pollutants within the mining area of Lausitz, especially sulphate and iron. Their existence in catchment areas comprising groundwater bodies or lakes often imposes negative effects on the water quality. The European Union Water Framework Directive [EU-WFD, 2000. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy. The European Parliament and Council, L327/1, p. 72] aims to achieve ‘good quality’ status for all water bodies across Europe by 2015. Consequently, predicting the development of ground and lake water quality is necessary and must be based on the geochemical composition of the mining dumps. Therefore, the dumps need to be quantified as pollutant sources.A method to calculate the amount of sulphate in mine dumps is presented. It is based on historic geological and geochemical data characterising the pre-mining situation. Additional information on the dump body, derived from the vertical extension of mining activities and the current Digital Elevation Model (DEM), allows the composition of the dump to be determined. This procedure is demonstrated for the Bärwalde site. An average total sulphur content of 0.62% (5.9 million tonnes) was calculated for the Bärwalde dump. About 40% of it is estimated to be pyrite sulphur. Applying an average pyrite oxidation rate for the whole dump body of 7% led to an additional water-soluble mass of 0.18 million tonnes of sulphate sulphur.Applying this technique to all mine dumps managed by the postmining administration company LMBV, will improve our knowledge of the catchment area for the different lakes of Lausitz and will form an essential basis for reactive transport calculations. 相似文献
16.
The factors controlling the chemistry of 69 low-order streams in the Blue Ridge and Valley and Ridge physiographic provinces of Virginia and Maryland were studied over a 13-month period. Principal component analysis was used to examine regional patterns in stream chemistry and to examine the degree to which the chemistry of low-order streams is controlled by the bedrock upon which they flow. Streams clustered into regionally isolated groups, strongly related to bedrock type, with SO2?4 and HCO?3 the chemical variables of most importance. Sulphate concentrations appear to be strongly controlled by climate and hydrology, and sorption in the soils within the watershed. Much of the atmospherically derived SO2?4 accumulates in watersheds during the growing season and is later flushed out. Weathering reactions were found to be particularly important in the production of HCO?3, accounting for 91 per cent on an annual basis, and export of divalent cations from these watersheds, accounting for 48–50 per cent on an annual basis. About half of non-anthropogenic Na+ was derived from weathering of silicates, whereas nearly all K+ was identified with leaching by SO2?4. Water chemistry was strongly related to the rock type in the watershed and the weatherability of the component minerals. Rock type is not a randomly distributed function; instead, it is controlled by geologic factors that result in clusters of similar rock types in a given region. When planning large synoptic studies, it is extremely important to consider that a sampling scheme based on random sampling of a non-randomly distributed function May, not provide the most accurate representation of the variables of interest. Instead, a hierarchical sampling scheme May, be indicated. Our results also suggest that, although one sample in time May, be sufficient to characterize the primary geochemical factors controlling stream chemistry throughout the year, it May, not be sufficient to detect subtle, flow-related alterations in chemistry. 相似文献
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18.
Felix Bilek 《Environmental Geology》2006,49(5):674-683
Dump groundwaters in the former East-German lignite-mining district are characterized by high amounts of ferrous iron and
sulphate. Both the pyrite weathering products endanger the surface water quality when discharged into lakes. Only the precipitation
of both contaminants in the subsurface can prevent the further contamination of surface waters. The two-step process of microbial
catalyzed sulphate reduction and iron sulphide precipitation is limited by the low availability of natural organic substances
as electron donators. Therefore, a new remediation technique is developed based on the injection of a liquid organic electron
donator (methanol) into the contaminated aquifer. The saturated aquifer is used as a bioreactor, where iron monosulphides
are precipitated in the groundwater-filled pore space. Column experiments were performed under natural pressure and temperature
conditions with natural anoxic groundwater and original sediments to test the remediation technology. The test showed that
a complete iron removal (4 mmol/l), even under rather acid conditions (pH 3.8), is possible after having established an active
sulphate reducer population. The turnover of the added organic substance with sulphate is complete and the amount of the resulting
sulphide controls the effluent pH. In addition, intensified microbial activity triggers the turnover of natural organic substances.
Also, natural Fe(III) hydroxides react with the sulphide produced. Considering the long natural retention times (decades),
artificially enhanced FeS precipitation is spontaneous, although it shows kinetic behaviour in the range of days. In light
of the promising results, the development of a field scale application of this technique is considered to be necessary. It
will have to focus on the improved precipitation control of the FeS in the subsurface. 相似文献
19.
In Lorraine, flooding of the iron mines leads to a degradation of groundwater quality. Based on a global approach, a numerical simulator has been built that can reproduce and predict the evolution of water quality at the overflow point of the mining basin. In order to specify the spatial distribution of these pollutant concentrations, a new model has been developed. The basin is represented as a network of homogeneous reservoirs. Although encouraging, the results show the need to specify the spatial organisation of water flow in order to reproduce the pollutant concentrations in the different monitored wells. To cite this article: P. Collon et al., C. R. Geoscience 337 (2005). 相似文献
20.
Ming Chee Yeung Sze Chung Lee Bit Hon Lun Peter A. Tanner 《Atmospheric Research》2007,86(3-4):241-248
During the summer monsoon period in south-east Asia marine airstreams normally prevail at the south China coast. However, when tropical cyclones approach then polluted airmasses from south-eastern China can impart high ionic concentrations and high acidity to rainwater. This is illustrated by two examples and the small-scale horizontal variations in rainwater composition are minor during these episodes. Since long-term quality-assured studies of the composition of rainwater in south-east Asia are scarce, the results at three sampling sites in Hong Kong during summer monsoon periods are compared with previous data from the same season. The results for the mid- to end-1990's show a similar trend to those for the ambient concentrations of sulphate and nitrate in aerosol in Hong Kong, which show flattened trends from 1995 to 1999. A marked increase in acidity is found in the summer monsoon period of 2004 which is attributed to the greater proportion of approaching cyclone weather systems in the dataset, reflecting both the increased local emission sources and the burgeoning economic growth of the Pearl River Delta Region. Comparison of the rainwater composition with that at other south-east Asian cities during the summer monsoon period shows that it is most acidic in Hong Kong. 相似文献