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991.
Pollution mitigation is an important target for restored wetlands, and although there is much information in relation to nutrient removal, little attention has been paid to emerging contaminants. This paper reports on the occurrence and attenuation capacity of 17 emerging contaminants in a restored wetland and two rivers in North-East Denmark. The compounds belong to the groups of pharmaceuticals, fragrances, antiseptics, fire retardants, pesticides, and plasticizers. Concentrations in surface waters ranged from 2 to 1476 ng L−1. The compounds with the highest concentrations were diclofenac, 2-methyl-4-chlorophenoxyacetic acid (MCPA), caffeine, and tris(2-chloroethyl) phosphate (TCEP). The herbicide concentrations increased after a rain-fall event, demonstrating the agricultural run-off origin of these compounds, whereas the concentration of the other emerging contaminants was rather conservative. The mitigation capacity of the restored wetland for the compounds ranged from no attenuation to 84% attenuation (19% on average). Hence, restored wetlands may be considered as a feasible alternative for mitigating emerging contaminants from river waters.  相似文献   
992.
Column leaching testing can be considered a better basis for assessing field impact data than any other available batch test method and thus provides a fundamental basis from which to estimate constituent release under a variety of field conditions. However, column testing is time-intensive compared to the more simplified batch testing, and may not always be a viable option when making decisions for material reuse. Batch tests are used most frequently as a simple tool for compliance or quality control reasons. Therefore, it is important to compare the release that occurs under batch and column testing, and establish conservative interpretation protocols for extrapolation from batch data when column data are not available. Five different materials (concrete, construction debris, aluminum recycling residue, coal fly ash and bottom ash) were evaluated via batch and column testing, including different column flow regimes (continuously saturated and intermittent unsaturated flow). Constituent release data from batch and column tests were compared. Results showed no significant difference between the column flow regimes when constituent release data from batch and column tests were compared. In most cases batch and column testing agreed when presented in the form of cumulative release. For arsenic in carbonated materials, however, batch testing underestimates the column constituent release for most LS ratios and also on a cumulative basis. For cases when As is a constituent of concern, column testing may be required.  相似文献   
993.
To include consequences emanating from former military sites on the drinking water supply, a catalog of criteria has been developed which permits the determination and assessment of the hazards in general and their impact on human health in particular. The assessment criteria correspond to the special requirements and standards for drinking water hygiene and protection in Germany. The criterion catalog is a completion module to the usual praxis and existing conceptions, and has proved its practical value in the initial assessment of military sites in the new federal states of Germany. The scheme is a control instrument suitable for obtaining an assessment concerning the extent to which drinking-water resources are and will be affected by former waste disposal and other contaminated sites at the present and in the future.  相似文献   
994.
Increasing human impact on stream ecosystems has resulted in a growing need for tools helping managers to develop conservations strategies, and environmental monitoring is crucial for this development. This paper describes the development of models predicting the presence of fish assemblages in lowland streams using solely cost-effective GIS-derived land use variables. Three hundred thirty-five stream sites were separated into two groups based on size. Within each group, fish abundance data and cluster analysis were used to determine the composition of fish assemblages. The occurrence of assemblages was predicted using a dataset containing land use variables at three spatial scales (50 m riparian corridor, 500 m riparian corridor and the entire catchment) supplemented by a dataset on in-stream variables. The overall classification success varied between 66.1–81.1% and was only marginally better when using in-stream variables than when applying only GIS variables. Also, the prediction power of a model combining GIS and in-stream variables was only slightly better than prediction based solely on GIS variables. The possibility of obtaining precise predictions without using costly in-stream variables offers great potential in the design of monitoring programmes as the distribution of monitoring sites along a gradient in ecological quality can be done at a low cost.  相似文献   
995.
Changes in Arctic vegetation can have important implications for trophic interactions and ecosystem functioning leading to climate feedbacks. Plot-based vegetation surveys provide detailed insight into vegetation changes at sites around the Arctic and improve our ability to predict the impacts of environmental change on tundra ecosystems. Here, we review studies of changes in plant community composition and phenology from both long-term monitoring and warming experiments in Arctic environments. We find that Arctic plant communities and species are generally sensitive to warming, but trends over a period of time are heterogeneous and complex and do not always mirror expectations based on responses to experimental manipulations. Our findings highlight the need for more geographically widespread, integrated, and comprehensive monitoring efforts that can better resolve the interacting effects of warming and other local and regional ecological factors.  相似文献   
996.
The ECOSYS model is the ingestion dose model integrated in the ARGOS and RODOS decision support systems for nuclear emergency management. The parameters used in this model have however not been updated in recent years, where the level of knowledge on various environmental processes has increased considerably. A Nordic work group has carried out a series of evaluations of the general validity of current ECOSYS default parameters. This paper specifically discusses the parameter revisions required with respect to the modelling of deposition and natural weathering of contaminants on agricultural crops, to enable the trustworthy prognostic modelling that is essential to ensure justification and optimisation of countermeasure strategies. New modelling approaches are outlined, since it was found that current ECOSYS approaches for deposition and natural weathering could lead to large prognostic errors.  相似文献   
997.
Nielsen KE  Degn HJ  Damgaard C  Bruus M  Nygaard B 《Ambio》2011,40(7):819-823
A new species has recently invaded coastal dune ecosystems in North West Europe. The native and expansive inland grass, Deschampsia flexuosa, progressively dominating inland heaths, has recently invaded coastal dunes in Denmark, occasionally even as a dominant species. A total of 222 coastal locations with 5,000 random sample plots have been investigated. These findings are in contrast to historical records, and D. flexuosa has never been considered belonging to coastal dune ecosystems. The occurrence of the typical inland grass in the coastal dunes is a strong indication of increase in nutrient level and that human influences may cause a native species to be invasive in new ecosystems. This could be a radical example of change in species composition due to a long lasting exceedance of critical load of nitrogen. The investigation also showed a general increase in cover of the most dominant species.  相似文献   
998.
NanoRem (Taking Nanotechnological Remediation Processes from Lab Scale to End User Applications for the Restoration of a Clean Environment) was a research project, funded through the European Commission's Seventh Framework Programme, which focuses on facilitating practical, safe, economic, and exploitable nanotechnology for in situ remediation of polluted soil and groundwater, which closed in January 2017. This article describes the status of the nanoremediation implementation and future opportunities for deployment based on risk‐benefit appraisal and benchmarking undertaken in the NanoRem Project. As of November 2016, NanoRem identified 100 deployments of nanoremediation in the field. While the majority of these are pilot‐scale deployments, there are a number of large scale deployments over the last five to 10 years. Most applications have been for plume control (i.e., pathway management in groundwater), but a number of source control measures appear to have taken place. Nanoremediation has been most frequently applied to problems of chlorinated solvents and metals (such as chromium VI). The perception of risk‐benefit balance for nanoremediation has shifted as the NanoRem Project has proceeded. Niche benefits are now more strongly recognized, and some (if not most) of the concerns, for example, relating to environmental risks of nanoremediation deployment, prevalent when the project was proposed and initiated, have been addressed. Indeed, these now appear overstated. However, it appears to remain the case that in some jurisdictions the use of nanoparticles remains less attractive owing to regulatory concerns and/or a lack of awareness, meaning that regulators may demand additional verification measures compared to technologies with which they have a greater level of comfort.  相似文献   
999.
Very few real-world measurements of road dust suspension have been performed to date. This study compares two different techniques (referred to as Sniffer and Emma) to measure road dust emissions. The main differences between the systems are the construction of the inlet, different instruments for recording particulate matter (PM) levels, and different loads on the wheel axes (the weight of Sniffer was much higher than that of Emma). Both systems showed substantial small-scale variations of emission levels along the road, likely depending on-road surface conditions. The variations observed correlated quite well, and the discrepancies are likely a result of variations in dust load on the road surface perpendicular to the driving direction that cause variations in the measurements depending on slightly different paths driven by the two vehicles. Both systems showed a substantial influence on the emission levels depending on the type of tire used. The summer tire showed much lower suspension than the winter tires (one nonstudded and one studded). However, the relative importance of the nonstudded versus studded tire was rather different. For the ratio of studded/nonstudded, Emma shows higher values on all road sections compared with Sniffer. Both techniques showed increased emission levels with increasing vehicle speed. When the speed increased from 50 to 80 km hr(-1), the relative concentrations increased by 30-170% depending on the tire type and dust load. However, for road sections that were very dirty, Sniffer showed a much higher relative increase in the emission level with the nonstudded tire. Sniffer's absolute concentrations were mostly higher than Emma's. Possible reasons for the differences are discussed in the paper. Both systems can be used for studying relative road dust emissions and for designing air quality management strategies.  相似文献   
1000.
Fine (PM2.5) and coarse (PM2.5–10) smoke particles from controlled biomass burnings of a shrub-dominated forest in Lousã Mountain, Portugal, enabled the quantification by chromatographic techniques of several molecular tracers for the combustion of Mediterranean forest ecosystems, which could be conducive to source apportionment studies. The major organic components in the smoke samples were pyrolysates of vegetation cuticles, mainly comprising steradienes and sterol derivatives, carbohydrates from the breakdown of cellulose, aliphatic lipids from vegetation waxes and methoxyphenols from the lignin thermal degradation. Most of these compounds are chiefly found in fine particles. Polycyclic aromatic hydrocarbons (PAH) were also present as minor constituents. Anhydrosugar and PAH molecular diagnostic ratios were applied as source assignment tools. Some biomarkers are reported for the first time in biomass burning smoke.  相似文献   
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