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881.
分析了《地表水环境质量评价办法(试行)》在应用过程中显现的问题,提出了增加地区特征污染物污染情况说明,补充水质状况定性评价特殊情况说明和变化趋势评价方法的判断优先级别,明确数据修约方式、检出限以下测值的评价方法及水质类别不同而标准限值相同的指标评价方法等建议。 相似文献
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884.
Economic Development,Rural livelihoods,and Ecological Restoration: Evidence from China 总被引:3,自引:0,他引:3
This article uses a case study in Southeast China to demonstrate how the substantial changes in rural livelihoods have been
driven by a combination of “pull” forces from external economic development, and “push” forces from local areas, leading to
a shift in rural household economic activities: household outmigration and de-population of the countryside, changes in energy
consumption, and most importantly, changes in land uses and eventually, ecological restoration. Such dramatic changes are
becoming common across the Chinese countryside. It is pointed out that economic development has generally caused a deterioration
of the environment at least at the early period of economic growth, but the positive impacts, especially in some ecosystem
in rural areas, have become more apparent. 相似文献
885.
Climate change scenarios predict lower flow rates during summer that may lead to higher proportions of wastewater in small and medium sized streams. Moreover, micropollutants (e.g. pharmaceuticals and other contaminants) continuously enter aquatic environments via treated wastewater. However, there is a paucity of knowledge, whether extended exposure to secondary treated wastewater disrupts important ecosystem functions, e.g. leaf breakdown. Therefore, the amphipod shredder Gammarus fossarum was exposed to natural stream water (n = 34) and secondary treated wastewater (n = 32) for four weeks in a semi-static test system under laboratory conditions. G. fossarum exposed to wastewater showed significant reductions in feeding rate (25%), absolute consumption (35%), food assimilation (50%), dry weight (18%) and lipid content (22%). Thus, high proportions of wastewater in the stream flow may affect both the breakdown rates of leaf material and thus the availability of energy for the aquatic food web as well as the energy budget of G. fossarum. 相似文献
886.
The concentrations of heavy metals (Cr, Cd, Hg, Cu, Zn, Pb and As) in the water, sediment, and fish were investigated in the middle and lower reaches of the Yangtze River, China. Potential ecological risk analysis of sediment heavy metal concentrations indicated that six sites in the middle reach, half of the sites in the lower reach, and two sites in lakes, posed moderate or considerable ecological risk. Health risk analysis of individual heavy metals in fish tissue indicated safe levels for the general population and for fisherman but, in combination, there was a possible risk in terms of total target hazard quotients. Correlation analysis and PCA found that heavy metals (Hg, Cd, Pb, Cr, Cu, and Zn) may be mainly derived from metal processing, electroplating industries, industrial wastewater, and domestic sewage. Hg may also originate from coal combustion. Significant positive correlations between TN and As were observed. 相似文献
887.
Evaluation of alternative PCB clean-up strategies using an individual-based population model of mink
Salice CJ Sample BE Miller Neilan R Rose KA Sable S 《Environmental pollution (Barking, Essex : 1987)》2011,159(12):3334-3343
Population models can be used to place observed toxic effects into an assessment of the impacts on population-level endpoints, which are generally considered to provide greater ecological insight and relevance. We used an individual-based model of mink to evaluate the population-level effects of exposure to polychlorinated biphenyls (PCBs) and the impact that different remediation strategies had on mink population endpoints (population size and extinction risk). Our simulations indicated that the initial population size had a strong impact on mink population dynamics. In addition, mink populations were extremely responsive to clean-up scenarios that were initiated soon after the contamination event. In fact, the rate of PCB clean-up did not have as strong a positive effect on mink as did the initiation of clean-up (start time). We show that population-level approaches can be used to understand adverse effects of contamination and to also explore the potential benefits of various remediation strategies. 相似文献
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Ben J. Kefford Liliana Zalizniak Dayanthi Nugegoda 《Environmental pollution (Barking, Essex : 1987)》2010,158(2):543-2129
The effects of suspended and deposited sediments on the macroinvertebrates are well documented in upland streams but not in slower flowing lowland rivers. Using species found in lowland lotic environments, we experimentally evaluate mechanisms for sediments to affect macroinvertebrates, and in one experiment whether salinity alters the effect of suspended sediments. Suspended kaolin clay reduced feeding of Ischnura heterosticta (Odonata: Coenagrionidae) at high turbidity (1000-1500 NTU) but had no effects on feeding of Hemianax papuensis (Odonata: Aeshnidae) and Micronecta australiensis (Hemiptera: Corixidae). In freshwater (0.1 mS/cm), survival of Ischnura aurora was poor in clear water, but improved with suspended kaolin. Growth and feeding of I. aurora were unaffected by suspended sediments and salinity. Burial (1-5 mm) of eggs with kaolin or sand reduced hatching in Physa acuta (Gastropoda: Physidae), Gyraulus tasmanica (Gastropoda: Planorbidae) and Chironomus cloacalis (Diptera: Chironomidae). Settling sediments may pose greater risk to lowland lotic invertebrates than suspended sediments. 相似文献
890.