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461.
De Rooij C Defourny C Thompson RS Garny V Lecloux A van Wijk D 《Environmental monitoring and assessment》2004,97(1-3):39-56
This risk assessment on 1,1,1-trichloroethane was carried out specifically for the marine environment, accordingly to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1996). 1,1,1-trichloroethane is being phased out of most uses because of its ozone depletion potential (ODP) under the Montreal Protocol. Production for emissive uses has already been phased out end 1995 in Europe and 1996 in the United States, Japan and other industrial countries. The risk assessment study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programmes in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the Predicted Environmental Concentration (PEC) and the Predicted No-Effect Concentration (PNEC) for the marine aquatic environment. In total 14 studies for fish, 7 studies for invertebrates and 9 studies for algae have been evaluated. Both acute and chronic studies have been taken into account and the appropriate assessment factors have been used to calculate a PNEC value of 21 microg/l based on long term exposure. The PEC was derived from monitoring data. The PEC was set at 0.206 microg/l (worst case) and 0.024 microg/l (typical case) for coastal waters and estuaries and 0.6 microg/l (worst case) and <0.1 microg/l (typical case) for river waters. The calculated PEC/PNEC ratios, which do not take into account any dilution factor within the sea, correspond to a safety margin of 35 to 1000 between the aquatic effect and the exposure concentration. 1,1,1-trichloroethane is not a 'toxic, persistent and liable to bioaccumulate' substance according to the criteria as mentioned by the Oslo and Paris Conventions for the Prevention of Marine Pollution (OSPAR-DYNAMEC). It can be concluded that the present use of 1,1,1-trichloroethane does not present a risk to the marine aquatic environment. 相似文献
462.
Decreasing reliance on mineral nitrogen--yet more food 总被引:2,自引:0,他引:2
Higher crop production normally demands higher nutrient application rates and consequently increased mineral nitrogen use. With food demand for 2030 estimated around 2800 mill. tonnes (t) yr-1, the corresponding mineral N consumption figure is 96 mill. t (78 mill. t yr-1 in 1995/1997). Global-level mineral N losses to the environment from mineral fertilizer use are currently 36 mill. t yr-1, worth USD 11,700 mill. and with adverse environmental impacts. However, innovative fertilizer-use efficiency (FUE) technologies enable increased production with a less than a proportionate increase in mineral-N use. Moreover, nitrogen-nutrient supplies can be augmented through improvements in agricultural production systems and in the exploitation of alternative sources such as biological nitrogen fixation (BNF). By 2030, with adequate policy, technology transfer, research and investment support, the on-farm adoption of BNF and FUE technologies could generate savings of 10 mill. t yr-1 of mineral N, worth USD 3300 mill. 相似文献
463.
Assessing Landscape Functions with Broad-Scale Environmental Data: Insights Gained from a Prototype Development for Europe 总被引:4,自引:0,他引:4
Felix Kienast Janine Bolliger Marion Potschin Rudolf S. de Groot Peter H. Verburg Iris Heller Dirk Wascher Roy Haines-Young 《Environmental management》2009,44(6):1099-1120
We examine the advantages and disadvantages of a methodological framework designed to analyze the poorly understood relationships
between the ecosystem properties of large portions of land, and their capacities (stocks) to provide goods and services (flows).
These capacities (stocks) are referred to as landscape functions. The core of our assessment is a set of expert- and literature-driven
binary links, expressing whether specific land uses or other environmental properties have a supportive or neutral role for
given landscape functions. The binary links were applied to the environmental properties of 581 administrative units of Europe
with widely differing environmental conditions and this resulted in a spatially explicit landscape function assessment. To
check under what circumstances the binary links are able to replace complex interrelations, we compared the landscape function
maps with independently generated continent-wide assessments (maps of ecosystem services or environmental parameters/indicators).
This rigorous testing revealed that for 9 out of 15 functions the straightforward binary links work satisfactorily and generate
plausible geographical patterns. This conclusion holds primarily for production functions. The sensitivity of the nine landscape
functions to changes in land use was assessed with four land use scenarios (IPCC SRES). It was found that most European regions
maintain their capacity to provide the selected services under any of the four scenarios, although in some cases at other
locations within the region. At the proposed continental scale, the selected input parameters are thus valid proxies which
can be used to assess the mid-term potential of landscapes to provide goods and services. 相似文献
464.
ABSTRACT In forest frontiers, smallholder agrarian livelihoods remain uneasily juxtaposed with conservation interests. Agricultural intensification is often considered a viable means of reconciling competing environmental and livelihood objectives given its potential to concentrate production on less land. However, intensification may have unintended consequences, including loss of resilient agricultural systems. The risks of smallholder agricultural intensification warrant a better understanding of its drivers. This study uses the case of Calakmul, Mexico, to examine the critical role of the state in intensification processes. Drawing on household surveys and key-informant interviews, it traces the linkages between state institutions and local farming practices. Statistical and qualitative analyses reveal how intensification is both incentivized and imposed by prevailing policies, the former via subsidies and the latter via regulations against field rotations. The outcome – increased external inputs and longer cultivation periods between fallows – may undermine the sustainability of smallholders’ agroecosystems, an undesirable consequence amid limited livelihood alternatives. 相似文献