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排序方式: 共有10000条查询结果,搜索用时 937 毫秒
861.
J.B. Mann J.J. Freal H.F. Enos J.X. Danauskas 《Journal of environmental science and health. Part. B》2013,48(5):529-543
Abstract EDB (ethylene dibromide) is of regulatory interest because it has cancer inducing properties and is a causative agent of aspermia. Previously evaluated methodology was used to determine the extent of exposure of workers to EDB in citrus fumigation stations and a warehouse used as a holding site before shipment. The purpose of this effort was to carry out environmental sampling, and to determine the exposure level of workers and related administrative personnel at two citrus fumigation centers and at a warehouse 相似文献
862.
863.
864.
近年来,随着经济的发展,高压输变电工程和移动通信基站越来越多地落户于大型居民小区,由此引发的环境投诉和纠纷呈快速上涨趋势。电磁辐射污染投诉产生的原因主要是:电磁辐射环境管理法制不健全,思想上不重视,项目环保审批环节脱节,环保与规划部门信息交流不畅,公众维权意识增强,寻求其他经济利益;针对原因提出的预防和解决办法为:加强法制建设、强化现场监管,理顺项目审批和监管程序,建立与规划部门的联动机制,加强宣传,引导司法解决。 相似文献
865.
866.
基于BP人工神经网络的城市PM2.5浓度空间预测 总被引:1,自引:0,他引:1
针对PM2.5日均质量浓度,采用BP人工神经网络模型,预测研究区空气中PM2.5浓度的空间变异,通过与普通克里格(Ordinary Kriging)插值方法对比验证BP人工神经网络预测模型的精度.结果表明:BP人工神经网络预测模型下研究区检验样本点位置的PM2.5仿真浓度与观测浓度之间的均方差、平均绝对误差、平均相对偏差和相关系数分别为0.296 μg2/m6、0.412 μg/m3、1.650%和0.851;而与此同时,普通克里格插值方法下的对应结果分别为1.041 μg2/m6、0.689 μg/m3、11.910%、0.638.研究成果在肯定BP人工神经网络预测模型可用于揭示PM2.5浓度空间变异特征的同时,也证实了其相对于普通克里格插值方法在固定空间点位准确预测PM2.5浓度方面的优势. 相似文献
867.
868.
Analyzing the cost effectiveness of Santiago, Chile's policy of using urban forests to improve air quality 总被引:4,自引:0,他引:4
Escobedo FJ Wagner JE Nowak DJ De la Maza CL Rodriguez M Crane DE 《Journal of environmental management》2008,86(1):148-157
Santiago, Chile has the distinction of having among the worst urban air pollution problems in Latin America. As part of an atmospheric pollution reduction plan, the Santiago Regional Metropolitan government defined an environmental policy goal of using urban forests to remove particulate matter less than 10 microm (PM(10)) in the Gran Santiago area. We used cost effectiveness, or the process of establishing costs and selecting least cost alternatives for obtaining a defined policy goal of PM(10) removal, to analyze this policy goal. For this study, we quantified PM(10) removal by Santiago's urban forests based on socioeconomic strata and using field and real-time pollution and climate data via a dry deposition urban forest effects model. Municipal urban forest management costs were estimated using management cost surveys and Chilean Ministry of Planning and Cooperation documents. Results indicate that managing municipal urban forests (trees, shrubs, and grass whose management is under the jurisdiction of Santiago's 36 municipalities) to remove PM(10) was a cost-effective policy for abating PM(10) based on criteria set by the World Bank. In addition, we compared the cost effectiveness of managing municipal urban forests and street trees to other control policies (e.g. alternative fuels) to abate PM(10) in Santiago and determined that municipal urban forest management efficiency was similar to these other air quality improvement measures. 相似文献
869.
870.
Inter-seasonal studies on the trace metal load of surface water, sediment and Tympanotonus fuscatus var. radula of Iko River were conducted between 2003 and 2004. The impact of anthropogenic activities especially industrial effluent,
petroleum related wastes, gas flare and episodic oil spills on the ecosystem are remarkable. Trace metals analyzed included
cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), vanadium (V) and zinc (Zn). Sediment
particle size analysis revealed that they were characteristically psammitic and were predominantly of medium to fine grained
sand (>73%), less of silt (<15%) and clay (<10%). These results correlated with low levels of trace elements such as Pb (0.03 ± 0.02 mg kg−1), Cr (0.22 ± 0.12 mg kg−1), Cd (0.05 ± 0.03 mg kg−1), Cu (0.04 ± 0.02 mg kg−1) and Mn (0.23 ± 0.22 mg kg−1) in the sediment samples. This observation is consistent with the scarcity of clayey materials known to be good scavengers
for metallic and organic contaminants. Sediments indicated enhanced concentration of Fe, Ni and V, while other metal levels
were relatively low. The concentrations of all the metals except Pb in surface water were within the permissible levels, suggesting
that the petroleum contaminants had minimal effect on the state of pollution by trace metals in Iko River. Notably, the pollutant
concentrations in the sediments were markedly higher than the corresponding concentrations in surface water and T. fuscatus tissues, and decreased with distance from point sources of pollution. 相似文献