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801.
对上海市1992-2007年湿沉降监测结果进行研究,16年来,上海市湿沉降主要呈现以下特征:pH总体呈现下降趋势,酸雨频率呈现上升趋势;2002年起升幅很大;硫酸根离子和钙离子浓度总体呈下降趋势,2003年后,各离子浓度都有一定程度下降;钙离子在总阳离子中的比例总体上明显下降,铵离子与总阳离子的百分比总体上呈上升趋势;硫酸根离子在总阴离子中的比例有所下降,硝酸根离子与总阴离子的百分比则一直呈上升趋势;硫酸根与硝酸根年均值的比值总体上呈明显的下降趋势,表明硫酸型在逐渐减弱;钙离子与铵离子的比值总体上也呈明显的下降趋势。  相似文献   
802.
Marine protected areas (MPAs) are the preferred tool for preventing marine biodiversity loss, as reflected in international protected area targets. Although the area covered by MPAs is expanding, there is a concern that opposition from resource users is driving them into already low-use locations, whereas high-pressure areas remain unprotected, which has serious implications for biodiversity conservation. We tested the spatial relationships between different human-induced pressures on marine biodiversity and global MPAs. We used global, modeled pressure data and the World Database on Protected Areas to calculate the levels of 15 different human-induced pressures inside and outside the world's MPAs. We fitted binomial generalized linear models to the data to determine whether each pressure had a positive or negative effect on the likelihood of an area being protected and whether this effect changed with different categories of protection. Pelagic and artisanal fishing, shipping, and introductions of invasive species by ships had a negative relationship with protection, and this relationship persisted under even the least restrictive categories of protection (e.g., protected areas classified as category VI under the International Union for Conservation of Nature, a category that permits sustainable use). In contrast, pressures from dispersed, diffusive sources (e.g., pollution and ocean acidification) had positive relationships with protection. Our results showed that MPAs are systematically established in areas where there is low political opposition, limiting the capacity of existing MPAs to manage key drivers of biodiversity loss. We suggest that conservation efforts focus on biodiversity outcomes and effective reduction of pressures rather than prescribing area-based targets, and that alternative approaches to conservation are needed in areas where protection is not feasible.  相似文献   
803.
化工企业拆迁场地健康风险评价   总被引:3,自引:0,他引:3  
随着城市的发展,越来越多的工业企业逐步搬迁出主城区,遗留下的场地将会用作商业或居住用地,对这些拆迁场地如不加强环境管理,可能会对公众健康造成危害。以化工企业拆迁场地为例,按照危害识别、暴露评估、毒性评估、风险表征4个步骤,介绍了健康风险评价的一般方法,着重介绍了"危害识别"步骤中对于化工企业拆迁场地环境调查方面的方法与注意事项。最后指出了我国在污染场地健康风险评价方面的不足,并提出了相应的建议。  相似文献   
804.
面向污染场地的环境修复功能材料   总被引:1,自引:0,他引:1       下载免费PDF全文
在回顾环境功能材料研究进展的基础上,将材料按功效分为固化/稳定化材料、氧化还原剂类材料以及催化剂类材料,重点对固化/稳定化材料进行了介绍。根据环境材料科学的发展前沿提出了污染场地环境修复功能材料的发展趋势,并总结了功能材料开发与应用中的一些问题。  相似文献   
805.
沙尘暴--一种跨区域的大气环境污染物   总被引:1,自引:0,他引:1  
文章对十多年来发生在我国西北地区的较大沙尘暴,沙尘暴尘的沉降量、沉降范围、化学组分、粒径分布、对大气环境降尘背景值的影响等问题进行了调查、分析,综述了这方面的一些研究成果。  相似文献   
806.
National networks detect multi-state trends in element deposition using direct measurement methods. Biomonitoring techniques have been used to examine deposition in local areas and around point sources. We sought to determine the efficacy of a moss bag technique to detect element deposition trends on a mid-range (state) scale, and to compare these results with those of the National Acid Deposition Program/National Trends Network (NADP/NTN, 1999). We sampled heavy metals, sulfur, and nitrogen deposition (21 elements) using mesh bags containing Sphagnum russowii at nine sites, over a 375 km transect crossing southern Wisconsin (upper Midwest, USA). We found statistically significant trends of decreasing deposition in a northwesterly direction for 13 elements: Al, B, Ca, Cd, Co, Cu, Cr, Fe, Mg, Mn, Ni, S, and Zn. Six of these have moderate to large changes in concentration (14–37%). The trends for Ca, Mg, and S are consistent with regional deposition patterns in 1998 isopleth maps from the NADP/NTN (1999) which are derived from a sampling array far less dense than the transect sites. This national network indicates that Ca and Mg increase to the southeast, beyond Wisconsin borders. The fact that the present study demonstrates strong correlations between both of these elements (Ca and Mg) and Al, B, Cr, Cu, Fe, Mn, Ni, and Zn (mean r for all correlations = 0.75, p < 0.02) implies that these correlated elements also increase to the southeast in neighboring states.  相似文献   
807.
A probabilistic analysis of atmospheric transport and deposition patterns from two nuclear risk sites-Kamchatka and Vladivostok-situated in the Russian Far East to countries and geographical regions of interest (Japan, China, North and South Koreas, territories of the Russian Far East, State of Alaska, and Aleutian Chain Islands, US) was performed. The main questions addressed were the following: Which geographical territories are at the highest risk from hypothetical releases at these sites? What are the probabilities for radionuclide atmospheric transport and deposition on different neighboring countries in case of accidents at the sites? For analysis, several research tools developed within the Arctic Risk Project were applied: (1) isentropic trajectory model to calculate a multiyear dataset of 5-day forward trajectories that originated over the site locations at various altitudes; (2) DERMA long-range transport model to simulate 5-day atmospheric transport, dispersion, and deposition of 137Cs for 1-day release (at the rate of 10(10) Bq/s); and (3) a set of statistical methods (including exploratory, cluster, and probability fields analyses) for evaluation of trajectory and dispersion modeling results. The possible impact (on annual, seasonal, and monthly basis) of selected risk sites on neighboring geographical regions is evaluated using a set of various indicators. For trajectory modeling, the indicators examined are: (1) atmospheric transport pathways, (2) airflow probability fields, (3) fast transport probability fields, (4) maximum possible impact zone, (5) maximum reaching distance, and (6) typical transport time fields. For dispersion modeling, the indicators examined are: (1) time integrated air concentration, (2) dry deposition, and (3) wet deposition. It was found for both sites that within the boundary layer the westerly flows are dominant throughout the year (more than 60% of the time), increasing with altitude of free troposphere up to 85% of the time. For the Kamchatka site, the US regions are at the highest risk with the average times of atmospheric transport ranging from 3 to 5.1 days and depositions of 10(-1) Bq/m2 and lower. For the Vladivostok site, the northern China and Japan regions are at the highest risk with the average times of atmospheric transport of 0.5 and 1.6 days, respectively, and depositions ranging from 10(0) to 10(+2) Bq/m2. The areas of maximum potentially impacted zones are 30 x 10(4) km2 and 25 x 10(4) km2 for the Kamchatka and Vladivostok sites, respectively.  相似文献   
808.
This study presents the results of the analyses of Cd, Pb, cations and anions present in precipitation and dust at a pre-alpine and a suburban site in Switzerland in the period from 1988 to 2003. The aim of these measurements was to monitor the success of measures taken to diminish pollutant emissions. No change was found for Ca2+, K+, Na+ and Mg2+ loads – in line with expectations, as no reducing measures had been taken. Statistically significant and largely decreasing values (50–90%) were found for Cl and Cd (linked to the fitting of filters in incineration plants), Pb (unleaded petrol), (diminishing the use of mineral oil with high S content), and the proton (lower HCl and SO2 emissions). A smaller decrease (up to 30%) or none was registered for oxidised nitrogen components (fitting cars with catalytic converters, but an increase in numbers of cars and trucks). No significant change was found for NH3 as farming techniques had undergone no major changes. The long-term measurements show that the measures taken to reduce emissions were successful. A shorter monitoring period would have been misleading owing to data variability and temporary incidents e.g. amount of precipitation.  相似文献   
809.
介绍了降水监测数据的阴、阳离子平衡和电导率平衡检验的计算方法,对国家环保总局发布的<酸沉降监测技术规范>(HJ/T165-2004)中公式存在的几个不妥之处提出修正意见.  相似文献   
810.
The temporal changes and spatial variability of phosphorus andnitrogen losses and concentrations in Finland during the period1981–1997 were studied in 15 small agricultural and forestedcatchments. In addition, four coastal river basins with highagricultural land use located in southern Finland were includedin the study in order to assess the representativeness ofagricultural loss estimates from small agricultural catchments.The mean annual loss specific for agricultural land was estimatedto be on average 110 kg km-2 a-1 for total phosphorusand 1500 kg km-2 a-1 for total nitrogen. The resultsfrom small agricultural catchments were in agreement with thecorresponding loss estimates from rivers, with an average of137 kg km-2 a-1 for total phosphorus and 1800 kg km-2a-1 for total nitrogen. The results from the studiedagricultural catchments and rivers during the period 1981–1997suggest that weather-driven fluctuation in discharge was usuallythe main reason for changes in nutrient losses, and little or noimpact of changes in agricultural production or managementpractises can be observed. In forested areas the total phosphorusloss (average 9 kg km-2 a-1) and total nitrogen loss(average 250 kg km-2 a-1) were lower than inagricultural areas. In forested catchments the impact of forestryoperations, such as clear-cutting and fertilization, and theimpact of atmospheric nitrogen deposition can be seen in changesin nutrient losses.  相似文献   
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