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111.
A fuzzy logic approach has been developed to assess the groundwater pollution levels below agricultural fields. The data collected
for Kumluca Plain of Turkey have been utilized to develop the approach. The plain is known with its intensive agricultural
activities, which imply excessive application of fertilizers. The characteristics of the soils and underlying groundwater
for this plain were monitored during the years 1999 and 2000. Additionally, an extensive field survey related to the types
and yields of crops, fertilizer application and irrigation water was carried out. Both the soil and groundwater have exhibited
high levels of nitrogen, phosphorus and salinity with considerable spatial and temporal variations. The pollution level of
groundwater at several established stations within the plain were assessed using Fuzzy Logic. Water Pollution Index (WPI)
values are calculated by Fuzzy Logic utilizing the most significant groundwater pollutants in the area namely nitrite, nitrate
and orthophosphate together with the groundwater vulnerability to pollution. The results of the calculated WPI and the monitoring
study have yielded good agreement. WPI indicated high to moderate water pollution levels at Kumluca plain depending on factors
such as agricultural age, depth to groundwater, soil characteristics and vulnerability of groundwater to pollution. Fuzzy
Logic approach has shown to be a practical, simple and useful tool to assess groundwater pollution levels. 相似文献
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113.
Robert K. Hall Gary A. Wolinsky Peter Husby James Harrington Patti Spindler Karen Vargas Gordon Smith 《Environmental monitoring and assessment》2000,64(1):17-30
U.S. EPA Region IX is supporting bioassessment programs in Arizona, California, Hawaii and Nevada using biocriteria program and Regional Environmental Monitoring and Assessment Program (R-EMAP) resources. These programs are designed to improve the state, tribal and regional ability to determine the status of water quality. Biocriteria program funds were used to coordinate with Arizona, California and Hawaii which resulted in these states establishing reference conditions and in developing biological indices. U.S. EPA Region IX has initiated R-EMAP projects in California and Nevada. These U.S. EPA Region IX sponsored programs have provided an opportunity to interact with the States and provide them with technical and management support. In Arizona, several projects are being conducted to develop the State's bioassessment program. These include the development of a rotational random monitoring program; a regional reference approach for macroinvertebrate bioassessments; ecoregion approach to testing and adoption of an alternate regional classification system; and development of warm-water and cold-water indices of biological integrity. The indices are projected to be used in the Arizona Department of Environmental Quality (ADEQ) 2000 water quality assessment report. In California, an Index of Biological Integrity (IBI) has been developed for the Russian River Watershed using resources from U.S. EPA's Non-point Source (NPS) Program grants. A regional IBI is under development for certain water bodies in the San Diego Regional Water Quality Control Board. Resources from the U.S. EPA Biocriteria program are being used to support the California Aquatic Bioassessment Workgroup (CABW) in conjunction with the California Department of Fish & Game (CDFG), and to support the Hawaii Department of Health (DoH) Bioassessment Program to refine biological metrics. In Nevada, R-EMAP resources are being used to create a baseline of aquatic information for the Humboldt River watershed. U.S. EPA Region IX is presently working with the Nevada Division of Environmental Protection (NDEP) to establish a Nevada Aquatic Bioassessment Workgroup. Future R-EMAP studies will occur in the Calleguas Creek watershed in Southern California, and in the Muddy and Virgin River watersheds in southern Nevada, and the Walker River watershed in eastern California and west-central Nevada. 相似文献
114.
Enrichment and fractionation of heavy metals in bed sediments of River Narmada, India 总被引:2,自引:0,他引:2
A metal fractionation study on bed sediments of River Narmada in Central India has been carried out to examine the enrichment
and partitioning of different metal species between five geochemical phases (exchangeable fraction, carbonate fraction, Fe/Mn
oxide fraction, organic fraction and residual fraction). The river receives toxic substances through a large number of tributaries
and drains flowing in the catchment of the river. The toxic substances of particular interest are heavy metals derived from
urban runoff as well as municipal sewage and industrial effluents. Heavy metals entering the river get adsorbed onto the suspended
sediments, which in due course of time settle down in the bottom of the river. In this study fractionation of metal ions has
been carried out with the objective to determine the eco-toxic potential of metal ions. Although, in most cases (except iron)
the average trace/heavy metal concentrations in sediments were higher than the standard shale values, the risk assessment
code as applied to the present study reveals that only about 1–3% of manganese, <1% of copper, 16–19% of nickel, 4–20% of
chromium, 1–4% of lead, 8–13% of cadmium and 1–3% of zinc exist in exchangeable fraction and therefore falls under low to
medium risk category. According to the Geo-accumulation Index (GAI), cadmium shows high accumulation in the river sediments,
rest of other metals are under unpolluted to moderately polluted class. 相似文献
115.
The US Army Corps of Engineers often requires wetland creation or restoration as compensation for wetlands damaged during
development. These wetlands are typically monitored postconstruction to determine the level of compliance with respect to
site-specific performance standards. However, defining appropriate goals and measuring success of restorations has proven
difficult. We reviewed monitoring information for 76 wetlands constructed between 1992 and 2002 to summarize the performance
criteria used to measure progress, assess compliance with those criteria, and, finally, to evaluate the appropriateness of
those criteria. Goals were overwhelmingly focused on plant communities. Attributes used to assess the quality of restored
plant communities, including percent native species and the Floristic Quality Index, increased over time but were apparently
unrelated to the number of species planted. Compliance frequencies varied depending on site goals; sites often failed to comply
with criteria related to survival of planted vegetation or requirements that dominant plant species should not be exotic or
weedy, whereas criteria related to the establishment of cover by vegetation or by wetland-dependent plants were often met.
Judgment of a site’s success or failure was largely a function of the goals set for the site. Some performance criteria were
too lenient to be of value in distinguishing failed from successful sites, whereas other criteria were unachievable without
more intensive site management. More appropriate goals could be devised for restored wetlands by basing performance standards
on past performance of similar restorations, identifying consistent temporal trends in attributes of restored sites, and using
natural wetlands as references. 相似文献
116.
环境空气质量评价的普适指数公式 总被引:4,自引:0,他引:4
在适当设定空气污染物的基准值和用相对于基准值的空气污染物的“相对”值情况下,采用S型曲线表示空气污染物对环境空气质量的危害程度,并应用遗传算法优化公式中的参数,得出了一个对多种空气污染物通用的环境空气质量评价的普适指数公式。借助于折衷型激励功效函数将单基污染物分指数加权为综合指数。该公式形式简单,容量计算、评价结果精度较高,且具有可比性。 相似文献
117.
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120.
基于国家新型城镇化与"T"字型发展战略理论内涵,选取长江沿岸上、中、下游中心城市重庆、武汉和南京为实证研究对象,以1980、1990、2000、2010年4期遥感影像资料为基础数据源,通过RS、GIS和景观生态结合分析,分别对其城市扩张强度、城市扩张类型和城市建设用地扩张弹性进行对比分析,并采用景观指数进行了进一步分析和验证,从而系统分析了近30 a来3个城市建设用地扩张的时空特征与内在机理。结果表明:(1)30 a来,南京、武汉和重庆3市城市扩张强度均呈明显上升趋势,总体呈现南京市>武汉市>重庆市,但2000年是一个分水岭,之后重庆市城市扩张增速赶超武汉市,南京市反而增速最低;(2)对城市扩张类型分析表明,南京市始终以边缘式增长为主;武汉市在2000年之前以飞地式扩张主导,2000年之后呈现边缘式增长;重庆市以边缘式增长为主,但2000年之后飞地式增长迅速;(3)从城市建设用地扩张弹性分析表明,1980~2010年南京市土地扩张相比城市人口开始减缓,而武汉市和重庆市在2000年以后城市扩张速度远远超过城市人口增长速度;(4)景观指数验证分析结果显示,遥感分析、地理信息分析和景观生态分析的结合能够很好反映城市建设用地的扩张过程及演化特征。 相似文献