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991.
香溪河流域土地利用格局演变对非点源污染的影响研究   总被引:5,自引:0,他引:5  
以分布式模型SWAT为研究工具,在气候、土壤等因素不变的情况下,模拟了三峡库区香溪河流域土地利用格局演变对于非点源污染的影响.研究结果表明,自20世纪80年代至2007年,研究区由土地利用所造成的非点源污染TN总体呈减少趋势,4种土地利用情景下模拟得到的年均非点源污染TN分别为1 841.60、824.86、1 790...  相似文献   
992.
放射源管理系统是一种基于环境地理信息系统平台的资源管理系统,是GIS技术与环境监测技术、环境管理技术、数据库技术等各种环境信息分析和处理技术的集成。系统为环保部门提供了一个功能强大的空间信息服务和管理工具,可以直观、方便地获取放射源的监控、管理等数据信息,为环境管理部门的决策提供依据。  相似文献   
993.
污染当量数在区域现状污染源评价中的应用   总被引:6,自引:0,他引:6  
阐述了污染当量数评价法中的污染当量含义和污染当量的应用、污染当量值、污染当量数以及计算等,介绍r污染当量评价方法和特点。通过对等标污染负荷法和污染当量数评价法的两种评价方法比较,表明污染当量数评价法的评价结果可靠、直观,具有可比性和合理性,是评价污染源区域现状简便、实用的方法。  相似文献   
994.
污染源大数据是环保大数据的重要组成部分,然而在以环境管理制度为基础的污染源数据管理过程中,一直存在制度衔接不流畅、数据不共享等诸多问题。本文调研考察了现有各项环境管理制度的衔接情况,提出以排污许可制度为核心,通过与其他环境管理制度有效衔接,实现环境管理的各个环节的有效覆盖。通过SWOT分析法对基于"一证式"改革的环境管理制度优化方案的可行性和必要性进行了深入分析,并以排污许可证为核心,设计企业环境管理信息系统框架。试生产与竣工环保验收实效不足,可转为企业自行备案;将环评审批结论纳入排污许可证,可大幅度减轻企业相关环境管理业务人员的负担。环境管理制度的优化必须建立在部门职能转变与整合之上;同时,还必须获得国家层面的立法与行政的支持;社会舆论的关注与支持也将推动环境管理制度优化的进程。以排污许可证管理为核心的信息系统框架可以有效实现污染源排放信息整合共享。  相似文献   
995.
谢云  石正坤 《四川环境》2009,28(1):57-63
超临界水氧化是一项对有机废液焚烧处理最有潜力的替代技术,在过去的20多年里,这项技术引起了广泛的关注。然而,作为一项管端技术,超临界水氧化仍存在许多不足,这些不足阻碍了它的工业应用。除了反应器腐蚀和盐析导致的技术问题外,超临界水氧化经常被认为是一项处理所有废液的“通用”技术,然而也是无法实现的“通用”技术。本文介绍了作为管端处理技术的超临界水氧化技术存在的问题,讨论了可能的解决办法,介绍了不同反应器的概念,提出了在超临界水氧化领域里开展进一步研究和发展新工艺流程的建议。此外,评价了超临界水氧化技术涉及到的自身能源供应问题。  相似文献   
996.
Gas/particle partitioning of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in ambient air was investigated in a satellite town in Eastern China from April 2007 to January 2008 comprehending large temperature variations (from 3 to 34 °C, daily average). Molecular weight, molecular structure and ambient temperatures are the three major factors that govern the gas/particle partitioning of atmospheric PCDD/Fs throughout the year. Generally, good agreements were obtained (except for winter) between measured particulate fractions and theoretical estimates of both the Junge–Pankow adsorption model and Harner Bidleman absorption model using different sets of subcooled liquid vapor pressure and octanol–air partition coefficient (Koa), respectively. Models utilizing estimates, derived from gas chromatographic retention indices (GC-RIs), are more accurate than that of entropy-based. Moreover, during winter, the Koa-based model using the GC-RIs approach performs better on lower chlorinated PCDD/Fs than that of -based. Furthermore, possible sources of mismatch between measured and predicted values in winter (3–7 °C) were discussed. Gas adsorption artifact was demonstrated to be of minor importance for the phenomena observed. On the other hand, large deviations of slopes (mr) and intercepts (br) in logKp vs. plots from theoretical values are observed in the literature data and these are found to be linearly correlated with ambient temperatures (P<0.001) in this study. This indicates that the non-equilibrium partitioning of PCDD/Fs in winter may be significantly influenced by the colder temperatures that may have slowed down the exchange between gaseous and particulate fractions.  相似文献   
997.
建设项目竣工环境保护验收监测对于落实“三同时”制度、实现总量控制目标、为环境监督管理提供重要技术支持具有重要意义与作用。目前,验收监测在管理体制、收费标准、成果应用等方面存在的突出问题,可通过创新管理机制、健全管理制度、提高管理水平等具体措施解决。  相似文献   
998.
Abstract: Unpaved road‐stream crossings increase sediment yields in streams and alter channel morphology and stability. Before restoration and sedimentation reduction strategies can be implemented, a priority listing of unpaved road‐stream crossings must be created. The objectives of this study were to develop a sedimentation risk index (SRI) for unpaved road‐stream crossings and to prioritize 125 sites in the Choctawhatchee watershed (southeastern Alabama) using this model. Field surveys involved qualitative and quantitative observations of 73 metrics related to waterway conditions, crossing structures, road approaches, and roadside soil erosion. The road‐stream crossing risk analyses involved elimination of candidate metrics based on redundancy, skewness, lack of data, professional judgment, lack of nonzero values, unbalanced box plots, and limited ranges of values. A final selection of 12 metrics formed the SRI and weighed factors involving soil erodibility, road sedimentation abatement features, and stream morphology alteration. The SRI was organized into narrative categories (excellent, good, fair, poor, and very poor) based on the distribution of scores. No excellent sites (scores ≥55) were found in this study, 17 (20.7%) were good (low sedimentation risk), 37 (45.1%) were fair (moderate sedimentation risk), 26 (31.7%) were poor (high sedimentation risk), and two (2.5%) were very poor (high sedimentation risk). There was no significant difference in SRI scores among crossing structure type (round culverts, box culverts, and bridges) (H = 4.31, df = 2, p = 0.058). A future study of the Choctawhatchee watershed involving the same study sites could assess the success of restoration plans and activities based on site score improvement or decline.  相似文献   
999.
Abstract: Assessment tools to evaluate phosphorus loss from agricultural lands allow conservation planners to evaluate the impact of management decisions on water quality. Available tools to predict phosphorus loss from agricultural fields are either: (1) qualitative indices with limited applicability to address offsite water quality standards, or (2) models which are prohibitively complex for application by most conservation planners. The purpose of this research was to develop a simple interface for a comprehensive hydrologic/water quality model to allow its usage by farmers and conservation planners. The Pasture Phosphorus Management (PPM) Calculator was developed to predict average annual phosphorus (P) losses from pastures under a variety of field conditions and management options. PPM Calculator is a vastly simplified interface for the Soil and Water Assessment Tool (SWAT) model that requires no knowledge of SWAT by the user. PPM Calculator was validated using 33 months of data on four pasture fields in northwestern Arkansas. This tool has been extensively applied in the Lake Eucha/Spavinaw Basin in northeastern Oklahoma and northwestern Arkansas. PPM Calculator allows conservation planners to take advantage of the predictive capacity of a comprehensive hydrologic water quality model typically reserved for use by hydrologists and engineers. This research demonstrates the applicability of existing water quality models in the development of user friendly P management tools.  相似文献   
1000.
Abstract: Multilevel or hierarchical models have been applied for a number of years in the social sciences but only relatively recently in the environmental sciences. These models can be developed in either a frequentist or Bayesian context and have similarities to other methods such as empirical Bayes analysis and random coefficients regression. In essence, multilevel models take advantage of the hierarchical structure that exists in many multivariate datasets; for example, water quality measurements may be taken from individual lakes, lakes are located in various climatic zones, lakes may be natural or man‐made, and so on. The groups, or levels, may effectively yield different responses or behaviors (e.g., nutrient load response in lakes) that often make retaining group membership more effective when developing a predictive model than when working with either all of the data together or working separately with the individuals. Here, we develop a multilevel model of the impact of farm level best management practices (BMPs) on phosphorus runoff. The result of this research is a model with parameters which vary with key practice categories and thus may be used to evaluate the effectiveness of these practices on phosphorus runoff. For example, it was found that the effect of fertilizer application rate on farm‐scale phosphorus loss is a function of the application method, the hydrologic soil group, and the land use (crop type). Further, results indicate that the most effective method for controlling fertilizer loss is through soil injection. In summary, the resultant multilevel model can be used to estimate phosphorus loss from farms and hence serve as a useful tool for BMP selection.  相似文献   
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