An integrated fuzzy-stochastic modeling approach for risk assessment of groundwater contamination

An integrated fuzzy-stochastic risk assessment (IFSRA) approach was developed in this study to systematically quantify both probabilistic and fuzzy uncertainties associated with site conditions, environmental guidelines, and health impact criteria. The contaminant concentrations in groundwater predicted from a numerical model were associated with probabilistic uncertainties due to the randomness in modeling input parameters, while the consequences of contaminant concentrations violating relevant environmental quality guidelines and health evaluation criteria were linked with fuzzy uncertainties. The contaminant of interest in this study was xylene. The environmental quality guideline was divided into three different strictness categories: "loose", "medium" and "strict". The environmental-guideline-based risk (ER) and health risk (HR) due to xylene ingestion were systematically examined to obtain the general risk levels through a fuzzy rule base. The ER and HR risk levels were divided into five categories of "low", "low-to-medium", "medium", "medium-to-high" and "high", respectively. The general risk levels included six categories ranging from "low" to "very high". The fuzzy membership functions of the related fuzzy events and the fuzzy rule base were established based on a questionnaire survey. Thus the IFSRA integrated fuzzy logic, expert involvement, and stochastic simulation within a general framework. The robustness of the modeling processes was enhanced through the effective reflection of the two types of uncertainties as compared with the conventional risk assessment approaches. The developed IFSRA was applied to a petroleum-contaminated groundwater system in western Canada. Three scenarios with different environmental quality guidelines were analyzed, and reasonable results were obtained. The risk assessment approach developed in this study offers a unique tool for systematically quantifying various uncertainties in contaminated site management, and it also provides more realistic support for remediation-related decisions.     

液化石油气槽车泄漏处置专用接头套组的应用探讨

针对消防救援车辆缺乏专业堵漏和倒罐装备、应急处置受限等问题,研究采用专用注压接头套组与消防车配合,通过向事故槽车阀门注水加压或惰性气体的方式实施辅助堵漏,能够实现因地制宜、快速有效地解决现场液化石油气大量泄漏的问题,降低事故危害。     

基于集对分析法的农田土壤环境质量评价

集对分析是一种新的不确定性分析方法,其联系度概念具有鲜明的辨证性、完整性,使其成为处理不确定性问题的有效方法。农田土壤环境质量受多种因素影响,具有较强的不确定性,因此拟引入集对分析理论,以江汉平原后湖农场为研究对象,应用单因子指数法和集对分析法对其农田土壤环境质量进行综合评价。结果表明,研究区9种单要素污染程度依次为Cd＞Zn＞As＞Cu＞DDT＞Hg＞Cr＞Pb＞HCH,Cd为主要污染元素,8个地块已受到Cd的轻度污染,土壤中的农药残留主要成分为滴滴涕;集对分析结果显示8745%的农田是安全的,1255%的农田处于轻污染状态。整体而言,江汉平原农田土壤环境质量属清洁和安全范围,符合发展现代农业的要求。集对分析法为农田土壤环境质量评价提供了一种新的思路。     

社会资本对农村贫困代际传递影响机制研究

社会资本在反贫困领域的重要作用已被理论和实践所证实。在新时代脱贫攻坚的决胜阶段,有效发挥社会资本的周急济贫功能,缓解乃至阻断贫困代际传递,已成为当前反贫困战略推进中亟待探讨的问题。研究整合了四期中国家庭追踪调查(CFPS 2010、2012、2014、2016)个体家庭和村庄的嵌套数据,建立了“认知型”和“结构型”两种类型以及“个体家庭”和“村庄”两个层级的社会资本框架,并基于探索性因子分析构建了社会网络、社会信任、社会声望、社会参与、集体参与以及公共服务6个社会资本变量。研究利用HLM软件构建了多层广义线性模型(HGLM),通过四阶段的空模型、截距模型、随机效应模型以及完整模型分析了绝对贫困背景下社会资本对农村贫困代际传递的影响机制。研究结果表明:①个体社会资本总量与贫困代际传递呈显著负相关。②在个体家庭层面,社会网络、社会声望、社会参与对贫困代际传递有显著负向影响,但社会信任和地方信任对贫困代际传递的影响并不显著。③在村庄层面,公共服务对贫困代际传递具有显著负向影响,集体参与对贫困代际传递具有显著正向影响,且公共服务水平对社会网络和贫困代际传递具有正向调节作用。研究提出要大力培植贫困群体和乡村两个层级的社会资本以缓解农村贫困代际传递趋势:①要通过协调“乡政”与“村治”以形成良性的乡村治理格局。②要促进精准扶贫与乡村振兴战略紧密衔接,在保障个体脱贫的同时完善农村公共服务及基础设施建设,推进城乡基本公共服务均等化;③须提振贫困群体脱贫信心,增强村级自治与集体参与的水平和能力。     

乡镇工业电镀行业主要污染物排放量的估算方法

电镀分有氰电镀与无氰电镀两类。乡镇工业电镀行业的环境污染最主要是氰污染和铬污染。本文针对乡镇电镀行业的特点,调查了湖南省沅江市、四川省新都县、湖北省黄陂县、汉川县以及江苏省部分县市乡镇电镀厂,将收集资料及实际监测资料进行回归分析,得出乡镇电镀行业的污染物发生量大小与原材料的消耗有关,可以用多元回归方程估算乡镇电镀行业主要污染物发生量。这一估算方法简单易行,实用可靠,操作方便。     

Validation of a Lagrangian dispersion model implementing different kernel methods for density reconstruction

In this paper the inert version of a Lagrangian particle model named photochemical Lagrangian particle model (PLPM) is described and validated. PLPM implements four density reconstruction algorithms based on the kernel density estimator. All these methods are fully grid-free but they differ each other in considering local or global features of the particles distribution, in treating the Cartesian directions separately or together and in being based on receptors or particles positions in space. Each kernel has been shown to have both advantages and disadvantages, but the overall good performances of the model when compared with the well known Copenhagen and Kincaid data sets are very encouraging in view of its extension to fully chemically active simulations, currently under development.     

模糊线性规划在灾害对策中的应用

本文把模糊线性规划方法引入灾害对策的研究当中。着重讨论了疏散人口和疏散地点间的关系,简单介绍了模糊疏散距离及其初步确定方法。     

直链烷基苯指示城市化过程初步研究

本研究以深圳市作为典型城市化地区代表,以直链烷基苯(LABs)作为环境分子标志物,在分析土壤LABs空间分布特征基础上,通过土壤LABs污染水平与城市化过程指标的相关分析,对直链烷基苯指示城市化过程可能性开展初步研究.结果表明,城市化过程中人口规模、用水状况、城市建设、收入与消费及产业结构这5个方面的因素与土壤中LABs污染水平均有相关性,表明环境LABs水平与城市化过程相关,可以作为环境分子标志物用于指示城市化过程.