新疆和田地区土壤中天然放射性核素含量水平的调查研究

和田地区土壤中天然放射性核素铀－２３８、钍－２３２、镭－２２６和钾－４０按面积加权的均值（Ｂｑ·ｋｇ－１）依次是３７．５２±８．７３、４０．１５±５．３０、３０．０１±４．６０和５３１．１４±４０．７７，属正常本底辐射水平．铀镭平衡状况富铀。     

悬浮液进样石墨炉原子吸收法直接测定土壤、底泥中的铅、镓、钴、镍

介绍一种悬浮液进样直接测定土壤、底泥中多种微量金属元素的快速分析方法。基体改进剂的使用，适宜的原子化温度的选择，使用水相标准溶液作校准曲线成为可能．对标准作品的测定证明了此方法的精密度和准确度较好，适合于常规环境样品分析．     

Evaluation of the optimal washing conditions for dioxin-contaminated soils from the circumference of an incinerator

 The optimal soil-washing conditions for dioxins were estimated on a soil sample from the circumference of an incinerator in Nose City, Osaka, Japan. The solvents ethanol, methanol, and acetone, together with a surfactant (100% of each) could extract 40% of the dioxins from contaminated soil at room temperature. From among these solvents, ethanol was chosen for a study on how to optimize the extraction conditions because of its low toxicity and its economic advantages. The time-course of the agitation showed that the extraction rate increased for 1 min, and thereafter the rate decreased. Therefore, the agitation time was fixed at 1 min. To estimate the effect of temperature on the extraction rate, the extraction temperature was changed. The amount of dioxins extracted was largest at the boiling point of ethanol (78.3°C), giving about 76% extraction. Furthermore, at this temperature, almost 100% of the dioxins in the contaminated soil were extracted when the ratio of water to ethanol was 20%. Received: March 6, 2002 / Accepted: September 9, 2002     

达县百节"水保生态园区"水土流失治理与生态环境保护

本文反映了严重的水土流失是导致达县百节河小流域生态环境恶化的主要原因。阐述了通过实施水土流失治理三大措施：工程措施、生物措施、农耕措施,有效地控制了水土流失等生态问题,极大地改善了当地生态环境,取得了显著的三大效益：经济效益、生态效益和社会效益。同时陈述了百节河小流域生态园区的建设特色：组织协调部门资金捆绑使用,集中投入：业主参与,责、权、利统一,投资渠道多元化,为水土保持和生态环境建设注入了生机与活力。     

微波辐射在二氧化锰诱导下对六氯苯污染土壤的修复研究

以二氧化锰为微波吸附剂,在密封体系中研究了微波辐射技术对六氯苯污染土壤的修复效果。分别以不同浓度的酸碱水溶液添加到土壤中,在模拟含水率为20%情况下,硫酸(50%)介质下六氯苯处理效果最好,10min的微波辐射即可使50mg/kg的六氯苯达到完全去除;但是在纯水和10mol/L氢氧化钠介质下,六氯苯基本上没有去除;随着硫酸浓度的降低,六氯苯的去除率显著降低。气相色谱/质谱联用(GC/MS)分析没有检测到新物质。六氯苯去除机理推测为,直接矿化或者HCB及其分解的中间产物同土壤发生化学结合而被固定起来,以致难以萃取出来。     

土壤污染物溶质运移模型研究进展

土壤中污染物溶质的运移已经成为了近年来研究的热点。本文回顾了关于土壤中溶质运移模型的研究成果,讨论了各个模型的优势及其不足之处,介绍了应用最为广泛的传统微分方程模型。对应用于非均匀介质中的随机运移模型进行了描述,并将其和传统微分方程模型进行了比较。介绍了可动-不可动水体模型并讨论了其相关参数的影响因素。列举了几种和其他学科或研究方向结合的溶质运移模型。最后提出了今后模型开发的发展方向。     

地下水曝气理论模型研究进展

地下水曝气(Air Sparging,AS)是修复饱和土壤及地下水有机污染的有效技术.AS多相流动过程中气液流动以及污染物传质过程的模型研究是AS技术的关键因素,详细介绍了近年来AS系统的理论模型方法及研究进展,并对其效果进行评价.     

Identifying hydrologically sensitive areas: bridging the gap between science and application

Researchers have noted that current water quality protection strategies, like nutrient management plans, lack a sound hydrological underpinning for pollutant transport processes. This is especially true for areas like the northeastern U.S. where copious research has shown that variable source area hydrology largely governs runoff generation. The goal of this study was to develop a scientifically justified method to identify the locations that generate overland flow. Furthermore, this methodology must be computationally simple enough that it can be utilized or incorporated into nutrient management plans and other established water quality tools. We specifically tested the reliability of the 'distance from a stream,'D(s), and the 'topographic index,'lambda, to predict areas with a high propensity for generating overland flow, i.e. hydrologically sensitive areas (HSA). HSAs were defined by their probability of generating runoff, P(sat), based on 30 year simulations using a physically based hydrological model. Using GIS, each location's P(sat) was correlated with D(s) and lambda. We used three Delaware Co., NY watersheds in the New York City watershed system with areas varying in size from 1.6 to 37 km2 and with forested and agricultural land uses. The topographic index gave stronger, more regionally consistent correlations with P(sat) than did D(s). Equations correlating lambda and P(sat) for each month are presented and can be used to estimate hydrological sensitivity in the region surrounding our study watersheds, i.e. in Delaware Co. This work is currently being incorporated into an Internet Mapping System to facilitate user-friendly, on-line identification of HSAs.     

A numerical study of soil cover performance

In the investigation of soil cover design options for final decommissioning of reactive mine waste, it is often necessary to analyze or predict the anticipated cover performance as a function of the cost of implementation, which is governed by the type, number and thickness of the layers in the cover system. An example of such investigation is presented in this study where one-dimensional evaporation from hypothetical moisture-retaining cover systems is simulated to assess the influence of several cover properties and hydrogeologic parameters on performance. The commercially available transient flow model, SoilCover, was used to compute suction and water content profiles for different cover design scenarios. The predicted water content profile and porosity of layers were then used to estimate the oxygen diffusion coefficients of the various layers. The oxygen diffusion coefficients were used to estimate oxygen flux through the cover systems. The oxygen flux was, in turn, related to the maximum acid flux. The studied cover and hydrogeologic parameters included soil type, thickness of barriers, and water table elevation. Two types of infiltration and oxygen barrier and two types of capillary layer with different thicknesses were studied. The water table was either kept constant at the base of the waste (tailings) or dropped by 0.5, 1, 2, and 3m over 120 days. The results showed that the relationship between water table depression and the thickness of capillary layers, on one hand, and desaturation of the infiltration and oxygen barrier, on the other, is not linear. Relationships between oxygen flux and barrier thickness and between cost increase and performance improvement of the studied cover systems are presented. Finally, a method that outlines steps for site-specific and economically feasible design of multi-layer cover systems is introduced.     

Socioeconomic Factors Affecting Farmers’ Perceptions of Land Degradation and Stonewall Terraces in Central Palestine

Land degradation by soil erosion is a socioeconomic and environmental problem facing many developing countries. Application of stonewall terraces for soil moisture conservation is vital to reducing the environmental impacts of this phenomenon. To this end, a field plot experiment was conducted in the study area along with the use of a closed-ended questionnaire. The object of the experiment was to study the socioeconomic impacts of soil erosion on local farmers and their adoption of the stonewall terrace technique. The study showed a higher net profit in areas that had implemented terrace conservation practices than in areas that had not (i.e., 3.5 to 6 times higher net profit). Correlation analysis indicated that the farmers’ perceptions, land ownership, and geomorphology were significantly related to the farmers’ incentives and willingness to adopt terraces as soil conservation measures (P < 0.05), although the correlations were negative. Smallholder farmers (52% of the interviewed farmers) were involved in the sale of the agricultural land for urban uses, largely because of the high price and immediate returns offered. However, the associated land use changes warrant greater involvement of both the private and public sectors. This cooperation may be accomplished through the introduction of a long-term agricultural loan system and the development of proper legislation accompanied by a comprehensive and durable infrastructure and service system with the goal of reducing the negative impact of land use changes and encouraging sustainable use of resources.