C市饮用水源风险评价实例分析

保护饮用水源、保障饮用安全是目前我国环境保护工作的重要任务.借鉴了美国科罗拉多州地表饮用水源风险评价的方法和思路,并根据C市饮用水源的特点,从污染物迁移可能性、污染危害、泄漏可能性以及污染物的量4个方面对C市136个饮用水源遭受污染的风险进行了定量和定性评价.结果表明:有5个饮用水源属于高风险级别,需要对其实施优先管理.这5个高风险的饮用水源具有共同的环境污染特点,即饮用水源保护区内土地利用率高、农业面源范围广,并且点源数量多、污染大. 风险评价结果与饮用水源保护区内的污染源特点表现出良好的一致性,同时也表明加强饮用水源保护区内的污染源防治工作是保障饮用水源免受污染的重要举措.      

Important organic matter sources and trophic pathways for the nutrition of Hilsa kelee (Cuvier, 1829) and Valamugil buchanani (Bleeker, 1853) in Pangani macro-tidal estuary,Tanzania

The study investigated the spatial variation in the main sources of organic matter (OM) and trophic pathways for zooplanktivorous Hilsa kelee and phytodetritivorous Valamugil buchanani in fresh-water-influenced zone versus sea-water-dominated zone of Pangani estuary. The findings indicated significant inter-specific variations in δ¹³C and δ¹⁵N values (ANOVA, F?≥?84.3, p?F?≥?9.4, p?=?0.001) in both estuarine zones. Results also showed significant zonal-intraspecific variations in stable isotopes (δ¹³C and δ¹⁵N), FA profile and marginal differences in diet for the V. buchanani while no considerable differences were observed for H. kelee from two estuarine zones. The isotope mixing models and FA biomarkers revealed that the most important carbon sources to the nutrition of H. kelee were derived from microphytobenthos, macro-algae and sea grasses transferred through phytoplankton and detrital trophic pathways. In contrast, C₃ terrestrial plants and microphytobenthos were the main carbon source to the diet of V. buchanani; and were transferred via the benthic and detrital trophic pathways. Therefore, both terrestrial and in-situ OM sources were the main trophic resources base fuelling the planktonic and benthic food webs in Pangani estuary.     

龙岩市某铁锰矿区土壤重金属地球化学空间分布特征与来源分析

采集了龙岩市某铁锰矿区基岩-不同层位土壤配套样品,测试了其中重金属Pb、Cd和As含量,采用普通克里金插值法,研究了土壤中3种重金属元素的地球化学空间分布特征,分析了Pb、Cd和As的来源.结果表明,研究区地处汇水盆地中,高含量Pb和As主要分布于工作区西部靠近露天采场的区域,中部两支河流交汇处及东部废石堆附近,而Cd大面积集中于西部露天采场周边及选矿厂附近.从水平剖面看,3种重金属在土壤各层位高值区域的含量变化整体表现为随着与矿区水平距离的增加而逐渐降低的趋势.从垂向剖面看,重金属在不同层位土壤间的相关度高.Pb、Cd和As在西部距离露天采场较近的区域,含量随深度增加呈先升高再降低的趋势.在其他高值区域,3种重金属含量随深度增加而降低.不同层位土壤Pb和As含量与花岗岩、闪长岩中的含量均呈显著正相关关系,Pb和As继承了矿床及其周边母岩的特性.研究区重金属As虽受到矿山开采等人为影响,但影响程度不高.部分点位母质（岩）自身具有较高含量的重金属,同时,土壤中重金属Pb和Cd的含量显著高于岩石含量,甚至远远超过土壤风险筛选值,受工矿业、交通运输和农业生产等人类活动影响较大,存在点源污染,需关注其对农产品质量安全、农作物生长及土壤生态环境可能产生的风险.     

氧化亚铁硫杆菌培养条件的筛选及脱硫效果研究

从湖南某煤矿附近的土壤中,分离出能有效脱除燃煤中硫的菌株TFD-9,鉴定为氧化亚铁硫杆菌。通过不同温度、pH值和底物浓度对TFD-9菌生物量的影响,确定了最适宜的培养条件;并试验了该菌株对不同能源物质的利用以及对煤的脱硫能力。实验表明:TFD-9菌的适宜生长条件为温度30℃、Fe2+浓度9g/L、pH值2.0,此时最大生物量达到9.26×107个/mL;菌株对能源物质的利用能力分别为Fe2+100%,S2O32-62%,S少于50%;生物处理20d燃煤总硫脱除率为75.6%,硫化物硫脱除率为82.75%。     

Metabolic and Environmental Control on Methane Emission from Soils: Mechanistic Studies of Mesotrophic Fen in West Siberia

The biological mechanisms regulating methane emission fromnatural wetlands are the focus of this article. A novel techniqueprovides estimates of the distribution of CH₄ sources withinan undisturbed soil profile by recording the transient gasdynamics after soil enclosure by deep (50 cm) chamber. Thecombined use of conventional surface and soil chambers across a200-m fen transect allowed us to relate the observed methaneemission to its instant generation and uptake. Surprisingly, themethane generation was relatively constant (9–12 mg CH₄-C hr^-1 m^-2) and highly variable net emission (0.2–20 mg CH₄-C hr^-1 m^-2) was closely correlated (r = –0.809)with methane uptake. In laboratory incubations, CH₄ uptakefollowed Michaelis-Menten kinetics. Added chloride and nitrateirrespective of the cation's nature suppressed uptake as a strongnoncompetitive inhibitors (K _i 0.5 mM). The methaneformation turned out to be unstable and under anaerobicincubation, the formation of CH₄, CO₂ andH₂displayed sustained weekly oscillations. We conclude that effectsof environmental factors alone are not sufficient topredict the variation in emission, which depends also on metabolic control of respective soil organisms. The multitude ofsuch controls is dependent on diversity of respective soilorganisms and could be grouped into a limited number ofcategories considerably simplifying large-scale simulations.     

Air pollutant emission potentials of cotton textile manufacturing industry

Cotton textile manufacturing operations cause air pollution. Air pollutants are generated by fossil fuel fired combustors due to their flues and/or a variety of chemicals in use for production. Excessive use of chemicals can be stopped or minimized by replacing them or by optimizing the production processes. Energy and water conservation are important goals in textile workplaces as well. There is substantial research and development to minimize pollution potentials of textile operations. In this paper air polluting potentials of cotton textile manufacturing operations are discussed and some quantitative examples are given for evaluating the risks to the environment. Studied impacts to environment cover direct discharges into the ambient air as well as the workplace atmosphere. Further studies are recommended for minimizing the impacts to the local and global air quality due to cotton textile production facilities.     

FLOW VARIABLE DISCHARGE PERMITS1

ABSTRACT: Current approaches to calculating discharge limitations and the use and intent of water quality standards are examined. Flow variable discharge permits, in which the amount of pollutant that may be discharged is based on the magnitude of the flow in the stream, are introduced as an alternative permit strategy that could reduce the cost of pollution control in certain instances while still meeting in-stream water quality objectives. Several possible designs of flow variable discharge permits are presented to show the flexibility of the concept; for example, permits can be based on instantaneous flows, seasonal flows, trigger values, and ranges of flows.     

H—G模式在油田开发工程总烃污染预测中的应用

本文依据油田开发工程的特点,合理地将H—G(Hanna—Grifford)面源叠加模式运用于油田开发工程总烃大气环境影响预测中,从而克服了运用经典的Ganssian点源模型预测大范围、低矮源大气污染水平的局限性与不足。最后给出了一个应用实列。     

当代河流系统研究中稳定性同位素的应用

对天然存在的稳定碳、氮同位素在河流系统中的有机物质（POM和DOM）来源、转换、运移规律、与沿岸生态系统的关系、河口区不同来源颗粒有机质的混合过程、河流系统中富营养的污染来源和土壤中的微生物过程、系统中的营养行为和食物来源途径以及河流有机物质在陆架上的分配、积累和运移规律的应用研究作了较为系统的论述。     

Information sources for flash flood warnings in Denver, CO and Austin, TX

This research examines sources of information for flash floods in two large metropolitan areas, Denver, CO, and Austin, TX. Previous research has noted that information delivery systems for weather forecasts are geared toward the cultural majority and suggests that inadequate warnings are a primary contributor to deaths and injuries from hazards. This investigation used chi-square analysis to determine the prime warning source preferences and preferred time of day for receiving different media. Results indicate that successful warning messages need to be targeted toward specific sub-populations if the warning is to be received, understood, and responded to properly.