考虑未来水资源配置的龙刘水库可调水量研究

论文针对黄河上游水沙关系恶化、水资源供需矛盾加剧等问题,围绕黄河全流域2012—2030年水资源规划的配置结果,以龙羊峡、刘家峡梯级水库联合调度为调控手段,考虑全流域综合供水、防洪、防凌、水资源供需平衡等要求,构建了黄河上游龙羊峡、刘家峡（龙刘）梯级水库联合调度模型,采用自迭代模拟优化算法,分别计算4种情景、4种模式下13个方案的可调水量,最终推荐以水定电模式下的计算结果为最佳模式。结果表明：随着未来需水量的增加,可调水量呈减小趋势,且调水工程的引水量未提高梯级水库的可调水量。研究成果可为黄河上游宽谷河段水沙调控、黄河上游梯级水库群科学规划和调度提供技术支撑。     

Tenax萃取技术用于养殖底泥中有机氯农药的生物有效性研究

本研究以经济底栖生物菲律宾蛤仔和河蚬为受试生物,分别对不同浓度梯度的海洋和淡水底泥中9种代表性有机氯农药(OCPs)进行累积实验;同时采用Tenax连续萃取法研究2类底泥中OCPs的脱附动力学,提供简单、快速评价养殖底泥中OCPs生物有效性的方法,并将Tenax萃取结果与2种底栖生物的累积结果进行比较。结果表明,菲律宾蛤仔和河蚬对OCPs的生物-底泥富集因子(BSAF)分别为0.31~1.89和0.12~2.12,且底泥中有机碳标化的OCPs浓度与生物体内脂肪标化的OCPs浓度之间的相关性较差。Tenax脱附动力学的结果表明,2类底泥中OCPs的快速脱附比例(F_(rap))均在50%左右,其快速、慢速和极慢速脱附速率常数数量级分别为10~(~(-1))、10~(-2)和10~(-4)。Tenax快速脱附组分与2种底栖生物累积结果之间具有良好的相关性(r~2=0.75,P0.0001),表明Tenax萃取技术可以预测OCPs在底栖生物体内的累积量,并且该方法克服了大型底栖生物累积实验结果重复性较差等缺点。另外通过与基于热力学平衡的方法对比发现,Tenax萃取技术更适用于滤食性或可消化底泥的底栖生物对底泥污染物的富集;同时Tenax 6 h和24 h单点萃取技术可以作为简单快速评价底泥疏水性有机污染物(HOCs)生物有效性的替代方法,进一步为养殖领域的底泥污染状况以及相关水产品的质量安全和食用风险提供生物有效性评价依据。     

Assessment of petroleum hydrocarbon in a tropical brackish water lagoon: Chilika,India

Assessment of petroleum hydrocarbon (PHC) in the Chilika Lagoon, India, revealed a significant spatio-temporal variation in surface water (analysis of variance: n?=?120, p?相似文献   

Concentrations of persistent organic pollutants and organic matter characteristics as river sediment quality indices

Selected persistent organic pollutants – polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and organochlorine pesticides – were determined in sediments, soils, and crops from the Asopos River area, Greece. The river has been receiving industrial effluents for the last 40 years and has been recently found to be polluted with metals. Sediments were collected in the dry (May) and wet (February) season. Agricultural soils and cultivated crops were sampled from adjacent fields. Polychlorinated biphenyls were below the limit of detection in all samples. In one tomato and two soil samples, DDT and DDE were found. Polycyclic aromatic hydrocarbons were observed in 5% of the sediments and in concentrations ranging from 4 to 57 μg kg^?1 dry weight, quite below sediment quality guidelines. Diagnostic ratios of polycyclic aromatic hydrocarbons indicated a strong influence of petrogenic point discharges. In the sediments, silicate minerals dominate over carbonates and the organic carbon content ranges from 0.4% to 3.5%, more than 70% being of natural origin. Compared to other rivers worldwide, the Asopos River was found to be not contaminated with persistent organic pollutants. Point loadings of organic pollutants were evident but continuous discharge is not occurring throughout the river basin.     

广东清远电子垃圾处理地沉积物对伸展摇蚊的慢性毒性效应

电子垃圾拆解引起的环境污染和生态风险已成为全球关注的热点问题,不适当的电子垃圾拆解过程造成处理区水体沉积物受到多类有机化合物和重金属污染,直接威胁生活在沉积物中的底栖动物。在典型电子垃圾处理地广东清远采集沉积物,测定样品中以烃类为主的色谱难分离混合物(unresolved complex mixture,UCM)的含量,开展伸展摇蚊全生命周期慢性毒性测试。结果表明,清远沉积物中的UCM浓度(0.08±0.01)%接近于这类污染物对伸展摇蚊的慢性半致死性效应浓度(0.073±0.022)%。同时发现清远沉积物对以摇蚊为代表的底栖无脊椎动物具有显著慢性毒性效应,且可通过测定UCM含量初步估算。这为开展以电子垃圾处理地沉积物为代表的,受到以麻醉作用为主要致毒机制的混合物污染的沉积物的毒性评价提供了一种有效方法。     

贵州草海沉积物重金属分布及其对底栖动物群落的影响

基于原子吸收和ICP-MS,研究了贵州威宁草海4种重金属Zn、Pb、Cd、Ni的分布规律,并分析了其对底栖动物群落结构的影响.结果表明,表层沉积物中Zn、Pb、Cd 3种重金属含量已超过加拿大环境质量标准,超标样品量分别达到样品总数的82%、65%和47%,可能和周边历史上大规模的土法炼锌有关;草海表层水及孔隙水4种重金属含量均未超过国家I类地表水质量标准,表明污染的沉积物对水体重金属含量影响有限.表层沉积物中Zn、Pb、Cd均表现出湖中心及上游湖口含量更高的趋势,并和有机质呈显著正相关关系(r=0.837, P < 0.01; r=0.785, P < 0.01; r=0.780, P < 0.01),表明有机质在Zn、Pb、Cd的迁移和沉积中扮演了重要角色.在湖心沉积物柱中,Zn、Pb、Cd 3种重金属从剖面上部约10cm往上均有逐渐升高富集的趋势,与草海周边近几十年的大规模土法炼锌历史吻合.不管在表层沉积物还是在沉积物柱中Ni都呈现与其它3种重金属相反的分布规律,可能与Ni主要来源于自然背景有关.底栖动物群落结构调查表明,周边采样点比湖内采样点的底栖动物种类更为丰富,栖息密度也更大,这可能与草海湖内采样点重金属含量远高于湖周边采样点有关,具体影响及机制需要进一步深入研究.     

Characterization of phosphorus species and modeling for its organic forms in eutrophic shallow lake sediments,North China

Variations of phosphorus （P） and its species in surface sediment of Baiyangdian Lake, a eutrophic shallow lake located in North China, were investigated through combination of field survey and numerical calculation based on cluster analysis. P fractionation was performed by a sequential extraction scheme, categorized as loosely bound P （NH4Cl-P）, reductant soluble P （BD-P）, metallic oxide bound P （NaOH-P）, calcium bound P （HCl-P） and organic P （Org-P）. P concentrations exhibited regional similarities and a total of four sub-areas were identified in which the same rank was HCl-P 〉 Org-P 〉 BD-P ,=NaOH-P 〉NH4Cl-E NH4Cl-P, BD-P and Org-P were found to contribute to P enrichment in overlying water column. Specifically, labile Org-P acted as a potential pool with a greater contribution in aerobic layer compared to anaerobic layer. A hysteresis （lag = 4 months） existed when labile Org-P concentration was negatively correlated with aerobic layer thickness. In view of magnitude of identified P contributors in sub-areas, higher potential of P release was present in Fuhe River and Tang River estuary areas. On the basis of calibration and verification, the mathematical model with parameter settings applied in this study was improved to serve as a tool for limnology management and eutrophic control.     

河北省衡水湖沉积物中汞的分布特征及生态风险

衡水湖是华北平原上第一个国家级内陆淡水湖泊湿地类型的自然保护区,为了解衡水湖沉积物中汞的分布特征及生态风险,于2013年8月在衡水湖采集了5根柱状沉积物,对其中的总汞、甲基汞、孔隙水溶解态汞、有机质、pH以及含水率进行了分析。结果表明,衡水湖沉积物中总汞的平均含量为22.5 ng·g-1,低于全国及河北省表层土壤背景值。但表层沉积物汞含量明显高于底层,说明近年来的外源汞输入对湖泊汞负荷产生了一定影响,且靠近湖泊东部106国道的采样点汞含量明显高于湖泊中西部的采样点,暗示交通运输等人为活动是该湖泊的一个重要汞输入源。利用潜在生态危害指数法进行评估,显示汞的生态风险较低,说明现阶段衡水湖的沉积物汞浓度不会对生态环境产生不利影响。     

Speciation of particulate trace metals in sediments of Anarbe reservoir∗

Total concentration and chemical forms of heavy metals in samples of sediment from a drinking water reservoir have been analysed. The result of total metal contest shows Fe and Mn concentration increase along the reservoir, from 4.4% in Fe and 0.07% in Mn in the end part to 6.4% Fe and 0.22% Mn at the dam. However, a decrease in organic matter along the reservoir is observed. In order to test the accuracy of the digestion methods used, a standard reference material was also analysed.

Trace metal concentrations, with exception of Cadmium, Pb and Mn, found in fraction 5 are higher than those observed in the others extractions, Fe, Ni, Zn, Cr and Cu content in non‐residual fraction is found mainly in moderately reducible fraction, but the percentage of this fraction in each metal is very different.     

Current trends in the research on soil changes due to deforestation,burning and cultivation in the Brazilian tropics

The effects of large‐scale destruction of the tropical forest on soil characteristics are presented, with emphasis on the Amazon Basin. Human activities progressively modify natural equilibrium in soils and streams, especially in Brazil, where about 25 000 km² of virgin forest are annually removed. Of the soil uses, the installation of annual crops and pastures in previously clear‐cut and burned areas is the main subject of this paper.