长江水系河流沉积物重金属元素含量的计算方法研究

采用长江水系约２６０个背景样点沉积物原样和小于６３μｍ细粒沉积物中１１种重金属元素（铜、铅、锌、镉、汞、钴、镍、砷、铬、锰和铁）含量的数据，研究了数据的频率分布特征和变异系数，比较了算术均值、几何均值和中位数与由Ｂｏｘ－Ｃｏｘ变换而得到的对称均值间的大小关系，结果表明，大多数重金属元素含量服从对数正态分布；采用算术均值表示均值会有较大的偏差，且这种偏差随变异系数的增大而增大；采用中位数偏差较小，但     

蘑菇湖水库浮游植物与富营养化关系初探

根据在蘑菇湖一个水文年度进行的7次调查结果,研究了蘑菇湖浮游植物群落生态学的主要变化(包括数量、种类组成、优势种类、季节变化、多样性指数和初级生产力),年平均总数为1138万个/升,年数量变动曲线为夏季的一个蓝藻高峰,而且数量大,延续时间长,冬季以蓝藻和绿藻占优势,夏季转为以蓝藻、硅藻占优势。结果表明,蘑菇湖的富营养化现象在调查的14个月中都存在。     

A Comparison of Sediment and Monitoring Data: Implications for Paleomonitoring a Small Lake

Long-term limnological monitoring data (from 1971 to 2001) were compared with sediment core record in Lake Viitna Linajärv (hereafter L. Viitna), a small lake in northern Estonia. The monitoring data show that L. Viitna changed from mesotrophic in the 1970s to eutrophic in the 1990s. The trends of paleodata thatintegrate the changes in the biogeochemical matter cycling in the lake over 2–3 years have clear signals about changes in the state ofthe ecosystem in L. Viitna during the last decades. A gradual increase in organic productivity should reflect a greater oxygen demand in the hypolimnion. As a result the hypolimnion becameseasonally anoxic earlier and its pH level remained low for a longer time. These fundamental changes near the sediment-water interface were recorded in the sediment core. The greatest changes occurred at the beginning of the 1980s (layers at a depthof ca. 20 cm), when the meso(eu?)trophic conditions in L. Viitnastarted to become increasingly more eutrophic. The variations ofpaleorecords in the upper part of the sediment core coincide temporally with changes in the water level of the lake.     

Determination of Endosulfans in Soil/Sediment Samples from Point Mugu, Oxnard, California Using Capillary Gas Chromatography/Mass Selective Detection (GC/MSD)

The extent of contamination by endosulfans in soil samples collected from the Point Mugu watershed near Oxnard, California was determined using capillary gas chromatography/mass selective detection (GC/MSD). The study was designed to detect three organochlorinated pesticides: endosulfan , endosulfan and endosulfan sulfate. Thirteen sets of two soil samples each were taken from various sites in the region. Our results show that the endosulfan levels in these soils range from trace amounts to nearly 30 ppm, with endosulfan being the most abundant and endosulfan sulfate the least. Two sites of the study, Hueneme and Revolon and Farm and Revolon, showed high amounts of endosulfans and , with concentrations between 20 and 30 ppm. The majority of the other sites studied in this research produced concentrations of less than 10 ppm for each of the three endosulfans monitored. At five areas in particular, Pleasant Valley and Creek, Laguna and Creek, Etting and Creek, Road and Creek and Hueneme and Creek, less than 2 ppm or only trace amounts of endosulfans , and sulfate were detected.     

Lake Ontario sediments in monitoring pollution

An investigation was carried out to select locations for long-term monitoring of inputs of contaminants into Lake Ontario using fine-grained bottom sediments as an historical record of pollution. The sediment sampling program was designed to determine sediment heterogeneity in the western, central and eastern depositional basins of the lake. Surficial sediments and sediment cores were collected in each basin to obtain information on horizontal distribution and concentration profiles of major and trace elements in the sediments (Si, Al, Ca, Mg, Fe, Na, K, Ti, Mn, P, As, Co, Cu, Cr, Ni, Pb and Zn). The results of the investigation indicated that fine-grained sediments in three Lake Ontario depositional basins are homogeneous to a high degree, and that only a few sediment cores need to be collected within each basin for the long-term monitoring of inputs of contaminants to the lake.     

Heavy Metal Transport and Behavior in the Lower Columbia river, USA

The primary objective of this study was to evaluate temporal changes in heavy metal content of lower Columbia River sediment following terminated or reduced soluble heavy metal loading from the world's largest lead-zinc refinery and mining districts in the USA and Canada. Sediment cores were collected from two fine sediment depositional sites (∼600 km downstream) in August 1999 and were analyzed for total metal content, texture, and age/dating parameters. Zinc, cadmium and lead contents in 1999 declined by only a factor of two over their depth profile maxima (dated as between 1970 and 1980). In sharp contrast, more than a 10-fold decrease in dissolved metal loading occurred during this same period. Zinc in filtered Columbia River water at downstream locations also declined by > 10-fold, consistent with the reduced upper river solute-metal loading. Once soluble metal releases are reduced or terminated, the solute half-time in Columbia River water is months versus ∼20 yr for adsorbed metals on surficial (or resuspended) bed sediments. The much slower rate of decline for sediment, as compared to the solute phase, is attributed to resuspension, transport and redeposition of irreversibly bound metals from upstream sedimentary deposits. This implies downstream exposure of benthic or particle-ingesting biota can continue for years following source remediation and/or termination of soluble metal releases. Accordingly, contaminant contents of both particulate and solute phases of river water, as well as sediment core sections, are suggested for assessing long-term biotic exposure/response to mitigation activities in the Columbia River and similar fluvial ecosystems.     

Sequential fractionation of phosphorus in lake sediments of Northern Greece

The amounts and forms of potentially mobile P in surface sediments from two lakes, Volvi and Koronia, located in Northern Greece were evaluated using a sequential chemical extraction. Five sedimentary P reservoirs were separately quantified: loosely sorbed P (NH₄Cl-P); iron associated P (BD-P); calcium bound P (HCl-P); metal oxide bound P (NaOH-P) and residual P (organic and refractory P). Samples were taken in two seasons and the average concentration of the fractions of phosphorus were calculated. The results indicated that the TP content and chemically extractable phosphorus in the sediments of Koronia Lake were higher than those of Volvi Lake. Sediment TP was also strongly and positively correlated with sediment Fe. Fine-sized sediments exhibited significantly higher concentrations for both lakes than the sand fraction. The P in the surface sediment mainly consisted of HCl-P and Res-P, while NH₄Cl-P and BD-P only constituted a minor part. The rank order of the different P extracts was the same for the two lakes and was Residual-P > HCl-P > NaOH-P > BD-P > NH₄Cl-P.     

甘家湖荒漠林区生态恢复工程的影响因素及其环境效益评价

主要从生态恢复方面对甘家湖荒漠林区的恢复措施及其所产生的环境效益、社会效益及综合效应进行论证，分析甘家湖荒漠林区目前的状况及采取恢复措施后所能达到的效果。     

湖库水质评价污染因子选择方案探讨

目前我国湖库水质评价中,评价项目不统一,造成评价结果不具可比性.为抓住水体污染的主要矛盾,同时节约监测成本,对有代表性的湖库监测数据进行分析,提出了湖库水质评价项目的选择方案.     

白洋淀表层沉积物重金属形态分布特征及生态风险评价

为了研究白洋淀全域表层沉积物重金属污染程度,采用BCR 3步提取法分析了沉积物中6种重金属（Cd、Cr、Cu、Ni、Pb和Zn）的含量及其赋存形态,讨论了6种重金属的生物可利用性大小,并运用次生相与原生相比值法（RSP）、潜在生态风险指数法（RI）和聚类分析进行了生态风险评价及重金属污染来源探讨.研究表明,白洋淀表层沉积物中重金属Cd和Cu含量均值分别达到背景值的2.9倍和1.3倍.Cd的可交换态及碳酸盐结合态和铁锰氧化物结合态的质量分数达到51.20%,生物可利用性较大;Pb主要赋存于铁锰氧化物结合态;Cr、Cu、Ni和Zn以残渣态为主要的存在形式.白洋淀的首要污染因子是Cd,整体面临较高Cd风险.圈头片风险最高,端村片风险最低;南刘庄片区域内风险相差较大,其中N4为白洋淀全域最高风险点.源解析结果显示,Cd、Cu、Pb和Ni受人类活动因素较多,Cr和Zn则更多的受到自然因素影响.