Heavy metals in surface water and stream sediments in Jamaica

The levels of heavy metals in water and stream sediments in Jamaica are presented and compared to levels in soils and environmental standards. Heavy metals (cadmium, chromium, copper, mercury, nickel, lead and zinc) appear to be less of a problem to Jamaica's freshwater environment than might be expected given the concentrations in soils. This can be explained by taking into account the dynamics of the Jamaican water environment and the relative absence of anthropogenic sources. The dynamics of the freshwater system on the other hand, could pass any environmental threat to the coastal environment. Because the stream sediments are relatively coarse and contain little organic material the bio-availability of micropollutants such as heavy metals from the sediments can be expected to be relatively high.     

南京和九江两地黄土母质发育的土壤性质比较

本文对南京和九江两地黄土母质发育的土壤性质作了较系统的分析研究,并进行了比较,发现这些土壤的属性存在较大的差别,因而这些土壤不宜归属于同一土壤类型。按《中国土壤系统分类》(首次方案),它们应分别归属于铁硅铝土纲、湿润铁硅铝土亚纲中的黄棕壤土类和棕红壤土类。     

Lead, Zinc, Copper, and Cadmium in Fish and Sediments from the Big River and Flat River Creek of Missouri's Old Lead Belt

The Old Lead Belt of Missouri was a major lead-producing region for over a century. Several large tailings piles and other industrial wastes remain behind, though mining operations in the region ceased in 1972. Samples of stream sediments and fish were collected from established sites on the Big River and Flat River Creek over a 3-year period from 1998 to 2000 to evaluate ongoing remediation efforts and determine the current impact of residual mining wastes. Benthic sediments and fish taken in the vicinity of inactive industrial sites were found to contain elevated concentrations of Pb, Zn, Cu, and Cd. Concentrations of Pb and Zn in fillets of suckers and sunfish, as well as in whole bodies of sunfish, correlate well with metal concentrations observed in surficial sediments. The results of analyses provide valuable quantitative information regarding specific sources, current levels of contamination, potential risk to public health, and will allow more accurate assessment of continuing remediation efforts.     

小流域水土保持综合治理效益指标体系及其应用

在分析总结已有水土保持综合治理效益评价指标与方法的基础上,结合黄土高原沟壑区自然、经济、社会条件及治理特点,遴选了9个评价指标,并采用层次分析的方法对两个典型小流域的效益进行了评价。     

碳酸盐对铜离子在黄土中吸持及形态影响的实验研究

选用黄土和重金属Cu为研究对象，通过等温吸持实验和Tessier形态提取实验，研究了碳酸盐对铜离子在黄土中吸持及形态的影响。结果表明：黄土去除碳酸盐后，其吸持铜离子的量大幅度降低；碳酸盐结合态、铁锰氧化物结合态和有机质结合态铜含量明显降低，而可交换态铜含量显著增加。     

Land-based sources of marine pollution: organochlorine pesticides in stream systems

BACKGROUND: Organochlorine pesticides (OCPs) have been dispersed ubiquitously in the environment. Bottom sediments act as sinks for these compounds and their concentrations often reflect the degree of anthropogenic pollution. This study was designed to evaluate the occurrence and distribution of OCPs in superficial streambed sediments and their relation to land use in two creeks that contribute to the coastal pollution of the southeastern region of Argentina. METHODS: Sampling sites were selected by a combination of land use and stream type. Las Brusquitas creek, which passes through vast agricultural areas, and La Tapera creek which originates in a natural wetland and passes through horticultural farming and urban areas. OCPs quantification was carried out by GC-ECD. RESULTS AND DISCUSSION: Results showed similar total OCP concentrations in sediments from both creeks in the range of 6-25 ng/g dry wt. However, when OCPs were expressed in ng/g total organic carbon (TOC), La Tapera creek presented 4-fold higher total levels as a consequence of a higher OCP input during the recent past in that watershed. La Tapera outfall showed 4-fold higher levels than that seen in Las Brusquitas, although both values were below the sediment quality criteria demanded to protect wildlife. Sigmaendosulfans, sigmaDDTs and sigmachlordanes were the main OCP group in all samples, with Endosulfan sulfate being the most frequent and abundant compound. The predominance of metabolites with respect to parent compounds suggests a contamination mainly by runoff from aged and weathered agricultural soils. CONCLUSIONS: Despite OCPs being banned, they still exist in creek sediments from the studied region, representing continuous contributions of land-based source contaminants to the marine environment. OUTLOOK: Future research on OCP levels in suspended sediments is recommended in order to determine the total OCP concentrations in the selected stream systems.     

黄土丘陵区降雨、径流、土壤水分的时空分布与利用对策

基于黄土丘陵区的延安燕沟多年监测资料，通过对燕沟流域的降雨、径流、及其不同土地利用方式下土壤水分等时空分布特征分析，明确了黄土丘陵区降雨的时间、空间分布具有显著差异性。降雨量在6～9月相对集中，年际、月际变异大；同时次降雨量、月降雨量均存在显著空间异质性，如降雨量沿燕沟沟道变化及坡向分异。径流特征是降雨及其下垫面特征的综合反映，3月左右由于气温上升，河道解冻，径流量出现小高峰，雨季后2个月出现最大高峰水量。对径流的利用则由于供水／需水时间错位，利用主要集中在枯水季节（4-6月），土壤水资源由于地形、降雨、植被覆盖等的差异性，特别是植被差异性利用，则存在时空异质性。土壤水分在雨季后1-2月在0～150cm形成高值期，150cm以下的土壤恢复缓慢。植被差异利用形成了土壤水分剖面不同：梯田〉草地〉拧条林〉拧条＋五角枫林〉沙棘林〉刺槐林。根据对水资源系统分析，提出了流域水资源开发利用的对策：农作物适雨种植制度；植被空间合理布局；降雨、土壤水、径流三水联合御旱，提高水资源利用效率。     

Metals, Boron, and Selenium in Neosho Madtom Habitats in the Neosho River in Kansas, U.S.A.

In 1991 and 1992 we determined the levels of metals, arsenic, boron, and selenium in the Neosho River drainage in southeastern Kansas, the primary habitat for the threatened Neosho madtom (Noturus placidus). We evaluated concentrations in sediments, mussels (Quadrula pustulosa and Q. metanevra), and fish(Percina phoxocephala, Cyprinus carpio,and Ictiobus bubalus) from three sites on theNeosho River and one site on the Cottonwood River. We also evaluated contaminant concentrations in C. carpio composite samples collected by theKansas Department of Health and Environment (KDHE)at two additional locations on the Neosho River in1990–92. Sediments were contaminated by lead. Concentrations of selenium, boron, and most metalsin mussels were low to normal for biota. Arseniclevels in mussels and fish suggest low-levelcontamination of biota. Aluminum, barium, manganeseand strontium concentrations were much higher inmussels than in fish. Five fish composite sampleshad cadmium concentrations that indicate chronicdeleterious effects on biota. Lead concentrationsin six fish samples were elevated. Mercuryconcentrations in most large fish compositesexceeded concentration for protection of animalsthat might consume them. We believe that reductionsin cadmium, lead, and mercury contamination, inparticular, would benefit aquatic life in theriver.     

A new voltammetric method for the simultaneous monitoring of heavy metals in sea water,sediments, algae and clams: application to the Goro Bay ecosystem

Arsenic(III), selenium(IV), copper(II), lead(II), cadmium(II),zinc(II) have been determined in sea water, sediments, algae andclams by differential pulse cathodic (DPCSV) and anodic (DPASV)stripping voltammetry. The voltammetric measurements are carriedout using a conventional three-electrode cell and the ammonia-ammonium chloride buffer pH 9.2 as supporting electrolyte.The analytical procedure has been verified by the analysisof the standard reference materials (Estuarine SedimentBCR-CRM 277, Ulva Lactuca BCR-CRM 279 and Mussel Tissue BCR-CRM278). The precision and the accuracy are less than 5%. Thisprocedure is utilized for the monitoring of heavy metals inthe Po river mouth area (Italy).     

Spatial variation of organochlorine pesticides and dissolved organic matter in urban closed lakes

Abstract

Closed lakes located in urban parks act as sinks of organochlorine pesticides (OCPs), which have been used, for decades, as insecticides, herbicides and fungicides. The closed lakes from Bucharest, Romania, are periodically managed to prevent eutrophication and accumulation of pollutants. However, it is not known if these practices reduce or enhance the legacy pollution with OCPs. The aim of this study was to explore the spatial variation of OCPs in closed lakes. The total concentration of OCPs in water and sediments ranged between 0.0176 and 37.1?µg/L, and between 122 to 1,890?ng/g, respectively. The concentrations of OCPs were compared with the consensus-based sediment quality guidelines (SQGs) in order to evaluate the ecological risks of sediments. The highest potential adverse effects were associated with γ-HCH exposure. Periodical draining and dredging of lakes lead to the resuspension of contaminants, increasing pesticide bioavailability and accumulation in sediments. In addition, we observed that fluorescent dissolved organic matter (DOM) might influence the OCPs cycle. The quantity and character of fluorescent DOM can provide further insight into OCPs degradation. Also, this study may help urban planners to determine the state of urban waters and to find the best solution for water management.