A ten year summary of concurrent ambient water column and sediment toxicity tests in the Chesapeake Bay watershed: 1990-1999

The goal of this study was to identify the relative toxicity ofambient areas in the Chesapeake Bay watershed by using a suiteof concurrent water column and sediment toxicity tests at seventy-five ambient stations in 20 Chesapeake Bay rivers from1990 through 1999. Spatial and temporal variability was examinedat selected locations throughout the 10 yr study. Inorganicand organic contaminants were evaluated in ambient water andsediment concurrently with water column and sediment tests toassess possible causes of toxicity although absolute causalitycan not be established. Multivariate statistical analysis wasused to develop a multiple endpoint toxicity index (TOX-INDEX) at each station for both water column and sediment toxicity data. Water column tests from the 10 yr testing period showed that49% of the time, some degree of toxicity was reported. The mosttoxic sites based on water column results were located inurbanized areas such as the Anacostia River, Elizabeth River andthe Middle River. Water quality criteria for copper, lead,mercury, nickel and zinc were exceeded at one or more of thesesites. Water column toxicity was also reported in localizedareas of the South and Chester Rivers. Both spatial and temporalvariability was reported from the suite of water column toxicitytests. Some degree of sediment toxicity was reported from 62% of the tests conducted during the ten year period. The ElizabethRiver and Baltimore Harbor stations were reported as the most toxic areas based on sediment results.Sediment toxicity guidelines were exceeded for one or more of thefollowing metals at these two locations: arsenic, cadmium,chromium, copper, lead, nickel and zinc. At the Elizabeth Riverstations nine of sixteen semi-volatile organics and two of sevenpesticides measured exceeded the ER-M values in 1990. Ambientsediment toxicity tests in the Elizabeth River in 1996 showedreduced toxicity. Various semi-volatile organics exceeded the ER-M values at a number of Baltimore Harbor sites; pyrene anddibenzo(a,h)anthracene were particularly high at one of thestations (Northwest Harbor). Localized sediment toxicity was alsoreported in the Chester, James, Magothy, Rappahannock, andPotomac Rivers but the link with contaminants was not determined.Both spatial and temporal variability was less for sedimenttoxicity data when compared with water column toxicity data. Acomparison of water column and sediment toxicity data for thevarious stations over the 10 yr study showed that approximatelyhalf the time agreement occurred (either both suite of testsshowed toxicity or neither suite of tests showed toxicity).     

Monitoring of Seasonal Vegetables for Pesticide Residues

Market samples (60) of six seasonal vegetables were monitoredduring 1996–1997 to determine the magnitude of pesticidalcontamination. The estimation of insecticide residuesrepresenting four major chemical groups i.e. organochlorine,organophosphorous, synthetic pyrethroid and carbamate, was doneby adopting a multiresidue analytical technique employingGC-ECD and GC-NPD systems with capillary columns. The testedsamples showed 100% contamination with low but measurableamounts of residues. Among the four chemical groups, theorganophosphates were dominant followed by organochlorines,synthetic pyrethroids and carbamates. About 23% of the samplesshowed contamination with organophosphorous compounds abovetheir respective MRL values. More extensive studies coveringdifferent regions of Haryana state are suggested to get a clearidea of the magnitude of vegetable contamination with pesticideresidues.     

中国水环境的NPSP问题及对策

介绍了我国水环境中的非点源污染（ＮｏｎｐｏｉｎｔＳｏｕｒｃｅｐｏｌｌｕｔｉｏｎ，缩写为ＮＰＳＰ）的情况，强调农业生产是最主要的非点源污染。同时，针对我国水污染防治的政策目标，提出一些建议。     

发光细菌法评价工业废水的毒性

用发光细菌测定法估算了两城市污水对河道水体污染的分担率，评价了工厂排放废水的毒性，并据此确定了污染源监督管理中应优先治理的工厂（车间）废水。     

太湖水质氮素质量浓度时空差异特征及影响因素分析

通过对2014—2016年湖体水质中氮素质量浓度分析,结合出入湖总氮浓度、水量、湖体水生生态等影响因素,发现太湖水体中总氮浓度呈现逐年下降的趋势,各监测点位总氮为0.530 mg/L～5.51 mg/L,时空分布不均,差异明显。时间上,总氮浓度表现为春季最高,夏季和秋季最低,且月均值变化曲线呈现出规律的正弦函数波形。空间上,总氮浓度大致表现出由西部湖区向东部湖区递减的趋势,呈现西部湖区﹥北部湖区﹥南部湖区﹥湖心区﹥东部湖区。要改善湖体水质,不仅要切断污染源,而且要加强水生生态功能修复。     

中国北方干旱地区沙尘矿物特征研究

为了开展对我国沙暴传输规律的研究,了解我国北方干旱地区沙尘矿物特征有重要意义。本文对我国新疆塔克拉玛干沙漠区,内蒙腾格里沙漠区,贺兰山及银川等处的沙尘样品用X射线粉末衍射法进行矿物分析鉴定,并用原子吸收法作了特征元素的分析对比,根据矿物的X射线粉末衍射结果,结合元素分析,对沙漠源区及其以东地区沙尘矿物特征作了比较,判析了两个源区的矿物组成,讨论了它们的传输过程。     

几种土壤质量评价方法的比较

分别用Ｔ值分级法，综合指数法，模糊数学综合评判法，灰色聚类法，等斜率灰色聚类法，宽域灰色聚类法对湖南某地１０个监测点的土壤质量现状进行评价，通过比较，认为宽域灰色聚类法较好。     

助催化无汞盐快速测定水中化学需氧量

在ψ（Ｈ２ＳＯ４）＝５６％硫酸介质，重铬酸钾的氧化体系中，以钼权铵，硫酸铝钾为助催化剂，可减少量化剂硫酸银的用量，消解１５ｍｉｎ即可测定水中化学需氧量，用硝酸银溶液代替硫酸汞去除水氯离子，避免了汞盐的污染，工业废水回收率在９７％～１０１％之间，有较好的准确度。     

土壤全氮的快速测定

本方法是过硫酸盐氧化消化样品的基础上测定土壤中全氮的光度法.采用碱性过硫酸钾溶液(0.37mol/L K_2S_2O_3,0.375N NaOH)消化土壤样品,然后用百里酚光度法进行测定,具有准确、灵敏、快速、简便等优点,适用于常规和大量样品的分析.     

哈尔滨市生活垃圾处理产业化探讨

随着我国经济发展和人民生活水平的不断提高,城市垃圾产生量也不断增加,垃圾处理越来越受到人们的重视,垃圾处理产业也逐渐兴起.由于地区差异,工业发达程度和生活水平不同,不同的国家和地区有着不同的垃圾组成,相应的也采取不同的垃圾处理方法.哈尔滨市的生活垃圾处理现状具有一定的典型性,文章结合哈尔滨市实际情况,主要论述哈尔滨市生活垃圾的产量、特性及目前的处理状况,分析哈尔滨市生活垃圾问题的实质,对垃圾处理产业化存在的问题及其对策进行探讨,以期更好地促进生活垃圾处理步入产业化的发展轨道.