土壤氨氮、亚硝酸盐氮、硝酸盐氮的测定试料保存实验

对测定土壤中氨氮、亚硝酸盐氲、硝酸盐氲的试料保存条件和时间进行研究。结果表明,在4℃、避光保存的条件下,试料可以保存7d,而各组份浓度值基本保持不变。其中,氨氮的本底试料值相对标准偏差为2．86％,加标试料值相对标准偏差为2．88％,加标回收率为85．8％～101％;亚硝酸盐氮加标量为0．5μg试料值相对标准偏差为3．55％,加标量为4．0μg试料值相对标准偏差为2．93％;硝酸盐氮与亚硝酸盐氮总量的本底试料值相对标准偏差为7．02％,加标试料值相对标准偏差为4．56％,加标回收率为82．6％～104％。     

硝化细菌富集培养方法研究

探讨利用提高基质－氨氮浓度的方式富集硝化细菌的可行性，结果表明，温度为３０℃，ｐＨ为６．５～８．０，溶解氧（ＤＯ）的质量浓度高于２ｍｇ／Ｌ时，经过１２～１３周的富集培养，污泥中硝化细菌浓度是未经富集污泥中硝化细菌浓度的１２．５～２０．０倍。     

纳氏剂比色法测氨氮数据可比性差的原因

ｐＨ值影响非常大：１１．７时几乎不显色;１１．７～１２．７范围内影响很大;１２．７～１２．９范围内,吸光度几乎无变化。改进办法：用０．０１ｍｏｌ／Ｌ硫酸代替硼酸做蒸馏吸收液使ｐＨ值控制在１２．７以上。改进后还有如下优点：①蒸馏过程中逸出的ＣＯ２不会被吸收;②用ＮａＯＨ中和Ｈ２ＳＯ４时等当点附近ｐＨ值突跃大,终点易掌握;③即使不中和馏出液中的硫酸,在不稀释情况下加入纳氏剂,ｐＨ值为１２．８７,与绘制标准曲线时试样ｐＨ值相近,测定结果有足够的准确度。纳氏剂比色法测氨氮数据可比性差的原因@许秉信$新民市…     

三氯杀螨醇在兰州地区蔬菜土壤中和解动态的研究

研究了三氯钉螨醇在兰州地区蔬菜土壤中的残留和降解动态，并讨论了不同土壤类型、有机肥含量、向生物和光照对降解动态的影响；得出三氯杀螨醇在田间土壤中的降解半衰期为７、８天，大约需５６天可基本降解完 毕。微生物、光对其降解具有促进作用，土壤有机肥含一的增加则会减缓降解过程，在耕种灌淤土中的降解速率明显大于淡灰钙土。     

污灌农田土壤镉污染状况及分布特征研究

对沈阳郊区某河沿岸部分乡镇的污灌农田土壤中重金属全镉含量进行了分析,评价了土壤镉污染状况,并探讨了该河沿岸土壤中镉的沿程分布特征、横向分布特征和垂向分布特征.结果表明,农田土壤重金属镉含量范围为0.15～8.23mg/kg,均值为1.75mg/kg.用土壤环境质量标准二级标准值对土壤中的全镉含量进行评价,平均镉污染指数为5.95,为重度污染;用土壤背景值标准评价,平均镉污染指数为5.95,超过当地背景值水平8.39倍,污灌已造成该地区重金属镉污染,且污染程度十分严重.该河渠从上游到下游,沿岸土壤镉含量呈降低趋势;横向分布上,距离该河渠越远,镉含量有逐渐减少的趋势;垂向分布上,表层土壤镉含量最高.     

地面水中氨氮样品稳定性试验

对三氮进行保存时间稳定性试验,结果发现,除硝酸盐氮、亚硝酸盐氮不宜保存外,１０００ｍｌ地面水氨氮水样滴加５ｍｌ硫酸酸化至ｐＨ＜２可抑制水样中氨氮的水解、氧化还原反应。水样于２０°Ｃ～２８°Ｃ温度下保存半个月,氨氮测定结果基本无影响,同一水样在不同时间所测数据经方差分析,Ｆ计＜Ｆ０．０５,无显著性差异。表明,本法保存氨氮水样,半个月后仍相当稳定,便于调整分析人员工作量。地面水中氨氮样品稳定性试验@周秀华$平湖市环境监测站!浙江平湖314200     

水中加氯对三氮转化的影响

经对具有一定本底氨氮浓度水样在不同浓度梯度的余氯作用下 ,水样稳定 4～ 6小时后对其进行 NH3 - N、NO-2 - N,NO-3 - N浓度分析 ,得出三氮随不同余氯浓度的变化曲线。由变化曲线可以看出 ,水中余氯浓度在 0 .51～ 1 .35mg/ L之间 ,三氮的转化呈锐势 ,当余氯浓度≥ 1 .35mg/ L时 ,三氮浓度基本趋于稳定状态 ,而氨氮转化过程的中间产物 NO-2 - N在水中余氯浓度≥ 0 .51 mg/ L时 ,几乎不存在。表明 ,在可行性余氯浓度范围内 (水中余氯浓度不超标 ) ,水中加氯能快速有效地促进氮的硝化 ,尤其对水中亚硝酸盐的抑制是极为有效的。水中加氯…     

北京西郊清灌区农业土壤的重金属含量调查

城市中没有使用污水灌溉的农田土壤环境质量如何?有害重金属合景是否就是我们所认为的背景使水平呢?对此,笔者在1987～1989年间对北京市区的主要农副业产基地之一,城区近郊的西郊非污水灌区(下称西郊清灌区)土壤中的重金属含量进行了调查,并将其调查结果与北京平原区土壤背景值和北京污灌     

L-半胱氨酸对氢化物发生原子吸收法测定砷增强信号作用的研究

将生化试剂Ｌ－半胱氨酸用于砷氢化物发生体系,在ｐＨ１．７～２．０,Ｌ－半胱氨酸用量大于１．５ｍ ｇ／ｍ ｌ时,Ｌ－半胱氨酸的存在使砷信号增强最大,该条件下使砷检出限低了２．６ 倍,水样加标加收率为９６％ ～９８．８％ ,应用于自来水和地表水中痕量砷的测定,获得了满意的结果。     

奎屯市北郊蔬菜污灌区土壤重金属污染调查

通过对奎屯市北郊污灌区菜地土壤中重金属含量的分析表明，所调查的污灌菜地土壤中铅、锌、镉、砷和汞均未超标，部分地块铜超标，说明多年来因工业废水的浇灌，已造成铜对局部区域土壤的污染。     

微波消解-原子吸收光度法测定土壤中铜锌铅镉镍铬

用微波消解－原子吸收光度法测定土壤中铜，锌，铅，镉，镍和铬。通过硝酸－氢氟酸－过氧化氢体系消解液对土壤样品消解，选择出微波最佳消解条件。对硝酸－盐酸－过氧化氢体系消解液和硝酸－氢氟酸－过氧化氢体系消解液进行消解对比试验，发现前者不能将土壤样品完全消解，后者能将样品消解完全，但需将消解液中剩余的酸赶尽，否则测定结果将明显偏低。微波消解土壤与传统电热消解相比，操作简便快速，可提高工作效率。     

Topsoil and Housedust Metal Concentrations in the Vicinity of a Lead Battery Manufacturing Plant

The aim of the study was to determine the extent of heavy metal pollution in the vicinity of a lead battery manufacturing plant in the Czech Republic, both in the general environment and within homes. Topsoils (0–5 cm) were sampled from 100 sites along 4 transects which crossed the battery factory, the town centre and outlying rural areas. Housedust samples were collected from 15 plant-workers' homes and 15 non plant-workers' homes located at various distances from the factory. Samples were analysed for levels of Pb, Zn, Cd, Cu, As and Sb, using ICP-AES. Soil concentrations of Pb, Cd, As and Sb peaked at the perimeter fence of the battery factory with Pb levels of up to 12 650 g g> ^-1. Concentrations of these metals decreased exponentially within 500 m of the plant. Whilst the battery factory does appear to be a source of all the metals with the exception of Zn, emissions do not appear to be transported to any great extent over distances of more than 0.5 km. Topsoil and housedust concentrations of Pb, Zn, Cd, Cu, As and Sb in the general Mlada Boleslav area do not appear to be significantly different from those recorded in a large scale survey of urban soils in the United Kingdom. A comparison of housedust Pb concentrations in homes of plant workers and non-plant workers suggests that there may be a small input of Pb into the home environment by battery plant employees.     

An Overview of Contaminant-Related Issues Identified by Monitoring in San Francisco Bay

The San Francisco Estuary Regional Monitoring Program for Trace Substances (RMP) began in 1993 and is sponsored by 74 local, state, and federal agencies and companies through their discharge or Bay use permits. The RMP monitors water, sediment, toxicity, and bivalve bioaccumulation at 25 sites in the Bay that are considered to represent "background" conditions. Several major environmental issues have been identified by the RMP. Polychlorinated biphenyls and mercury were often above water quality guidelines, and often occurred in fish tissues above U.S. Environmental Protection Agency (U.S. EPA) screening values. Concentrations do not appear to be decreasing, suggesting continuing inputs. Episodes of aquatic toxicity often occurred following runoff events that transport contaminants into the Bay from urbanized and agricultural portions of the watershed. Sediment toxicity occurred throughout the Bay, and has been correlated with concentrations of specific contaminants (chlordanes, polynuclear aromatic hydrocarbons) at some locations; mixtures of contaminants were probably also important. Since the RMP does not monitor all ecosystem components, assessments of the overall condition of the Bay cannot be made. However, in terms of contamination, the RMP samples suggest that the South Bay, and North Bay sites are moderately contaminated.     

Biomagnification factors (fish to Osprey eggs from Willamette River,Oregon, U.S.A.) for PCDDs,PCDFs, PCBs and OC pesticides

A migratory population of 78 pairs of Osprey (Pandion haliaetus) nesting along the Willamette River in westernOregon was studied in 1993. The study was designed to determinecontaminant concentrations in eggs, contaminant concentrationsin fish species predominant in the Ospreys diet, andBiomagnification Factors (BMFs) of contaminants from fish specieseaten to Osprey eggs. Ten Osprey eggs and 25 composite samplesof fish (3 species) were used to evaluate organochlorine (OC)pesticides, polychlorinated biphenyls (PCBs), polychlorinateddibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans(PCDFs). Mercury was also analyzed in fish. Geometric meanresidues in Osprey eggs were judged low, e.g., DDE 2.3 g g^-1 wet weight (ww), PCBs 0.69 g g^-1, 2,3,7,8-TCDD 2.3 ng kg^-1, and generally well below known threshold values for adverse effects on productivity, and the population was increasing. Osprey egg residue data presentedby River Mile (RM) are discussed, e.g., higher PCDDs were generally found immediately downstream of paper mills and eggsfrom the Willamette River had significantly elevated PCBs and PCDDs compared to reference eggs collected nearby in the CascadeMountains. Prey remains at nest sites indicated that the Largescale Sucker (Catostomus macrocheilus) and NorthernPikeminnow (Ptychocheilus oregonensis) accounted for an estimated 90.1% of the biomass in the Osprey diet, and composite samples of these two species were collected from different sampling sites throughout the study area for contaminant analyses. With the large percentage of the fishbiomass in the Osprey diet sampled for contaminants (and fisheaten by Ospreys similar in size to those chemically analyzed),and fish contaminant concentrations weighted by biomass intake, a mean BMF was estimated from fish to Osprey eggs for the largeseries of contaminants. BMFs ranged from no biomagnification(0.42) for 2,3,7,8-TCDF to 174 for OCDD. Our findings for themigratory Osprey were compared to BMFs for the resident HerringGull (Larus argentatus), and differences are discussed. Webelieve a BMF approach provides some basic understanding ofrelationships between contaminant burdens in prey species offish-eating birds and contaminants incorporated into their eggs,and may prove useful in understanding sources of contaminants inmigratory species although additional studies are needed.     

The Draft of the New German Guideline VDI 3782/8 to Model Automobile Exhaust Dispersion

The draft of the German guideline to calculate automobile exhaust dispersion is explained. It contains a two-stage-system: For first quick estimates the guideline contains the simple models MLuS and STREET. In case these models are not applicable or their results shows concentration levels close to the air quality standards, the more complex models PROKAS_V and MISKAM are recommended. PROKAS_V is a Gaussian plume model, MISKAM is a 3-dimensional microscale non hydrostatic flow model for built-up areas with an Eulerian dispersion model. The guideline comprises cases in rural areas without or with few adjacent buildings as well as urban areas with buildings near the roads. The contribution gives information about the models, typical results and some of the problems showing up presently.     

Hydrocarbon Utilization in Yeast Isolates Found to Grow in Association with Petroleum in a Polluted Ultisol of Midwestern Nigeria

The population counts of hydrocarbon-utilising yeasts weremonitored at six sampling stations in the Benin City municipalarea over a four-week period. Although the population countswere relatively constant in each locality, the highest countsoccurred in areas heavily polluted by domestic and industrialeffluents. A total of thirty-five hydrocarbon-degrading yeastswere isolated from soil at the sampling stations usingn-hexadecane as sole carbon source. The isolates were identifiedas belonging to the genera Candida (27 strains), Endomycopsis (4 strains). All the organisms grew on long-chainn-alkane, kerosene, diesel oil and crude oil but failed to growon short-chain n-alkane, aromatic and alicyclic hydrocarbons.Measurement of growth attributes of the isolates usingn-hexadecane, diesel oil and crude oil as substrates showed thatthe Candida species were better utilizers of hydrocarbonsubstrates relative to Endomycopsis and Schizosaccharomyces species.     

Hydrologic–Economic Model for Managing Irrigation Intensity in Irrigation Areas under Watertable and Soil Salinity Targets

This paper gives mathematical details and sample applications of SWAGMAN Farm (SWAGMAN, Salt Water and Groundwater Management), a farm-scale hydrologic economic model that integrates agronomic, climatic, irrigation, hydrogeological and economic aspects of irrigated agriculture. The model is capable of determining optimum mix of land use to keep watertable and soil salinity within acceptable limits while maximising the economic returns. Alternatively, the model can simulate water and salt balance and economics of a given cropping preference. Web-based and Geographic Information Systems versions of the model are available for integration with the environmental reporting systems of the irrigation areas.     

火焰原子吸收光谱法测定苏州开发区26种蔬菜中铜锌铁锰镍

用火焰原子吸收光谱法测定了苏州开发区26种蔬菜中的铜、锌、铁、锰和镍的含量。蔬菜样品用硝酸高氯酸混合酸进行消解。4次测定值的相对标准差<5%,加标回收率在92%～107%之间。26种蔬菜中铜、锌、铁、锰、镍的含量基本均在世贸组织规定的范围内。     

Using Multiple Taxonomic Groups to Index the Ecological Condition of Lakes

Biological indicators of communitiestypically reflect a common environmental signalreflecting the general condition of the ecosystem, as well asindividual signals by indicators differentiallysensitive to particular environmental conditions. Wedescribe here a method of integrating and interpretingsuch indicators from 19 New England lakes for fivetaxonomic groups (diatoms, benthos, zooplankton, fish,and birds). Our approach provides a systematicstandardized way to integrate multiple metrics fromdifferent taxonomic groups by addressing four elementscrucial to analyzing data from multiple indicators: covariate control, re-scaling of data, standardizing the sign of responses, and dimensional reduction. We evaluated the biologicalmetrics against individual environmental stressors andagainst multivariate physicochemical metricscharacterizing general anthropogenic stress among thelakes. The method detected a response to variationin the gross environmental condition of the lakes thatwas correlated across taxa and metrics. In addition,a differential response to near shore conditions wasdemonstrated for fish. The success of the approach inthis study lends support to its general application toecological monitoring involving complex data sets.     

Cyanobacterial Flora from Polluted Marine Shores

Citation of cyanobacterial cultures from the shores of south west coast of Gujarat, India and their relationship with sea water quality, influenced by extensive pollutant runoff is reported in this study. Intensity of pollution was evaluated by physico-chemical analysis of water. Higher load of suspended solids (60–1000 mg l⁻¹) and nutrients (PO₄ ⁻P: 1.3–4 μmole l⁻¹ and NO₃ ⁻N: 12.5–17.8 μmole l⁻¹) were persistent throughout the analysis. Community structure is seen to be influenced by such persistent pollution. Twenty nine cyanobacterial species were isolated belonging to 9 genera of 4 families, with an elevated occurrence of Oscillatoria and Lyngbya species. No heterocystous cyanobacteria were isolated throughout the study.