褪色光度法测定微量碘的研究

研究了在硫酸介质中、溴化钾催化下 ,碘酸根氧化酸性铬蓝K褪色的最佳条件。其最大吸收波长λmax为 5 2 0nm ,表观摩尔吸光系数为 1 .1× 1 0 4 L·mol- 1·cm- 1,碘浓度在 0～ 3 .6mg/L内呈线性关系。方法用于测定加碘食盐中的碘 ,结果令人满意     

硫化物标样分析的预案

由计算结果可以确定如下方案 ,首先样品分析前需先将 Na2 S2 O3和碘溶液浓度配制成0 .0 0 1 mol/L,其次 1当给定标样浓度在 1 0～5 0 mg/L之间时 ,选取 2 0 ml稀释后标液进行一组平行分析 ,空白试验中硫代硫酸钠标液用量 V0( ml)减去样品滴定中其标液用量 V1( ml)的值在1 .2 5～ 6.2 4之间 ,其中 V0 约为 1 0 ml,则 V1在3.76～ 8.75之间 ,测定结果能保证较为准确可靠。 2当给定浓度在 5 0～ 1 0 0 mg/L时 ,选取 1 0 ml稀释后进行一组平行分析 ,( V0 - V1)值在 3.1 2～6.2 4之间 ,其中 V0 约为 1 0 ml,则 V1在 3.76～6.88之间 ,同样可…     

背景噪声在边界噪声测量中的影响及修正

1现行方法未考虑非稳态背景噪声影响 ,经计算得表 1数据 ,可直观选取δ值 :表 1　 ︾与 ηL 的关系 (d B)ΔL 3 .0～ 3 .2 3 .3～ 3 .94.0～ 4.84.9～ 6.0 6.1～ 7.98.0～ 1 1 .0δ 3 .0～ 2 .82 .7～ 2 .3 2 .2～ 1 .81 .7～ 1 .3 1 .2～ 0 .80 .7～ 0 .3δ取值 3 .0 2 .5 2 .0 1 .5 1 .0 0 .5表中δ由ΔL确定 ,ΔL=L- L0 ,式中 L为边界噪声等效声级 ;L0 为同一地点背景噪声等效声级。2背景噪声较高且波动较大时 ,适当延长 L和 L0 的测量时间。背景噪声在边界噪声测量中的影响及修正@金庆先$昆山市环境监测站!江苏昆山215300…     

亚硫酸钠标准溶液标定方法的改良

1标定方法 :吸取 0 .0 1 0 0 mol/L 碘溶液1 0 .0 0 ml,置于 2 5 0 ml碘量瓶中 ,加入 40 ml新蒸馏水 ,用待标定的亚硫酸钠溶液滴定至淡黄色 ,加0 .5 %淀粉溶液 2 ml,继续滴定至蓝色刚好退去 ,记录消耗体积 V。 2计算公式 :SO2 ( μg/ml) =( 0 .0 1 0 0× 1 0 .0 0× 32 .0 2×     

关于水和废水中硫化物测定的几个问题

1碘量法测定硫化物时 ,当采用低浓度 ( 0 .0 1mol/L )硫代硫酸钠标液 ,用 1 0 ml微量滴定管 ,在水样硫化物浓度在 0 .0 4～ 1 mg/L内可取得满意结果 :相对偏差 <4.0 % ,回收率 96%～ 98%。 2预处理时可将过滤好的硫化锌沉淀连同滤纸 (剪成几块 )放入碘量瓶 ,加 50 ml水浸泡几分钟 ,盖上瓶塞轻摇即可。 3用对氨基二甲基苯胺光度法测定时 ,用醋酸调节 p H值或不调吸收液 p H值均可取得较好准确度和精密度。关于水和废水中硫化物测定的几个问题@车轩$河北省环境监测中心站!河北石家庄050051…     

接种稀释法测定BOD5方法改进

1稀释水质量 :DO为 9左右 ,1 L水中营养液加入量 1 ml,p H7.2 ,BOD50 .0 5 0～ 0 .2 0 0 mg/L。 2接种稀释水质量 :1 L稀释水中接种液加入量 ( mg/L) :河水上清液 1 0 0～ 2 0 0 ;生活污水上清液 2 0～ 30 ;植物表层浸出液 30～ 5 0。BOD50 .40 0～ 0 .80 0 mg/L。 3水样稀释倍数确定 :2 0℃时 ,五天培养前后消耗溶解氧 3.6～ 6.3mg/L,样品取样量 :V1=6.3× 1 0 0 0 /BOD估值 ;V2 =3. 6×1 0 0 0 /BOD估值。稀释倍数 δ1=1 0 0 0 /V1,δ2 =1 0 0 0 /V2 。 4计量器具和操作 :移液管取样 ,容量瓶定容 ,转入烧杯静置平衡。接种稀释法…     

维多利亚蓝B与碘在水溶液中的显色反应-吸光光度法测定海产品中的碘

研究了水相中,维多利亚蓝B与碘离子(I~-)的显色反应.当磷酸浓度为1.6mol/L,聚乙烯醇为0.08％时,维多利亚蓝B与碘形成络合比为1∶3的络合物,最大吸收峰位于375nm处,表观摩尔吸光系数为1.02×10~4L/mol·cm,碘在(0～16)μg/ml范围内符合比耳定律.方法可用于海洋生物等样品中的微量碘测定,结果满意.     

测定水中硫化物新方法

1试样测定 :准确移取 50 .0 ml水样加入反应管中 ,依次加 4粒玻璃珠 ,3片自制硼氢化钾片 ,迅速倒入 8ml0 .5mol/L硫酸 ,立即安好导气管 ,另一端迅速插入盛有 2 0 ml1 %氢氧化钠溶液2 5ml比色管中 ,待吸收管内无气泡冒出时取下吸收管 ,用分光光度法测吸光度。硫化物浓度较高的水样 ,用碘量瓶加 80 ml吸收液 1 [取 1 0 0 ml醋酸锌 -醋酸钠储备液 (见水和废水监测分析方法第三版 )稀至 50 0 ml]吸收后以碘量法测定 (导气管尖端也要参与反应 ,避免沾带损失 )。 2变异系数为0 .34 98%～ 0 .650 6%之间 ,回收率为 73.0 5%～1 0 9.8%之间。测定水…     

苯酚标准贮备液标定小改进

空白试验中 Na2 S2 O3 消耗量与 KBr O3 - KBr液加入量直接相关 ,要将空白试验的滴定值 V1减至 50 ml以内 ,须将 KBr O3 - KBr量减少 ,而其他反应条件不变。标定过程 :吸 5ml酚储备液 (或水 )于 2 50 ml碘量瓶中 ,加水稀至 1 0 0 ml,加5.0 0 ml0 .1 mol/L KBr O3 - KBr溶液 ,立即加 5mlHCl,加塞轻摇于暗处放置 1 0 min,加 1 g KI摇匀放暗处 5min,用 Na2 S2 O3 标液滴定至淡黄色 ,加1 ml淀粉液滴定至蓝色刚褪 ,分别记录用量 V2 ,V1,即可计算出 C=1 .0 2 0 2 mol/L。优点 :1省时30 min～ 50 min。 2节约药品。 3误差小。苯酚标准…     

海水、地面水中磷酸盐测定方法

以人工海水、纯水为介质 ,采用先加钼酸盐后加抗坏血酸进行显色 ,在 70 0 nm波长下测定校准曲线 ,线性较好且没有显著性差异 ,方法稳定 ,可同时测定海水和地表水无机磷、地表水总磷。检出限低于 0 .0 1 mg/L;测定天然水样 ,相对标准偏差5.1 %～ 0 .9% ;测定加标水样加标回收率为 95%～ 1 0 5% ;重复测定加标回收率相对标准偏差为1 .3%～ 2 .7% ;重复测定质控样品和标准样品误差范围 - 0 .0 0 2～ + 0 .0 0 5mg/L、- 0 .0 0 8～ +0 .0 0 4 mg/L、- 0 .0 8～ + 0 .0 0 7mg/L,相对标准偏差 0 .8%、1 .2 %、1 .3% ,精密度、准确度可满足方法要…     

A New Mathematical Approach in Environmental and Life Sciences: Gene–Environment Networks and Their Dynamics

An important research area in life sciences is devoted to modeling, prediction, and dynamics of gene-expression patterns. As clearly understood in these days, this enterprise cannot become satisfactory without acknowledging the role of the environment. To a representation of past, present, and most likely future states, we also encounter measurement errors and uncertainties. This paper surveys and improves recent advances in understanding the foundations and interdisciplinary implications of the newly introduced gene–environment networks, and it integrates the important theme of carbon dioxide emission reduction into the networks and dynamics. We also introduce some operational and managerial issues of practical working and decision making, expressed in terms of sliding windows, quadrants (modules) of parametric effects, and navigating (controlling) between such effects and directing them. Given data from DNA microarray experiments and environmental records, we extract nonlinear ordinary differential equations that contain parameters that have to be determined. For this, we employ modern (Chebychevian) approximation and (generalized semi-infinite) optimization. After this is provided, time- discretized dynamical systems are studied. A combinatorial algorithm with polyhedra sequences allows to detect the region of parametric stability. Finally, we analyze the topological landscape of gene–environment networks with its structural (in)stability. By embedding as a module and investigating CO₂ emission control and figuring out game theoretical aspects, we conclude. This pioneering work is theoretically elaborated, practically devoted to health care, medicine, education, living conditions, and environmental protection, and it invites the readers to future research.      

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.     

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.     

An investigation on biological stability of product water generated by lab-scale and pilot-scale distillation systems

Material Disposal Area G is the primary low-levelradioactive waste disposal site at Los Alamos NationalLaboratory, New Mexico, and is adjacent to Pueblo of SanIldefonso lands. Pueblo residents and Los Alamos scientists areconcerned about radiological doses resulting from uptake of AreaG radionuclides by mule deer (Odocoileus hemionus) andRocky Mountain elk (Cervus elaphus), then consumption ofdeer and elk meat by humans. Tissue samples were collected fromdeer and elk accidentally killed near Area G and were analyzedfor ³H, ⁹⁰Sr, total U, ²³⁸Pu, ^{239, 240}Pu,²⁴¹Am, and ¹³⁷Cs. These data were used to estimatehuman doses based on meat consumption of 23 kg y^-1. Humandoses were also modeled using RESRAD, and dose rates to deer andelk were estimated with a screening model. Dose estimates tohumans from tissue consumption were 2.9 × 10^-3 mSv y^-1and 1.6 × 10^-3 mSv y^-1 from deer and elk, respectively,and RESRAD dose estimates were of the same order of magnitude. Estimated dose rates to deer and elk were 2.1 × 10^-4 mGyd^-1 and 4.7 × 10^-4 mGy d^-1, respectively. Allestimated doses were significantly less than established exposurelimits or guidelines.     

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.