硫化物存在时直接测定工业废水中氰化物

硫化物存在时直接测定工业废水中氰化物金芳澄（福建省环境监测中心站３５０００３）一般来说废水中氰化物测定，先进行蒸馏，然后将馏出液用硝酸银标准溶液进行滴定。由于蒸馏操作耗时又麻烦，本文探讨革除蒸馏、直接滴定废水中氰化物，用硝酸铅沉淀样品中硫化物以排除干...     

生活废水中悬浮物对挥发酚测定的影响及其消除

针对用4-氨基安替比林直接光度法测定未经处理的生活污水中，预蒸馏后仍有悬浮物存在这一现象，进行了预处理后蒸馏和预蒸馏后用中速定量滤纸过滤的对比实验。结果证明预处理后蒸馏和预蒸馏后过滤均能达到消除悬浮物的目的。     

苯胺测定中蒸馏预处理程序改进

苯胺测定中蒸馏预处理程序改进张向东，李峰（滨州地区环境保护监测站２５６６１４）苯胺类化合物的测定方法按文献［ｌ］操作。在实践中，我们对该法的预蒸馏处理进行了改进。对色泽较深，含酚量较高的水样，苯胺的测定均通过蒸馏处理，并规定在蒸出原水样的８０％体积后...     

对挥发酚测定时预蒸馏处理方法的改进

对挥发酚测定时预蒸馏处理方法的改进陈国云（江都市环境监测站２２５２００）测定水中挥发酚时，需进行预蒸馏处理，据《水和废水监测分析方法》（以下简称《方法》）规定：预蒸馏时，取２５０ｍｌ水样，在加热蒸馏出约２２５ｍｌ馏出液时，停止加热，放冷．向蒸馏瓶中加...     

偶氮比色法测定工业废水苯胺时预蒸馏操作的改进

偶氮比色法测定工业废水苯胺时预蒸馏操作的改进姜军（江苏盐城市环境监测站，盐城２２４００２）苯胺测定的水样预蒸馏通常都是在蒸馏快结束前加入２０ｍｌ蒸馏水继续蒸至所需体积。本文改为２０ｍｌ水在蒸馏前先加入，一次蒸馏至馏出液为１００ｍｌ止。经对照试验，结果...     

固相萃取光度法测定食品中挥发酚的研究

研究了用Waters Sep-Park-C18固相萃小柱固相萃取测定食品中挥发酚的方法，用自动水蒸汽蒸馏仪蒸馏分离出食品中的挥发酚，然后用4－氨基安替比林显色，显色产物可用Waters Sep-Park-C18固相萃小柱萃取，用乙醇洗脱后用分光光度法测定，该方法污染小，操作简便，便于样品批量处理，用于食品样品中挥发酚的测定，结果令人满意。     

橡胶初加工废水挥发酚测定预蒸馏方法初探

橡胶初加工废水挥发酚测定预蒸馏方法初探岳平（海南省环境监测中心站，海口５７０００３）橡胶初加工废水具有较强的皂化作用，如将水样直接进行蒸馏，会产生大量泡沫溢出使蒸馏无法进行。处理方法：在２５０ｍｌ水样中加人２ｍｌ异戊醇，即可消除预蒸馏过程中的废水泡沫...     

二氧化硫对大气中酚测定的干扰及干扰排除的研究

文章探讨了二氧化硫对大气(污染源和环境)中酚测定的干扰程度以及通过预蒸馏消除干扰，得到准确的测定结果。在实际大气样品测试中，测定结果的准确度和精密度都较高。     

蒸馏体积100ml测定水中氰化物探讨

实验表明，水中氰化物测定，蒸馏体积１００ｍｌ即能达到环境监测技术要求，与标准方法规定蒸馏体积２００ｍｌ相比，可提高工效、节约用电和节省试剂。     

电解铝行业中氟化物监测方法研究

采用直接蒸馏法对固定污染源中固态氟化物样品进行处理。使用离子色谱或离子选择电极对样品进行测定。结果表明，其测定范围，精密度。准确度，均能满足环境监测的要求。     

中国水中油类监测存在的问题与解决办法研究

通过调查和实验研究 ,对我国油类监测中存在的诸如采样、提取、使用的油标准及监测方法选择等问题进行了分析。并对质控要求、油的概念等监测中存在的一系列问题提出了解决办法。     

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％。     

二氧化氮标准物质校准氮氧化物分析仪的差异性

采用一氧化氮、二氧化氮标准物质对化学发光法的氮氧化物分析仪进行校准,并分析校准系统中零气源、连接管路、动态气体校准仪和标准物质对二氧化氮校准的影响,发现一氧化氮标准物质中的二氧化氮杂质会影响氮氧化物的校准结果,得出氮氧化物分析仪校准需要进行二氧化氮补偿的结论;同时,通过比较国产二氧化氮和进口二氧化氮标准物质产生的校准结果,得出进口二氧化氮标准物质较国产二氧化氮标准物质的稀释结果具有更好的稳定性和一致性。     

氮氧化物的污染控制对策

详细地介绍了日本针对不同的排放源－－固定源和流动源－－所采取的氮氧化物污染控制对策。对固定源，在实施全国统一的排放标准的基础上，对于一些工厂相对集中、污染问题严重的地区实施总量控制，同时积极促进技术革新以及降低氮氧化物的排放；对流动源所采取的措施有，确定不同车型汽车排放尾气递减的短期目标和长期目标，实施汽车氮氧化物法，积极推进低公害车的普及。通过采取上述措施，在日本，固定源排放的氮氧化物得到了较好     

Using Insurance to Enhance Nitrogen Fertilizer Application to Reduce Nitrogen Losses to the Environment

The advantage of using insurance to help a farmer adopt a best nitrogen management plan (BNMP) that reduces the impact of agricultural production on the environment is analytically and empirically demonstrated. Using an expected value analysis, it is shown that an insurance program can be structured soas to reduce a farmer's cost of bearing the adoption risk associated with changing production practices and, thus, to improve the farmer's certainty equivalent net return thereby promoting the adoption of a BNMP. Using the adoption of growing-season only N fertilizer application in Iowa as a case study, it is illustrated how insurance may be used to promote the adoption of this practice to reduce N fertilizeruse. It is shown that it is possible for a farmer and an insurance company both to have an incentive to develop an insurance adoption program that will benefit both the farmer and the insurance company, increasing net social welfare and improving environmental quality in Iowa.     

亚硝酸盐氮对次溴酸钠氧化法氨氮测定的影响

次溴酸盐氧化法是一种海水或高盐度水质氨氮的常用检测方法,但实验发现该方法在亚硝酸盐氮存在时氨氮测定结果有较大误差。研究了次溴酸盐氧化法中亚硝酸盐氮对氨氮测定结果的影响。结果显示,氨氮的测量误差随着水样中亚硝酸盐氮含量的升高而变大,且具有明显的正相关性;探讨误差产生的机理发现,误差可能是次溴酸盐不能将氨氮完全氧化为亚硝酸盐氮导致的;研究了氧化率的影响因素发现,氧化时间对氧化率的影响可忽略,温度对氧化率有很大影响。在室温为(23±1)℃时,拟制出亚硝酸盐氮浓度对氨氮测量绝对误差的影响曲线,曲线方程为y=1.834x+0.018,r=0.996 7。利用修订的氨氮测定计算公式,可大大提高亚硝酸盐氮存在时水中氨氮的测量精度。     

Nitrogen Dioxide in the Workplace Environment

Concentrations of nitrogen dioxide were measured in shops and car parks over a 19 week period during the winter. For the shops indoor:outdoor ratios varied from 0.34 to 0.54 with an average value of 0.44. NO2 levels ranged from 13 to 38 µg m-3. With little or no contribution from indoor sources, ambient concentrations are the primary factor in determining indoor levels. Concentrations of NO2 in car parks were similar to those measured at the kerb side. Concentrations in the payment booths were higher than those in shops and ranged from 42 to 60 µg m-3. Despite ventilation systems in the payment booths ratios of booth:car park NO2 varied from 0.65 to 0.86.     

总氮测定中应注意的几个问题

对总氮测定中影响空白值偏高的因素进行了实验和分析,并提出了改进意见。     

Trends in Nitrogen Transport in Swedish Rivers

Concern about nitrogen loads in marine environments has drawn attention to the existence and possible causes of long-term trends in nitrogen transport in rivers. The present study was based on data from the Swedish environmental monitoring programme for surface water quality; the continuity of these data is internationally unique. A recently developed semiparametric method was employed to study the development of relationships between runoff and river transport of nitrogen since 1971; the observed relationships were then used to produce time series of flow-normalised transports for 66 sites in 39 river basins. Subsequent statistical analyses of flow-normalised data revealed only few significant downward trends (p 0.05) during the time period 1971–1994, and the most pronounced of these downward trends were caused by reduced point emissions of nitrogen. The number of significant upward trends was substantially larger (15 for total-N and 18 for NO₃-N). Closer examination of obtained results revealed the following: (i) the most pronounced upward trends were present downstream of lakes, and (ii) observed increases in nitrogen transport coincided in time and space with reduced point emissions of phosphorus or organic matter. This indicated that changes in the retention of nitrogen in lakes were responsible for the upward nitrogen trends. The hypothesis that nitrogen saturation of forest soils has caused a general increase in the riverine export of nitrogen from forested catchments in Sweden was not confirmed. Neither did the results indicate that improved agricultural practices have reduced the export of nitrogen from agricultural catchments.     

Using Measurements of Nitrogen Oxides to Estimate the Emission Controls Required to Meet the UK Nitrogen Dioxide Standard

In this paper we introduce a new method of analysing the relationship between nitrogen dioxide (NO₂) and oxides of nitrogen (NO_x) concentrations using data from the UK National Air Quality Archive. The study includes analyses of measurements from two different types of site in London, a kerbside site: Cromwell Rd, and three background sites: Bridge Place, London Bloomsbury and West London, over several years (1991–7). The data in some years showed that hourly NO₂ concentrations exceeded the UK Standard of 150 ppb. Data were binned, averaged, and polynomials fitted at each site. Analysis of the resulting polynomials was used to estimate reductions in NO_x emission required to achieve the National Air Quality Strategy Objective. Examination of the empirical ratio NO₂:NO_x (the 'yield') gives an indication of the sensitivity of the NO₂ to NO_x controls and the amount of NO₂ that would arise from modelled values of total oxides of nitrogen. The response of NO₂ to emission changes is very non-linear, implying 30–45% controls on NO_x may be required.