废水的BOD_5测定中根据BOD_5／COD_（cr）值确定稀释比的一种方法

废水的ＢＯＤ５测定中取稀释比是一个很重要的问题。本文根据数学推导得出ＢＯＤ５测定中取稀释比的一种方法。ＢＯＤ５／ＣＯＤｃｒ值在０．０５－０．１，０．１－０．３，０．３－０．６，０．６－１．０四个范围内其稀释比ｆ２可对应取５５／ＣＯＤｃｒ、２２／ＣＯＤｃｒ、９／ＣＯＤｃｒ、５／ＣＯＤｃｒ。     

高压蒸汽消化法测定废水化学需氧量的再研究

用＂自控式高压蒸汽消解器＂作为高压蒸汽消化法测定废水化学需氧量的消化装置，详细研究了消化条件，最后确定，消化体系中（１／６）Ｋ２Ｃｒ２Ｏ７浓度为０１ｍｏｌ／Ｌ，Ｈ２ＳＯ４浓度为１０．１ｍｏｌ／Ｌ，催化剂Ａｇ＋浓度为０．０３ｍｏｌ／Ｌ，消化温度为１３０℃，恒温时间为２０ｍｉｎ。用此方法和条件测定了１２种单纯有机化合物和１６种不同工业废水的化学需氧量，与标准回流法相比，相对误差在－５．５－６．０％之间。     

投菌水解（酸化）—生物接触氧化—混凝法处理酵母生产废水

研究了采用投菌水解（酸化）－生物接触氧化－浊凝化处理酵母生产废水。试验结果表明，进水浓度控制在ＣＯＤＣｒ值５０００ｍｇ／Ｌ左右，生化系统可取得较高的处理效率；生经处理出水再以碱式 化铝为混凝剂，聚丙烯酰胺为助凝剂进行混凝处理，其出水ＣＯＤＣｒ值可控制在２００ｍｇ／Ｌ以下，并且可部分回流使用。     

废水化学需氧量测定中稀释倍数的确定

废水化学需氧量测定中稀释倍数的确定漆利之（江苏淮阴县环境监测站，淮阴２２３３００）根据实测经验、资料或物料衡算了解ＣＯＤ大致浓度范围，当①ＣＯＤｃｒ值小于８００ｍｇ／Ｌ的水样可直接测定不必稀释。②ＣＯＤｃｒ估算值ｍ＞８００ｍｇ／Ｌ时，计算其最小稀释倍...     

高氯废水中COD_(Cr)的快速测定

本文介绍了一种快速测定高氯废水中ＣＯＤＣｒ的方法。提出以ＡｇＮＯ３和ＣｒＫ（ＳＯ４）２·１２Ｈ２Ｏ代替ＨｇＳＯ４作为消除氯离子干扰的抑制剂。试验结果表明，它能有效地抑制水样中高达２５０００ｍｇ／Ｌ氯离子的干扰。本法具有较高的准确度和精密度。     

污水COD_(Cr)测定中氯离子的去除

污水ＣＯＤＣｒ测定中氯离子的去除石志平（吉林洮南市环境监测站，洮南１３７１００）①实验方法：取污水样５０ｍｌ，加１０ｍｌ硫酸银液（４．３９７ｍｇ／ｍｌ）、２％碳酸氢钠液１．０ｍｌ、２％硫酸铝钾液０．５ｍｌ，混匀静置５ｍｉｎ过滤，取３０ｍｌ滤液供测定。...     

异相平衡流动注射分光光度法测定水中痕量SO^2—4

根据异相平衡的原理,确立了用流动注射分光光度法测定水样中痕量ＳＯ＾２－４的新方法。利用Ｂａ（Ⅱ）与偶氮氯磷Ⅲ的二元络合显色反应及ＢａＳＯ４＝Ｂａ＾２＋＋ＳＯ＾２－４进入微溶化合物ＢａＳＯ４反应柱前后吸光值的改变,从而求得ＳＯ＾２－浓度。表观摩尔吸光系数ε＝２．３＊１０＾４Ｌ．ｍｏｌ＾－１．ｃｍ＾－１,ＳＯ＾２－４检的线性范围为０－４０ｍｇ／Ｌ,检测限为０．８０ｍｇ／Ｌ,相对标准偏差为１．２％,试     

氨氮测定中水样混凝沉淀预处理的改进

氨氮测定中水样混凝沉淀预处理的改进陈淑贞（福建连江县环境监测站，连江３５０５００）改取１００ｍｌ水样于１００ｍｌ比色管，加１０％ＺｎＳＯ４溶液１ｍｌ混匀后加２４％ＮａＯＨ溶液０．２ｍｌ，使ｐＨ为１０．５，这时浓度＞１０ｍｇ／ＬＣａ－ＣＯ３的水样可自然...     

N─苯甲酰苯基羟胺／吡啶偶氮染料配体交换反应萃取分光光度法测定固体废物浸出液中的微量钒

在强酸性介质中，ＶＯ３与Ｎ－苯甲酰苯基羟胺（ＢＰＨＡ）反应生成紫红色络合物，能定量地被ＣＨＣＬ３萃取．萃取液加入２－（５－溴－２－吡啶偶氮）－５－二乙氨基酚（５—Ｂｒ—ＰＡＤＡＰ）后可发生配体交换反应，并生成橙红色的Ｖ（Ｖ）－５—Ｂｒ—ＰＡＤＡＰ络合物，有机相可直接用于光度测定．Ｖ（Ｖ）－５—Ｂｒ－ＰＡＤＡＰ的最大吸收波长为６００ｎｍ，摩尔吸光系数为５．４Ｘ１０￣４Ｌ·ｍｏｌ－１·ｃｍ－１，线性范围为０～０．７６μｇｖ／ｗｌ。     

水中微量五氯酚的气相色谱法测定

提出ＧＣ－ＦＣＤ分析方法测定水中微量五氯酚残留量。水样经萃取分离、衍生后，采用石油醚提取醋酸五氯酚酯，然后进入色谱柱，柱内填充２％ＯＶ－１７＋２％ＱＦ－１／ＣｈｒｏｍｏｓｏｒｂＷ－ＨＰ（８０～１００目），柱温２００℃，Ｎ＿２流量８０ｍＬ／ｍｉｎ，五氯酚酯３ｍｉｎ内出峰，最低检测浓度为０．１μｇ／Ｌ，各种样品回收率均在９０％以上，样品测试结果满意，可用于多种水体中微量ＰＣＰ残留量的测定。     

Performance of methods for measurement of exposure to inorganic acids in workplace air

BGIA has organised round robins for the analysis of samples of inorganic acids in workplace air for a number of years. Test samples of the volatile acids HCl and HNO(3) are collected from a standard atmosphere and samples of the non-volatile acids H(3)PO(4) and H(2)SO(4) are prepared by spiking filters with acid solution. The last two round robins have also covered the sampling of volatile acids, with up to 15 "active" participants able to visit the test facility in Dresden and take samples themselves. For other "passive" participants, BGIA takes samples from the same atmosphere. The acid concentrations generated lie between 0,1 and 1 times the German limit values for HCl and HNO(3). The results for the last round robin showed no significant difference between the performance of the "active" and "passive" participants. The participant means were in good agreement with the theoretical concentrations and the quality control measurements. For "active" participants RSDs were between 7% and 14% and for all participants between 8% and 16%. The round robin for the non-volatile acids showed similar results. The participant means were again in excellent agreement with the quality control measurements and RSDs were between 12% and 15%. The BGIA round robins have demonstrated the proficiency of laboratories measuring exposure to inorganic acids in air. However, concerns remain about the performance of published methods. It has shown that the sampling efficiency of sorbent tubes falls off with increasing particle size and hence silica gel tube methods may give low results for acid mists. Another issue with silica gel tubes is that a substantial proportion of the sample can be collected on the glass wool plugs that retain the sorbent. This can be up to 50% for HCl and 100% for HNO(3). Hence, low results may be obtained if the glass wool plugs are discarded. Similarly, methods for volatile inorganic acids that use a pre-filter to remove particulates usually overlook the fact that the acids can react with co-particulate matter on the pre-filter. Low recoveries in the range 30%-50% have been found when sampling HCl through filters loaded with potential interferents. Finally, particulate salts interfere with filter sampling methods for non-volatile inorganic acids. A two-part International Standard is in preparation for inorganic acids by ion chromatography and the issues discussed above are being taken into consideration during its development.     

Estimating the background air concentration excluding the contribution of an individual source

This paper presents two simple methods for the estimation of the instantaneous background air pollution level in a study area around an emitting point source. The methods allow estimation of concentrations non-inclusive of the contribution of the local emitting source. Hourly records of several monitoring stations located around the point source and results of the diagnostic Lagrangian particle dispersion model LADISMO are used in the calculations. A hypothetical case study is used to demonstrate the application of the two methods. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparison of two carbon analysis methods for monitoring diesel particulate levels in mines

Two carbon analysis methods are currently being applied to the occupational monitoring of diesel particulate matter. Both methods are based on thermal techniques for the determination of organic and elemental carbon. In Germany, method ZH 1/120.44 has been published. This method, or a variation of it, is being used for compliance measurements in several European countries, and a Comité Européen de Normalization Working Group was formed recently to address the establishment of a European measurement standard. In the USA, a 'thermal-optical' method has been published as Method 5040 by the National Institute for Occupational Safety and Health. As with ZH 1/120.44, organic and elemental carbon are determined through temperature and atmosphere control, but different instrumentation and analysis conditions are used. Although the two methods are similar in principle, they gave statistically different results in a previous interlaboratory comparison. Because different instruments and operating conditions are used, between-method differences can be expected in some cases. Reasonable agreement is expected when the sample contains no other (i.e., non-diesel) sources of carbonaceous particulate and the organic fraction is essentially removed below about 500 degrees C. Airborne particulate samples from some mines may meet these criteria. Comparison data on samples from mines are important because the methods are being applied in this workplace for occupational monitoring and epidemiological studies. In this paper, results of a recent comparison on samples collected in a Canadian mine are reported. As seen in a previous comparison, there was good agreement between the total carbon results found by the two methods, with ZH 1/120.44 giving about 6% less carbon than Method 5040. Differences in the organic and elemental carbon results were again seen, but they were much smaller than those obtained in the previous comparison. The relatively small differences in the split between organic and elemental carbon are attributed to the different thermal programs used.     

Size distribution in ultraphytoplankton: A comparative analysis of counting methods

Water samples taken at three depth layers from the offshore oligotrophic Cretan Sea were analyzed for ultraphytoplankton size fractionation using different methods: (a) sequential filtration on filters of pore size 5, 1 and 0.2 m, (b) separate filtration using filters 5 and 0.2 m as well as 1 and 0.2 m and (c) direct filtration on 0.2 m filters after staining of the samples with DAPI. Total abundance of photosynthetic organisms as well as the abundance of different groups such as flagellates and cyanobacteria measured by means of sizing after DAPI staining were significantly higher than those obtained by the other methods. This indicates that although there were no significant differences between the estimates provided by the separate and sequential filtration, both these methods underestimated total abundance by at least 25–50%. The estimates for the size fractions were also found to range from relatively imprecise to completely unreliable depending on the group and the size range. Although size fractionation through direct observation after staining largely depends on the expertise of the observer, this study suggests that it may provide more informative estimates than the other two methods. Although it is difficult to generalize the results of this study in a global context, the paper provides strong indications on the limitations of the sequential and separate methods for size fractionation of photosynthetic organisms and implies that their results are likely to be less accurate than is presently believed.     

Comparison between electrofishing and snorkeling surveys to describe fish assemblages in Laurentian streams

We evaluated the relative performance of electrofishing and visual surveys (snorkeling) for estimating the abundance of combinations of fish species and size classes in rivers. We also assessed the effect of environmental conditions on potential differences between the results obtained using these two sampling methods. Sampling sites were distributed in the Laurentian region of Québec. Both methods were used while sections were blocked. Three snorkelers swam the river sections upstream while identifying and counting fish of each species and size classes. Three-pass electrofishing was performed in the same sites and abundances were estimated with a maximum likelihood depletion model. Greater abundances of fish were observed by snorkeling than by electrofishing at all sites. Snorkeling species richness was higher or equal to electrofishing richness in, respectively, 60 % and 40 % of sampled sites. Differences in the fish communities observed by both sampling methods were not related to environmental conditions. The results of our work are therefore contrary to that of most published studies that suggested the use of electrofishing over visual surveys. This study highlights that conclusions derived from previous work on sampling gear comparisons may not be generalisable; rather survey methods might benefit from being selected based on fish community composition.     

Comparison of macroinvertebrate sampling methods for nonwadeable streams

Bioassessment of nonwadeable streams in the United States is increasing, but methods for these systems are not as well-developed as for wadeable streams. In this study, we compared six macroinvertebrate field sampling methods for nonwadeable streams adapted from those used by three major programs: the U.S. Environmental Protection Agencys Environmental Monitoring and Assessment Program-Surface Waters, the U.S. Geological Surveys National Water Quality Assessment Program, and the Ohio Environmental Protection Agency, Division of Surface Water Biocriteria Program. We performed all six methods at 60 sites across four rivers and measured water chemistry and physical habitat at each site to assess abiotic conditon. Sites were divided into two groups: those influenced by navigational lock and dam structures (restricted flow, or RF) and those free-flowing or with lowhead dams (run-of-the-river, or ROR). Metrics based on passive Hester-Dendy artificial substrate samplers differed greatly from active sampling methods (i.e., using nets) but represented abiotic conditions well in both ROR and RF sites. Although metric values were similar across certain sampling methods, the metrics significantly correlated with abiotic variables varied among methods and between ROR and RF sites. These results emphasize that methods are not interchangeable, and the ability to detect certain stressors depends on sampling method.The U.S. Governments right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

Occupational exposure to rubber vulcanization products during repair of rubber conveyor belts in a brown coal mine

Several hundred chemical compounds were found in workroom environments in the rubber industry, but most of the published exposure data relate to the production of tyres; information from the "non-tyre" sections are very limited, if any. This study was carried out to identify chemical substances and measure their air concentrations in the repair shop of a brown coal mine in which damaged rubber conveyor belts were repaired. GC-MS and HPLC analysis of stationary air samples resulted in identification of aliphatic and aromatic hydrocarbons to C12, PAHs, alcohols, phenols, ketones, heterocyclic nitrogen and sulfur compounds. Quantitative evaluation of occupational exposure included determination of organic compound vapours collected on charcoal (GC-MSD), polycyclic aromatic hydrocarbons (HPLC), N-nitrosoamines and other amines (GC-NPD) and DNPH derivatives of aldehydes (HPLC) in the breathing zone of workers representing all job titles. The concentrations of investigated compounds were very low. Carcinogenic substances: N-nitrosoamines, benzene, PAHs were not present in workroom air in concentrations exceeding limits of detection of the analytical methods being applied; concentrations of methylisobutylketone, tetrachloroethylene, naphtha, aromatic hydrocarbons, phthalates and aldehydes were much lower than the respective occupational exposure limit values. The results indicate much lower exposure than that reported in the production of tyres and other fabricated rubber products.     

基于不同方法的水生态健康评估 ——以北京市典型水体为例

在北京选择密云水库、昆明湖、福海和北运河水系河流等9个典型水体,利用基于不同水生生物的多样性指数法和综合指数法开展水生态健康评价.结果表明,基于浮游植物和底栖动物的Shannon-Wiener多样性指数所指示的水生态状况分别对应轻污染～中污染和中污染～重污染等级,而结合生境、水质和水生生物指标的两项综合指数反映出的水生...     

Efficiency of a standardized artificial substrate for biological monitoring of river water quality

Before using macroinvertebrates in water quality assessment in the Chusovaya River (Russia, the Urals, 50°55N, 60° E), preliminary results of three sampling methods were compared: handnet, circular shovel and a standardized artificial substrate sampler. The artificial substrate consisted of glass marbles ( 20 mm). To compare the efficiency of these sampling methods the total numbers of taxa found at each location per sampling data were considered to be 100%. The highest efficiency was reached with the artificial substrate sampler. 75–100% of the taxa at the different locations were collected with this sampler. Only 5–19% and 10–20% of the taxa at each location per sampling date were collected with the circular shovel in the sand and gravel substrate respectively, being the lowest efficiency. Intermediate results were obtained with the hand net. 23–38% of the taxa were collected with this net. Based on these results and requirements placed upon sampling methods in general, the standardized artificial substrate sampler has been considered to be an optimal sampling device for macroinvertebrates in biological monitoring.     

An Evaluation of Selenium Concentrations in Water, Sediment, Invertebrates, and Fish from the Republican River Basin: 1997–1999

The Republican River Basin of Colorado,Nebraska, and Kansas lies in a valley which contains PierreShale as part of its geological substrata. Selenium is anindigenous constituent in the shale and is readily leached intosurrounding groundwater. The Basin is heavily irrigated throughthe pumping of groundwater, some of which is selenium-contaminated, onto fields in agricultural production. Water,sediment, benthic invertebrates, and/or fish were collected from46 sites in the Basin and were analyzed for selenium to determinethe potential for food-chain bioaccumulation, dietary toxicity,and reproductive effects of selenium in biota. Resultingselenium concentrations were compared to published guidelines orbiological effects thresholds. Water from 38% of the sites (n = 18) contained selenium concentrations exceeding 5 g L^-1, which is reported to be a high hazard for selenium accumulation into the planktonic food chain. An additional 12 sites (26% of the sites) contained selenium in water between 3–5 g L^-1, constituting a moderate hazard. Selenium concentrations in sedimentindicated little to no hazard for selenium accumulation fromsediments into the benthic food chain. Ninety-five percent ofbenthic invertebrates collected exhibited selenium concentrationsexceeding 3 g g^-1, a level reported as potentially lethal to fish and birds that consume them. Seventy-five percent of fish collected in 1997, 90% in 1998, and 64% in 1999 exceeded 4 g g^-1selenium, indicating a high potential for toxicity andreproductive effects. However, examination of weight profilesof various species of collected individual fish suggestedsuccessful recruitment in spite of selenium concentrations thatexceeded published biological effects thresholds for health andreproductive success. This finding suggested that universalapplication of published guidelines for selenium may beinappropriate or at least may need refinement for systems similarto the Republican River Basin. Additional research is needed todetermine the true impact of selenium on fish and wildliferesources in the Basin.