BOD_5TraK仪器测定水中5日生化需氧量

BODTraK仪器测定水中 5日生化需氧量 ,操作简便 ,测定直接、快速。五日生化需氧量在 0- 35 0mg/L浓度范围内 ,相对误差在 - 5 2 %— 6 4 %。葡萄糖 -谷氨酸校核实验结果BOD5值为 2 10mg/L- 2 2 3mg/L     

STREAMFLOW MEASUREMENT USING SALT DILUTION IN TUNDRA STREAMS,NORTHWEST TERRITORIES,CANADA1

ABSTRACT: With the recent increased exploration and mining activity in the Northwest Territories, there has been growing interest in streamflows. However, streamflow monitoring in Canada's north is limited, especially in the central Northwest Territories where the exploration activity is concentrated. To complicate matters, the standard approach of measuring discharge with current meters or weirs is often inadequate or prohibitively expensive, as many streams in the region are shallow, braided and rocky. In response, alternative techniques such as salt dilution can be used. A salt tracer's competence in turbulent and rocky channels makes it ideal for discharge measurements in these situations. This paper summarizes the work performed by Indian and Northern Affairs Canada and Canamera Geological Ltd. staff in determining the stream discharge of a lake outlet using a potassium chloride (KC1) tracer. A variety of streamflow measurement methods were performed and compared to determine the viability and rigor of the dilution method. Results suggest the dilution method compares favorably to other measurement techniques both in accuracy and operational ease.     

Dilution with air to minimise consequences of toxic/flammable gas releases

Dilution has long been considered a solution to many problems of toxic/flammable material releases. It implies diluting to a concentration that is below physiologically dangerous levels for a toxic substance (generally below TLV), or to a level below LFL for a flammable material release, ensuring that the process adopted for dilution does not itself enhance the risks.

In this paper, we discuss the dilution of a gaseous release by deliberate and cautious mixing with air to reduce its concentration to a harmless level. The idea bears its origin to the Bhopal Gas Tragedy where some families saved themselves by turning the ceiling fans on when MIC reached their bedrooms at the dead of very cold night on December 2–3, 1984. The air pushed in by the fans diluted the MIC to below the harm level.

Some of the advantages of using air dilution are: no cost of air, no air storage needed, no need to treat the air after use as in case of water curtains; required equipment, its maintenance and staff training in its use are very likely to cost less than in other ways of handling a release.

Air dilution may not be feasible in all cases, such as gaseous release within a congested equipment layout, release that forms a liquid pool, etc. The method needs to be evaluated for each case.     

Characterization of environmental water samples using strontium and lead stable isotope compositions

A simple procedure using both cation and anion exchange chromatography has been applied in the study of lead and strontium isotope composition in rain and stream water samples from remote catchments in Scotland. Whereas the soil released strontium to stream waters, lead was removed from rain water and the concentrations in stream waters were very low. Highly precise analysis by thermal ionisation mass spectrometry proved necessary in the determination of strontium isotope composition. The ⁸⁷Sr/⁸⁶Sr ratio in rain water was close to that of marine strontium but the ratios in stream waters were constant and highly characteristic for the stream. In the case of the stream at the Sourhope site, the ratio (0.70798 ± 0.00005) was less than that in rain water and probably resulted from the weathering of one specific mineral. The results suggested that the ⁸⁷Sr/⁸⁶Sr ratios could be used as a stable isotope tracer of waters and to provide information on the weathering processes. Two major anthropogenic components of lead were identified in water samples. One had its origin in petrol additives whereas the other was probably of industrial origin. The low ²⁰⁶Pb/²⁰⁷Pb ratios observed in stream waters confirmed the lead as being of anthropogenic origin and the data suggested that there was a movement, albeit very small, of lead from the soil to waters.     

环境样品稀释方法的探讨

环境样品分析中，特别是污染源样品分析经常遇到样品浓度高于方法的检出范围。为此，根据不同分析项目的分析方法和质量控制的要求，研究和探讨了样品稀释可采用原始样品、中间样品和分析后样品进行稀释。稀释倍数可根据日常积累的基础资料推算、肉眼观察和简单试验的方法确定。探讨了稀释误差的来源及降低稀释误差的方法。     

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。     

测定高锰酸盐指数考核样品时的计算方法修正

针对测定高锰酸盐指数考核样品时的结果偏高现象，经过查找，其原因是由于按公式计算没有考虑稀释用纯水的空白值响应。经修正公式后计算，其考核样品的结果则均为正确。     

Stable carbon isotope analysis (δ13C values) of polybrominated diphenyl ethers and their UV-transformation products

Polybrominated diphenyl ethers (PBDEs) are frequently detected in food and environmental samples. We used compound specific isotope analysis to determine the δ¹³C values of individual PBDEs in two technical mixtures. Within the same technical product (DE-71 or DE-79), BDE congeners were the more depleted in ¹³C the higher brominated they were. In contrast, the products of light-induced hydrodebromination of BDE 47 and technical DE-79 were more enriched in ¹³C because of more stable bonds between ¹³C and bromine. As a result, the δ¹³C values of the irradiated solution progressed diametrically compared to those of the technical synthesis. The ratio of the δ¹³C values of BDE 47 to BDE 99 and of BDE 99 to BDE 153 are thus suggested as indicators to distinguish native technical products from transformation products. Ratios <1 are typical for native congeners (e.g. in DE-71) while the reversed ratio (>1) is typical of transformation products.     

测定废水BOD5时水样稀释倍数的确定

根据测定BOD5所须具备条件,经过理论推导,得出水样稀释倍数的大致范围,对多种工业废水测试证,表明方法简便易行。