关于挥发酚测定中有关问题的探讨

本文对在挥发酚测定中，通过提纯显色剂纯度及控制去离子水的电导率，以达到降低测定空白值的目的，提出了较新的见解。     

离子选择电极法测定水中氟化物的注意事项

离子选择电极法测定水中氟化物应注意的事项。1　空白电位值电极在使用前必须在 1 0 - 3 ｍｏｌ/ＬＮａＦ溶液中浸泡 1ｈ～ 2ｈ进行活化 ,再用去离子水反复清洗 ,直至空白电位值达 +2 70ｍＶ左右。氟电极使用一段时间后就很难达到 +2 70ｍＶ空白电位值 ,这是由于电极头部敏感部分受到油类污染所致 ,采用酒精浸泡再用现制的去离子水洗涤处理 ,可使空白电位值恢复到 +2 70ｍＶ左右。这里还要注意清洗电极和绘制校准曲线以及样品测量时应使用同一种水质的去离子水 ,以避免因水质不同所引起的测量误差。2　温度温度对测量结果的影响很大 ,当温度…     

环境空气监测中NO_x、SO_2空白值的研究

本文研究了惠州市市区环境空气监测中氮氧化物、二氧化硫的现场空白值与室内空白值的差异,得出了二氧化硫测定的两种空白值相差无几,氮氧化物测定的两种空白值相差较显著的结论。提出了在计算环境空气氮氧化物浓度时,扣除现场空白值是消除分析误差的一个不可忽视的环节。讨论了现场空白值受环境条件（气温、光照强度等）影响的情况     

对利用回归方程式计算空白浓度及样品含量出现负值时的处理意见

利用校准曲线的回归方程式计算空白浓度值和样品含量(痕量样品)时,有时会出现负值,对于这个负值如何处理?《环境水质监测质量保证手册》及《环境监测技术规范—地表水和废水部分》都没有明确的规定。有的同志遇到这种情况,便将负值处理成“零”或“未检出”,这样做不太妥当。 根据回归方程式y=bx+a计算空白浓     

空气质量监测中现场空白测定方法探讨

探讨了空气质量监测中现场空白的测定方法，通过对封口的现场空白与实验室对白比对及采样过程现场空白吸收管开口与封口对照试验，认为采样时应对现场空白吸收管作封口处理，才能体现现场空白的真实性。     

测定地表水中悬浮物的空白校正

进行了测定地表水中悬浮物空白校正与不作空白校正的对比试验 ,得出不作空白校正存在较大误差 ,认为测定地表水中悬浮物时应作空白校正。同时用测定海水中悬浮物的方法作测定地表水中悬浮物的试验 ,试验效果较好 ,符合测定要求。建议可用测定海水中悬浮物的方法来测定地表水中悬浮物     

水质监测质控考核数据处理方法

质控试验中对大部分项目要求以纯水或纯溶剂为参比,每批测定两个空白值(b_1、b_2),共测五批。由测得的五批信号值计算出空白浓度值,进而求出空白浓度的总平均值(?)、空白浓度批内标准偏差(S_(wb))与检出限(L)。     

测定地表水中石油类的空白用水制备

目前常用红外分光光度法(GB/T16488-1996)测定地表水中石油类,该方法规定空白用水为蒸馏水或同等纯度水。根据多次实验发现,常规的空白用水会使试验结果出现异常。故对空白用水的选择和制备进行了试验。1　空白试验实验证实,蒸馏水、去离子水、自来水空白吸光值波动性较大,不宜直接用于空白试验用水。未受污染的源头水及锅炉冷凝水空白吸光值较低,但取水不易,且很难排除偶然性的外界干扰。2　空白用水的制备2 1　活性炭吸附柱的制备和实验用水的纯化先将实验用分析纯颗粒状活性炭(天津市津北精细化工厂500g/袋)活化。取1000g颗粒状活…     

4-氨基安替比林-氯仿萃取比色法测定挥发酚的疑难问题

1.试剂空白高,波动大。 空白值的大小和重现性影响分析结果的精密度、准确度以及方法的检测限。分析方法要求,试剂空白以氯仿为参比的吸光度应在0.10以下,但测定中一般难以达到,且波动较大,使用相同的试剂,十天之内六天测定的空白吸光度极差为0.032,相对偏差为12.3％。这主要与4-氨基安替比林的纯度及其接触空气时间的长短有关,另外也受无酚水质量的影响。 4-氨基安替比林与空气接触,易被氧化为安替比林红,引起空白增高。用配制的同一溶液,先后连续测定三个标准系列,其空白吸光     

在线富集流动注射-火焰原子吸收法中样品空白值的测定

提出了在线富集-FAAS法中样品空白值测定的方法,讨论了不正确的样品空白值对测定结果准确度的影响.     

中俄界河--黑龙江水环境分析与评价

采用“有机污染综合评价法”对黑龙江干流上、中游江水水质进行分析评价,分析与评价结果表明,黑龙江总体水质较好,主要污染物为高锰酸盐指数。     

化学需氧量光度测定法探索

试验证明,ＣＯＤ光度测定法是可行的,本法测定范围为０～２００ｍｇ／Ｌ,测定波长为４３４ｎｍ,Ｋ２Ｃｒ２Ｏ７标准溶液最佳使用浓度为０．０６７５ｍｏｌ／Ｌ（１／６Ｋ２Ｃｒ２Ｏ７）在此浓度下ＣＯＤ为２００ｍｇ／Ｌ,的葡萄糖溶液实际测得值只比标准滴定法低１．８％。     

关于“十二五”国家环境监测的思考

根据环境监测面临的新形势和新任务,提出了"十二五"期间做好国家环境监测工作需在九个方面下功夫,并对国家环境监测"十二五"规划的有关内容提出了建议。     

库尔勒市农村"白色污染"现状与对策探讨

随着地膜在农村的广泛使用,在增加了农民收入的同时也给农村带来了污染,这种“白色污染”逐年加剧了对农村生态环境的破坏.本文在对库尔勒市农村“白色污染”开展调查的基础上,提出了治理农村“白色污染”的相关措施.     

浅谈国家环境监测网建设

总结了“十一五”期间我国环境监测网络建设的成绩,提出了“十二五”国家环境监测网建设的指导思想和发展目标以及当前应当重点做好的几项工作.     

Exposure Assessment to Mercury Vapor in Chloralkali Industry

The aim of the study was to develop a sampling method aimed at individual sampling of mercury vapor and subsequent individualexposure assessment of the worker. Hopcalite available fromInowrocawskie Zakady Chemiczne (in Poland) was founduseful for mercury vapor sampling in active and passive individual samplers. However the sampling rate determined forpassive sampler in steady-state laboratory chamber cannot be usedunder fluctuating conditions of mercury vapor concentration andair movement typical for field measurement. In order to check comparativeness of passive and active sampling methods, sampleswere taken in the same time and individual samplers fixed toworker's clothes were used. Mercury vapor concentration wasmeasured at two chloralkali industries in Poland and the resultswere presented. Excessive exposure in both industries wasconfirmed by finding elevated mercury concentration in urinesamples from the workers.     

Proximity analysis of air pollution exposure and its potential risk

Proximity analysis and spatial variability of the ambient nitrogen dioxide (NO(2)) concentration in Rayong province, Thailand, were analyzed using geostatistics and spatial modeling techniques. Annual concentrations of nitrogen dioxide were predicted and spatially interpolated using various interpolation techniques (i.e. kriging, IDW and spline). Sensitivity analysis was carried out to assure the accuracy of the predicted results. The GIS-based exposure map was simulated and was assisted to identify high exposure areas. A health risk warning system was set for "action" (exceeds 100% of the annual average NO(2) guideline), for "alert" (between 66-100% of the annual average NO(2) guideline) and for "some concern" (between 33-66% of the annual average NO(2) guideline). Although no areas were exposed to an action level, many locations in the study area could have levels of "some concern". Potential risk to the population was analyzed by spatial interpolation of the nitrogen dioxide concentration with population data. The result indicated the number of people exposed to air pollution, as well as the areas which have a high risk to air pollution. About 88.3% of the total population in the study area live in areas where levels of air pollution are designated as being in the "some concern" zone. About 6.7% of the registered population have their residence in an area where action should be taken for air quality management. The study demonstrates the application of GIS-based prediction for the evaluation of exposure mapping, in order to determine the spatial extent and frequency of areas where pollution levels exceed target values, and their potential health impacts.     

太湖流域水生态环境功能分区管理指标达成效率评估和预警研究

太湖流域严峻的水生态环境形势备受关注,而水生态环境功能分区管理体系实施现状和效果无法被准确把握。以太湖流域水生态环境功能分区为研究对象,基于四象限法则和二维向量结构指标体系等方法论,综合障碍因子分析与目标可达性分析,对太湖流域水生态环境功能分区管理绩效评估目标达成效率进行评估和预警,为水生态环境功能分区管控提供技术指导。结果表明,江苏省太湖流域目标达成效率情况较好,"高效"、"一般"、"低效"的比例依次下降,高预警级别的区域较少;环境效率指标中单位面积污染物减排管控效率较高,环境质量指标整体表现良好,须谨防向"低效"转变。     

Manganese air exposure assessment and biological monitoring in the manganese alloy production industry

One hundred workers carried personal air sampling equipment during three days to assess exposure to inhalable and respirable Mn. A novel four-step chemical fractionation procedure developed for the speciation of Mn in workroom aerosols was applied for selected aerosol filters. Blood and urine samples were analysed for Mn. The geometric mean (GM) concentrations of inhalable (n = 265) and respirable (n = 167) Mn determined in all filters were 254 microg m(-3) and 28 microg m(-3) respectively. Only 10.6% (95% CI 8.9-12.5) respirable Mn was found in the inhalable fraction when inhalable and respirable samples collected in parallel were considered (n = 153 pairs). There was a high correlation (Pearson's r = 0.70; p < 0.001) between respirable and inhalable Mn. The largest amounts of Mn in the inhalable aerosol fraction were found as Mn0 and Mn2+ (47.4%), whereas 28% was practically "insoluble". The associations between B-Mn and aerosol concentrations of Mn were weak, but an association was found between U-Mn and respirable Mn; Pearson's r being 0.38 between "soluble" respirable Mn and U-Mn. No significant association was found between the "insoluble" components (probably SiMn) and Mn in biological samples.     

Sampling of Sparse Species with Probability Proportional to Prediction

In this article, a 3P sampling (Probability Proportional to Prediction) approach is presented for surveying sparse species connected to certain types of substrates. The method uses the surveyors judgement of the probability of finding the species on a substrate as the base for selection of substrates for species inventories. The method is presented together with estimators, variances and variance estimators. The method is first presented for sampling based on all substrates in a study area and then as a subsampling technique in a two-stage design in which plots or strips are selected in a first stage. The presented approach was evaluated as a subsampling technique in a strip survey of calicioid lichen species associated with coarse broadleaf trees. In comparison with a simple random subsampling without replacement, 3P subsampling was in one study area found to be an improvement with 30–55% in terms of standard errors. The improvement was more modest in the other study area, only between 10–16%. The strip survey with 3P subsampling was more cost-efficient than a strip survey without subsampling except in one case. Based on the results in the test, 3P sampling seems to have a potential for sampling sparse species.