微量铊~(Ⅲ)的螯合滴定

本文比较了4-(2-吡啶偶氮)间苯二酚(PAR)、1-(2-吡啶偶氮)-2-萘酚(PAN)、2-(2-噻唑偶氮)-5-二乙氨基苯酚(TAF)、二甲酚橙(XO)、2-(2-苯骈噻唑偶氮)-5-二乙氨基苯酚(BAE)、1-(2-噻唑偶氮)-2-萘酚(TAN)、4-(2-噻唑偶氮)间苯二酚(TAR)、甲基百里酚兰(MTB)等八种金属指示剂于直接螫合滴定微量铊(Ⅲ)的适宜酸度范围、适宜温度范围和可测范围。其中以PAR、PAN XO和TAE更适宜于微量铊(Ⅲ)的滴定,其测定最低限可达4微克铊(Ⅲ),且酸度范围也较广,终点变色敏锐。本文还讨论了以PAR、XO、TAE为指示剂滴定铊(Ⅲ)时,其它离子干扰情况以及部分干扰离子的消除方法。最后还以PAR为指示剂螫合滴定测定天然水和工厂废水中微量铊,以及铊(Ⅲ)和铊(Ⅰ)共存时的连续测定。     

用广义λ—分布拟合空气污染数据

广义λ-分布是一个四参数可变通的概率模型,包括多种单变量分布,这一模型可用于表示空气污染浓度的频率分布。本文采用土耳其安卡拉每日的烟和SO_2监测数据,来证明广义λ-分布具有良好的拟合性质。这里还讨论了与分位数估计和拟合优度有关的一些结果,并与经典对数正态分布进行了比较。     

新疆核试验场周围各类土壤中~(90)Sr、~(137)Cs分布与迁移

本文对新疆核试验场周围10个调查地区和5个对照地区采集180个土壤样品进行了~(90)Sr、~(137)Cs放射性含量的分析,结果表明,在各类土壤中~(90)Sr、~(137)Cs的放射性含量除黄粘土与潮土、盐土及风沙土有非常显著性差异外(p<0.01),其余各类土壤之间均无显著性差异(p>0.05)。~(90)Sr、~(137)Cs在各类土壤中的垂直分布随深度的增加而含量减少。0～10Cm剖层中的~(137)Cs含量高于~(90)Sr的含量,而在10～20Cm和20～30Cm剖层中则~(90)Sr含量高于~(137)Cs的含量。其迁移速度,潮土、盐土、风沙土之间看不出多大的差别,但黄粘土较慢。~(90)Sr、~(137)Cs在各类土壤中均呈现出~(90)Sr的迁移比~(137)Cs快的总趋势。     

基体改进-石墨炉原子吸收光谱法直接测定土壤中的镉和铅

环境中Cd、Pb是危害人体健康的有害元素,人们广泛开展了对铅、镉的分析方法的研究,火焰原子吸收法测定土壤中的Cd、Pb因基体复杂,含量较低,要采用分离富集的技术,来消除干扰,提高方法的灵敏度,但手续繁琐。采用石墨炉原子吸收直接测定,灵敏度高,但也存在基体干扰严重的问题。同时,Cd、Pb在灰化期间易挥发损失,许多文献介绍采用基体改进剂提高灰化温度,以消除基体干扰。本实验对文献所介绍的基体改进剂进行了实验,表明以H_3PO_4为改进剂测定土壤中Cd、Pb抑制干扰的效果明显,并有效地提高了灰化温度。我们采用高压罐消解土壤样品,把H_3PO_4直接注入石墨管以测定Cd、Pb。其方法简便,检     

新疆饮用水中~(222)Rn浓度

自然界中,到处都有~(226)Ra,不断地释放出~(222)Rn.空气中~(222)Rn及其子体所致居民剂量,约占天然电离辐射所致居民剂量的45％.调查饮用水中~(222)Rn浓度,对了解它对空气中~(222)Rn的贡献,制定饮用水~(222)Rn放射卫生标准,探讨肺癌发病原因和保护人民健康都具有一定的意义。为此,我们于1985年,调查了新疆饮用水中~(222)Rn浓度,评价了它对居民健康的影响.     

公共场所可吸入尘(IP)测定时滤膜处理及分析中若干问题

可吸入尘(IP)作为主要的空气质量监测指标之一,已广泛应用于环境监测工作中,尤其是大气卫生监测和公共场所及住宅室内空气卫生状况的调查,并已制定出相应的卫生标准.目前国内广泛采用的测定方法均为分级采样器——滤膜称重法,本法在空气颗粒物质浓度较高,且可长时间采样的现场监测中,结果还是比较稳定     

Naphthalene and its biomarkers as measures of occupational exposure to polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAH) include compounds with two or more fused benzene rings, many of which are carcinogens. Industrial sources produce hundreds of PAH, notably in the coke- and aluminium-producing industries. Because PAH are distributed at varying levels between gaseous and particulate phases, exposure assessment has been problematic. Here, we recommend that occupational exposures to naphthalene be considered as a potential surrogate for occupational PAH exposure for three reasons. Naphthalene is usually the most abundant PAH in a given workplace; naphthalene is present almost entirely in the gaseous phase and is, therefore, easily measured; and naphthalene offers several useful biomarkers, including the urinary metabolites 1- and 2-hydroxynaphthalene. These biomarkers can be used to evaluate total-body exposure to PAH, in much the same way that 1-hydroxypyrene has been applied. Using data from published sources, we show that log-transformed airborne levels of naphthalene are highly correlated with those of total PAH (minus naphthalene) in several industries (creosote impregnation: Pearson r= 0.815, coke production: r= 0.917, iron foundry: r= 0.854, aluminium production: r= 0.933). Furthermore, the slopes of the log-log regressions are close to one indicating that naphthalene levels are proportional to those of total PAH in those industries. We also demonstrate that log-transformed urinary levels of the hydroxynaphthalenes are highly correlated with those of 1-hydroxypyrene among coke oven workers and controls (r= 0.857 and 0.876), again with slopes of log-log regressions close to one. These results support the conjecture that naphthalene is a useful metric for occupational PAH exposure. Since naphthalene has also been shown to be a respiratory carcinogen in several animal studies, it is also argued that naphthalene exposures should be monitored per se in industries with high levels of PAH.     

纯二氧化氯的制备及其检测方法

报道了一种价格低廉的纯二氧化氯的制备方法，并根据二氧化氯制备过程中产生气体的特点，提出了针对发生过程的氯气。二氧化氯含量的检测方法。     

火力发电厂废水回收利用研究

文中以永昌电厂废水回收工程为例，对火电厂废水回收工艺进行了阐述，并着重分析、探讨了用阻垢剂加硫酸处理火电厂循环补水，以提高火力发电厂循环水浓缩倍率，进而提高回收废水利用量的实际可行性。     

The importance of temperature in assessing iron pipe corrosion in water distribution systems

Temperature is expected to play a significant role in the corrosion of iron pipes in drinking water distribution systems. Temperature impacts many parameters that are critical to pipe corrosion including biological activity, physical properties of the solution, thermodynamic and physical properties of corrosion scale, and chemical rates. Moreover, variations in temperature and temperature gradients may give rise to new corrosion phenomena worthy of consideration by water treatment personnel.