Speciation of iron in river water using a specific catalytic determination and size fractionation

A comprehensive speciation scheme was proposed for the speciation of iron in river water (0.45 microm filtrate). The speciation was based on the catalytic determination of reactive iron as Fe3+ and Fe(III)Li/(3 -in)+, where i = 1 or 2 for a unidentate and i = 1 for a bidentate ligand, Ln-. The scheme incudes size fractionation and acid decomposition of the sample and determination of the coexisting species. The proposed scheme was applied to natural and artificial samples and acidified preparations of these. Resulting fractionation patterns of reactive and unreactive iron and of coexisting humic acid were useful for the characterization of iron species in the natural samples. The reactive iron in the molecular weight (Mr) > or = 10(4) fraction was associated with humic iron aggregates and estimated as iron complexed with them. The unreactive iron in this fraction dissociated in 0.1 M HCI and was estimated as iron in the aggregates of iron(III) hydroxide (s) and humic iron. From the fractionation results of the artificial sample, the reactive and unreactive iron in the Mr < 10(3) fraction may be formed by complexing simple anions like F- and C2O4(2-) at their naturally-occurring concentration levels. The fractionation results also suggested that humic acid and Si contributed to the formation of reactive and unreactive iron in the Mr > or = 10(4) fraction.     

Multi-objective, decision-based assessment of a water quality monitoring network in a river system

Water quality monitoring network design has historically tended to use experience, intuition and subjective judgement in locating monitoring stations. Better design procedures to optimize monitoring systems need to simultaneously identify significant planning objectives and consider a number of social, economic and environmental constraints. The consideration of multiple objectives may require further decision analysis to determine the preference weights associated with the objectives to aid in the decision-making process. This may require the application of an optimization study to extract such information from decision makers or experts and to evaluate the overall effectiveness of locating strategies. This paper assesses the optimal expansion and relocation strategies of a water quality monitoring network using a two-stage analysis. The first stage focuses on the information retrieval of preference weights with respect to the designated planning objectives. With the aid of a pre-emptive goal programming model, data analysis is applied to obtain the essential information from the questionnaire outputs. The second stage then utilizes a weighted multi-objective optimization approach to search for the optimal locating strategies of the monitoring stations in the river basin. Practical implementation is illustrated by a case study in the Kao-Ping River Basin, south Taiwan.     

用新制蒸馏水代替重蒸蒸馏水配制测定亚硝酸盐氮、氨氮、酚的试液

用新制蒸馏水代替重蒸蒸馏水配制测定亚硝酸盐氮、氨氮、酚的试液ＣｏｍｐｏｕｎｄｅｄＴｈｅＳｏｌｕｔｉｏｎＮｉｔｒｉｔｅ－Ｎ，Ａｍｍｏｎｉａ－ＮａｎｄＰｈｅｎｏｌＷｉｔｈＮｅｗ－ｍａｄｅＤｉｓｔｉｌｅｄＷａｔｅｒｉｎｓｔｅａｄｏｆＡｆｒｅｓｈＤｉｓｔｉｌ...     

山东省首家县级环境监测网在博山成立

为提高博山地区的整体环境监测能力,准确、及时、全面地掌握环境质量和污染源变化动态,根据《中华人民共和国环境保护法》、《全国环境监测网络管理规定》、《全国环境监测管理条例》等法律、法规的要求,山东省淄博市博山区于1996年1月19日率先在省内成立首家地区性环境监测网,即博山地区环境监测网(以下简称博山网)。     

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。     

用碱性玫瑰精代替罗丹明B做水动力扩散试验示踪剂的分光光度法的研究

本文研究了碱性玫瑰精和罗丹明B的PH、水温、稳定时间、吸收峰扫描,河水影响,检出下限,回收率等方面的试验,结果表明,性能一致。利用碱性玫瑰精完全可以代替罗丹明B做水动力扩散试验的示踪剂。以河水为参比可扣除本底影响,检出下限达5PPb。     

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.