All of Bangladesh’s approximately 10 million drinking-water tube wells must be periodically tested for arsenic. The magnitude of this task and the limited resources of Bangladesh have led to the use of low-cost, semiquantitative field kits that measure As to a relatively high 50 μg/L national drinking water standard. However, there is an urgent need to supplement and ultimately replace these field kits with an inexpensive laboratory method that can measure As to the more protective 10 μg/L World Health Organization (WHO) health-based drinking water guideline. Unfortunately, Bangladesh has limited access to atomic absorption spectrometers or other expensive instruments that can measure As to the WHO guideline of 10 μg/L. In response to this need, an inexpensive and highly sensitive laboratory method for measuring As has been developed. This new method is the only accurate, precise, and safe way to quantify As < 10 μg/L without expensive or highly specialized laboratory equipment. In this method, As is removed from the sample by reduction to arsine gas, collected in an absorber by oxidation to arsenic acid, colorized by a sequential reaction to arsenomolybdate, and quantified by spectrophotometry. We compared this method with the silver diethyldithiocarbamate [AgSCSN(CH2CH3)2] and graphite furnace atomic absorption spectroscopy (GFAAS) methods for measuring As. Our method is more accurate, precise, and environmentally safe than the AgSCSN(CH2CH3)2 method, and it is more accurate and affordable than GFAAS. Finally, this study suggests that Bangladeshis will readily share drinking water with their neighbors to meet the more protective WHO guideline for As of 10 μg/L.
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机译:孟加拉国大约1000万个饮用水管井中的所有井都必须定期进行砷测试。这项工作的艰巨性和孟加拉国的资源有限,导致使用了低成本,半定量的现场试剂盒,该试剂盒可测量相对较高的50μg/ L国家饮用水标准。但是,迫切需要用一种廉价的实验室方法来补充并最终替换这些现场工具包,该方法可以测量出更具保护性的10μg/ L世界卫生组织(WHO)基于健康的饮用水准则。不幸的是,孟加拉国只能使用原子吸收光谱仪或其他昂贵的仪器来测量世界卫生组织10μg/ L的指南。响应于此需求,已经开发了用于测量As的廉价且高度灵敏的实验室方法。这种新方法是在不使用昂贵或高度专业化的实验室设备的情况下唯一准确,精确和安全的方法来定量As <10μg/ L。在这种方法中,通过还原为砷化氢气体从样品中去除砷,通过氧化为砷酸将其收集在吸收器中,通过与砷酸钼的顺序反应进行着色,并通过分光光度法进行定量。我们将该方法与二乙基二硫代氨基甲酸银[AgSCSN(CH2CH3)2]和石墨炉原子吸收光谱法(GFAAS)进行了比较。我们的方法比AgSCSN(CH2CH3)2方法更准确,精确和环境安全,并且比GFAAS更准确和负担得起。最后,这项研究表明,孟加拉国将很容易与邻国共享饮用水,以符合世界卫生组织关于As As 10μg/ L的更具保护性的准则。
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