The Development and Use of an Innovative Laboratory Method for Measuring Arsenic in Drinking Water from Western Bangladesh Seth H. Frisbie,1 Erika J. Mitchell,1 Ahmad Zaki Yusuf,2 Mohammad Yusuf Siddiq,2 Raul E. Sanchez,3 Richard Ortega,4 Donald M. Maynard,5 and Bibudhendra Sarkar6,7 1Better Life Laboratories, Inc., East Calais, Vermont, USA; 2Bangladesh Association for Needy Peoples Improvement, Chorhash, Kushtia, Bangladesh; 3Green Mountain Laboratories, Inc., Montpelier, Vermont, USA; 4Laboratoire de Chimie Nucléaire Analytique et Bioenvironnementale, Université de Bordeaux, Gradignan, France; 5Johnson Company, Inc., Montpelier, Vermont, USA; 6Department of Structural Biology and Biochemistry, Hospital for Sick Children, and 7Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada Abstract 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. Key words: arsenic, arsenomolybdate, Bangladesh, chronic arsenic poisoning, drinking water, graphite furnace atomic absorption spectroscopy, silver diethyldithiocarbamate, spectrophotometry. Environ Health Perspect 113:1196-1204 (2005) . doi:10.1289/ehp.7974 available via http://dx.doi.org/ [Online 19 May 2005] Address correspondence to B. Sarkar, Department of Structural Biology and Biochemistry, Hospital for Sick Children, Department of Biochemistry, University of Toronto, 555 University Ave., Toronto, Ontario M5G 1X8, Canada. Telephone: (416) 813-5921. Fax: (416) 813-5379. E-mail bsarkar@sickkids.on.ca We thank K. Adam, M. Quader, and M.A. El Shakankiri. This study was supported by Better Life Laboratories, the Bangladesh Association for Needy Peoples Improvement, Green Mountain Laboratories, CNRS (Centre national de la recherche scientifique) at the Université de Bordeaux 1, the Hospital for Sick Children, SETU (Services for Education, Training and Unity) , and L. Spence. The authors declare they have no competing financial interests. Received 28 January 2005 ; accepted 19 May 2005. The full version of this article is available for free in HTML or PDF formats. |