Tag Archives: point-of-entry (POE)

Arsenic Removal by Table Top Water Pitcher Filters

Barnaby R, Liefeld A, Jackson BP, Hampton TH, Stanton, BA. Effectiveness of table top water pitcher filters to remove arsenic from drinking water. Environmental research. 2017 Jul 15;158:610-615. doi: 10.1016/j.envres.2017.07.018.

Arsenic contamination of drinking water is a serious threat to the health of hundreds of millions of people worldwide. In the United States ~3 million individuals drink well water that contains arsenic levels above the Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10μg/L. Several technologies are available to remove arsenic from well water including anion exchange, adsorptive media and reverse osmosis. In addition, bottled water is an alternative to drinking well water contaminated with arsenic. However, there are several drawbacks associated with these approaches including relatively high cost and, in the case of bottled water, the generation of plastic waste. In this study, we tested the ability of five tabletop water pitcher filters to remove arsenic from drinking water. We report that only one tabletop water pitcher filter tested, ZeroWater®, reduced the arsenic concentration, both As3+ and As5+, from 1000μg/L to < 3μg/L, well below the MCL. Moreover, the amount of total dissolved solids or competing ions did not affect the ability of the ZeroWater® filter to remove arsenic below the MCL. Thus, the ZeroWater® pitcher filter is a cost effective and short-term solution to remove arsenic from drinking water and its use reduces plastic waste associated with bottled water.

Colford et al 2005: A randomized, controlled trial of in-home drinking water intervention to reduce gastrointestinal illness

This study examined the health benefit of in-home treatment of tap water from a well-run water utility in the United States (Iowa). No reduction in gastrointestinal illness was detected after in-home use of a device designed to be highly effective in removing microorganisms from water. In other words, the additional treatment in the home for tap water did not lower reported illnesses compared to having no additional tap water treatment in the home.

Colford, J.M. Jr., T.J. Wade, S.K. Sandhu, C.C. Wright, S. Lee, S. Shaw, K. Fox, S. Burns, A. Benker, M.A. Brookart, M. van der Laan, and D.A. Levy. 2005 A randomized, controlled trial of in-home drinking water intervention to reduce gastrointestinal illness. Am J Epidemiol. 2005 Mar 1;161(5):472-82.

Abstract: Trials have provided conflicting estimates of the risk of gastrointestinal illness attributable to tap water. To estimate this risk in an Iowa community with a well-run water utility with microbiologically challenged source water, the authors of this 2000-2002 study randomly assigned blinded volunteers to use externally identical devices (active device: 227 households with 646 persons; sham device: 229 households with 650 persons) for 6 months (cycle A). Each group then switched to the opposite device for 6 months (cycle B). The active device contained a 1-microm absolute ceramic filter and used ultraviolet light. Episodes of “highly credible gastrointestinal illness,” a published measure of diarrhea, nausea, vomiting, and abdominal cramps, were recorded. Water usage was recorded with personal diaries and an electronic totalizer. The numbers of episodes in cycle A among the active and sham device groups were 707 and 672, respectively; in cycle B, the numbers of episodes were 516 and 476, respectively. In a log-linear generalized estimating equations model using intention-to-treat analysis, the relative rate of highly credible gastrointestinal illness (sham vs. active) for the entire trial was 0.98 (95% confidence interval: 0.86, 1.10). No reduction in gastrointestinal illness was detected after in-home use of a device designed to be highly effective in removing microorganisms from water.

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Stauber et al 2011: A Cluster Randomized Controlled Trial of the Plastic BioSand Water Filter in Cambodia

C.E. Stauber, E. Printy, F.A. McCarty, K. Liang, and M. Sobsey. A Cluster Randomized Controlled Trial of the Plastic BioSand Water Filter in Cambodia. Environ Sci Technol. 2011 Nov 30.

About half of the rural population of Cambodia lacks access to improved water; an even higher percentage lacks access to latrines. More than 35,000 concrete BioSand Water filters (BSF) have been installed in the country. However, the concrete BSF takes time to produce and weighs hundreds of pounds. A plastic BSF has been developed but may not perform to the same benchmarks established by its predecessor. To evaluate plastic BSF performance and health impact, we performed a cluster randomized controlled trial in 13 communities including 189 households and 1147 participants in the Angk Snoul district of Kandal Province from May to December 2008. The results suggest that villages with plastic BSFs had significantly lower concentrations of E. coli in drinking water and lower diarrheal disease (incidence rate ratio of 0.41, 95% confidence interval: 0.24-0.69) compared to control villages. As one of the first studies on the plastic BSF in Cambodia, these are important findings, especially in a setting where the concrete BSF has seen high rates of continued use years after installation. The study suggests the plastic BSF may play an important role in scaling up the distribution/implementation of the BSF, potentially improving water quality and health in the region.

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