Limited effectiveness of household sand filters for removal of arsenic from well water in North Vietnam

Abstract

Since well water utilized for domestic purposes in the Red River Delta of North Vietnam has been reported to be polluted by arsenic, barium, iron, and manganese, household sand filters consisting of various components are used. Information regarding the effectiveness of various sand filters for removal of the four toxic elements in well water is limited. In this study, arsenic levels in 13/20 of well water samples and 1/7 of tap water samples exceeded World Health Organization (WHO) health-based guideline value for drinking water. Moreover, 2/20, 6/20, and 4/20 of well water samples had levels exceeding the present and previous guideline levels for barium, iron, and manganese, respectively. Levels of iron and manganese, but not arsenic, in well water treated by sand filters were lower than those in untreated water, although previous studies showed that sand filters removed all of those elements from water. A low ratio of iron/arsenic in well water may not be sufficient for efficient removal of arsenic from household sand filters. The levels of barium in well water treated by sand filters, especially a filter composed of sand and charcoal, were significantly lower than those in untreated water. Thus, we demonstrated characteristics of sand filters in North Vietnam.

Increased Fasting Serum Level of Arsenic Caused by Intake of Fish Meat Promotes a Potential Risk of Hypertension

“…In this study, we tried to find the source of serum arsenic. Well drinking water contaminated with arsenic has been shown to be a major source of arsenic in humans in developing countries including Bangladesh (Kato et al, 2013), Vietnam (Ilmiawati et al, 2016) and Afghanistan (Kato et al, 2016). However, drinking water provided as tap water in Japan has been estimated to be a minor (less than 2%) source of exposure to arsenic (Ohno et al, 2010).…”

Multidisciplinary approach to assess the toxicities of arsenic and barium in drinking water

“…Fieldwork studies focusing on well drinking water have been performed in Asian countries including Bangladesh [8][9][10][11], Vietnam [6,12], Malaysia [7], and Afghanistan [13]. Those studies showed that arsenic levels exceeded the WHO health-based guideline level for drinking water in these countries, suggesting that well drinking water is polluted with arsenic in large areas of Asian countries.…”

“…As the first step, environmental monitoring for well drinking water is essential to identify toxic elements contaminating in well water. In fact, elevated concentrations of toxic elements including arsenic, barium, manganese, iron, and uranium in well water were identified by our environmental monitoring in developing countries in Asia [6][7][8][9][10][11][12][13]. After considering the health risks for known toxic elements according to the healthbased guideline levels for drinking water developed by WHO (World Health Organization), we could issue a global alert.…”