Are existing drinking water sources safe from As contamination in Hanam province, Vietnam?

Abstract

This study investigated arsenic (As) concentrations in existing drinking water sources in Hanam province, Vietnam. Sand-filtered groundwater, piped water, raw groundwater, and a type of drinking water mostly sourced from rainwater (hereafter referred to as the "stored rainwater") are commonly used for drinking purposes in this area. It was found that all water sources contained different levels of toxic As. The highest levels were found in raw groundwater, followed by sand-filtered water, piped water, and stored rainwater. More than 50% of the stored rainwater samples contained As levels above the WHO recommendation value. As such, the daily As uptake in local residents from this kind of stored rainwater may be larger than previously considered because they consume stored rainwater as an alternative drinking water source. Relatively high levels of As in the stored rainwater samples also suggested that residents possibly mix rain and groundwater in rainwater containers in order to meet their daily water demand.