Contamination by arsenic and other trace elements of tube-well water along the Mekong River in Lao PDR

► Tube-well waters were significantly contaminated with As, B, Ba, Mn, U and Fe. ► As contaminated areas were mostly floodplains in the central and southern parts of Laos. ► As (III) was a predominant species in 46% of tube-well water samples. ► A positive association between water characteristics, B and Sr contents was found. ► Total As, As (III) and Fe concentrations were positively associated among each other.