SEARCH FOR SAFE UNDERGROUND WATER THROUGH OBSERVATION OF TUBEWELL CONCRETE PLATFORM COLOR IN SOUTHERN BANGLADESH

Search for arsenic safe drinking water for millions of people in this densely populated south Asian country remains a challenge for policy makers and non-government organizations. Even though the permissible level of arsenic (As) in groundwater in Bangladesh is 50 µg/l, vast population in the southern part of Bangladesh are exposed to As at levels close to 200-300 µg/l. Various safe water options have been introduced in arsenic affected areas. However the pace of installation of such options is not able to cope with the demand of safe water. Recently, tubewell platform color as screening tool for searching As safe water has been suggested in literature. The arsenic and iron rich groundwater develops reddish to orange color with the silica of concrete while groundwater with low levels of As and iron (Fe) develops diffuse ash color with the concrete. In our study we have investigated 200 tubewell water with different degrees of platform color in the Sharasti Upazila in Chandpur district of Bangladesh. Using inductively coupled plasma optical emission spectroscopy (ICP-OES) we have determined 28 trace elements in these tubewells in two Unions and six villages. In tubewells with reddish color platform the correlation coefficients for As vs Fe were much higher (R²= 0.3908) than the corresponding coefficient (R²= 0.0573) for As vs Fe in tubewells with blackish to ash color platform. The arsenic (As) and strontium (Sr) correlated highly for both groups of platform colors (R²= 0.7526 and R²= 0.6357). Inter-element correlation have been investigated for both the groups of platform color. The screening of platform color for tubewells does indicate that the tubewells with blackish to ash color platform provide groundwater at a much lower level of arsenic. In absence of other safe water options, the screening of tubewells through platform color does offer a viable tool for searching arsenic safe water.