Comparison of the trace metal concentration of drinking water supply options in southwest coastal areas of Bangladesh

Abstract

In the coastal areas of Bangladesh, scarcity of drinking water is acute as the fresh water aquifers at reasonable depths are not available and surface water is highly saline. Households are mainly dependent on rainwater harvesting, pond sand filter (PSF), and rain-fed pond water for drinking purposes. To ascertain the water quality for human consumption, chemical parameters such as pH, conductivity and the concentrations of calcium, magnesium, iron, manganese, copper, zinc, lead, chromium, cadmium, nickel and arsenic were evaluated in the alternative drinking water supply options employed in the southwest coastal areas of Bangladesh. An inductively coupled plasma-optical emission spectroscopy was used for determination of trace metal concentrations. pH and conductivity were measured using HANNA Instrument. The mean iron and manganese concentrations for rain-fed pond and PSF water were much higher than harvested rainwater. The iron concentrations for 41 % of the pond water samples were higher than the Bangladesh guideline value. Iron and manganese removal by PSFs was found to be 74 and 51 %, respectively. Scarcity of calcium and magnesium were found in harvested rainwater. Furthermore, one pond water sample showed arsenic concentration above the 10 μg/l WHO drinking water guideline. The presence of an elevated iron and manganese and low calcium and magnesium concentrations in the drinking water could be a matter of public health concern.