Drinking appraisal of coastal groundwater in Bangladesh: An approach of multi-hazards towards water security and health safety.

In Bangladesh, groundwater serves as the sole major potable water source. Salinization along with the elevated presence of metals become the major threat for this resource in coastal districts of Bangladesh. Therefore, a multi-hazard approach is planned to appraise the groundwater quality. Probabilistic health risks assessment was employed to quantify risk due to drinking from polluted water in coastal districts. Geostatistical tools, pollution indices, and health risk models were conducted using water quality data from 925 samples (n = 566 in the wet season, and n = 359 in the dry season). Groundwater quality index (GWQI) reveals about 65% of the samples are 'poor to unsuitable' as potable water in the study area. Metals pollution indices are correlated to each other, and demonstrated a diversified outcome. In addition, the multivariate analyses of water quality confirmed the major influencing factors that come from the geogenic processes along with the anthropogenic contribution. Probabilistic health risk assessment results depicted as a medium to high level of non-carcinogenic threats for consumers in the study area. Districts such as Khulna, Satkhira, Bhola, Pirojpur, Bagerhat, Jhalakati, Patuakhali, Barguna, and Lakshmipur possesses a high level of threat due to poor water-quality. Finally, it can be said that the study area is exposed to multi-hazards such as salinization, and elevated metals in groundwater. Substantial human health concerns might arise in the study area due to contaminated water consumption. This study clearly explained the groundwater quality challenges considering the multi-hazard in the coastal districts of Bangladesh, that could be applicable in policy formulation.