Impact of massive flood on drinking water quality and community health risk assessment in Patna, Bihar, India

Many places on Earth have been experiencing the impact of climate change. Due to a rise in the frequency of hydrological and climatic events, the worsening trend of potable water quality due to floods has increased, which has possible health repercussions. Hence, the present study was planned to examine the water quality following a flood event. This study determined water quality by estimating physicochemical parameters and quality indices. Moreover, health risks associated with water intake through ingestion and dermal contact were assessed. Consequently, all of the samples were found to be polluted to varying degrees, and the majority of them were found unsuitable for human consumption as the high values of total dissolved solids (TDS) 1120 mg/L, total hardness (TH) 575 mg/L, total alkalinity (TA) 3516.75 mg/L was observed. Further, 60% of the samples exceeded the recommended values of Mg⁺ and Cl⁻ showing that the quality of floodwater, handpump and well water was found to be extensively poor. Furthermore, the Water Quality Index (WQI) revealed that 20% of samples had poor water quality with the highest value of 161. The elemental analysis revealed that arsenic (As) had a high value (0.0516 mg/L). Additionally, it was discovered that the oral (66.03) and dermal (201.43) pathways had high hazard quotients (HQs), indicating health risks to both adult and children. The Pearson correlation and principal component analysis revealed a positive association between physicochemical and heavy metals, indicating a similar origin.