Hydrochemical analysis and its implications for drinking water safety and irrigation uses in the coastal region of Patuakhali, Bangladesh

Groundwater and surface water contamination have become common issues in the coastal regions, which is alarming for public health and farming. The study was conducted by collecting 71 water samples to assess the water quality and health hazard across the Patuakhali coastal region, Bangladesh. Water quality parameters, water quality index (WQI) were employed to analyze hydro-chemical properties. All collected samples showed slightly acidic to weakly alkaline, ranging from 6.49 to 8.17. About 81.7, 80.3 and 87.3% samples have high electrical conductivity, total dissolve solids and soluble sodium percentage, respectively, indicating salinity contamination in this region. 19.71, 14.08 and 23.94% of total samples were suitable for irrigation, according to Richard’s scale, WQI and Kelly’s scale, respectively. The United States Salinity Laboratory (USSL) diagram also verified the unsuitability for drinking or irrigation usages as most of the samples showed salinity hazard. Principal component analysis was also confirmed that maximum samples showed positive correlation with salinity parameters. Hazard quotient ˃1 for Na indicated that consuming saline-contaminated water can cause health problems for adults. Therefore, the study revealed that the water sources in the Patuakhali coastal region are highly vulnerable to saline contamination and associated human health risks. Local government should prioritize managed aquifer recharge (MAR), centralized purification, and rainwater harvesting to reduce salinity and ensure safe drinking and irrigation water. Public health actions must focus on monitoring saline exposure, providing alternative safe water sources, and raising community awareness to prevent sodium-related health risks during late-spring (March-April).