Investigation of groundwater and its seasonal variation in a rural region in Natore, Bangladesh

In Bangladesh, groundwater is the most widely used source of drinking water for rural communities. However, the groundwater quality is degraded by natural contaminants and anthropogenic pollution. Groundwater is a reliable and sustainable source of safe water for irrigation and domestic purposes, especially during the dry season. The water quality assessment data for the study area was not found in the literature. This study aims to assess groundwater quality and seasonal variation in a rural area of five unions of Bagatipara Upazila, Natore, and its suitability for drinking purposes by measuring the Water Quality Index (WQI). The groundwater of five unions, namely Dayarampur, Bagatipara, Faguardiar, Jamnagar, and Pacca, has been selected for investigation. The electrical conductivity (EC), color, and turbidity exceeded the ECR guidelines. EC showed a positive correlation with total dissolved solids (TDS), total solids (TS), and turbidity. On the other hand, dissolved oxygen (DO), hardness, chloride, carbon-di-oxide (CO2), and iron (Fe) concentrations varied based on the location of the sampling points. The bacteriological parameters TC and E. coli were found in most of the samples, which indicate the potential sources of contaminants such as septic tank leakage and inadequate waste disposal systems. The groundwater quality was found not to be influenced by seasonal variation except by pH, DO, and CO2. The Water Quality Index (WQI) spatial mapping demonstrated that during the post-monsoon period, the water quality of the central part of Bagatipara upazila was in ‘good’ condition, which was in Bagatipara, Fagurdiar, and Pacca unions, whereas during the pre-monsoon season, the ‘good’ condition was found very limited to Fagurdiar union only. The study revealed that the groundwater of Bagtipara Upazila is not suitable for drinking water due to the presence of TC and E. Coli as well as ‘poor’ to ‘unsuitable’ conditions in most of the areas based on WQI.