Temporal assessment of water and soil quality near Barapukuria coal mine, Bangladesh.

This study assessed the water suitability for various purposes, evaluated heavy metal contamination and soil fertility, and investigated seasonal variations in water and soil parameters near the Barapukuria coal mine in Bangladesh. A total of nine sampling locations were selected, resulting in 18 samples (12 water and 6 soil) collected during the summer and winter seasons. The water samples were analyzed at the Environmental Engineering Laboratory, while the soil samples were analyzed at the Soil Resource Development Institute (SRDI). The suitability of drinking water was evaluated using the Water Quality Index (WQI), and heavy metal contamination was assessed using the geo-accumulation index. The findings indicate that surface water is generally suitable for irrigation due to several positive attributes, with slight to moderate seasonal variations. However, treatment is required for high turbidity and chemical oxygen demand (COD). On the other hand, wastewater quality exhibits elevated levels of turbidity, total suspended solids, and chemical oxygen demand, although most parameters are within acceptable limits. The assessment of drinking water quality using the WQI reveals that both hand and deep tubewells are generally unfit for consumption. The WQI values peak at 441.84 in summer and 202.79 in winter for the hand tubewell, and 129.66 in summer and 95.88 in winter for the deep tubewell. This finding emphasizes the need for effective treatment and continuous monitoring. The soil analysis indicates that most heavy metals are not present in significant amounts, except for cadmium, which shows uncontaminated to moderately contaminated conditions during the summer. Moreover, the soil treated with coal water exhibits significantly higher levels of organic matter, micronutrients, and macronutrients compared to the normal field soil. Further analysis of the coal water treated soil shows a shift from a slightly acidic pH in summer (6.30) to a neutral pH in winter (7.10). The organic matter content remains consistently high, and nutrient analysis shows high to very high levels of Zn, Cu, K, Ca, Mg, Mn, and Fe, while phosphorus remains low. Seasonal analysis reveals increased levels of zinc, potassium, and phosphorus in winter, whereas other nutrients generally decrease. The primary novel contribution of this study is the detailed seasonal analysis of water and soil quality near the coal mining area, capturing changes across summer and winter. Additionally, it compares coal water treated soil with normal field soil, revealing significant improvements in soil quality and fertility.