Assessment of sediment quality in pit-lakes of Raniganj coal fields, West Bengal, India

Pit lakes form when surface-level mines shut down, and water fills the open pit due to active pumping, surface water diversion, or groundwater recharge.In the current study, pit lakes generated by open-cast coal mining have been studied at various mining locations for four years within the Raniganj coalfields, West Bengal, India, focusing on sediment quality.This paper focused on analysing physicochemical parameters such as colour and texture, pH, bulk density, conductivity, particle density, water-holding capacity, organic carbon, available nitrogen and available phosphorus, impacting overall sediment quality from 2020-2023.A quantitative assessment of various sediment parameters showed that pH was 6.41 to 7.96, bulk density 1.21 to 2.08 grams/cm3, conductivity 0.21 to 0.45 S/cm, particle density 1.02 to 1.96 g/cm3, water-holding capacity 12.09 to 18.50%, organic carbon 2.31 to 6.64%, available nitrogen 19.81 to 50.25 Kg/ha and available phosphorus varied from 10.90 to 17.85 Kg/ha.The overall nutrient content of the sediment was found to be higher to medium range than the standard value.The major objective of the current investigation is to evaluate the sediment quality of a few chosen pit lakes of the RCF region of West Bengal, India.