Environmental Impact Assessment of Manganese Mining Activities On Groundwater, River Water, Land, and River sediments in Daranna, Bagudo Local Government Area, Kebbi State, Nigeria

Abstract

Mining of minerals is very important for economic growth, but mining sites are associated with pollution of groundwater, surface water and sediments from the land and river channels in particular by manganese, heavy metals, and trace elements. This research assessed the degree and impact of geochemical interaction of the open-pit manganese mining with various water and sediment sources and the health implication on the inhabitants at Daranna Area in Bagudo Local Government of Kebbi State, Nigeria. The samples were obtained based on the human, plant and aquatic organism relationship with water and sediment sources. The methodology involved sample collections: twenty (20) hand-dug water and borehole, twenty (20) sediment samples from same different locations with the groundwater, ten (10) samples each for the river water and river sediment samples. The water samples were collected in sterile bottles, while the sediments were retrieved into polythene bags, and each sample was labeled appropriately. Atomic Absorption Spectrophotometer (A.A.S.) was used to analyze the samples, except the Na and K elements with Flame Photometer. The results  of the well water shows that only the K and Pb ions concentration values are higher than the WHO (2022) toxicity limit, while in the anions, only the Cl and NH4 have higher values than the limits . However, only Cr, Cd, and Co trace elements are having contaminant values. The river water results show similar trend for the heavy metals, anions, PO₄, and the trace elements. In the case of the land sediments, only Cd in Sample DS7 has conc. value greater than Threshold Effect Concentration (TEC) level. The river sediments have Mg and Mn (ions) higher than safe limit in only Sample DRS10 due to its proximity to discharge point of the mine wash into the river, and all the samples show high toxicity value for Fe.   These pollutants have anomalous values greater than tolerant level of WHO (2022) and recommended Threshold Effect Concentration (TEC) limits, thereby, chronically hazardous to human, animals, and aquatic life ecosystem. The Daranna community should be sensitized on the danger of the continuous consumption of the contaminated water and sediments to the plants and crops, while the state government should urgently provide alternative safe water and remediate the land for farming activities.