Impacts of Artisanal Gold Mining on Surface and Groundwater Quality around Maiwayo and Gada-Eregi Minig Sites, North-Central Nigeria

Abstract

A study on the impacts of artisanal gold mining on water quality around Gada-Eregi and Maiwayo gold mining sites, North-central Nigeria was undertaken. Geological mapping of the area was conducted and the major rock types in the area are granites and schists. The area is drained by River Chanchaga and its tributaries, which flows in northeast-southwest direction. It corresponds with the main joint direction in the area. Twenty water samples were collected from streams, hand-dug wells and mine-pits located in the study area. The samples were analysed for cations, anions and heavy metals. Physical parameters such as temperature, pH and conductivity were measured in-situ using standard instruments. The samples were analyzed using Atomic Absorption Spectrometer (AAS). The recorded average values for the major ions: chloride, nitrate, phosphate, sodium, potassium and bicarbonate are: 29.27mg/l, 1.74mg/l, 0.08mg/l, 20.02mg/l, 11.65mg/l and 151.32mg/l respectively. The heavy metals such as manganese, copper, zinc, iron and lead had the following respective mean values: 0.65mg/l, 0.05mg/l, 0.10mg/l, 5.70mg/l and 2.70mg/l. These results show that the major cations and anions are presently within safe concentration limits while concentrations of lead, manganese, zinc and iron are higher than their respective WHO maximum permissible limits. This implies that the water sources in Gada-Eregi and Maiwayo are not suitable for domestic and drinking purposes. Treatment of the water before use is recommended due to the toxic nature of the heavy metals. A regular follow up study to determine the level of heavy metals in soils in the area is recommended to avert danger of heavy metal poisoning.