Determination of Cyanide Concentration Levels in Surface Water and Soil from Artisanal Small-Scale Gold Mining Villages at Chunya, Mbeya - Tanzania

Abstract

This study aimed to determine levels of cyanide (CN) pollution in the soil and surface water at selected mining sites of Mbeya region. A total of (n = 124) samples were collected and analyzed by spectrophotometry. The cyanide levels of soil-based samples and water-based samples at Mwasenga, and Ifumbo mining sites were above the permissible limits. This was due to poor disposal of tailing from the gold processing plants and mismanagement of wastewater. On the other hand, the Cyanide was within the allowable limit for both soil and water at Godima, Itewe, Ashishira and Nyatula mining sites. This was attributed by proper management of wastewater by using artificial tanks, ponds and trenches. Also, it was observed that there is a mobility of cyanide from the processing mining site, if the tailings and wastewater are not well managed. The concentration of cyanide in the soil and water samples of about 2 mg/L was observed at distance of more than 70 m from the processing plant at Mwasenga, the situation is even worse at Ifumbo, where the cyanide concentration in soil and water were about 25 and 8 mg/L respectively, at a distance of more than 50 m from processing plant