Mercury residues in free-grazing cattle and domestic fowl form the artisanal gold mining area of Geita district, Tanzania

Abstract

Environmental contamination with mercury from artisanal gold mines in Tanzania has been widely reported. People living around mining villages keep domestic animals which are allowed to feed freely in mercury-contaminated areas. This study investigated Hg accumulation in the liver and muscle tissue of cattle and domestic fowl reared in mining villages. Total mercury levels up to 436 and 820 µg/kg wet weight were found in liver samples taken from cattle and domestic fowl, respectively. Significantly higher mercury concentrations were found in liver samples collected at mining villages (p < 0.05) than those taken from the reference area. While mercury concentrations in liver samples exceeded the acceptable maximum concentrations for humans set in the Netherlands and Poland, the Hg concentrations in muscle were below the limits of most countries. It is recommended that the keeping of freely grazing cattle and domestic fowl in or around artisanal gold mines should be avoided.

Keywords:

• AAS
• heavy metals
• mercury
• animal products
• meat

Acknowledgements

This research was funded by the Organization for Prevention of Chemical Weapons (OPCW) through the International Foundation for Science (IFS) under grant No.B/3760-1. We are deeply indebted to M. Matelu, the Geita district council meat inspector for his field assistance.