Artisanal gold mining in western Tanzania. The ore can be exploited only after water has been carried away. Photo: C. Glahder, DMU

In 1999, scientists from DMU and GEUS visited southwestern Tanzania to develop a model for sustainable mining. The Danish Council supported the project for Development Research (RUF). DMU evaluated the environmental effects of the present artisanal gold mining, and studied the metal pollution of the nearby river and the Katavi National Park some 50 km away from an abandoned lead-copper mine. Especially mercury concentrations in humans and in the environment were studied in connection to the gold mining activities. In this area and in the Victoria Lake area in Northwest Tanzania gold mining is performed with nearly no machinery. It is estimated that more than 350.000 people in Tanzania are dependent of the income from gold mining. The gold ore is initially crushed and ground by hand, then mercury is added to the crushed material and an amalgam is formed. Finally the amalgam is heated over open fire, mercury evaporates and the gold is left. About 20 tons of mercury is annually released to the environment in Tanzania.

Mercury evaporates and the gold is left in the cup. Photo: P. Appel, GEUS

Hair from 22 men, both miners and controls, were cut and analysed for mercury concentrations. The amalgamists and burners contained about 30 times more mercury in their hair than did men on a restaurant in town.

A small sample from a miner's hair is cut for later mercury analysis. Photo: P. Appel, GEUS

Fish and sediments were analysed for mercury as well and in fish the concentrations were equal to or above the Danish threshold value for fish used for consumption. The study is reported in GEUS: An integrated approach to mineral exploration and environmental assessment in southern and eastern Africa - a pilot study in Tanzania (2000). Search for: www.geus.dk (publications, publication catalogue 2000, Tanzania).

During the autumn 2000 the above studies were continued in Tanzania. Here, an application with the title: "Educational programme in economic geology and environmental assessment in south-west Tanzania" was prepared for ENRECA, Danida, by GEUS and DMU in co-operation with Department of Geology, University of Dar es Salaam and Geological Survey of Tanzania. Search for: www.geus.dk (Projects, Tanzania).

Purchase of soap containing mercury at the market in Dodoma, the capital of Tanzania. Photo: C. Glahder, DMU

During the pilot project in Tanzania in 1999 we discovered another environmental mercury problem: Especially women used soaps and creams containing about 1% mercury to bleach their skin and hair. The study is reported in NERI Technical Report No. 306: Mercury in Soap in Tanzania (PDF-format 1.1 MB). The report contributed to a contact from the Danish minister of Energy and Environment to his English college regarding a possible production of mercury containing soaps. The Danish Environmental Protection Agency performed a study on the trade of mercury containing products in Denmark. Search for: www.mst.dk/presse/02080000.htm (e.g. also /02120000.htm and /02520000.htm).

An example of a commercial that accentuate blond skin and hair of African women. Photo of the shop shown above from the market in Dodoma, Tanzania, that sells mercury-containing soaps. Photo: C. Glahder, DMU