Artisanal gold mining is one of the major sources of mercury contamination, especially in developing countries. Whilst the gold extraction process (known as amalgamation) is a simple technology, it is potentially very harmful to the environment and can contaminate air, soil, rivers and lakes with mercury. The health of the miners and other people living within the area affected by mercury contamination may be negatively affected through inhalation of mercury vapour or contaminated dusts, direct contact with mercury, through eating fish and other food, and through the ingestion of waters and soils affected by the mercury contamination. Environmental and health impacts resulting from the use of mercury (Hg) in the artisanal gold extraction process require concerted and coordinated global responses. The objective of the ongoing GEF/UNDP/UNIDO project Removal of Barriers to the Introduction of Cleaner Artisanal Gold Mining and Extraction Technologies (also referred to as the Global Mercury Project (GMP)) in Brazil, Indonesia, Lao PDR, Sudan, Tanzania, and Zimbabwe is to assist these countries located in key transboundary river/lake/marine basins in assessing the extent of Hg pollution, introducing cleaner gold extraction technology, which eliminates or reduces Hg releases and developing capacity and regulatory mechanisms. The GMP Project is accompanied by the development of monitoring programmes. In order to ensure sustainability, capacity is being built to carry out continuous monitoring beyond the project three-year term. The ultimate goals of the GMP Project are: 1. to reduce Hg pollution of international waters by emissions emanating from small-scale gold mining; 2. to introduce cleaner technologies for gold extraction and to train people in their application; 3. to develop capacity and regulatory mechanisms that will enable the sector to minimize mercury pollution; 4. to introduce environmental and health monitoring programmes; 5. to build capacity of local laboratories to assess the extent and impact of Hg pollution. The GMP Project will also aim to increase knowledge and awareness of miners, Government institutions and the public at large by explaining in detail the results of the Public Health and environmental studies conducted in the mercury hot spot" areas. The selection of project demonstration sites was done in accordance with the objective of alleviating the impact of Hg on international waters. Two sites were selected in Brazil (Creporizinho and Sao Chico in the Tapajos area draining into the Amazon river) and Indonesia (Galangan mine in Central Kalimantan, draining into the Java Sea and Talawan near Manado, draining into the Celebes Sea). One demonstration site was selected in each of the other four countries: Lao PDR (Luang Prabang, draining into the Mekong river), Sudan (Gugob, near Al Damzain, draining into the Blue Nile), Tanzania (Rwamagasa, draining into Lake Tanganyika) and Zimbabwe (Chakari, draining to a tributary of the Zambezi river). In August 2003, the British Geological Survey (BGS), acting under the UK Natural Environment Research Council, signed a contract with UNEDO to carry out limited Environmental and Health surveys and assessments in the Rwamagasa artisanal gold mining area in the Republic of Tanzania (Appleton et al., 2004). The environmental assessment was executed by the BGS whilst the medical and toxicological investigations were subcontracted to the Institut fur Rechtsmedizin der Ludwig-Maximilians-Universitat Miinchen, Germany. The regional health authorities in Geita supported the medical investigations, whilst the environmental assessment was carried out in collaboration with staff from the Geita Mines Office and from the Kigoma and Mwanza offices of the Tanzania Fisheries Research Institute (TAFIRI). Rwamagasa is located in Geita District, which has an area of 7,825 kmM2, 185 villages, and a population around 712,000 (census of 2002). The number of artisanal miners in the Geita District is unknown but it is estimated to be as many as 150,000, most of whom are illegal panne s. Primary artisanal workings in the Rwamagasa area are centred on quartz veins in sheared, ferruginous, chlorite mica schists. Grab samples of vein and wall rock grade 6-62 g/t Au. The only legal mining in the Rwamagasa area is carried out within the boundaries of the Primary Mining Licence held by Blue Reef Mines where approximately 150 people are involved in mining and mineral processing activities. This is the only site in the Rwamagasa area where primary ore is being mined underground. All other mineral processing activity of any significance is concentrated at the northern margin of Rwamagasa, especially on the land sloping down to the Isingile River. In this area, there are about 30 groups of historic and active tailings dumps and about ten localities where small (200 litre) ball mills are operating. The number of people actively involved, at one particular time, in ball milling, sluicing and amalgamation is probably no more than 300. Amalgam is burned in a small charcoal fire, which releases Hg to the atmosphere. Amalgamation mainly takes place adjacent to amalgamation ponds, which are usually formed of concrete, but sometimes have only wood walls even though environmental legislation dictates that the Hg contaminated mineral concentrates and tailings should be stored in concrete lined structures. The Blue Reef Mine is reported to produce about 1 kg Au per month whereas artisanal miners re-working tailings produce about 0.5 kg per month. On this basis, approximately 27 kg of Hg will be released to the environment from the Rwamagasa area each year. Of this, atmospheric emissions from amalgam burning will be about 14 kg from the Blue Reef mine site and 7 kg from the other amalgamation sites. About 2 to 3 kg Hg will remain in heavy mineral tailings in the amalgamation ponds, which are frequently reprocessed. It is reported that the number of miners working in the Rwamagasa area was much larger in the past, so the historical release of mercury would probably have been higher than at present. The young and strong men, so called healthy workers, are mainly found in the bigger and more technically equipped properties. Older people, women of all ages and children mainly work in the smaller artisanal mining properties. Retorts are not used, neither is there any other protection, such as ventilation, against any kind of mercury contamination. Housing areas, food stalls and the schools are located close to the sites where amalgamation and burning of the amalgam is carried out. Mineral processing tailings containing mercury are found within the village adjacent to cultivated land or near local water wells. Mercury is usually stored in the miner's houses in small softdrink bottles, near to where they and their families sleep. The mercury is mainly obtained from Nairobi in Kenya and the gold is either used for jewellery in Tanzania or sold to Dubai. Hygiene standards are extremely low and are a reason for many infectious diseases such as diarrhoea, typhoid and parasitism. There is no effective waste disposal system for either mercury, sanitary or other domestic waste. Road accidents, accidents in insecure tunnels and amalgamation plants, malaria, tuberculosis, and sexually transmitted diseases including AIDS are the dominant causes of morbidity and mortality. No special health service exists for the mining community-the nearest dispensary is about 10 km away. A local dispensary is under construction, but the construction has been stopped due to lack of money. The village lacks social welfare services and a police post for security. The nearest district hospital is in Geita, 45 km to the northeast. All non-minor illnesses have to be transferred to Geita hospital, which is adequately equipped for a district hospital. Background information on mercury contamination associated with artisanal gold mining in Tanzania is available in a number of published reports and scientific papers (Appel et al, 2000; Asanao et al, 2000; Campbell et al, 2003a,b; Harada et al, 1999; Ikingura and Akagi, 1996; Ikingura et al., 1997; Ikingura and Akag , 2002; Kahatano et al., 1997; Kinabo, 1996; Kinabo, 2002a,b; Kinabo and Lyimo, 2002; Kishe and Machiwa, 2003; Machiwa et al, 2003; Mutakyhwa, 2002; Semu et al, 1989; Sindayigaya, 1994; University of Dar es Salaam, 1994; van Straaten 2000a,b)."
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