EURO-ECO 2006 Hanover 1 - 2 December 2006	Environmental and Engineering Aspects for sustainable living
	European Academy of Natural Sciences, Hanover European Scientific Society, Hanover Russian Academy of Natural Sciences, Moscow

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The city of Svirsk belongs to Cheremkhovsky state municipal formation in Irkutsk region and is located on the left bank of Bratsk water reservoir. The city is spread over 7 km along the bank and the overall territory is 20 km2.

Angarsk metallurgical plant was built at the beginning of 30s. In 1935-1949 the plant produced gray and white arsenic from arsenopyrite concentrates from Zapokrovky mine (concentration of arsenic up to 19%) and gold containing concentrates from Darsunky mine (concentration of arsenic up to 13%). Furnace dross and gold containing production rests were sent to Sredneuralsky Plant to extract gold. The concentrates from Zapokrovky mine were processed in a limited amount and the dross were stockpiled over the plant’s site adjoining to the furnace until now. In 1949 the production of arsenic was terminated, the plant was closed down, its main assets depreciated and abandoned with the equipment, the buildings and the waste intact. This accounts for two chief sources of arsenic contamination in the city, which are not removed so far: arsenopyrite waste, the buildings and the equipment of the plant.

Due to research data obtained at the territory of the former plant and its wastes during 1990 – 2005 it was revealed that:

• arsenic in the furnace dross was presented in the form of iron arsenate (FeAsO4) with solubility 0,0575-3,0 mg/l; the content of arsenic in the waste comes to 0,15-0,6% and exceeds the permitted soil level in 3000 times.
• arsenic content in the soil is decreased proportionally with the distance from the plant and on the distance of 300 meters is 20 mk/kt, which is 10 times above the norms, the average penetration of arsenic into the soil rates from 2,92 to 6,0 meters, whereas its horizontal spread is up to 170 meters.
• in the waste high contents of gold (from 0,4 up to 11,4 g/t) and silver (from 5,8 up to 27,4 g/t) are reported; the degree of exploration of this highly specific source corresponds to an initial exploration stage.

The liquidation of the contamination source can be carried out according to 2 options:

1. Attracting private investments and setting up a tender for the remnants of the arsenic plant as an object of geological resources with the condition of its utilization in accordance with the ecological norms. Nowadays, there are findings of researches on cyanic, gravitation-cyanic and thio-ureatic technologies as well as a technology on joint processing of furnace dross and gold containing ores.
2. Utilization of the arsenic site is to be carried out by a licensed and experienced enterprise.

Eventually it should be observed that any decontamination works should be combined with a reliable system of environmental monitoring. The primary challenge in removing the dross and dumps is that the former arsenic plants is located directly in the city centre being only 700 ?eters apart from the apartment blocks and 200 meters - from a cottage community. The distance from the water edge of the Bratsk water reservoir is only 500 meters.