More on Environmental Impacts of Site C - Mercury Contamination

Here, we continue our discussion of the environmental impacts of Site C. One of the major impacts would be mercury/methyl mercury contamination.

Mercury would contaminate both the reservoir waters and the downstream portions of the river, which already suffer from high levels of mercury poisoning from two existing dams.

Mercury exists naturally in the ground in an insoluble and harmless form. When unnatural flooding occurs, as in the case of a reservoir, abnormally saturated materials cause bacteria growth. These bacteria in turn convert the mercury into soluble methyl mercury. Once in the water, this pollutant freely enters the food chain, contaminating the flesh of fish, and moving from there into fish-eating animals, including humans (Rougerie, 1990).

The Peace River already suffers the effects of mercury contamination from the two already existing hydro dams. Mercury tests taken in the proposed Site C area (many kilometres downstream) show that the river is already contaminated beyond the BC Water Quality Criteria for acceptable mercury levels, which sets its upper limit at .02µg/L. The test sample showed a level of .21µg/L, 10½ times the provincial limit (BC Hydro Fish Movements and Population Status 1990 Studies Interim Final Report).

Another dam across the river would only increase this effect. At the BC Hydro Open House, we need to ask about methyl mercury contamination.