Pollution with arsenic and heavy metals of soils and some components of the food chain in the environment of Goliam Bukovets mine tailings impoundment, Chiprovtsi mining area, NW Bulgaria

The Chiprovtsi mining area is contaminated as a consequence of past mining. The 20-year existing of Goliam Bukovets mine tailings impoundment has affected all elements of its surroundings. As a result elevated concentrations of arsenic and heavy metals in upper soil layers and in grass are established. The low distributions of arsenic and heavy metals in depth allow assuming their low mobility which restricts their unfavourable environmental impact. The sheep’s milk has elevated Zn and Cu contents and so it transfers them to the humans. The carry-over of Pb, Cd and As from grass to the milk is low. Metal concentrations in livestock’s excrements are low and seem not to pose risk for secondary soil contamination if used as organic fertilizer. Although the tailings impoundment is almost recultivated and the dust pollution is finished the contaminated soils of the surroundings contain arsenic and heavy metals and continue to transfer them through the food chain. Besides, the soil cover of the impoundment is not sufficient to avoid the penetration of grasses root to the mine tailings.