Distribution of sulfide-rich black shales in Finland and applications for environmental risk evaluation

Sulfide-rich black shales have environmental impacts, in some cases even hazardous ones, especially if the bedrock is broken and exposed and the rocks are in contact with surface waters. Release of harmful elements such as arsenic from sulfide-rich black shales have, for example, caused fish kills (Pasava et al., 1995). In the natural environment, the distribution of sulfide-rich black shales in the bedrock is reflected in elevated heavy metal concentrations in till, lake and stream water and sediments, and groundwater (Loukola-Ruskeeniemi et al., 1998).