Arsenic removal by gypsum and calcite in lacustrine environments

International audienceAfter the closure of the coal mining activities in the Massif Central range, France, several lakes were formed as a consequence of mine collapse. The old mines, located at the bottom of lakes, are certified sources of As and heavy metals. During a time period of one year, we have monitored the water column of one of these lakes in order to identify geochemical process controlling water quality dominated by precipitation of gypsum and calcite. We have therefore performed laboratory experiments to study how As is trapped during calcite and gypsurn precipitation in presence of As III and V respectively