Cyanide and environment

Cyanide and other dangerous chemicals, such as mercury, are commonly used in artisanal gold mining.
Since gold mines are almost always set up near rivers, often excess chemicals are distributed directly into waterways, thus polluting water sources.
Once it becomes imbedded in soil or water, cyanide is extremely toxic to humans. Artisanal gold mining also presents several environmental challenges due to the inherent digging of soil and rinsing involved in artisanal mining.
Siltation, erosion, and soil degradation can be issues in rivers used for mining. Rivers are also commonly diverted as a way to access mineral rich riverbeds.
http://www.herald.co.zw/cyanide-and-environment/