Over the last decade, thousands of Chinese gold-seekers have streamed into Ghana, falling into conflict with local authorities and rival miners.

There are many other grave consequences. Heavy metals such as cadmium, lead, copper, arsenic, and mercury leak into the soil as gold is separated from its ore. Often these metals filter into local water supplies, where it is often pumped out into nearby rivers and the fish that dwell within them. Riverbed levels are often raised by excess silting, and local water levels are depleted. Changing drainage patterns due to the mining pits and silting and can lead to flooding of nearby villages, and the pits themselves have become well known drowning hazards.
http://fpif.org/ghanas-chinese-gold-rush/