Another source of Buyat pollution?

A review of the research on the Buyat Bay pollution case has concluded that mercury, arsenic and other chemicals have contaminated the bay. However, researchers have focused on tailings dumped by PT Newmont Minahasa Raya without considering other possible sources of pollution.

In my view, the mercury contamination has most likely resulted from illegal gold mining, using traditional methods.

Two gold extraction methods are known: a method in which sodium cyanide is used as a solvent, and the traditional amalgamation method that uses mercury, which produces an amalgam of gold and mercury.

In order to separate the gold, the amalgam is heated to evaporate the mercury. The correct way to separate the gold is distillation, by which mercury can be recovered for further use. The simple way is to heat the amalgam openly, which releases mercury vapor into the air. The vapor precipitates and falls to the ground, then is carried by rainwater and wind to the sea -- in this case, toward Buyat and Totok bays.

To prevent further pollution, I would like to make an appeal to non-governmental organizations engaged in environment control that they provide information on the above to traditional gold miners and distribute distillation equipment to them.

When I visited a former gold mine applying the amalgamation method in Johannesburg, South Africa, I observed distillation equipment 120 meters underground. So far, no pollution has been recorded around the mining site.

SUNARTO PRAWIROSUJANTO, Jakarta