Influence of illegal gold mining on mercury levels in fish of North Sulawesi's Minahasa Peninsula, (Indonesia)

North Sulawesi's Minahasa Peninsula currently is experiencing intense illeg al gold mining activity. It has been estimated that 200 t of mercury are us ed annually in Indonesia in the recovery of gold from the illegal mines. To date no study has assessed the environmental impact of this illegal activi ty on the nearby aquatic biota. To address this concern, we compared tissue mercury levels from several sites, including a reference site and a site n ear an illegal mine. Fish from the region of the illegal mine contained 30 times the mercury content of fish at the reference site. Moreover, whole fi sh tissue levels were four times those recommended by the World Health Orga nization for consumption restrictions and often two-fold higher than recomm ended for total restriction on fish consumption. The environmental and huma n health implications of these levels are of grave concern; citizen educati on programmes are required to alert indigenous peoples of the risks associa ted with mercury exposure and fish consumption guidelines put into place. A more comprehensive effort to identify major sources and effects are requir ed. Such information can be used to determine the correct course of action that needs to be taken to close existing illegal mines and prevent future i llegal mining activities. (C) 2001 Elsevier Science Ltd. All rights reserve d.