HEAVY-METALS IN STREAM SEDIMENTS - A GOLD-MINING AREA NEAR LOS-ANDES,SOUTHERN COLOMBIA SA

In an area of small-scale gold mining in southern Colombia, data for t oxic trace-metal pollution: nickel, chrome, lead, zinc, mercury, cadmi um and arsenic (Ni, Cr, Pb, Zn, Hg, Cd, As) have been determined in st ream sediments. Analyses have been carried out using AAS and AES/ICP t echniques. The data show different contamination factors due to differ ent mining processes, and give hints on possible severe pollution of d ownstream areas, especially by Hg and As. The risks involved include c ontamination of drinking water and agricultural products and introduct ion of toxic elements into the food chain. Possible solutions to the p roblems are discussed.