Notes on the geochemical dispersion of elements in the beach sediments along the coast west of the Atlas Mines, Visayas, Philippines

Abstract

The copper operations of the temporarily closed Atlas Mines in Cebu has released silt and tailings in the Tañon Strait during the past 40 years. The silt has caused stress to local coral communities but the toxic effects of high metal values continues to concern the coastal population north and south of the tailings outfall. Recent sampling of beach sediments along the western coast gave geochemical data which indicated higher Cu, Pb, Zn, Fe and Co values immediately around the outfall. The values, however, decreased markedly towards the north and south. Nickel appears to show some association with these elements. In the north, manganese seems to be influenced by dispersion from the Balamban river which drains a catchment containing manganiferous sediments upstream. Mercury and As show negative correlation with each other. They show no affinity with the other elements and do not appear to have any geological significance. The geochemical data, therefore, point to a zone immediately around the outfall as the only area affected by high metal values. Regular sampling and analysis should be done to ascertain the extent of dilution within the beach and near-shore environments and the influence of seasonal variation in ocean currents on the configuration of the affected area.