Indicators of heavy metal contamination of the environment: Mine tailings contamination in Marinduque Island, Philippines

This study aims to characterize mine tailings contamination in Marinduque Island, Philippines through the investigation of several heavy metal indicators. In the marine environment, sediment geochemistry is used to trace the spatial extent and temporal evolution of a mine tailings spill that occurred in 1996. Aside from this event, the sediment profile also reveals an older history of contamination in the area. The examination of heavy metal concentrations in the growth bands of corals provides a complementary dataset to the sediment record. Corals record distinct input events from both natural processes and anthropogenic sources in the 1990s. In both marine indicators, copper shows the largest deviation from the calculated baseline value. Heavy metal contamination from mine tailings deposited along the riverbanks of the Boac-Makulapnit River and from acid mine drainage formation from the Marcopper Mine is also assessed through annual sampling of river water, bed sediment, algae and benthic insects. Again, copper is the most elevated metal in these environmental media, and shows a distinct gradient away from the mine. Moreover, Cu levels in caddisfly larvae suggests contamination throughout the whole length of the river. This is further substantiated by insect taxa richness data which shows a huge disparity in community diversity between the impoverished Boac-Makulapnit River fauna and those of local uncontaminated streams.