Mercury and Other Heavy Metals in Groundwater in the Abandoned Mercury Mine in Puerto Princesa City, Philippines

Abstract

A rapid environmental assessment of the abandoned Palawan Quicksilver Mines, Inc. (PQMI) mined-out area and vicinities in Puerto Princesa City, Philippines was conducted from October 2018 to December 2019 to trace the pathways of mercury (Hg) concentration in different media, including groundwater. In this study, existing wells, drilled boreholes, and hand water pumps near the PQMI pit lake were used as sampling wells. Hg and other heavy metals – arsenic (As), barium (Ba), chromium (Cr), manganese (Mn), and nickel (Ni) – were analyzed to determine the concentrations and compared to the international and Philippine standard for drinking water. Results showed that As, Ba, and Hg concentrations in the entire groundwater samples collected from sampling wells have concentrations that are within the international and Philippines standards for drinking water. Groundwater samples from drilled boreholes have the measured Cr, Mn, and Ni concentrations exceed the standards for drinking water. The results further suggest that there is no mixing of groundwater and surface waters within the aquifer.