Rapid site assessment in a small island of the Philippines contaminated with mine tailings using ground and areal technique: The environmental quality after twenty years

Abstract

Abstract This paper illustrates the impacts of mining disaster after more than 20 years. A two – day rapid assessment was carried out at Mogpog and Boac River catchment in Marinduque Island in March 2019. The target site included Maguilaguila Pit that connects the river catchment and formerly used as mining wastes pit. This is to understand the impacts of 1993 and 1996 mining disasters in the Boac-Mogpog river basin at Marinduque, Philippines. The island of Marinduque has been considered as among the top ten most vulnerable islands in the country due to its environmental condition and geographical location which affected the island demography. The island has suffered the impacts of one of the country’s biggest mining disasters. The instruments used to conduct rapid site assessment were SciAps X-300 Handheld X-ray Fluorescence (XRF), Unmanned Air Vehicle (UAV) Model DJI Mavic Air, Google Earth, Hannah Multiparameter HI 9811-5 with HI 1285-5 probe and HI 70007, 70031, 70032 and 700661 solutions. The DJI Mavic Air captured images of Mogpog and Boac River catchment which helped direct the research team to take the right sampling locations. The DJI Mavic Air captured site images of the two rivers as dead rivers and use as land transportation route during dry season. The Google Earth captured the historical images of the target areas. The recorded data showed that the pit and nearby river water is acidic with pH equivalent to 2.9 and 4.1, respectively. The range of concentration of total dissolved solids in Mogpog and Boac river water was 100–1360 and 160–1150 ppm, respectively. The recorded concentration of iron near the pit was 125,587 ppm, and chromium concentration range was 80–99 ppm. The concentration of copper and manganese in the sediments was 5 and 158 times higher (respectively) than the 1998 detected concentrations. Based on the recorded data and images, the Maguilaguila pit, Boac and Mogpog River catchment need immediate attention. It could be concluded that based on the recent assessment results, leaks at the pit are likely. Also, the combination of areal-aerial and ground technique produced two – day rapid site assessment for areas contaminated by mine tailings. The information could aid in preparing prompt action and setting strategies that are helpful in carrying out risk reduction programs in the island.