The sight of bluish green water flowing through the Boac River in Marinduque province has raised suspicions of a high level of acid seeping from mine wastes left in the defunct Marcopper mining site. The Environmental Management Bureau (EMB) in Mimaropa (Mindoro, Marinduque, Romblon, Palawan) region said it will test the river’s water quality this month, after the Boac town government, through its municipal planning and development office, called its attention to what was reported as an “acid mine drain” or outflow of acidic water from metal mines. But Roland de Jesus, regional director of the Mines and Geosciences Bureau, described an acid mine drain as a “natural occurrence,” especially in areas with large deposits of copper. Copper ore, when submerged in water, becomes acidic giving off the bluish green color, he said.

Cinco, M. (2016, September 2). Copper residue shows in river water. Philippine Daily Inquirer, p. A8.