Groundwater Pollution by Industry

Abstract

Groundwater accounts for more than half of the municipal water supply in Finland. In general, Finnish groundwaters are unpolluted, but there are numerous risk factors. Information about these and about the impact of activities under different hydrogeological conditions is scarce. The National Board of Waters and the Environment has therefore been carrying out studies to find out more about factors representing a pollution risk to groundwater. Three cases of pollution in important groundwater areas in southern Finland are discussed here. The polluters represent the pharmaceutical (PH), food (FO) and sawmill (SA) industries.

Hydrocarbon compounds have leaked into the groundwater in the grounds of a PH plant, and ammonium sulphate, lye and CS₂ have leaked into the groundwater in the grounds of an FO plant. At both the PH and the FO factories, the flow of groundwater into the surrounding area has now been prevented. The SA used the fungicide containing tetra-, penta- and trichlorophenol. The solute-transport model was used to simulate contaminated groundwater flow from the sawmill to the groundwater intake.

The three companies are located in areas where ground permeability is good. Both the PH and the FO factories have subsurface piping for sewage and chemicals and both have used corrosive substances. At the PH factory the storage area for containers used to be too small and the ground surface had not been made impermeable. At both factories, the flow of water to the nearby water intake has now been prevented. The total concentration of chlorinated phenols in the groundwater at the groundwater intake near the sawmill was far higher than the maximum value recommended by WHO, and the water intake was closed.