Application of pollution indices for the spatiotemporal assessment of the negative impact of a municipal landfill on groundwater (Tychy, southern Poland)

Risk assessment plays an essential role in the protection of groundwater resources, especially in the regions of potential contamination sources. The present research was aimed at assessing the risk of groundwater contamination in the vicinity of the Tychy-Urbanowice municipal landfill systems (southern Poland), using the contamination index tool. Groundwater samples from the Quaternary Aquifer were collected from 22 piezometers located near the former landfill site (currently closed) and the new sealed landfill site during a monitoring period from 1995 to 2015. Extremely high values (1700) of the groundwater contamination index were observed in a piezometer that captures water beneath the abandoned landfill. Very high index values (154 or 216) were also noticed in piezometers located in the groundwater outflow from the landfill site. Results of interpolation for individual piezometers, which capture only the upper or lower part of an aquifer, are unrepresentative. The interpolation for the mean values of the contamination index increased the groundwater risk assessment.