Geophysical investigation of leachate contamination around selected dumpsites in Calabar, Nigeria

Abstract

This study employed electrical resistivity tomography (ERT) to investigate leachate contamination around selected dumpsites in Calabar, Cross River State, Nigeria. Seven profiles were surveyed: five close to the dumpsites and two away from the dumpsites as controls. Data were collected using a Wenner array configuration, with spread lengths varying from 55.0 to 105.0~m. The major equipment used was a Resistivity Meter Model SSR-MP-ATS from IGIS (India), with its accessories. The measured subsurface resistance values were converted to apparent resistivity using the appropriate formula. Data analysis was performed using Microsoft Excel and RES2DINV software. The findings revealed the presence of leachate, characterized by low resistivity values (less than 10 Ωm), at the Lemna (profile 2), CROSPIL (profile 4), and UNICROSS (profile 7) dumpsites. Profiles 1, 3, 5, and 6 did not show evidence of leachate contamination. These results imply that the long-term buildup of organic pollutants in leachate may pose a threat to aquatic life, plants, and eventually people. In addition, the introduction of landfill leachate into soil, groundwater, and surface-water bodies poses environmental risks. To mitigate health hazards, it is strongly recommended that groundwater be thoroughly treated before consumption. This approach will help to address the potential health implications associated with leachate from the dumpsites and protect community health and well-being.