Multi-disciplinary investigation for detection, characterisation and monitoring of contamination from a solid waste illegal dumpsite, Peshawar, NW Pakistan

Leaching of organic and inorganic contaminants from illegal solid waste dumpsites negatively affects local environments, with hazards to human health in local communities. To detect, characterize and monitor contaminant pollutants, conventional site investigation methods such as drilling are costly, limited in spatial coverage, and destructive. This study aims to evidence how geophysical and geochemical surveys offer a non-invasive, cost-effective alternative to detect and characterize contamination from a dumpsite in Pakistan. The study included space-borne and ground-based (geophysical) remote sensing constrained by borehole, geochemical soil and groundwater data analysis. Results quantified the illegal dumpsite spatial extent and thickness as well as growth over two years, with a leachate plume of very low resistivity (<10 Ω.m) significantly attenuating GPR datasets. Geochemical sample analysis evidenced the leachate plume contained significant heavy metals (HMs), with mean concentrations of Ni 48 mg/kg, Cr 72 mg/kg, Pb 88 mg/kg, Zn 372 mg/kg, and Fe 537 mg/kg being recorded. Pb, Fe and Mn groundwater sample concentrations had levels exceeding permissible limits established by the WHO. The detected leachate plume contaminated both the 40-m-deep local aquifer, and the nearby Bara River. The study shows that multi-disciplinary site surveys can assist local authorities and environmental agencies to rapidly detect, characterize and monitor environmental contamination.