Tracking of Groundwater Pollution Plumes at Landfill Sites Using Borehole Hydrodynamic and Hydrochemical Profile (Bhhp) Method

Human health and ecological security are vulnerable to groundwater pollution at landfill sites. It is essential to monitor groundwater quality downstream of landfills, but evaluating the pollution plumes within a multi-component contaminated aquifer remains a challenge. In order to track the spatial distribution of groundwater pollution plumes, the in-situ borehole hydrodynamic and hydrochemical profile (BHHP) method was proposed. Total dissolved solids (TDS), ammonia nitrogen (NH4+-N), and oxidation-reduction potential (ORP) were selected as representative hydrochemical indicators. The BHHP method was applied to investigate groundwater pollution at a valley-type landfill site. Consequently, the sources of leachate leakage were investigated, and the principal leakage affected about 100 m of V-level groundwater horizontally, while the vertical pollution of V-level groundwater exceeded 50 m. The correlation between TDS, NH4+-N and ORP was analyzed within the affected range, it was further clarified that TDS and NH4+-N were two pollution indicators and ORP was a relative indicator for verification. Additionally, three principal components that contributed 52.54%, 18.60%, and 14.39% were obtained by principal component analysis. And these three components represented the overall situation of groundwater pollution, redox environment and replenishment capacity, and depth successively.