Pathway, flux and accumulation of pollutant emission from landfill receiving As- and Hg-containing hazardous waste

Secondary pollution emitted from hazardous waste landfills can pose potential risks to surrounding populations and the environment. An investigation was performed during the relocation process of a hazardous waste landfill to identify pollutant emission, and its route, flux and accumulation in environmental medium during its disposal of As-and Hg-containing waste. As and Hg are released at the flux of 51.1 and 2.5 kg/year/ha through dust transport and precipitation during the 4-year operation, which impacted the shallow soil within 200 m around it, leading to a maximum increase of 2280 times in soil metal concentration. Seven and two leaks were identified, respectively, on the primary and secondary geomembranes (GMBs), resulting in 79.45 kg of As and 0.24 kg of Hg leaking from the primary GMB, though not entering the soil beneath the secondary GMB. Moreover, the study also found that the radial diffusion of pollutants in the clay liner after leakage from GMB was much higher than expected, reaching 58 m, which is 5.51-20.0 times higher than the theoretical value. This study provides in-formation on the area and extent impacted by hazardous waste landfill operation and also helps understand the emission route of heavy metals for secondary pollution control. Meanwhile, the amount and flux of pollutant emission, and also the diffusion radius in composite liner under on-site conditions, were quantified for accurate assessment of population exposure and environmental pollution.