Former landfills as environmental liabilities in central Chile: Evidence from a pilot study in Lepanto

The former Lepanto landfill in the Santiago Metropolitan Region in Central Chile ceased operations in 2002 after 24 years. Currently, a biogas recovery center operates on this site. The objective of this pilot study was to evaluate the atmospheric concentrations of two polycyclic aromatic hydrocarbons (PAHs, i.e., phenanthrene and fluoranthene) at three points downwind from the former Lepanto landfill using passive air samplers and polyurethane foam disks to provide 3-month average concentrations of contaminants during winter months. The results showed concentrations ranging between 2 and 65 ng m⁻³ and decreasing with distance from the former landfill. Given that the distance to other potential sources was similar in all sampling sites, the evidence found suggested that the former Lepanto landfill may contribute to the local PAH inventory. Thus, we suggest that former landfills are potential candidates for long-term monitoring as they can represent a less-known environmental liability for residents. Additionally, we provide insights on how the Chilean environmental protection system can establish reclamation steps for their management after closure.