Risk analysis of a disused landfill as support tools for defining strategy and priority of the remediation actions

Landfills have been the most common form of waste disposal, and old landfills are present or in close proximity to most communities. Many old landfills, built before the environmental laws could properly regulating waste disposal, often not lined, are now considered potentially contaminated sites and can represent a severe environmental issue posing a long-term risk to health and the environment. In this paper a risk analysis procedure aimed at investigating the long-term risk of groundwater contamination posed by old Municipal Solid Waste (MSW) landfills was applied in combination with LandSim (Landfill Performance Simulation) model with the aim of obtaining an integrate tool to assist decision makers establishing priorities for remediation action. A case study was carried out at an old landfill site filled with MSW, the oldest of which dated back to 1970. Risk analysis was carried out according to international and Italian guidelines. The risk for groundwater was considered by comparing the concentration at the compliance point with the Italian regulatory limits (CSC contamination concentration threshold), whereas the risk for humans was based on maximum chronic population exposure. The adopted risk analysis approach, for old landfills, appears to be a key tool to assist decision makers in establishing priorities for remediation action