Oil Spill in Lac-Mégantic, Canada: Environmental Monitoring and Remediation

In North America, investment in unconventional oil extraction has increased due to the scarcity of conventional reserves. The rapid production growth has induced an extensive transportation activity, sometimes using aging pipelines and inadequate rail tank cars. Without surprise, in recent years, several high impact oil spills have occurred, as the taken place in Lac-Mégantic, the worst terrestrial oil spill in the history of North America. The accident caused dramatic human, material, and environmental damages. The transported petroleum hydrocarbons contained thousands of compounds, in varying proportions with a variety of properties making evaluations extremely complex. Despite the emergency actions had been undertaken, the pollution was detected in surface water, groundwater, sediments and soils, at different areas: Chaudière River, Lake Mégantic, and Lac-Mégantic City. After a brief return on the context of the Lac-Mégantic oil spill, this paper describes and discusses the undertaken pollution characterization and monitoring, as well as the applied remediation technologies. Several recommendations of unresolved issues are proposed. Indeed, the following issues are addressed: the lack of updated monitoring in some cases; the threshold of certain pollutants; the pollution release from sediments and its ecotoxicological impact; and the role played by complex mixtures of pollutants on ecotoxicity (case of polycyclic aromatic hydrocarbons and derivatives).