Assessment of Hydrocarbons (C-10-C-50), Polycyclic Aromatic Hydrocarbons (PAHs), and Trace Metals (TMs) Contamination in the Riverbanks of the Chaudiere River Three Years after the Lac-Megantic Railway Disaster (Southern Quebec, Canada)

摘要

On July 6, 2013, in downtown Lac-Megantic (southern Quebec, Canada), several tank cars carrying crude oil derailed. This resulted in a series of explosions and a huge fire that led to the terrible Lac-Megantic disaster. This study deals with the characterization of the Chaudiere River banks and bed in order to determine the current state of contamination by hydrocarbons (C-10-C-50), polycyclic aromatic hydrocarbons (PAHs), and trace metals (TMs). The highest concentrations of hydrocarbons found in the Chaudiere River are respectively 960mgkg(-1) dry weight in soil and 760mgkg(-1) dry weight in river sediment. Over half of the all samples were under the detection threshold (i.e. > 300mgkg(-1) in soil and > 832mgkg(-1) in sediment). The concentration in river sediment PAH concentrations were low, with values below the detection threshold. TM concentrations in the soil and sediment are also very low, rarely exceeding class A and B thresholds and chronic effect reference values (164mgkg(-1)) which constitute the criteria for soil quality and the protection of aquatic life established by the Quebec Environment Ministry. These low levels are largely due to the efforts deployed by government authorities to limit the infiltration and dispersal of contaminants along the river, and to the hydrological conditions that also favoured the dispersal and dilution of pollutants.