Asbestos mining waste impacts on the sedimentological evolution of the Bécancour chain of lakes, southern Quebec (Canada)

Olivier Jacques; Reinhard Pienitz

doi:10.1016/j.scitotenv.2021.151079

Asbestos mining waste impacts on the sedimentological evolution of the Bécancour chain of lakes, southern Quebec (Canada)

Sci Total Environ. 2022 Feb 10;807(Pt 3):151079. doi: 10.1016/j.scitotenv.2021.151079. Epub 2021 Oct 20.

Authors

Olivier Jacques¹, Reinhard Pienitz²

Affiliations

¹ Laboratoire de paléoécologie aquatique (LPA), Département de géographie, Université Laval, Québec, QC G1V 0A6, Canada; Centre québécois de recherche sur l'eau (CentrEau), Université Laval, Québec, QC G1V 0A6, Canada. Electronic address: olivier.jacques.7@ulaval.ca.
² Laboratoire de paléoécologie aquatique (LPA), Département de géographie, Université Laval, Québec, QC G1V 0A6, Canada; Centre québécois de recherche sur l'eau (CentrEau), Université Laval, Québec, QC G1V 0A6, Canada; Centre d'études nordiques (CEN), Université Laval, Québec, QC G1V 0A6, Canada.

PMID: 34687705
DOI: 10.1016/j.scitotenv.2021.151079

Abstract

More than a century (1877-2011 CE) of asbestos mining activities in the Thetford Mines region have resulted in the accumulation of gigantic mineral waste piles on the banks of the Bécancour River (southern Quebec, Canada). This river widens downstream from the mining sites to form a chain of lakes, successively: Stater Pond, Trout Lake, Lake William and Lake Joseph. A previous paleolimnological investigation revealed that waste erosion and transport strongly modified and polluted Trout Lake. However, questions remain about the extent of the mining contamination within the Bécancour River Basin and its impacts at other spatial scales. Here, we aimed to address this lack of knowledge by analyzing the sedimentological evolution of Stater Pond and lakes William, Joseph and Bécancour (upstream reference site). Radiometric dating (²¹⁰Pb, ¹³⁷Cs, ¹⁴C) and analyses of geochemical composition (ICP-AES/ICP-MS), computed tomography, magnetic susceptibility, loss-on-ignition and grain size were performed on sediment cores retrieved at these sites. In contrast to Lake Bécancour, yet similar to Trout Lake, we found that Stater Pond and Lake William have received high mineral matter loads since the creation of the Lake Asbestos Mine during the 1950s. Recent lake sediments at these downstream sites were highly enriched in magnesium, chromium and nickel. Comparison of their geochemical signature with that of sedimentary source materials from within the drainage basin demonstrated that they predominantly originate from mining waste erosion. Because of this issue, Stater Pond and lakes Trout and William are nowadays exposed to very high sediment accumulation rates (up to 1.4 cm yr^-1; 0.6 g cm^-2 yr^-1) and heavy metal enrichment. Evidence for contamination was also found in Lake Joseph, indicating that wastes are transported and deposited over ≥25 km downstream from the mining sites. Our study highlights the high risks and dangers associated with asbestos pollutants in aquatic ecosystems.

Keywords: Accumulation rates; Asbestos tailings; Metal pollution; Paleolimnology; Sediments; Thetford Mines.

MeSH terms

Asbestos*
Ecosystem*
Lakes*
Mining
Quebec
Water Pollutants, Chemical*

Substances

Water Pollutants, Chemical
Asbestos