Phytotoxicity of weathered petroleum hydrocarbons in soil to boreal plant species

Prama Roy; Allison Rutter; Amy Gainer; Elizabeth Haack; Barbara A Zeeb

doi:10.1016/j.envres.2023.117136

Phytotoxicity of weathered petroleum hydrocarbons in soil to boreal plant species

Environ Res. 2023 Dec 1;238(Pt 1):117136. doi: 10.1016/j.envres.2023.117136. Epub 2023 Sep 17.

Authors

Prama Roy¹, Allison Rutter², Amy Gainer³, Elizabeth Haack⁴, Barbara A Zeeb⁵

Affiliations

¹ School of Environmental Studies, Queen's University, Kingston, ON, K7L 3N6, Canada. Electronic address: 14pr4@queensu.ca.
² School of Environmental Studies, Queen's University, Kingston, ON, K7L 3N6, Canada. Electronic address: ruttera@queensu.ca.
³ Clear-Site Solutions (formerly with Advisian/Worley Canada Services), 9807 83 Ave Edmonton, AB, Canada. Electronic address: amy@clearsitesolutions.ca.
⁴ Ecometrix Incorporated, 6800 Campobello Road, Mississauga, ON, L5N 2L8, Canada. Electronic address: ehaack@ecometrix.ca.
⁵ Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON, K7K 7B4, Canada. Electronic address: zeeb-b@rmc.ca.

PMID: 37717802
DOI: 10.1016/j.envres.2023.117136

Abstract

Canada has extensive petroleum hydrocarbon (PHC) contamination in northern areas and the boreal forest region from historical oil and gas activities. Since the 2013 standardization of boreal forest species for plant toxicity testing in Canada, there has been a need to build the primary literature of the toxicity of weathered PHCs to these species. A series of toxicity experiments were carried out using fine-grained (<0.005-0.425 mm) background (100 total mg/kg total PHCs) and weathered contaminated soil (11,900 mg/kg total PHCs) collected from a contaminated site in northern Ontario, Canada. The PHC mixture in the contaminated site soil was characterized through Canadian Council of Ministers of the Environment Fractions, as indicated by the number equivalent normal straight-chain hydrocarbons (nC). The soil was highly contaminated with Fraction 2 (>nC₁₀ to nC₁₆) at 4790 mg/kg and Fraction 3 (>nC₁₆ to nC₃₄) at 4960 mg/kg. Five plant species (Elymus trachycaulus, Achillea millefolium, Picea mariana, Salix bebbiana, and Alnus viridis) were grown from seed in 0%, 25%, 50%, 75%, and 100% relative contamination mixtures of the PHC-contaminated and background soil from the site over 2-6 weeks. All five species showed significant inhibition in shoot length, shoot weight, root length, and/or root weight (Kruskal-Wallis Tests: p < 0.05, df = 4.0). Measurements of 25% inhibitory concentrations (IC₂₅) following PHC toxicity experiments revealed that S. bebbiana was most significantly impaired by the PHC-contaminated soil (410-990 mg/kg total PHCs), where it showed <35% germination. This study indicates that natural weathering of Fraction 2- and Fraction 3-concentrated soil did not eliminate phytotoxicity to boreal plant species. Furthermore, it builds on the limited existing literature for toxicity of PHCs on boreal plants and supports site remediation to existing Canadian provincial PHC guidelines.

Keywords: Bioavailability; Boreal; Ecotoxicology; Petroleum hydrocarbons; Plant science; Soil contaminants.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biodegradation, Environmental
Hydrocarbons / toxicity
Ontario
Petroleum* / toxicity
Plants
Soil
Soil Pollutants* / analysis

Substances

Soil
Petroleum
Hydrocarbons
Soil Pollutants