Steven Siciliano

Soil Science

I explore how humans poison soil and how soil poisons humans. In Canada, soil cleanup guidelines protect the most sensitive organism at a site for a specific contaminant. For example, typically humans are very sensitive to polycyclic aromatic hydrocarbons (PAH) pollution, whereas soil nutrient cycling is sensitive for Total Petroleum Hydrocarbons (TPH) [REFs 96,92,76]. Thus, at a site contaminated with PAHs and TPH, the site would have to be cleaned up to protect humans and nutrient cycling if both receptors are present. As a result, improving policy and technologies in Canada requires that we investigate how humans and all other ecosystem components interact with, and are affected by polluted soils. Incidental ingestion of soil by humans is the primary exposure pathway by which polluted soils poison humans. And among soil biogeochemical cycles, the nitrogen cycle is proving to be the most sensitive to pollutants. Thus, I focus on incidental soil ingestion and the soil nitrogen cycle to understand how human activities impact ecosystems and how these ecosystems impact human health.

The laboratory has two divisions: toxicology and ecology.

Toxicology

• Modelling and assessing the transfer of pollutants from soil to children.
• Development of new soil toxicity test methods and approaches for Antarctic and the Arctic.
• Assessment of cardiovascular effects of metals and polycyclic aromatic hydrocarbons.
• The fate of mercury in soil: how do soil ecosystems purge mercury from their systems?
• Industrial barrens and metals: how do ecological and toxicological stressors impact the nitrogen cycle.

Ecology

• Unravelling the mechanisms of greenhouse gas production in Arctic desert ecosystems.
• Exploring how liquid water at sub-zero temperatures influences the expression of degradation genes.
• The Arctic nitrogen cycle in Polar deserts.

With Eric Lamb

• Smooth brome invasion in the tall grass prairie: root competition and the nitrogen cycle.
• Root competition in the polar deserts: the role of diapirs in ecosystem sustainability.
• Global drivers of microbial composition in the Arctic and Antarctic: nano to global scale synthesis.
• Landscapes of the four kingdoms: roots, bacteria, archae, and fungi competition in the prairie pothole region.

• Ph.D. (Toxicology), University of Saskatchewan
• B.Sc. (Biochemistry), Concordia University

SD Siciliano, AS Palmer, T Winsley, EG Lamb, A Bissett, MV Brown, J van Dorst, J Ji, BC Ferrari, P Grogan, H Chu, I Snape.  Accepted June 2014. Soil fertility is associated with fungal and bacterial richness whereas pH is associated with community composition in polar soil microbial communities. Soil Biology and Biochemistry

Peters, RE, M Wickstrom, SD Siciliano.   Accepted June 2014. The absolute bioavailability of polycyclic aromatic hydrocarbons from different dose media after single and sub-chronic exposure in juvenile swine.  Human and Ecological Risk Assessment.

Pannu, R. SD Siciliano, NJ O'Driscoll.  Accepted 2014.  Quantifying the effects of soil temperature, moisture and sterilization on elemental mercury formation in boreal soils.  Environmental Pollution. I was co-supervisor of R. Pannu and this manuscripts summarizes his PhD work.

Winsley T, I Snape, J McKinlay, J Stark, J van Dorst, M Ji, B Ferrari, SD Siciliano.  Accepted 2014. The Ecological Controls on the Prevalence of Candidate Division TM7 in Polar Regions. Frontiers in Terrestrial Microbiology.

van Dorst, J, SD Siciliano, T Winlsey, IS Snape, and B Ferrari. Accepted 2014. Bacterial targets as potential indicators of diesel fuel toxicity in subantarctic soils.   Applied & Environmental Microbiology. I designed the data interpretation and link to soil risk assessment for this diesel impacted soil.

Undergraduate courses:

• EVSC 420: Environmental Fate Analysis
• EVSC 421: Contaminated Site Management
• TOX 400: Quantitative Toxicology

Graduate courses:

• TOX 820: Advanced Environmental Fate Modelling
• TOX 821: Human Health Risk Assessment
• EVSC 821: Contaminated Site Remediation