Phenolic profiles in natural and reconstructed soils from the oil sands region of Alberta

Abstract

This research was conducted in the Athabasca oil sands reclamation area of northeastern Alberta, where land reclamation entails reconstruction of soil-like profiles using salvaged materials such as peat and mining by-products. Successful reclamation is in part dependent on the quality of the organic capping of these reconstructed soils. This study investigated organic matter composition between reconstructed and natural soils. Soil samples (0-10 cm) were taken from 45 plots to represent a range of reclaimed and undisturbed sites. The botanical origin of soil organic matter was characterised through cupric oxide oxidation, which yields lignin monomers hypothesized to reflect vegetation inputs and extent of decomposition based on time since reclamation. Additional soil organic matter parameters were obtained using acid hydrolysis, physical separation and ramped cross polarisation C-13 nuclear magnetic resonance techniques. Yields of vanillyl phenols, coumaryl phenols, p-hydroxy phenols, summed lignin phenols and total phenolic constituents were significantly higher in natural soils than in reconstructed soils. We suggest that there may be an accelerated decomposition of peat phenols in reconstructed soils, which would leave only those phenols representative of the vascular plant history accumulated in the initial peat profile.