Wood species affect the degradation of crude oil in beach sand

Abstract

The addition of wood chips as a co-substrate can promote the degradation of oil in soil. Therefore, in the present study, the tree species-specific impact of wood chips of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.) and Western balsam poplar (Populus trichocarpa L.) on the degradation of crude oil was tested in beach sand in a 4-week incubation experiment. The CO₂-C release increased in the order of control without wood chips < +spruce < +pine < +poplar. Initial and final hydrocarbon concentrations (C₁₀ to C₄₀), as indicators for the oil degradation, were determined with gas chromatography-flame ionization detection (GC-FID). The degradation increased for the light fraction (C₁₀ to C₂₂), the heavy fraction (C₂₃ to C₄₀) as well as the whole range (C₁₀ to C₄₀) in the order of control without wood chips (f_degrad. = 23% vs. 0% vs. 12%) < +poplar (f_degrad. = 49% vs. 19% vs. 36%) < +spruce (f_degrad. = 55% vs. 34% vs. 46%) < +pine (f_degrad. = 60% vs. 44% vs. 53%), whereas the heavy fraction was less degraded in comparison to the light fraction. It can be concluded, that the tree species-specific wood quality is a significant control of the impact on the degradation of hydrocarbons, and pine wood chips might be promising, possibly caused by their lower decomposability and lower substrate replacement than the other wood species.

Keywords:

• Soil remediation
• crude oil
• spruce
• pine
• poplar
• wood

Acknowledgment

We acknowledge the Laboratory of Environmental Analytics (Schwerin, Germany) for the determination of the hydrocarbon content in the samples. The authors are grateful to Elena Heilmann (University of Rostock, Germany) for her contribution to the presented work.