Investigating Potential Toxicity of Leachate from Wood Chip Piles Generated by Roadside Biomass Operations

Abstract

Roadside processing of wood biomass leaves chip piles of varying size depending upon whether they were created for temporary storage, spillage, or equipment maintenance. Wood chips left in these piles can generate leachate that contaminates streams when processing sites are connected to waterways. Leachate toxicity and chemistry were assessed for pure aspen (Populus tremuloides Michx.), lodgepole pine (Pinus contorta Dougl.), hybrid white spruce (Picea engelmannii x glauca Parry), and black spruce (Picea mariana (Mill.) Britton) as well as from two wood chipping sites using mixes of lodgepole pine and hybrid or black spruce. Leachate was generated using rainfall simulation, a static 28-day laboratory assay, and a field-based exposure. Leachate generated by these exposures was analyzed for organic matter content, phenols, ammonia, pH, and toxicity. Findings indicate that all wood chip types produced a toxic leachate despite differences in their chemistry. The consistent toxicity response highlights the need for runoff management that will disconnect processing sites from aquatic environments.

Keywords

• Biomass Leachate
• Aquatic Toxicity: MicrotoxTM
• Chemical Oxygen Demand
• Resin Acids
• Rainfall Simulation