Peer Reviewed: The Bioturbation-Driven Chemical Release Process

Conventional wisdom has it that the primary process responsible for natural recovery of polluted streambeds and their adjoining water columns is fresh-particle deposition onto the sediment bed surface. In addition, until recently, the only significant chemical transport process was believed to be water velocity-generated particle resuspension from the polluted bed. But the latest computer modeling results show other forces may be at work in the sediment bed. Bioturbation: an in-bed particle translocation phenomenon driven by the activity of bottom-living animals that moves sediment-bound pollutants and homogenizes surface layers: has been proposed as an additional and very significant pollutant transport process. Bioturbation may be responsible for a major, if not dominant, fraction of the chemical quantities released from sediments to the water column. Including bioturbation may change our ideas about how natural attenuation processes work and enable engineers and scientists to make credible long-term predictions of remediation's impact and consequences.