Sorption of pollutants by plant detritus: a review

Detritus particles derived from the decomposition of vascular plants appear to have a high sorptive capability for a wide range of pollutants. Evidence is presented and reviewed which shows detrital concentration of heavy metals, radionuclides, and organochlorine insecticides. A study of a roadside marsh indicates that lead originating from automobile exhausts may reach concentrations as high as 1415 ppm on marshgrass detritus. We suggest that these elevated concentrations may, in turn, be passed on to detritivores which ingest the contaminated particles and experience desorption and assimilation of the pollutant within the digestive tract. Finally, potential mechanisms are listed which might explain detrital sorption; these include; microbial uptake (adsorption and metabolic absorption), association with detrital and microbial lipids, electrostatic adsorption in response to charges on the detritus particles, and formation of complexes and chelates at active sites on the organic molecules of the decomposing detritus.