Submitted to: Great Lakes By-Product Management Association
Publication Type: Abstract Only
Publication Acceptance Date: August 30, 2002
Publication Date: October 31, 2002
Agricultural, municipal and industrial byproducts contain numerous trace elements depending on source and processing. Extensive research with biosolids has identified natural processes of soils and plants which limit risks of phytotoxicity, risks to animals which ingest soil, and to food-chains. For Cd, co-occurring Zn normally inhibits transfer of Cd to edible crop tissues, and reduces bioavailability of crop Cd to animals. For most other elements, insolubility in soils, or in crop roots, prevents excessive transfer to plants and animals. When food-chain and crop are protected, soil ingestion risks need to be estimated; for most elements, the matrix of byproducts or amended soils limit bioavailability of byproduct-applied trace elements. Research has also shown that the inorganic adsorbents in byproducts are important in limiting solubility and bioavailability of trace elements. Increasing Fe and Mn in soil amendments can reduce potential risk from most trace elements. Indeed, Tailor-Made Mixtures or Composts including Fe-rich organic amendments and limestone equivalent have been used to remediate severely phytotoxic mine wastes and smelter-contaminated soils. Fe in such mixtures is also beneficial in reducing potential P leaching or runoff. Finding and combining different organic and inorganic byproducts to make such Tailor Made Mixtures offers valuable social benefit while reducing disposal in landfills.