Bioavailability (soil)

Bioavailability, in environmental and soil sciences, represents the amount of an element or compound that is accessible to an organism for uptake or adsorption across its cellular membrane.[1][2][3] In environmental and agricultural applications, bioavailability most often refers to availability of contaminants, such as organic pollutants or heavy metals, in soil systems and is also used frequently in determining potential risk of land application of sewage sludge or other inorganic/organic waste materials.

Almost exclusively, plant roots and soil organisms uptake contaminants that are dissolved in water. Therefore, the bioavailable fraction is often likened to the dissolved (aqueous) fraction in these systems. Depending on its chemical properties, a contaminant may or may not be found in the aqueous phase. Organic contaminants may become sorbed or sequestered in organic matter through weak Van der Waals interactions or through hydrogen- or covalent bonding.[4][5] Ionic compounds, such as heavy metals, can be precipitated into the solid phase.[6] Volatile compounds can be lost as aerosols to the soil atmosphere. In these forms, contaminants are relatively inaccessible to microbial or plant uptake and must dissociate and re-dissolve into the soil solution to become biological available.

  1. ^ American Society for Testing and Materials (ASTM). 1998. Standard guide for conducting laboratory soil toxicity or bioaccumulation test with the lumbricid earthworm Eisenia foetida. E 1676-97. Philadelphia, PA: ASTM.
  2. ^ Casarett, & Doull. 2001. Toxicology. The Basic Science of Poisons, Sixth Edition. C. D. Klaassen (ed.)
  3. ^ Semple, K. T., Doick, K. J., Jones, K. C., Burauel, P., Craven, A., & Harms, H. 2004. Peer reviewed: defining bioavailability and bioaccessibility of contaminated soil and sediment is complicated. Environmental Science & Technology, 38(12), 228A-231A. New York: McGraw-Hill.
  4. ^ National Research Council (US). 2003. Committee on Bioavailability of Contaminants in Soils and Sediments. Bioavailability of contaminants in soils and sediments: Processes, tools, and applications. Washington, DC: National Academies Press.
  5. ^ Semple, K. T., Morris, A. W. J., & Paton, G. I. 2003. Bioavailability of hydrophobic organic contaminants in soils: fundamental concepts and techniques for analysis. European journal of soil science, 54(4), 809-818.
  6. ^ Traina, S. J., & Laperche, V. 1999. Contaminant bioavailability in soils, sediments, and aquatic environments. Proceedings of the National Academy of Sciences 96 (7): 3365-3371.