, Volume 7, Issue 2, pp 137–149

Biodegradation of atrazine in surface soils and subsurface sediments collected from an agricultural research farm

  • Mark Radosevich
  • Samuel J. Traina
  • Olli H. Tuovinen

DOI: 10.1007/BF00114626

Cite this article as:
Radosevich, M., Traina, S.J. & Tuovinen, O.H. Biodegradation (1996) 7: 137. doi:10.1007/BF00114626


The purpose of the present study was to assess atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) mineralization by indigenous microbial communities and to investigate constraints associated with atrazine biodegradation in environmental samples collected from surface soil and subsurface zones at an agricultural site in Ohio. Atrazine mineralization in soil and sediment samples was monitored as 14CO2 evolution in biometers which were amended with 14C-labeled atrazine. Variables of interest were the position of the label ([U-14C-ring]-atrazine and [2-14C-ethyl]-atrazine), incubation temperature (25°C and 10°C), inoculation with a previously characterized atrazine-mineralizing bacterial isolate (M91-3), and the effect of sterilization prior to inoculation. In uninoculated biometers, mineralization rate constants declined with increasing sample depth. First-order mineralization rate constants were somewhat lower for [2-14C-ethyl]-atrazine when compared to those of [U-14C-ring]-atrazine. Moreover, the total amount of 14CO2 released was less with [2-14C-ethyl]-atrazine. Mineralization at 10°C was slow and linear. In inoculated biometers, less 14CO2 was released in [2-14C-ethyl]-atrazine experiments as compared with [U-14C-ring]-atrazine probably as a result of assimilatory incorporation of 14C into biomass. The mineralization rate constants (k) and overall extents of mineralization (Pmax) were higher in biometers that were not sterilized prior to inoculation, suggesting that the native microbial populations in the sediments were contributing to the overall release of 14CO2 from [U-14C-ring]-atrazine and [2-14C-ethyl]-atrazine. A positive correlation between k and aqueous phase atrazine concentrations (Ceq) in the biometers was observed at 25°C, suggesting that sorption of atrazine influenced mineralization rates. The sorption effect on atrazine mineralization was greatly diminished at 10°C. It was concluded that sorption can limit biodegradation rates of weakly-sorbing solutes at high solid-to-solution ratios and at ambient surface temperatures if an active degrading population is present. Under vadose zone and subsurface aquifer conditions, however, low temperatures and the lack of degrading organisms are likely to be primary factors limiting the biodegradation of atrazine.

Key words

atrazine bacteria biodegradation mineralization sorption 



solution phase atrazine concentration at equilibrium


amount of atrazine sorbed




first-order mineralization rate constant


sorption coefficient




maximum amount of CO2 released



Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Mark Radosevich
    • 1
  • Samuel J. Traina
    • 2
  • Olli H. Tuovinen
    • 3
  1. 1.Department of AgronomyThe Ohio State UniversityColumbusUSA
  2. 2.School of Natural ResourcesThe Ohio State UniversityColumbusUSA
  3. 3.Department of MicrobiologyThe Ohio State UniversityColumbusUSA

Personalised recommendations