Record Display for the EPA National Library Catalog


Main Title Rates of Transformation of Methyl Parathion and Diethyl Phthalate by Aufwuchs Microorganisms.
Author Lewis, David L. ; Holm, Harvey W. ;
CORP Author Environmental Research Lab., Athens, GA.
Year Published 1981
Report Number EPA-600/J-81-492;
Stock Number PB82-158155
Additional Subjects Toxicology ; Insecticides ; Plasticizers ; Cultures(Biology) ; Concentration(Composition) ; Microorganisms ; Transformations ; Phosphorus organic compounds ; Reprints ; Methyl parathion ; Aufwuchs ; Phosphorothioic acid/(dimethyl-ester)-(nitrophenyl-ester)
Library Call Number Additional Info Location Last
NTIS  PB82-158155 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 8p
Using batch cultures, the authors determined transformation rates for low concentrations of two toxicants--an insectide, methyl parathion, and a plasticizer, diethyl phthalate--by aufwuchs. Aufwuchs samples were collected from field sites, an indoor channel, and a continuous-flow fermentor. Aufwuchs fungi, protozoa, and algae did not tranform the chemicals but bacteria rapidly transformed both. Second-order transformation rate coefficients, Kb, based on total plate counts of bacteria in aufwuchs, were determined for potential use in a mathematical model capable of predicting the transport and fate of chemicals in aquatic systems. Kb for both chemicals decreased as the concentration of total bacteria, (B), increased in aufwuchs. This effect resulted from the proportion of nontransformer to transformer bacteria increasing as (B) increased and from the rate of transformation per transformer cell decreasing as (B) increased. First-order transformation rate coefficients, K1, were relatively stable per unit of surface area colonized by aufwuchs because Kb decreased as (B) increased (K1 = Kb X (B)).