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RECORD NUMBER: 33 OF 42

OLS Field Name OLS Field Data
Main Title Seasonal Effects on Microbial Transformation Rates of an Herbicide in a Freshwater Stream: Application of Laboratory Data to a Field Site.
Author Lewis, D. L. ; Freeman, L. F. ; Watwood, M. E. ;
CORP Author Environmental Research Lab., Athens, GA. ;Georgia Univ., Athens.
Year Published 1986
Report Number EPA/600/J-86/235;
Stock Number PB87-168100
Additional Subjects Herbicides ; Stream pollution ; Field tests ; Aquatic microbiology ; Water chemistry ; Reprints ; Microbial degradation ; Temperature effects ; Biodegradation ; Toxic substances ; Acetic acid/(butoxyethyl-ester)-dichlorophenoxy
Holdings
Library Call Number Additional Info Location Last
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Status
NTIS  PB87-168100 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. NTIS 06/21/1988
Collation 8p
Abstract
Seasonal effects on microbial transformation rates of an herbicide, 2,4-dichlorophenoxyacetic acid butoxyethyl ester (2,4-DBE), in a freshwater stream were investigated using low concentrations (less than 100 micrograms L(-1)) of the herbicide mixed with an inert dye, rhodamine WT, to correct for dilution. Although water temperatures decreased from 22 + or - 0.5 to 8.0 + or - 0.5 degrees C and water velocities decreased from 0.09 + or - 0.01 to 0.03 + or - 0.003 m s(-1), microbial transformation rates, as indicated by pseudo-first-order transformation rate coefficients, increased as much as threefold in the cold months over those in the spring and summer. The increased winter transformation rates were associated with leaf-litter accumulation, which provided additional colonized surface area in the stream. Therefore, the increased colonized surface area more than compensated for the effects of temperature and water velocity (under conditions of mass-transport limitation) that otherwise would have reduced microbial transformation rates in the winter months. (Copyright (c) 1986, Environmental Toxicology and Chemistry.)