SEDL / STP / STP865-EB / STP35250S

Comparison of Microbial Transformation Rate Coefficients of Xenobiotic Chemicals Between Field-Collected and Laboratory Microcosm Microbiota

Lewis, DL
Microbiologist and chief, Environmental Systems Branch, U.S. Environmental Protection Agency, Environmental Research Laboratory, Athens, GA

Kellogg, RB
Microbiologist, Department of Health and Human Services, Centers for Disease Control, Atlanta, GA

Holm, HW
Microbiologist and chief, Environmental Systems Branch, U.S. Environmental Protection Agency, Environmental Research Laboratory, Athens, GA

Pages: 11    Published: Jan 1985

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Abstract

Two second-order transformation rate coefficients—kb, based on total plate counts, and kA, based on periphyton-colonized surface areas—were used to compare xenobiotic chemical transformation by laboratory-developed (microcosm) and by field-collected microbiota. Similarity of transformer to nontransformer community structure in blended aufwuchs was indicated by kb values, and similarity of transformation rates per unit of periphyton-colonized surface area was indicated by kA values. Xenobiotic chemicals used for the comparisons were methyl parathion (MP), diethyl phthalate (DEP), and 2,4-dichlorophenoxyacetic acid butoxyethyl ester (2,4-DBE). Even though rate coefficients of each of the chemicals were similar among microcosm- and field-collected microbial samples, not all of the field-collected samples showed MP or DEP transformation. The MP transformation was suppressed by aqueous extracts of field-collected, algae-dominated aufwuchs. Lack of DEP transformation appeared to have resulted from an absence of DEP-transforming bacteria in field-collected aufwuchs samples.