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Kinetics of alachlor and atrazine biotransformation under various electron acceptor conditions
Author(s) -
Wilber Gregory G.,
Parkin Gene F.
Publication year - 1995
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620140208
Subject(s) - alachlor , biotransformation , electron acceptor , atrazine , chemistry , reaction rate constant , sulfate , environmental chemistry , electron donor , nitrate , kinetics , substrate (aquarium) , biodegradation , pesticide , photochemistry , organic chemistry , biology , enzyme , ecology , catalysis , quantum mechanics , physics
Second‐order rate constants were developed for the biotransformation of the herbicides atrazine and alachlor under aerobic, nitrate‐reducing, sulfate‐reducing, and methanogenic conditions. Batch‐reactor techniques were used, with seed cultures taken from acclimated biofilm columns. The reactors were fed acetate as a primary substrate. Pesticide biotransformation appeared to depend upon the continued presence of the primary substrate, indicating co‐metabolic transformations. All four electron acceptor conditions tested resulted in some biotransformation of both pesticides. Rate constants for alachlor ranged from 6.25 × 10 −5 to 1.60 × 10 −4 L/mg volatile suspended solids (VSS)·h, with the highest rate constant occurring under sulfate‐reducing conditions, and the lowest under methanogenic conditions. Rate constants for atrazine ranged from 1.04 × 10 −5 to 3.32 × 10 −5 L/mg VSS·h, although differences among the four electron acceptor conditions were not statistically significant.