52 The effects of secondary carbon sources and electron aceptors on the bioransformation of alachlor and propa chlor

摘要

The detection of agricultural chemicals in both raw ground waters and finised drinking waters has resulted in increased concern about the fate, transport, and health effects of these compounds upon their release. It has also resulted in the addition of many berbicides to the list of drinking water contaminats regulated by the United States Environmental protection Agency. among these are two commonly used acetanilide herbicides, alachlor (2-chloro-2', 6'-dietyl-N-methoxymenthyl acetantilide) and propachlor (2-chloro-N-isopropyl acetanilide), which are applied as pre- and post-emergence herbicides on numerous crops including corn and wheat~1. Both of these pesticides have been detected in ground water samples in Oklahoma and in orther agricultural areas in the U.S.~(2, 3) Current standards of the Safe Drinking Water Act include a maximum contaminant level (MCL) of 2 mu g/L for alachlor.~4 propachlor currently has only monitoring requirements, and may have a specific MCL established in the future.