Fate of the herbicides mecoprop, dichlorprop, and 2,4-D in aerobic and anaerobic sewage sludge as determined by laboratory batch studies and enantiomer-specific analysis.
Aerobic degradation experiments with the racemic mixtures of mecoprop and dichlorprop revealed that activated sludge collected from the aeration tank of a municipal waste water treatment plant degraded both enantiomers of mecoprop and dichlorprop within 7 days, albeit in an enantioselective manner; the (S) enantiomers were preferentially degraded. Mecoprop, dichlorprop, and 2,4-D were completely metabolized under aerobic conditions, as shown by the 86-98% elimination of dissolved organic carbon. Under anaerobic conditions, the concentration of 2,4-D decreased exponentially with a first-order reaction rate constant of 0.24 per day and without a lag-phase. After an incubation time of 17 days, 2,4-D was completely removed. 2,4-Dichlorophenol was the main metabolite of anaerobic 2,4-D degradation; only traces of 4-chlorophenol were detected. In contrast, the chiral phenoxypropionic acid herbicides mecoprop and dichlorprop persisted under anaerobic conditions during 49 days of incubation.
Zipper
C
C
Swiss Federal Institute for Environmental Science and Technology, Dübendorf, Switzerland.
Bolliger
C
C
Fleischmann
T
T
Suter
M J
MJ
Angst
W
W
Müller
M D
MD
Kohler
H P
HP
D015084:2,4-Dichlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001673:Biodegradation, Environmental; D002851:Chromatography, High Pressure Liquid; D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000378:metabolism*; D007700:Kinetics; D012722:Sewage / Q000382:microbiology*; D013237:Stereoisomerism
D006540:Herbicides; D012722:Sewage; D015084:2,4-Dichlorophenoxyacetic Acid; C008340:mecoprop; D008456:2-Methyl-4-chlorophenoxyacetic Acid; C010571:dichlorprop