Effect of Exposure History on Microbial Herbicide Degradation in an Aerobic Aquifer Affected by a Point Source
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- 作者：Nina Tuxen ; Julia R. de Lipthay ; Hans-J
//pubs.acs.org/images/gifchars/oslash.gif" border="0">rgen Albrechtsen ; Jens Aamand ; and Poul L. Bjerg
- 刊名：Environmental Science & Technology
- 出版年：2002
- 出版时间：May 15, 2002
- 年：2002
- 卷：36
- 期：10
- 页码：2205 - 2212
- 全文大小：146K
- 年卷期：v.36,no.10(May 15, 2002)
- ISSN：1520-5851
文摘
The effects of in situ exposure to low concentrations(micrograms per liter) of herbicides on aerobic degradationof herbicides in aquifers were studied by laboratorybatch experiments. Aquifer material and groundwaterwere collected from a point source with known exposurehistories to the herbicides mecoprop (MCPP), dichlorprop,BAM, bentazone, isoproturon, and DNOC. Degradation of thephenoxy acids, mecoprop and dichlorprop, was observedin five of six sampling points from within the plume.Mecoprop was mineralized, and up to 70% was recoveredas 14CO2. DNOC was degraded in only two of six samplingpoints from within the plume, and neither BAM, bentazone,nor isoproturon was degraded in any sampling point. A linearcorrelation (R2 
0.83) between pre-exposure and amountof herbicide degraded within 50 days was observed forthe phenoxy acids, mecoprop and dichlorprop. An improvedmodel fit was obtained from using Monod degradationkinetics compared to zero- and first-order degradationkinetics. An exponential correlation (R2 0.85) was alsofound between numbers of specific phenoxy acid degradingbacteria and pre-exposure. Combination of these resultsstrongly indicates that the low concentration exposure tophenoxy acids in the aquifer resulted in the presence ofacclimated microbial communities, illustrated by the elevatednumbers of specific degraders as well as the enhanceddegradation capability. The findings support application ofnatural attenuation to remediate aerobic aquiferscontaminated by phenoxy acids from point sources.
0.83) between pre-exposure and amountof herbicide degraded within 50 days was observed forthe phenoxy acids, mecoprop and dichlorprop. An improvedmodel fit was obtained from using Monod degradationkinetics compared to zero- and first-order degradationkinetics. An exponential correlation (R2 0.85) was alsofound between numbers of specific phenoxy acid degradingbacteria and pre-exposure. Combination of these resultsstrongly indicates that the low concentration exposure tophenoxy acids in the aquifer resulted in the presence ofacclimated microbial communities, illustrated by the elevatednumbers of specific degraders as well as the enhanceddegradation capability. The findings support application ofnatural attenuation to remediate aerobic aquiferscontaminated by phenoxy acids from point sources.