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This article in JEQ

  1. Vol. 31 No. 1, p. 144-149
    Received: Jan 29, 2001

    * Corresponding author(s): eschwart@du.edu
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Impact of Methylene Chloride on Microorganisms and Phenanthrene Mineralization in Soil

  1. Egbert Schwartz *,
  2. Sinh V. Trinh and
  3. Kate M. Scow
  1. Graduate Group in Ecology and Dep. of Land, Air and Water Resources, One Shields Ave., Univ. of California at Davis, Davis, CA 95616-8627


This study investigated the effects of the quantity of methylene chloride, used as a carrier solvent for phenanthrene when added to soil, on phenanthrene mineralization kinetics, soil phospholipid fatty acid profiles (PLFA), and phenanthrene distribution. Methylene chloride dosages of 25 μL/g soil or more resulted in an enrichment of saturated PLFAs, suggesting soil microorganisms had adjusted their cell membranes in response to the solvent. A greater fraction of phenanthrene mineralized when spiked in 5 μL/g than in 25 μL/g methylene chloride suggesting that the methylene chloride became toxic to phenanthrene-degrading organisms in soil. Phenanthrene was more equally distributed among 0.1 g soil subsamples if spiked in 25 than 5 or 1 μL methylene chloride per gram soil. Thus the amount of methylene chloride used to spike phenanthrene in soil strongly impacted the mineralization kinetics, phenanthrene distribution, and microbial community in soil. Because a variety of spiking methods are used in biodegradation research, scientists should consider the quantity of solvents used when comparing results among different studies.

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Copyright © 2002. American Society of Agronomy, Crop Science Society of America, Soil Science SocietyPublished in J. Environ. Qual.31:144–149.