Collections > Electronic Theses and Dissertations > A microscale investigation of naphthalene dissolution and biodegradation

Biodegradation of PAHs by soil microbes is often hindered because the compounds are not always available to the microorganisms responsible for metabolism. Light microscopy, with digital photography and image analysis, was used to observed naphthalene dissolution. A small scale flow cell containing a naphthalene crystal was viewed at 100x magnification. Abiotic, biotic, and azide-inhibited systems were examined in this experimental system. Changes in the crystal's mass were determined from image analysis, and changes in the aqueous naphthalene's mass were determined with a fluorescence detector. Naphthalene's mass decreased approximately 6 x 10-3 mg/hr, 1.5 x 10-3 mg/hr, and 1.0 x 10-3 mg/hr for abiotic, biotic, and azide-inhibited experiments, respectively. Cellular material around the crystal caused slower dissolution rates for the biotic and azide-inhibited experiments. There was no evidence that bacterial metabolism was occurring in the system. A model was developed which underestimated the dissolution rate by approximately one order of magnitude.