Bacterial biodegradation of Benzoapyrene

1
Bacterial biodegradation of Benzoapyrene

• Min Schrader Alexis Brandow

?
2
Polyaromatic Hydrocarbons (PAHs)
3
Sources Natural vs. Anthropogenic
Pictures from various sources
4
Path of PAHs

• Airborne PAHs precipitate to the ground.
• Carried by runoff into surface waters.
• Consumed by aquatic life.

5
Process of bioaccumulation.

• 1 µg 10 µg 100 µg 1000 µg
• No known, or studied, risk to the seafood.
• Larger animals store all of the accumulated PAHs
  in their fatty tissues.
• Shoreline spills contaminate more than off-shore
  spills.

6
Epoxidation Toxicity

• Can occur in environment or inside human body.
• Complete process will
• Increases polarity, increases mobility, easily
  excreted.
• Increased mobility can either increase or
  decrease reactivity.
• More reactive epoxidation steps increase
  carcinogenic potential.
• Incomplete process can
• Increase polarity, decrease mobility, and
  decrease normal excretion rate.
• Epoxidases epoxidation enzymes in some species.

7
Volatility Remediation

• Volatile compounds.
• PAHs size evaporation trends.
• Water turbulence, dispersion, sedimentation.
• Efficient remediation must be self-sustaining and
  on-site.
• Avoid potential adverse effects of introducing
  new substances.

8
Natural Remediation

• Environment equipped to remediate some PAHs in
  some quantities.
• Capable of handling some anthropogenic excess of
  smaller PAHs
• With time, natural processes heal the ecosystem.
• Some can be aided.
• Weathering processes.

9
Anthropogenic Remediation

• Off-site Remediation
• Dig up and transport to process.
• Exorbitant cost, time, and labor.
• Only used for the most toxic and immediate
  concerns.
• In-situ remediation
• Applying remedy on-site.
• Cheaper, less reliance on machine and human
  labor.
• Some processes can be self-sustaining.

10
In-Situ Remediation

• Photo-degradation (flash chromatography and
  photolysis).
• Thermal enhancements.
• Phytoremediation.
• Microbial activity.

11
Benzoapyrene (BaP)

• Less volatile. Larger, heavier, bioaccumulative
• Known cause of cancer, heritable genetic damages,
  impaired fertility, and fetal harm
• Known toxin to larger land aquatic organisms.
• Bap and Bep Essentially the same.
• Molecular formula C20H12
• Formula weight of 252.31 grams per mole.
• Bep is only known for carcinogenic and aquatic
  effects.

12
Question Hypotheses

• Identify a benign, site-specific bacteria guild.
• Efficient, in situ treatment.
• Decompose benzoapyrene (Bap) into less toxic
  products.
• Cultured, site-specific guild bacteria.
• Bacteria guilds composed of diverse group of
  bacteria.
• Each species crucial for a particular step of the
  reaction.
• Cultured, site-exotic guild bacteria.
• No cultured bacteria guild are successful.

13
Persistance

• Bap persists in the environment for 84 years.
• Small PAHs like naphthalene last for 8 months.
• Biodegradation - decomposition of compounds by
  plants, animals, microbes.
• Dominant, natural remediation.
• Biodegredation better than clean up.
• Hydrocarbons are energy for 90 species of
  bacteria.

14
Spring Quarter Plans

• Site tests and lab experiments.
• Choose specific contaminated site.
• Take samples to determine the most contaminated
  one-mile square area in most urgent need of
  bioremediation.
• Test new samples from area.
• Take at least three samples from each sample site
  
• Ideal to use native bacteria.
• Test whether exotic bacteria affects adversely.

15
Needs Future Questions

• Determine a supplier, if necessary.
• Obtain permits, or other permissions.
• Time restrictions on use of site vs. length of
  lab study?
• Compare other remediation methods, times, and
  costs to our method.
• Success with Bap work on other PAHs?

16
References

• 1.      Awata H. Bates S. Knuab D. Popelka
  R.. Environmental Organic Chemistry. 1998,
  Spring.
• 2.      American Petroleum Institute
  Environmental, Health and Safety Mission and
  Guiding Principles. (November 1996). February
  2002, http//api-ec.api.org/environ/index.cfm?bitm
  ask001003000000000000
• 3.      Rodgers R. P. Lazar A. C. Reilly P. T.
  A. Whitten W. B. Ramsey J. M.. Analytic
  Chemistry. 2000, 5040-5046.
• 4.      Jim Neitzel. Evergreen State College,
  Olympia, WA, January 2002 interview.
• 5.      Brad Jackson. EPA, Renton, WA, January
  2002 e-mail.
• 6.      Cometabolic Bioventing Field Test
  Conducted at Dover Air Force Base 2000 U.S.
  Environmental Protection Agency. National Risk
  Management Research Laboratory.
• 7.      In Situ RemediationStatus Reports.
  (January 1996). February 2002,
  http//www.epa.gov/tio/products/newsltrs/gwc/gwcab
  iot.htm
• 8.      EPA Grows Solutions to Clean-Up Problems
  at Toxic Sites. (March 2001). February 2002,
  http//www.epa.gov/epahome/other_031501.htm
• 9.      A Citizens Guide to Phytoremdeiation.
  (n.d.). February 2002, from http//www.epa.gov/sw
  ertiol/download/citizens/citphyto.pdf
• 10.  New Technology Transfer Products Coming Your
  Way. (January 2001). February 2002,
  http//www.epa.gov/ttbnrmrl/ca.html
• 11.  Lahlou M Harms H. Springael D.
  Ortega-Calvo J-J. Environmental Science
  Technology 2000, 34, 3694-3656.
• 12.  Search on benzopyrene at
  http//www.chemexper.com

17
 Acknowledgments

• Rachel Jameton, TESC Chemistry faculty, Matter
  and Motion
• Melissa Barnhart, TESC Chemistry tutor, Matter
  and Motion
• Aaron Barnes, TESC Science Instruction Technician
• Carolyn Mayer, PSC