Phytoremediation of Lead and Characterization by AAS

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Phytoremediation of Lead and Characterization by
AAS

• By Alle Taylor
• Intermediate Lab II
• Independent Project

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Phytoremediation

• The use of plants for the reduction/removal of
  contaminants from water, soil, or sediments
• Removal
• Degradation
• Containment
• Low to moderate Levels
• Advantages vs. Limitations

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How does it work?
Volatilization
Extraction
Degradation
Stabilization
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Lead and Phytoremediation

• Frequently Used in Industrial Processes
• Commercial Products
• Forms of Lead
• Pb2
• Lead Oxides
• Lead Hydroxides
• Lead Phosphates
• Lead Carbonates
• Tetramethyl Lead

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Lead and Phytoremediation

• Most difficult to remove from soil matrix
• 0.1 is bioavailable
• Chelating agents
• Residing in upper 6-8 inches of soil
• EPA Standards for contaminated soils
• 500ppm

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Experimental

• Plants
• Tomatoes
• Basil
• Watermelon
• Crook Neck Squash
• Lead Nitrate
• 0.8g of PbNO3 in 1 Liter of Water 500ppm
• Plants watered for 2 successive days with the
  500ppm Lead Nitrate Solution

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Experimental

• Samples
• Basil 200mL 100mg Pb
• Tomatoes 100mL 50mg Pb
• Watermelon 75mL 37.5mg Pb
• Squash 75mL 37.5mg Pb
• Absorption detected by Atomic Absorption
  Spectroscopy
• Internal Standard 4ppm, 6.7ppm, 10ppm

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Atomic Absorption Spectroscopy (AAS)

• Analytical method for determining metal
  concentration
• Use of thermal energy and light energy to excite
  an atom to emission
• Kirchhoff Theory of Atomic Spectra
• Walsh applied atomic absorption spectroscopy to
  chemical analysis and outlined instrumental
  techniques

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Calibration Curve
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Calculations

• Equation of the line
• y 0.0035x0.0034
• X (y 0.0034)/0.0035
• Y absorbance
• Divide by total plant mass and multiply by 106
• Result ppm of Pb in sample!

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Calculations
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Percent Uptake

• Basil
• 0.27
• Tomatoes
• 0.36
• Watermelon
• 0.4
• Squash
• 0.8

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Conclusions

• Crook Neck Squash is a good accumulator
• Future Work
• Use chelating agents EDTA, citric/malic acid

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References

• Henry, Jeanna R. (2000) Overview of
  Phytoremediation of Lead and Mercury U.S.
  Environmental Protection Agency, Office of Soild
  Waste and Emergency Response
• Blaylock, Michael J. et al. (1997) Enhanced
  Accumulation of Pb in Indian Mustard by Soil
  Applied Chelating Agents. Environmental Science
  Technology 31(3)860-865
• Huang J.W., Cunningham, S.D. (1996) Lead
  Phytoextraction Species variation in lead uptake
  and translocation. New Phytologist 13475-84
• A Citizens Guide to Phytoremediation. United
  States Environmental Protection Agency Office of
  Solid Waste and Emergency Response. April 2001
• Miller, Gloria., Begonia, Gregorio., Begonia,
  Maria., Ntoni, Jennifer. (2008) Bioavailability
  and Uptake of Lead by Coffeeweed (Sesbania
  exaltat Raf.). Int. J. Environ. Res. Public
  Health 5(5)436-440
• Pictures
• http//schwoit.com/wp-content/uploads/2008/01/swee
  t_basil.jpg
• http//3.bp.blogspot.com/_KSAB9xqp6_E/Rml0GU-eRLI/
  AAAAAAAAAUA/4JownPKJwUI/s400/crooknecksquash.jpg
• http//images.craveonline.com/article_imgs/Image/s
  eedless-watermelon.jpg
• http//www.worldcommunitycookbook.org/season/guide
  /photos/tomato.jpg