Mark Winter

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Heavy Metal Study

• By
• Mark Winter
• Alex Peroff
• Matthew Magrini

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Background Info

• To learn more about the effects of heavy metals
  the Weston scholars worked with Dr. Lee Lee in
  her ever going research in the field of
  microbiology and the study of heavy metals.
• The MAM group (Mark, Alex, and Matt) worked with
  the heavy metal Ferric Chloride, and used it on
  Cyanobacteria.

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Cyanobacteria

• Anacystis nidulans are strains of cyanobacteria
  and are excellent indicators to study the toxic
  metabolic levels of heavy metals.
• Cyanobacteria are rod-shaped, unicellular,
  photoautotrophic and are prokaryotic.
  Cyanobacteria also live in fresh water habitats.

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Ferric ChlorideFeCl3

• Ferric Chloride has three generals uses.
• Principally as a flocculating agent for water
  treatment.
• Used for metal surface treatment as etching agent
  for engraving, photography and printed circuitry
• And is used as a disinfectant

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More on Ferric Chloride

• Formula is FeCl3
• Appearance- dark brown liquid
• Health hazard- toxic by ingestion, strong
  irritant to skin and tissue.
• Ferric Chloride is also on the EPA heavy metal
  list.

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Methods and Material

• First made 3M medium for cell growth, using
  pipettes and micropipettes.
• Sterilized it by autoclaving at 121 C
• Mixed cyanobacteria with medium. Then
  distributed in 5 flasks. Each flask with 100mL
  of cyanobacteria.
• 1st flask has no FeCl3
• 2nd flask has 50mg/l of FeCl3
• 3rd flask has 100mg/l of FeCl3
• 4th flask has 150mg/l of FeCl3
• 5th flask has 200mg/l of FeCl3

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Methods and Material (cont.)

• Used micropipette to transfer FeCl3
• Then took pH. 7.95
• Then we observed the cyanobacteria by two methods
• First by absorbance levels, using a
  spectrophotometer 20
• Then observed them by microscope. And used a
  special slide called a hemocytometer or a
  bacterial counting chamber.

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PH Levels of Cyanobacteria
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Control Graph Results

• Has no Ferric Chloride concentration
• Standard Growth Curve
• Cell growth are monitored by OD readings
• And the cell numbers.
• The cells grew then leveled off
• We monitored it for 18 days

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Second Graph Results

• Has 50mg/L of Ferric Chloride
• Growth of the cells are slightly reduced in the
• Presence of 50 mg/L of Ferric Chloride

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Third Graph Results

• Has 100 mg/L of Ferric Chloride
• 100 mg/L severely inhabited the growth of the
  cells

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Fourth Graph Results

• Has 150mg/L of Ferric Chloride
• Completely inhabited the growth of the cells

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Fifth Graph Results

• Has 200mg/L of Ferric Chloride
• 200mg/L of Ferric Chloride completely inhabited
  the growth of the cells

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Analysis

• The pH levels increased with the amount of FeCl3.
• From 100mg/l and up the bacteria stayed smaller
  than the control and the 50mg/l.
• Cyanobacteria can grow in small amounts of FeCl3,
  but in high amounts the cyanobacteria will stop
  growing and become acidic.
• The cyanobacteria were probably dying because the
  acidic level was high and the absorbance was
  lower than normal. This suggests the inhibition
  of the growth of those cyanobacteria may be due
  to the combination of heavy metals and acidic
  conditions

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Dr. Lee Lee
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Pat
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Mrs. English
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Mrs. Portas
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And to most of all
Mr. and Mrs. Weston
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