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By:
Mark Winter
Alex Peroff
Matthew Magrini
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.
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.
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
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.
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
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.
PH Levels of Cyanobacteria
Concentration DAY 1 DAY 23
Control 7.95 9.69
50 Mg/L 7.95 10.62
100 Mg/L 7.95 4.0
150 Mg/L 7.95 3.51
200 Mg/L 7.95 3.16
0.10
1.00
10.00
100.00
Cel
l #/ m
L x
107
0.00
0.50
1.00
1.50
2.00
OD
750
0 5 10 15 20
Day
Growth Curve of Anacystis nidulansControl
Cell #/ mL
OD
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
0.10
1.00
10.00
100.00
Cel
l #/ M
L. x
107
0.00
0.50
1.00
1.50
2.00O
D75
0
0 5 10 15 20
Day
Growth of Anacystis nidulans50mg/l
Cell #/ ML.
OD
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
Growth Curve of Anacystis nidulans 100mg/L
0.1
1
10
100
Cel
l C
ou
nt
0
0.5
1
1.5
2
OD
0 5 10 15 20
Day Cell Count
OD
Third Graph Results
• Has 100 mg/L of Ferric Chloride
• 100 mg/L severely inhabited the growth of the cells
0.1
1
10
100
Cel
l C
ou
nt
0
0.5
1
1.5
2
OD
0 5 10 15 20
Day
Growth Curve of Anacystis nidulans 150mg/L
Cell Count
OD
Fourth Graph Results
• Has 150mg/L of Ferric Chloride
• Completely inhabited the growth of the cells
0.1
1
10
100
Cel
l C
ou
nt
0
0.5
1
1.5
2O
D
0 5
10
15
20
Day
Growth Curve of Anacystis nidulans 200mg/L
Cell Count
OD
Fifth Graph Results
• Has 200mg/L of Ferric Chloride
• 200mg/L of Ferric Chloride completely inhabited the growth of the cells
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
And to most of all:
