1. Dominic Aebi and Caitlin Henderson-Toth
March 31, 2011
CHEE 591 Environmental Bioremediation

2. 
April 26, 1986
 Reactor #4 at Chernobyl NPP
melts down and explodes
 Cause: human error
▪ Disabled cooling system
during testing

4. 

Radioactive
material released
into air, water, soil.
Exclusion Zone
 30 km radius
around Chernobyl

Units
 1 Bq = 1 decay / s
 1 Ci = 3.7 x 1010 Bq

6. 



Iodine
Cesium
Strontium
Barium
 Degradation
product of Cs

Plutonium
 Small amounts

8. 
Without Intervention
 200 yrs to farm within 30 km radius
 20,000 yrs to inhabit land within 1.5 km radius

Contaminates Water, Food, Soil
 Illegal farming in Exclusion Zone
 Effect on animal life
 Plant workers monitoring sarcophagus

Health Affects





Iodine irradiates thyroid
Strontium causes bone cancer
Cesium mimics potassium
Plutonium can cause lung, liver cancer
Birth defects

9. 
Use of Plants, their associated microbes to
accelerate remediation of organic and nonorganic contaminants
 TCE, Hydrocarbons, PCBs


Cost Effective
Option to use native/common plants
 Sunflower
 Poplar
 Reed

10. Mechanisms





Phytodegradation
Rhizosphere Remediation
Phytostabilization
Phytoextraction
Phytovolotalization
 Evapotranspiration
Figure 2. The phytoremediation mechanisms. Pollutants
may be stabilized or degraded within the rhizosphere,
accumulated or degraded within the plant body, or
transpired into the air .

12. 
Chernobyl Cooling Pond 23 km2
 1 km from reactor, dilute contaminant

Small Pond (75 m2)
 9.2x106 Bq 137Cs
 1.4x108 Bq 90Sr

Phytotech Inc. Researchers sampled water
 Over 1000 plants tested
 600 L sample treated
 Conclude sunflowers rapidly/preferentially remove
137Cs/90Sr

13. 
Ex Situ
 8 wk old plants
 Placed in 50 L water, for 48 hrs each
 12 days - Removal 90% 137Cs, 80% 90Sr

In Situ




1.0 m2 raft
4-8 weeks floating
24 plants
Anaylsis: 137Cs in roots, 90Sr in shoots
▪ Found that 55 kg dry weight Sunflower could remove all
contaminants
▪ 60 Sunflowers employed for complete remediation

14. 
Bad
 Information limited on remediated levels
 “Black Box” approach
▪ Limited understanding of mechanism
▪ No information on uptake of other contaminants
 Pilot study short
▪ Questions as to seasonal variation in 137Cs, 90Sr uptake

Good
 Sunflowers grow naturally in the Ukraine, acclimated,
resist pestilence
 Successful remediation (2nd attempt)
 Valuable bioaccumulation coefficient obtained

15. 
Bioaccumulation coefficients determined
 Can calculate sunflower biomass required to
remediate other ponds

After 4-8 wks
 Sunflower accumulate 8x the 137Cs in roots as
other plants
 Shoots contain enough 90Sr to warrant
quarrantine (2.5x106 Bq 90Sr /kg dry biomass)

17. 
Dushenkov et. al., Env. Sci. Tech., 1999.

Goals
1. Find an additive to desorb 137Cs from soil
2. Find a plant which bioaccumulates 137Cs
3. Test additive for bioaccumulation stimulation
4. Test nascent bioremediation effectiveness in-
situ

21. 

Using Indian Mustard
Improvement measured
 More than control?

22. 
Encasement
 Prevents further contamination

Natural Attenuation
 Adsorption/Encasement with minerals
 Very long time period

Capping/Vitrification (ex situ)
 Useful for very high concentrations
 Expensive

Permeable Reactive Multibarriers
 Efficient for removal of radionuclides in groundwater

23. 

Chernobyl phytoremediation of WATER
shows excellent promise
Chernobyl phytoremediation of SOIL
hampered by adsorption phenomena
 Has shown minimal but measureable
effectiveness

Phytoremediation
 Versatile, Inexpensive, In situ, Natural

Apply lessons to present day Fukushima NPP
disaster.

24. 
Any questions?