Phytoremediation of PetroleumPAHs

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Phytoremediation of Petroleum/PAHs

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Problem

• Petroleum Spills
• Industrial Processing
• Manufactured Gas Plant Sites
• Wood Preservation Sites
• Railways
• Landfarms

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Oil Spill
(EPA, 1999)
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Oil Spill
(EPA, 1999)
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Phytoremediation Processes Organic Contaminants
ROOTING CHARACTERISTICS
TRANSPIRATION
PHYTOREMEDIATION
PLANT SPECIES
CONTAMINANT(S)
MICROBIAL POPULATIONS
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Field Assessments

• Craney Island Site - Sediment material
  contaminated with diesel fuel located in a
  biotreatment facility.
• Port Hueneme Site - Fuel oil contaminated soil
  located in test cells at a DoD National Test
  Site.
• Bedford Site - Manufactured gas plant site with
  high PAH contamination at depths of 3 to 6 feet.

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Craney Island Site (1995-1998)

• Site was located at the Navy Craney Island Fuel
  Terminal Biological Treatment Facility near
  Norfolk, VA.
• Study area was 180 x 100 with four treatments
  and six replicates.
• Tall fescue
• Treatments were
• Bermuda grass with annual rye
• White clover
• Unvegetated
• Plots were fertilized and irrigated as needed.
• Soil samples were analyzed for petroleum
  contaminants and microbial characteristics over
  two years.

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Above-Ground Biomass Craney Island Site
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Microbial Analysis (Total Plate Counts)Craney
Island Site
9.5
9
Bare
Fescue
8.5
Bermuda
Clover
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7.5
Log CFUs
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6.5
6
5.5
5
5 months
11 months
17 months
23 months
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Microbial Analysis (BIOLOG) Craney Island Site
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Microbial Analysis (Petroleum Degraders)Craney
Island Site
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Contaminant Analysis ( TPH Degradation) Craney
Island Site
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Contaminant Analysis (Target PAHs)Craney Island
Site
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Plant Uptake (PAHs) Craney Island Site
60
Fescue
50
Bermuda
40
30
Concentration (ug/kg)
20
10
0
Fluor.
C1-Napth.
Phenan.
Chrysene
Benzoap.
Napth.
Pyrene
C1-Pyr.
Target Compounds
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Port Hueneme Site (1997-2000)

• Site was located at the Port Hueneme DOD National
  Test Site.
• Study area consisted of 60 x 100 plots with
  three treatments and four replicates.
• Fertilizer and irrigation was used as needed.
• Soil samples were analyzed for petroleum
  contaminants, microbial characteristics, and
  toxicity for 30 months.

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Above-Ground Biomass Port Hueneme Site
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Microbial Analysis (Total Plate Counts)Port
Hueneme Site
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Microbial Analysis (Petroleum Degraders)Port
Hueneme Site
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Toxicity Analysis (Germination)Port Hueneme Site
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Toxicity Analysis (Microtox)Port Hueneme Site
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TPH Degradation () Port Hueneme Site
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Contaminant Analysis (PAHs)Port Hueneme Site
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Bedford Site (2000-2002)

• MGP site with PAH contamination at depths between
  3 and 6 feet.
• Two treatments are being compared hybrid
  poplar/grass cover and natural attenuation.
• Fertilization and irrigation is used as needed.
• Soil from three depths are being analyzed for
  contaminant concentration, microbial
  characteristics, and toxicity over the three year
  study.

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Toxicity Analysis (Germination)Bedford Site
100
90
Unvegetated
Vegetated
80
70
60
Germination
50
40
30
20
10
0
0 months
6 months
12 months
18 months
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Toxicity Analysis (Earthworm)Bedford Site
140
Unvegetated
120
Vegetated
100
80
Biomass (mg dry biomass)
60
40
20
0
0 months
6 months
12 months
18 months
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Microbial Analysis (Petroleum Degraders)Bedford
Site
8
Unvegetated
7
Vegetated
6
5
Log CFU
4
3
2
1
0
6 months
12 months
18 months
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Contaminant Analysis (PAHs)Bedford Site
300
Unvegetated
250
Vegetated
200
Anthracene (mg/kg)
150
100
50
0
0 months
6 months
12 months
18 months
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Supporting Greenhouse Study SpriggsBedford Site

• Soil cores were taken in the field and placed in
  the greenhouse.
• Trees (ash, poplar, and willow) were established
  in the columns with two takedowns (9 and 18
  months).
• Water was added to the columns from the bottom
  to simulate field conditions.
• Contaminant concentrations, microbial
  characteristics, and toxicity was assessed.

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Microbial Analysis (Petroleum Degraders) Bedford
Greenhouse Study Spriggs
8
9 months
7
18 months
6
5
Log Petroleum Degraders (MPN)
4
3
2
1
0
Control
Ash
Poplar
Willow
Treatment
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Contaminant Analysis (PAHs)Bedford Greenhouse
Study - Spriggs
300
Control
Ash
250
Poplar
Willow
200
mg/kg dry soil
150
100
50
0
Napth.
Phen.
Chrys.
Pyr.
BaP
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Plant Chamber Study - Chih

• Mass balance approach
• 14C tracer
• Assess fate of contaminant

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Plant Chamber
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Growth Chamber
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Plant Chamber Study Root Chamber
70.00
60.00
50.00
40.00
Control
Switchgrass
Cumulative 14CO2 evolution ()
Fescue
30.00
20.00
10.00
0.00
0
20
40
60
80
100
120
140
160
180
200
Time (Days)
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Plant Chamber Study Shoot Chamber
6.00
5.00
4.00
Cumulative Mineralization ()
3.00
2.00
1.00
0.00
0
20
40
60
80
100
120
140
160
180
200
-1.00
Time (Days)
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Plant Chamber Study Mass Balance
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Results
Time Zero
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Contaminant Distribution
100
80
60
Mineralized
Extractable by-product
Extractable pyrene
Residual phase
40
20
0
Initial
Control
Switchgrass
Tall Fescue

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PCR-DGGE
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Greenhouse Research

• Fertilization Effects
• Irrigation Effects
• Bioavailability

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Greenhouse Study - Hutchinson (Fertilization)
25000
Bare
LSD 2039
Fescue
Bermuda
20000
15000
TPH (mg/kg)
10000
5000
0
0N/0P
120N/12P
1000N/100P
1000N/250P
2500N/100P
2500N/250P
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Greenhouse Research Hutchinson (Irrigation)
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Greenhouse Results - Parrish
350
300
250
200
PAH concentration, mg PAH / kg
dry soil
150
100
50
0
0
4
8
12
Sampling period, months
Tall Fescue
Yellow Sweet Clover
Annual Ryegrass
Unvegetated, Unfertilized Control
Unvegetated, Fertilized Control
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Conclusions

• Degradation of target PAHs is higher in the
  rhizosphere than in bulk soil.
• Microbial community changes were noted during
  phytoremediation.
• Fertilization and irrigation have been shown to
  significantly affect degradation rate.
• There is a correlation between PAH degradation
  and root biomass development and decay.

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New Field Trials

• Indiana Harbor Site Petroleum contamination in
  a riparian zone
• Merrillville, IN Site Constructed wetland for
  high pH leachate from slag
• Wisconsin CDF PAH and PCB contaminated dredged
  sediments

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On-going Laboratory and Greenhouse Research

• Molecular Microbial Methods to Identify Optimal
  Rhizosphere Characteristics
• Effects of Plants on Contaminant Toxicity
• Fate of PAHs in the Rhizosphere
• Phytoremediation as Affected by Contaminant
  Bioavailability
• Phytoremediation of Cyanide Contaminated Soil
• Phytoremediation of Lead in Soil Adjacent to
  INDOT Bridges

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Recommendations for Applications

• Implementation of phytoremediation is not
  technically complicated, however, expertise is
  needed to maximize process efficiency.
• Considerable time is needed for phytoremediation
  projects to achieve target levels, depending on
  the initial concentrations and the desired end
  point.
• Environmental factors such as available water and
  nutrient conditions should be carefully managed
  to enhance the phytoremediation process.

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Recommendations cont.

• Phytoremediation can be used as a final polishing
  step or as the sole means of contaminant
  remediation.
• A deeper understanding of the mechanisms involved
  in this remediation approach is needed to better
  select, breed, or genetically engineer plants for
  phytoremediation projects.
• Root turnover and new root growth could impact
  the microbial responses for sustained TPH
  degradation.