1 Practical Aspects of Phytoextraction: Six Years of Field Studies at Sites Historically Contaminated with Persistent Organic Pollutants (POPs) B. Zeeb, Canada Research Chair Dept. Chemistry & Chemical Engineering Royal Military College of Canada Kingston, ON CANADA A. Rutter Dept. of Environmental Studies Queen’s University Kingston, ON CANADA Session 5C – Emerging Technologies for Destruction of Obsolete Pesticides & Residues Pesticides and Ag Plastics Stewardship 10 th Annual Conference February 23, 2010 Phytoremediation defined: ‘a diverse group of green technologies that use either naturally occurring or genetically engineered plants to remove , reduce, degrade, or immobilize contaminants from soil , sediment, air or water’ • 1991 – term ‘phytoremediation’ coined • 1999 – 1 st issue of International Journal of Phytoremediation published
13
Embed
Practical Aspects of Phytoextraction: Six Years of Field ... defined: ... Root Systems of Prairie Plants - From the U.S. EPA Handbook on Natural Landscapes Kentucky Bluegrass Lead
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1
Practical Aspects of Phytoextraction: Six Years of Field Studies at Sites Historically Contaminated with Persistent Organic Pollutants (POPs)
B. Zeeb, Canada Research ChairDept. Chemistry & Chemical EngineeringRoyal Military College of CanadaKingston, ON CANADAA. RutterDept. of Environmental StudiesQueen’s UniversityKingston, ON CANADA
Session 5C – Emerging Technologies for Destruction of Obsolete Pesticides & ResiduesPesticides and Ag Plastics Stewardship 10th Annual Conference
February 23, 2010
Phytoremediation defined:
‘a diverse group of green technologies that use either naturally occurring or genetically engineered plants to remove, reduce, degrade, or immobilize contaminants from soil, sediment, air or water’
• 1991 – term ‘phytoremediation’ coined
• 1999 – 1st issue of International Journal of Phytoremediation published
Site #2 - Lindsay, ONformer industrial chemical plantAroclor 1248[PCB]soil = ~4.7 µg/g
Cucurbita pepoCucurbita pepo ssp. ssp. pepopepo var. var. Howden (pumpkin)Howden (pumpkin)
• known phytoextractor
• exhibits vigorous growth
• long diffuse root system (>1 m length) to access greater volume of soil
• accumulates sig. above ground biomass & hence extracts high volumes of contaminant
8
PCB vs. DDT Phytoextraction
0
100
200
300
400
C. pepo var.Howden
(Pumpkin)
F. arundinacea(Tall Fescue)
C. pepo var.Goldrush(Squash)
PC
Bs
(ug
)
Shoot
Root
7274.19412.2
184.8
2042.7
2094.01519.1
116.1
57536.3
123.2
35277.1
0
10000
20000
30000
40000
50000
60000
zucchini tall fescue alfalfa rye grass pumkin
DD
T (ng)
1. Lunney, A. Zeeb, B.A., and Reimer, K. J. 2004. Uptake of weathered DDT in vascular plants: potential for phytoremediation. Envt. Sci. Tech. 38: 6147-6154.2. Whitfield Aslund, M., Lunney, A., Rutter, A., and Zeeb, B.A. 2010. Effects of amendments on theuptake and distribution of DDT in Cucurbita pepossp pepo plants. Environ. Poll. 158: 508-513.3. Lunney, A., Rutter A., and Zeeb, B.A. Effect of organic matter additions on uptake of weathered DDT in Cucurbita pepo ssp pepo cv. Howden. Int. J. Phytoremediation (in press).
2. Soil Amendments to Increase 2. Soil Amendments to Increase Plant BiomassPlant Biomass
• Numerous amendments tried over the years in greenhouse & field including:
– various surfactants
– fertilizers
– mycorrhizal fungi
– root exudates
0200400600800
1000
control myke fertilizer
Treatment
sho
ot
PC
Bs
(ug
)
A A
B
control
myke
fertilizer
9
3. Agricultural Practices to 3. Agricultural Practices to Increase Plant BiomassIncrease Plant Biomass
1. Pruning
– to ↑ biomass of plant near base to maximize PCB uptake
2. Encouraging Nodal Roots
– to ↑ # of PCB uptake pathways
0
246
81012
141618
20
0 100 200 300 400 500Distance from root (cm)
[PC
B] (
pp
m)
Leaves
Leaf Stems
Main Stem
5 mWhitfield Åslund, M., Zeeb, B.A., Rutter, A., and Reimer, K.J. 2007. In situ phytoextraction of polychlorinated biphenyls (PCBs) from weathered, PCB-contaminated soil. Sci. Tot. Envt. 374: 1-12.
10
4. Use of Native Plant Species 4. Use of Native Plant Species for PCB phytoextractionfor PCB phytoextraction
OxOx--Eye DaisyEye Daisy
GoldenrodGoldenrod
• 27 species of free-growing weeds harvested in triplicate from 2 field sites
• [PCB] weed shoot compared to [PCB] pumpkin shoot
Scotch ThistleScotch Thistle
Density Effects
to compare plant extraction efficiencies, determine amount of PCB extracted per unit area of soil; – this will vary based on optimal plant density– e.g. Cucurbita pepo grows optimally at 1
plant per m2
11
6. On6. On--site Treatment of PCBsite Treatment of PCB--Contaminated Plant WasteContaminated Plant Waste
• How much volume reduction can be achieved?
Compost Over 1 Field SeasonCompost Over 1 Field Season
April 24th April 24th May 28th June 5th
June 12th June 19th June 26th July 3rd
12
SummarySummary1. PCB phytoextraction appears to be constant over
time
2. Use of fertilizer and simple cultivation techniques can be used to create larger plants & phytoextract more PCBs
3. Many weed species have potential to extract ≥ quantities of PCBs than C. pepo per m2
4. Composting is effective means of significantly reducing plant biomass prior to disposal
ConclusionsConclusions
• new work shows phytoextraction to be viable remediation technology for some POPs- contaminated soils – slow, but effective
– useful in areas with limited resources
– most applicable for large areas with low level contamination
– leaves soil matrix intact
– less expensive than traditional remediation technologies