Phytoremediation of Salt (& PHC) Phytoremediation of Salt (& PHC) Impacted Soils Using Biochar Impacted Soils Using Biochar Augmentation; Implications of Salt Augmentation; Implications of Salt Tolerance Mechanisms Tolerance Mechanisms Dr. Barbara A. Zeeb Canada Research Chair – Biotechnologies & Environment Dept. Chemistry & Chemical Engineering Royal Military College of Canada Kingston, ON CANADA RPIC Federal Contaminated Sites National Workshop Stream C - Remediation 26 April, 2016; 10:30-11 am
︎ Salinization Causes ︎ The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. Weathering • Natural processes ︎ • Landfilling of high salt Currently estimated that Canada has >7.2 million ha of content wastes ︎ salinized soils Landfilling Waste Consequences ︎ • Land degradation Agricultural Practices • Reduction in plant The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. growth & yield • Reduction water quality • Toxic to aquatic, microbial, veg communities http://blogs.oregonstate.edu
Phytotechnologies the application of plants to engineering and science problems • remediating environmental contaminants (phytoremediation ) • ecorestoration & habitat creation • carbon sequestration
Mechanisms of Phytoremediation 1. Accumulate 2. Excrete
Biochar carbon rich by-product of pyrolysis The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.
︎ Phytotechnologies Phytoextraction Biochar ︎ � Use vegetation to � Improve soil structure ︎ mobilize salts into � Improve seed germination ︎ above ground tissues � Improve plant growth ︎ Accumulation ︎ Uptake ︎ 6
Halophytes 2. Accumulation Na + ¡ ¡ Cl ¡ -‑ ¡ 1. Exclusion 3. Excretion
The image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again. Adapted from Yensen & Biel 2006
Cement Kiln Dust (CKD) Landfill � Operating Cement Plant in Bath, ON � 30 min west of Kingston � CKD landfilled from 1973 – 2009 � Saline sodic material, slightly alkaline, low TOC � Project Objectives: i) improve aesthetics & ii) reduce [salt] ︎
CKD Site Characterization Electrical Sodium Chloride Conductivity Absorption ( µ g/g) (dS/m) Ratio MOE Guideline <0.7 5 -- Soil Saline: >4 Sodic: >13 Average: ~100 Characterization CKD Site 11-20 15.4 5800-13500
Objectives 1. Compare the phytoextraction efficiency of 3 halophytes – P. australis – P. nuttalliana – S. pectinata 2. Investigate different salt tolerance mechanisms & their ability to remove salt from soil 3. Role of biochar augmentation
Phytoextract Phytoextraction of Chloride wit ion of Chloride with h Phragmites austral Phragmites australis is 12
Phytoextraction Phragmites australis = accumulator species ︎ • large, perennial grass ︎ • growth prolifically ︎ • effectively extracts Cl - from soils ︎ July 2014 July 2014 ︎ Oct 2013 Oct 2013 ︎ July 2013 July 2013 ︎
Temporal Study Temporal Study
Remediation Timeframe Remediation Timeframe • Total chloride in top 10 cm of soil: ︎ • 464 ± 193 kg ︎ • Based on yearly extractions of 72-82 kg ︎ 3 - 9 years 3 - 9 years ︎ McSorley, K., Rutter, A. Cumming, R., and Zeeb , B.A. 2015. Phytoextraction of chloride from a cement kiln dust (CKD) contaminated landfill with Phragmites australis . J. Waste Management (accepted Oct 2015).
Field Trial Field Trial Addition of 60 lbs of biochar (5% w/w) Addition of 60 lbs of biochar (5% w/w) ︎ Planted 36 seedlings per plot Planted 36 seedlings per plot ︎
5% Biochar ︎ Buffer Zone ︎ Control ︎ S. pectinata S. pectinata ︎ A. elongatum A. elongatum ︎ P. P. nuttalliana nuttalliana ︎ A. A. elongatum elongatum & & ︎ P. P. nuttalliana nuttalliana seeds seeds ︎
︎ Biochar Biochar Effects Effects • Significant ↓ in uptake of Na + in P. nuttalliana & K + and Cl - in S. pectinata ︎ • No ↓ uptake of divalent cations ︎ • Improved germination of P. nuttalliana by 67% ︎ 5% Biochar 5% Biochar ︎ Control Control ︎
Accumulation • Conventional phytoextraction calculation ︎ i.e. [shoot ion] x biomass at harvest ︎ P. australis has highest 20 phytoextraction potential ︎
Implications of Salt Tolerance Implications of Salt Tolerance Mechanisms on Extraction Efficiency Mechanisms on Extraction Efficiency excreted salts 82X mag salt glands 2200X mag S. pectinata growing in RMC lab
Characterization of Excreted Salts � EDS for identification of salts excreted on stem & leaf surfaces of S. pectinata � Cl - and K + main ions excreted � Mean weekly excretion � Cl - 8500 ± 1200 µ g/g � K + 5800 ± 940 µ g/g
Salt Excretion When considering excretion in lieu of accumulation: • Cl - removal increased 160% • K + removal increased 30% S. S. pectinata pectinata ︎ • highest salt phytoextraction potential ︎ • native to Ontario ︎ McSorley, K., Rutter, A. Cumming, R., and Zeeb , B.A. Chloride Accumulation vs Excretion: Variations in phytoextraction potential of three halophytic grass species growing in a salinized landfill. J. Waste Management (submitted April 2016).
Fate of Salts � Potential for wind dispersion and dilution � haloconduction theory � micro (Cl - ) and macro (K + ) nutrients released by S. pectinata & wind dispersed � potential beneficial effects � Further research needed to determine extent of redistribution
Summary • P. australis can extract 65 ± 4 kg/km 2 Cl - /season � remediate site in 3-9 years • Biochar can be used for assisted re-vegetation at the CKD landfill – ↑ germination of P. nuttalliana by 67% • Salt tolerance mechanisms affect phytoextraction efficiency – Salt excretion with S. pectinata most efficient
Acknowledgements Co-Authors: • Dr. Allison Rutter, Queen’s University • Kaitlin McSorley, Pinchin Envt. • Rob Cumming, Lafarge, Canada
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