Transcript New soil remediation strategies targeted at reduction of

New soil remediation strategies targeted
at reduction of PACs contaminant
exposure and mobility
Geoffrey Marchal
National Environmental
Research Institute
Aarhus University
I. Concept & hypothesis
Two and three ring PAC are weakly bound to soil particles and
4-7 ring PAC are strongly bound to organic soil particles.
Environmental Fate
• Polycyclic aromatic compounds (PACs) do not dissolve easily in water
and they bind to particles, and settle to the bottom of lakes and rivers.
• Due to their lipophilic nature and their affinity for organic carbon,
PACs become sequestered to the soil matrix for a long time.
Phenanthridine
Benz[a]anthracene
Fluoranthene
PhD Studentship REMTEC presentation
10/09 - 09
I. Concept & hypothesis
New bioremediation concepts for the reduction of environmental and
human risks will be developed and validated by turning the
limitation of existing remediation technology (limited bioavailability)
into an advantage (reduction of mobility and uptake).
BIOSTABILISATION
A number of soil amendments will be investigated for their potential to
facilitate
chemical degradation | Biodegradation | transformation into non accessible forms
while, if possible, at the same time improving other core functions of the
soil.
PhD Studentship REMTEC presentation
10/09 - 09
I. Concept & hypothesis
Soils amendments:
1. Biochara: biomass-derived black carbon (incomplete combustion) made
from wood-char.
2. Charcoalb: 1 – 100 µm particles made from incomplete combustion of
organic matter with identifiable morphological features of the original fuel.
3. Activated carbon: Activated carbon (particule size 0.15 to 1 mm) is a form
of carbon that has been processed to make it extremely porous and thus to
have a very large surface area available for adsorption or chemical reactions.
4. Black carbonb: the remnants carbon rich matter of incomplete combustion.
And also Compost and Artificial humus
a. Lehmann J et al. . 2006 Bio-char sequestration in terrestrial ecosystems – a review. Mitigation and Adaptation Strategies
for Global Change 11, 403 - 427.
b. Cornelissen G et al. . 2005. Extensive Sorption of Organic Compounds to Black Carbon, Coal, and Kerogen in Sediments
and Soils: Mechanisms and Consequences for Distribution, Bioaccumulation, and Biodegradation. Environmental science
and technology 39, 6881-6895.
PhD Studentship REMTEC presentation
10/09 - 09
I. Concept & hypothesis
TOPSOIL
(1a) add stable organic matters
(1a’) add high porous matters
(1b) bind and sequester PACs
(2) transform to increase inaccessibility
(2’) sequester PACs inside pores
(3) increase hydrophobicity
(3’) block pores by oil/lipid/bacteria
(4) increase stabilization by interaction
with mineral surfaces
(5) Transform into highly recalcitrant
matter
PhD Studentship REMTEC presentation
10/09 - 09
I. Concept & hypothesis
•add amendment
•bind and sequester PACs
SOIL
amendment
•sequester PACs inside pores
bacteria
•Decrease chemical activity and
mobility of PACs in soil.
•Increase PACs concentration
on amendment. Chemical
activity on amendment?
•growth of PACs degrader
Fungi
bacteria increase on
amendment loaded with PACs
•PACs degrader fungi hyphae
grow into pores of amendment
PACs
bacteria and fungi can reach PACs
•Decrease total concentration
of PACs
PhD Studentship REMTEC presentation
10/09 - 09
II. Experimental Approach
First Experiment - Screening of soil amendments:
We study the sequestration capacities of amendment. The purpose
of this experiment is to screen and to select different amendments
for the future experiments.
Mass balance study:
measure PAC trapped
amendment
to
amendment
and
not
trapped
to
simple system:
cyclodextrin solution (140 mg L-1)
14C labeled single PAC
specific C-amendment
Soil amendments :
PACs :
• Biochar
• Compost
• Anthracene
• Phenanthridine
• Activated carbon
• Artificial humus
• Fluoranthene
• Pyrene
• Charcoal
• Phenanthrene
PhD Studentship REMTEC presentation
10/09 - 09
III. General Method
step 2
Filter each vials
Measure 14C in the
solution
Shake vials for 0, 2,
6, 12, 24, 48, 72,
and 144h at room
temperature
Measure 14C on the
filter (amendment)
step 3
0
24
48
72
144
step 1
Add amendment
with cyclodextrin
solution
Evaporation of
methanol solution
Calculation of mass balance
estimate PACs sequestration
capacity of amendment
Loading vials with 14C
labeled PAC methanol
solution
PhD Studentship REMTEC presentation
10/09 - 09
V. Future Prospect
2nd experiment:
Screening of soil amendments with bacteria. Repetition of first
experiment with bacteria and/or fungi
3th experiment:
Studying interaction among a few selected amendments with
effects on chemical activity and indigenous bacteria extracted from
soil.
4th experiment:
“fungal highway”: study capacity of hyphae to improve bacterial
biodegradation of inaccessible PAC sequester into pores of
amendment.
PhD Studentship REMTEC presentation
10/09 - 09
IV. PhD Project Description
QUESTION ?
PhD Studentship REMTEC presentation
10/09 - 09
The End
Thank you for your
attention
PhD Studentship REMTEC presentation
10/09 - 09