New soil remediation strategies New soil remediation strategies targeted at reduction of PACs targeted at reduction of PACs contaminant exposure and contaminant exposure and

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National Environmental Research Institute

Aarhus University

Geoffrey Marchal

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.

I. Concept & hypothesis

PhD Studentship REMTEC presentation 10/09 - 09

Two and three ring PAC are weakly bound to soil particles and 4-7 ring PAC are strongly bound to organic soil particles.

Phenanthridine Benz[a]anthracene FluorantheneFluoranthene

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).

BIOSTABILISATIONBIOSTABILISATION

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

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

PhD Studentship REMTEC presentation 10/09 - 09

Soils amendments:

I. Concept & hypothesis

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.

I. Concept & hypothesis

(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

TOPSOIL

I. Concept & hypothesis

SOIL amendment

PACs

bacteria

Fungi

bacteria and fungi can reach PACs

PhD Studentship REMTEC presentation 10/09 - 09

•add amendment

•bind and sequester PACs

•sequester PACs inside pores

•Decrease chemical activity and mobility of PACs in soil.

•Increase PACs concentration on amendment. Chemical activity on amendment?

•growth of PACs degrader bacteria increase on amendment loaded with PACs

•PACs degrader fungi hyphae grow into pores of amendment

•Decrease total concentration of PACs

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 to amendment and not trapped to amendment

simple system:cyclodextrin solution (140 mg L-1)14C labeled single PACspecific C-amendment

PhD Studentship REMTEC presentation 10/09 - 09

Soil amendments :

• Biochar

• Activated carbon

• Charcoal

• Compost

• Artificial humus

PACs :

• Anthracene

• Fluoranthene

• Phenanthrene

• Phenanthridine

• Pyrene

step 3

step 1

step 2

III. General Method

PhD Studentship REMTEC presentation 10/09 - 09

Loading vials with 14C labeled PAC methanol solution

Evaporation of methanol solution

Add amendment with cyclodextrin solution

Shake vials for 0, 2, 6, 12, 24, 48, 72, and 144h at room temperature

Filter each vials

Measure 14C in the solution

Measure 14C on the filter (amendment)

Calculation of mass balance

estimate PACs sequestration capacity of amendment

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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 ?QUESTION ?

PhD Studentship REMTEC presentation 10/09 - 09

The End The End

Thank you for your Thank you for your attentionattention

PhD Studentship REMTEC presentation 10/09 - 09