Cleaning up the past to enable the future – lower carbon, more accurate approaches to redevelopment

LIMITLESS POTENTIAL | LIMITLESS OPPORTUNITIES | LIMITLESS IMPACT LIMITLESS POTENTIAL | LIMITLESS OPPORTUNITIES | LIMITLESS IMPACT LIMITLESS POTENTIAL | LIMITLESS OPPORTUNITIES | LIMITLESS IMPACT Copyright University of Reading

CLEANING UP THE PAST TO ENABLE THE FUTURE – LOWER CARBON, MORE ACCURATE APPROACHES TO REDEVELOPMENT

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Stephen Lowe – University of Reading/ British Geological Survey

Under the supervision of Chris Collins and Tom Sizmur (University of Reading); Chris Vane and Mark Cave (British Geological Survey)

Ecobuild 2017

LIMITLESS POTENTIAL | LIMITLESS OPPORTUNITIES | LIMITLESS IMPACT

CONTEXT •  Pressure to build new homes. Can we do this sustainably? •  Protection of greenspace is key, but may lose out.

•  Is there a better way? What about contaminated sites? 2


LEGACY ORGANIC CONTAMINANTS •  Accidental release, use, dispersion, accumulation in soil and biota

•  PAHs (polycyclic aromatic hydrocarbons) •  PCBs (polychlorinated biphenyls)

•  Ingestion of soil material. Significant pathway.

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Elevated cancer risk

Birth defects

Developmental neurotoxicity

Bioaccumulation Ubiquity

Risk – but how do we assess it?


BIOACCESSIBILITY ASSESSMENT • We can examine the path of a contaminant following ingestion

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Contaminant absorbed

Contaminant excreted

Bioaccessibility: The fraction of contaminant that is dissolved in the gastro-

intestinal tract and available for uptake

Bioavailability: The fraction of the

bioaccessible fraction that crosses the cell wall


A NEW OPPORTUNITY

Bioaccessibility presents: •  Less conservative approach.

•  Are we over-stating risk? • Greater physiological relevance.

• … and realism 5

Currently we assess organics in terms of total concentration. •  Assumes 100% soil contaminant bioavailability - over-cautious? •  Remediation expensive and energy intensive.

LIMITLESS POTENTIAL | LIMITLESS OPPORTUNITIES | LIMITLESS IMPACT 6

THE BIOACCESSIBILITY METHOD •  The FOREhST method. •  Fed state, physiologically accurate bioaccessibility method.

0.3g soil 2 hour mixing at 37°

Simulated gastric and salival fluid

Clean-up and

analysis 0.813g porridge

2 hour mixing at 37°

Simulated duodenal and bile fluid


BIOACCESSIBILITY DATA

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CONGENER VARIATIONS

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•  Significantly lower bioaccessibility in Cl 7 compounds (higher log Kow).

•  Reduction in method or sample clean up?


THE WIDER PROJECT

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1: Bioaccessibility using FOREhST

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Submission: 30th June 2017

4: Application of method with London soils

1: Bioaccessibility using FOREhST

3: London background survey 2: Comparison of methods – FOREhST vs CE-PBET

4: Application of method with London soils


THANK YOU

“The soil is the great connector of lives, the source and destination of all. It is the healer and restorer and resurrector, by which disease passes into health, age into youth, death into life. Without proper care for it we can have no community, because without proper care for it we can have no life.” ― Wendell Berry, The Unsettling of America: Culture and Agriculture

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Science

Cleaning up the past to enable the future – lower carbon, more accurate approaches to redevelopment