Download SHE-Net Soil Health Environment Network

SHE-Net
Soil Health Environment Network
Chris Collins – University of Reading
George Shaw – University of Nottingham
Tanja Pless-Mulloli – Newcastle University
Ian Martin – Environment Agency
David Mortimer – Food Standards Agency
Dr Raquel Duarte-Davidson – Health Protection Agency
http://www.reading.ac.uk/soilscience/Research/SHES-Net
Background
• Project funded under NERC Environment
and Health Initiative.
• Partnership of academics and regulators
• Aim ‘To improve our estimates of human
exposure to toxic organic chemicals in soil
through the consumption of home grown
and allotment produce and consequently
improve the protection of public health.’
Workshops
1) Transfer of organic pollutants from soil to
plants (University of Reading, 26-27,
September, 2007)
2) Human health and organic pollutants
(Newcastle University, 29-30th January)
3) Risk assessment procedures for
contaminated soils and the foodchain.
(University of Nottingham, 2-3rd July, 2008)
Workshop 1 - Questions
• Important processes in the transfer of organic
pollutants from soils to plants.
– How good do models have to be?
– Do we need to focus on a particular set of
chemicals?
– Which are the critical pathways?
– Can crops be placed into groups? e.g. all
herbaceous crops together.
– How do we address data variability?
Workshop 1 - Outcomes
• Initially regulators need to know if there is a
potential risk or not. A simple screening model
may be enough at the stage.
• One order of magnitude was deemed a
reasonable margin of error for a model; although
two orders of magnitude maybe useful because
of the high uncertainty associated with some
plant processes.
Workshop 1 - Outcomes
• The modelling approach needs to be able to address the
whole suite of organic pollutants. Some ionisable
compounds such as the perfluorooctane sulponates may
need further experimentation.
• Uptake processes should be modelled dynamically, but
steady state solutions maybe reasonable.
• One core model with crop groups would be the most
efficient.
• A screening matrix was developed at the workshop to
determine which chemicals would be transferred by
which transport processes and hence to what plant
organ.
Workshop 1 – Outcomes
• Metabolism is known to occur in a number of cases,
but there is insufficient data to include this in a
model. Modelling will be conservative for those
compounds where metabolism does occur.
• Data variability encountered across experiments
was a considerable problem. Guidelines are
required.
• Screening matrix produced which will allow
regulators to quickly establish potential risk to
human health via crop ingestion.
• Clear pointers for future modelling.