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

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, th January) 3) Risk assessment procedures for contaminated soils and the foodchain. (University of Nottingham, 2-3 rd 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.