The project involved a combination of laboratory, semi- field and field studies which assessed the degradability and leachability of six pesticides that would normally be applied to a winter cereal crop. Two biobed systems were investigated, a lined system (with butyl liner) and an unlined system (without butyl liner). Studies indicated that biobeds can adsorb high concentrations of pesticide and subsequently degrade them. Whilst a proportion of the applied pesticide may leach (less than 0.2%), the amounts leached are likely to be small and similar to leachate from currently available systems (eg Sentinel). Field and semi-field studies showed that the ‘lined’ biobed system is prone to water-logging. The management of water is, therefore, an important factor in the working of the biobed and the current design for a ‘lined’ system is inadequate for the high volumes of waste generated on UK farms. Further studies are required to refine the current design and test it at the pilot stage.