Background The impact of biocidal products on the environment is significant and this has led to increased regulation in recent years. The European regulatory framework for biocides is established in the Biocidal Products Directive (98/8/EC) and the Biocidal Product Regulation, approved in 2012 (EU 528/2012). This European legislation establishes the need to carry out risk assessments for biocidal products and specifies the data required to perform them. A crucial measurement is the risk quotient, as calculated by the PEC-PNEC ratio. A biocidal product is judged to be environmentally acceptable if the Predicted No Effect Concentration (PNEC) - the concentration that causes no adverse effect to the Environment - is higher than the Predicted Environmental Concentration (PEC) - the concentration one expects to find in the environment. However, in practice it is extremely difficult for authorities to be certain of the accuracy of the data used by industry to make these risk calculations. This makes it difficult to apply the regulations effectively, resulting in delays in the full assessment of products on the market and uncertainties about the strength and rigour of environmental protection. Objectives The main objective of the LIFE BIOREG project is to improve the quality and strength of biocidal risk assessments. The project hopes to develop new methodologies that will provide precise and robust data for conducting risk assessment of biocidal products, as well as more information on the influence on risk of different parameters. It specifically aims to establish a scientifically validated methodology for the risk assessment of film preservatives (PT7) and masonry preservatives (PT10), which will be the next biocides studied and authorised under the biocidal products legislation. The project will optimise laboratory and semi-field experimental methods for determining the leaching of active ingredients from PT7 and PT10 product types, and explore the possibility of defining standardised procedures for determining leaching. It will then assess the eco-toxicity of the leachates obtained in the laboratory and semi-field studies and correlate the results with the eco-toxicological data obtained from the pure formulated product. It expects to determine the most relevant factors affecting the results and performance of leaching tests and the most important parameters for risk assessment. The methodologies and results will be published with guidelines to perform environmental risk evaluation of PT7 and PT10 products, with a view to their possible registration. It hopes to enable the regulatory authorities to establish robust biocidal risk assessment, have confidence in the resulting data and avoid unnecessary trials and delays. Expected results: A scientifically robust methodology of biocidal risk assessment for PT7 - film preservatives - and PT10 - masonry preservatives; Calculation of the eco-toxicity of the pure biocidal product, as well as of the leachates obtained and the relation between the two; Definition of the most relevant factors affecting risk assessment; Reduced delays in the delivery of risk assessments; Improved confidence in the rigour of biocidal risk assessments.