This book documents the outcome of the EU-funded research project 'LIBERATION', aimed at the development of a decision support system (DSS) for sustainable management of contaminated land with special focus on organic contaminants. The book is geared to providing guidance to risk assessors and stakeholders of contaminated land in their decision-making process. The DSS, which follows a stepwise approach, is divided into three different stages: - Stage I: Site characterisation and description of land use; - Stage II: Determination of ecological aspects and - Stage III: Site-specific assessment (The Triad) consisting of four tiers: 1. Simple screening; 2. Refined screening; 3. Detailed assessment and 4. Final assessment. Each of the tiers is based on a weight of evidence approach combining three lines of evidence (LoEs), Chemistry, Toxicology and Ecology. The book also contains useful lists of techniques and tools dedicated to each tier within the three LoEs. In this book it is shown how measures of bioavailability are systematically incorporated into a framework for ecological risk assessment of contaminated soil. However, most techniques for assessing bioavailability are relatively novel and hence not yet fully validated; the challenge to fully understand the underlying processes controlling bioavailability is still immense. Nevertheless, this book will hopefully generate a discussion, encourage further development of tools and, most important of all, promote more practical experience in site-specific evaluation of ecological risk.