The pollution of water by chemicals and other pollutants affects all life on Earth as habitats and ecosystems are disturbed, and biodiversity is reduced. The Water Quality (Dangerous Substances) Regulations, SI 12 of 2001, prescribe water quality standards in relation to certain substances in surface waters, for example rivers, lakes and tidal waters. The Regulations give further effect to the European Union (EU) Dangerous Substances Directive (76/464/EC) and give effect to certain provisions of the EU Water Framework Directive (WFD) (2000/60/EC). In 2003 and 2004, Ireland’s National Dangerous Substances Expert Group developed lists of priority action, candidate relevant pollutant and candidate general component substances for surface waters in Irelandand designed a substances screening monitoring programme as part of the implementation of the WFD. Many knowledge gaps exist in relation to managing PSs and PHSs in Irish waters. The objective of the EPA-funded project (Monitoring Criteria for Priority Chemicals Leading to Emission Factors) was to develop a model based on emission criteria in order to assist the monitoring of PSs. This project, which started in 2008, represents an important collaboration between two research centres (Dublin City University and Cork Institute of Technology) with analytical expertise, and three councils (Fingal, Cork and Dublin Councils), building capability to establish risk factors for PSs and PHSs.