The EU Water Framework Directive (WFD) (2000/60/EC) was transposed into Irish law in 2003 as the European Communities (Water Policy) The level of priority substances present in water bodies is most commonly judged against set environmental quality standards (EQSs) . These standards dictate the maximum allowable concentrations (MAC EQS) or range of concentrations (Annual Average or AA EQS) of specific pollutants allowed to ensure compliance with the EC guidelines. The EU WFD was transposed into Irish Law in 2003 and as such these EQS values now form the basis of priority substance water monitoring in Ireland.