Water pollution is one of the biggest concerns as a potential hazard for the environment and consequently for human health. Contaminants of emerging concern (CECs) are increasingly being shown to occur in water samples across the world, present at ng/L to μg/L concentrations, and their risks require further investigation. The breadth of such compounds is increasing and therefore there is a constant need for reliable analytical methods for identification and their determination in order to detect them due to their presence at low levels. Limited previous studies have explored the spatial occurrence and relative distribution of pharmaceutical residues in the Irish environment and demonstrated their presence, however, Irish studies evaluating more comprehensively these pollutants and matrices are required. In this study a broad range of CECs including pharmaceuticals, pesticides, and personal care products were detected, monitored and risk assessed in the environment from a rural and an urban influenced area in Ireland for surface waters and wastewater samples (both influent and effluent). Quantitative analysis has been carried out for target compounds; this will allow contaminants which are not efficiently removed during treatment to be highlighted and provide critical information for tools to evaluate their potential risks to human health. Occurrence frequency was established and interpreted to inform prioritisation of these compounds. This will support wastewater treatment plants to develop and optimise strategies for the efficient removal of identified CECs and to minimise the potential risk posed by them. Additionally, an international case study has been carried out comparing occurrence in Irish, UK and Spanish rivers. The monitoring data collected is used to demonstrate the application of a decision support system for monitoring these pollutants as a risk assessment tool for Irish water catchments. This research provides comprehensive insight into the occurrence, fate and impact of CECs in Irish waters.