Improved water quality monitoring techniques based on biosensor, optical, microfluidic and information technologies are leading to radical changes in our ability to perceive, understand and manage the aquatic environment. There is a need for real-time environmental monitoring systems to implement and verify compliance with health and environmental legislation. To do this it is necessary to monitor a many different chemicals and toxins with simple and cost-effective techniques. Biosensor and microfluidics based systems could potentially detect and monitor all these contaminants. Current research is leading to solutions to problems that were previously irresolvable due to their high degree of complexity.