University of Dundee

Influencing water safety policy to reduce the risk of blue-green algal toxins

Scientists at the University of Dundee applied their knowledge to inform worldwide health agencies, and governmental and regulatory policy on cyanotoxins, among the most hazardous natural poisons in the aquatic environment.

Cyanobacteria (blue-green algae) occur globally and produce a wide range of potent toxins in such concentrations that they poison and even kill animals and humans. Some cyanobacterial toxins can cause death by respiratory failure while others target the liver and nervous system. In the late eighties/early nineties, documented effects on human and animal health following exposure to cyanobacterial blooms, including in the UK, caused increasing public concern. Suitable techniques for the analysis of cyanotoxins in recreational lakes and drinking water supplies were not available, and there were insufficient toxicological data to set health-based guidelines for cyanotoxin control.

In 1990, Professor Carol MacKintosh together with Professor Geoff Codd FRSE uncovered the biochemical mechanism of action of the microcystins, a family of potent hepatotoxins produced by cyanobacteria. These toxins act by binding irreversibly to essential enzymes named protein phosphatases. This work led to microcystins becoming valuable research reagents for studying the roles of protein phosphatases in health and disease.

Moreover, their biochemical insights enabled the Dundee teams to develop new detection methods for the toxins and to explain their wider health risks. Advice provided by Professor MacKintosh resulted in new analytical methods being applied to maintain drinking water safety during a period of cyanobacterial  blooming in reservoirs in the Thames area. A key report made by Professor Codd with medical colleagues established that the death of 60 patients in a haemodialysis unit in Caruaru, north-east Brazil, could be attributed to exposure to highly toxic microcystins in the water supply from a lake with a massive growth of cyanobacteria.

This research has had a major impact on the recognition, toxicity-assessment and risk-management of cyanobacterial blooms and cyanotoxins in waterbodies worldwide. Professor Codd has been involved in the safety assessment and protection of numerous waterbodies affected by cyanobacteria throughout the British Isles beyond and has played a major role in preparing World Health Organisation guidelines on the public health consequences, monitoring and management of toxic cyanobacteria in water. These guidelines represent the current position of ‘UN Water’, the body that coordinates programmes concerned with water issues amongst the 24 United Nation agencies. This research has provided primary guidance in the formulation and adoption of safety plans by several governmental and regulatory authorities for health protection against cyanobacterial  in human drinking water supplies, aquaculture, agriculture  and veterinary practice. Further benefits of the research include current programmes for the sharing of best practices for cyanobacterial and toxin monitoring and control throughout Europe.