You are here

Harmful Algal Blooms: Workshop Explores how Nuclear Techniques can Reduce Toxicity, Prevent Health Impact


IAEA researchers taking samples for toxin analysis using the Receptor Binding Assay technique. (Photo: IAEA)

Monaco – At a workshop organized by the IAEA and its partners last month, 60 scientists from over 30 countries learned how nuclear techniques can be used to combat biotoxins from harmful algal blooms.

Microscopic algae at the base of the marine food chain provide nutrients for marine organisms and are responsible for producing more than half of the earth’s oxygen supply. However, factors such as the natural movement of water towards the surface and the accumulation of agricultural run-off into the sea can increase nutrient levels in coastal waters and trigger algal blooms, which can sometimes include toxic species.  

Each year, these harmful algal blooms (HABs) are responsible for the poisoning of thousands of people worldwide due to the consumption of contaminated seafood and the inhalation of toxins in the air. “Faced with the apparent increase in frequency, geographical distribution and intensity of such blooms, addressing them on a global scale has become urgent,” said Marie-Yasmine Dechraoui Bottein, a research scientist at the IAEA Environment Laboratories in Monaco.

Although strategies to control the impact of planktonic toxic HABs, which float in the water, are well-defined, there remain gaps in the scientific understanding of those on the ocean floor, known as benthic species. Environmental changes linked to climate change could make matters worse, as dead coral reefs constitute good habitats for macroalgae, said Clemence Gatti, a research scientist at the Louis Malardé Institute in French Polynesia, and a speaker at the meeting. With the increasing number of corals dying, a proliferation in benthic harmful algal blooms and associated health risks are likely.

One of the most common illnesses is ciguatera fish poisoning — a non-bacterial seafood intoxication caused by ingesting fish that has been contaminated by ciguatera toxin that comes from benthic harmful algal blooms.

“It is a complex disease still poorly understood,” Gatti said. “It can express itself through 175 different symptoms that can last for months or even decades, which makes its diagnosis and management a challenge for physicians.” She highlighted the threat that ciguatera poses to populations, adding that some people may have 10 to 15 ciguatera poisonings in their life. Some fish such as red snapper can remain toxic for up to 30 months.

Scientists from Morocco and Tunisia are learning how to use the Receptor Binding Assay to quantify the amount of toxins in seawater. (Photo: IAEA)

The IAEA is working with scientists from around the world to develop capacity to accurately detect toxins in the environment and seafood, so that they can implement countermeasures such as fishery closures and bans on eating seafood when there is an elevated risk of poisoning (see The Science box).

Angelika Tritscher, coordinator in the Department of Food Safety and Zoonoses at the World Health Organization (WHO) stressed that “the impact of foodborne illnesses is of the same magnitude of illnesses like malaria and tuberculosis”. She added that “more work is needed to gather data and develop methodologies so states can address this issue”.

The IAEA will continue working with other United Nations agencies to address the emerging risks caused by HABs. This will include continued training on toxic species identification, sampling strategies and the quantification of toxins in the environment and in seafood. “A better assessment of risks associated with HABs will help reduce their impact on human health, the economy and society at large,” said Dechraoui Bottein. “This will contribute to the achievement of the sustainable development goals.”

Sixty scientists from over 30 countries came to Monaco in April 2018 to learn how nuclear techniques can be used to accurately detect toxins in the marine environment and seafood. (Photo: C. Fruneau)

The workshop was organized by the IAEA and RAMOGE – an agreement between France, Italy and Monaco to address pollution in the marine environment – in partnership with the Scientific Committee on Oceanic Research and the Intergovernmental Oceanographic Commission of UNESCO (IOC-SCOR Global HAB) and the United States’ National Oceanic and Atmospheric Administration (NOAA). Participants came from both developed and developing countries from a wide range of regions: Latin America and the Caribbean, Asia and the Pacific, Africa and Europe, as well the Food and Agriculture Organization (FAO), the United Nations Educational, Scientific and Cultural Organization (UNESCO) and the WHO. The workshop took place 9-13 April.

Stay in touch