Swimmers volunteer their summer to help assess the chemical content of the oceans

Since the ocean is the final receptacle of continental water and its pollution, people immersed in it may risk exposure to cocktails of chemical micro-pollutants which are hazardous to their health
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For the second year in a row, volunteers working with the Surfrider organization are devoting their summer to a special mission: measuring the chemical content of their swimming areas using a sampling kit that gets immersed in the water. The samples will then be sent to a laboratory to evaluate the impact of exposure to chemical pollutants present in seas and oceans on the health of swimmers.

If you're strolling along the beaches of France's Atlantic or Mediterranean coasts, don't be surprised if you come across water sports aficionados with a strange object hanging from their ankle. No, it's not a leash, but rather a sensor designed to be immersed in water to measure its chemical content. And the experiment is quite serious, since it is piloted by the non-profit organization for the protection and quality of water, Surfrider Foundation Europe.

"Since the ocean is the final receptacle of continental water and its pollution, people immersed in it may risk exposure to cocktails of chemical micro-pollutants which are hazardous to their health," outline researchers from the University of Bordeaux in regards to the project. However to date studies haven't shown the effects on humans. Which was the motivation behind the CURL research project, which was launched several months ago as a collaboration between the team from the EPOC lab (CNRS/Université de Bordeaux), the NGO Surfrider Foundation Europe and oceanographic research institute Ifremer.

The aim of the study is to get a precise idea of the health consequences for users exposed to chemical pollutants in the seas and oceans. The first experimental phase is taking place (for the second consecutive year) from June to October. The kits used by the volunteers, who have committed to go in the water regularly during this period, have been designed by Ifremer and CNRS laboratory in Bordeaux and have been used for years to detect chemical pollutants in rivers or oceans.

Surfrider had the idea of adapting them for volunteers, who only have to tie them around their ankles each time they go for a dip. "These passive sensors work a bit like sponges. The more they are immersed in water, the more they will store pollutants, such as fertilizers, hydrocarbons, and drug residue," explains Clément Moreno, in charge of the Participative Sciences mission at Surfrider Foundation Europe.

"We can no longer dissociate the health aspect from the environmental aspect"

Each sensor needs to be exposed for about 100 hours. About 30 volunteers divided into small groups (3 to 15 people) share a dozen sensors and relay them on to one another, noting each time the location (the ideal being to change each time over an area of about 50 km) and the duration of swimming. In the meantime, the sensors are kept in a cool place. At the end of the summer, the samples will then be analyzed by the CURL project partner laboratories.

"At the same time, we are going to continue the sampling on other coastlines, with more kits. Once the first results are obtained, the next step will be to look at the health impact, in particular with professionals in ecotoxicology, and then to work at the local level to identify more precisely the sources of pollution and try to find solutions," says Clément Moreno. Before adding: "going through the health angle makes it easier to bring people into the project, since they are directly affected."  

In the long term, the association hopes to build awareness among policy-making authorities, advocating a monitoring of water quality that would take into account ecotoxicological criteria. "Currently, the quality control of coastal waters is limited to bacteriological monitoring in bathing areas and during the summer season. But surfers and other sportsmen are likely to swim farther away and at other times of the year, and therefore not be exposed to the same contaminants. We want to encourage assessment of these additional parameters, across larger areas and throughout the year. We can no longer dissociate the health aspect from the environmental aspect," says Clément Moreno.