Tackling Mercury Pollution with Marine Bacteria

Mercury pollution is a critical problem worldwide, with large socio-economic, environmental and health impacts. The toxic effects of mercury are significant at all ages, but children are particularly sensitive to this toxin.

Despite the drastic reduction of mercury emissions in recent years, the concentration of this element in marine fish from different European seas has not been significantly reduced.

The EU-funded MER-CLUB project has contributed to tackling mercury pollution in waters, making major progress towards achieving a mercury clean-up system based on marine bacteria, which can be used to clean up pollution in a process called bioremediation.

Coordinated by Azti (a Spanish Marine Research Centre) and funded under the European Maritime and Fisheries Fund (EMFF, now EMFAF), the project involved universities and research centres from Spain, France, Sweden and Germany, and a Spanish company specialised in waste management and soil decontamination.

"Reducing mercury levels in sediments through bioremediation is the basis to restore polluted environments. The mercury decontamination of marine ecosystems will, undoubtedly, have a direct and positive impact on human health”, ensures Dr. Andrea G. Bravo, young researcher of MER-CLUB.

Testing a thousand bacterial strains

Marine microorganisms hold the genetic potential for mercury detoxification. MER-CLUB partners used advanced isolation methods for obtaining more than 1,000 bacterial strains from highly polluted European sediment samples in the Baltic, Mediterranean and the Atlantic Ocean. 

They identified marine bacteria with high potential for mercury bioremediation using molecular markers and tested the capability of the most promising candidates to reduce mercury in the laboratory. This established the basis for future development of a mercury clean-up system able to operate in dredged marine sediments.

The enormous complexity of marine sediments has proven challenging, but..

The enormous complexity of marine sediments at both chemical and biological levels has been a major obstacle to obtain a successful bioremediation solution during the lifetime of the project. Partners have worked on alternative solutions, such as using microbial consortia and deepening the analysis of the chemical species associated with mercury sediments.

… the challenge was accepted and overcome!

MER-CLUB overcame the challenges, providing novel scientific knowledge on the microorganisms transforming mercury in complex marine sediments, including those with a previously unrecognised role in mercury demethylation and reduction. 

The project has also provided technical advances towards the design of a pilot-scale mercury bioremediation plant for ex situ decontamination of sediments.

The pilot plant performance still needs to be optimised before assessing its technology readiness level for its commercialisation.  Nonetheless, the pilot plan constitutes a crucial advance establishing the basis for a viable clean-up solution.

By tackling water pollution through innovations like bioremediation, we can work towards ensuring that our fresh and marine water ecosystems are toxin free, thus helping to ensure a healthy environment, functioning water cycle, and a thriving #WaterWiseEU.

#WaterWiseEU campaign 

This story has been submitted by a partner of the #WaterWiseEU campaign. The EU-wide campaign focuses on water resilience, aiming to change the way we see, use and value water. Find out more about the campaign and how you can get involved.