Mercury is a global issue with local implication in Finland
Harmful compounds are continuously released to the environment by human activities. Mercury is one of them
and
according to the World Health Organization it is one of the 10 chemicals of major public health concern.
Mercury sources are primarily coal combustion, industrial use, mining and waste incineration
(USGS, 2019). The emissions travel long distances and mercury remains in nature for an extremely long
time (USGS,
2019, Marnane,
2018).
As mercury pollution is a global problem, mercury and its most toxic form methylmercury also cause local
issues. Finland is a land of many marshlands and lakes. These marshlands have been drained overtime to be
used
for agriculture and forestry. As the result of the ditching process the dangerous methylmercury that has
bioaccumulated to the biomass for centuries, is released to nearby water bodies in the runoff water and then
the Baltic Sea.
Why is mercury toxic?
Mercury is a toxic heavy metal that damages lungs, kidneys, skin and eyes. It causes individuals to have
weakened immune system, problems with their digestive system and damaged nervous system. It also harms
the
development of young children and fetuses.
(Mercury and Health. World
Health Organization. 2017)
Mercury can be found naturally from the atmosphere, bodies of water and soil. The most toxic form of
mercury
is methylmercury. It binds into organic substances and enriches in the food chains. Methylmercury has a
harmful impact on behavioral, neurological and reproductive functions in animals. (Burbacher et al., 1987-1988. &
Newland et al., 2006.) Humans get exposed to
methylmercury most often by consuming large predator fish and crustaceans that have high concentrations
of
methylmercury.
Numbers about mercury
Weekly tolerable intake of methylmercury is 1.3 μg/kg - The European Food Safety Authority (EFSA)
"Almost all people in the world have at least trace amounts of methylmercury in their tissues, reflecting its pervasive presence in the environment.” - United States Environmental Protection Agency
Developing children and youth and fertile women should eat large fish only 1 or 2 times a month - Finnish Food Authority
Current solutions
The current solution to remove mercury from water is to filter it. There are various methods to filter mercury such as reverse osmosis filters and water distillers which both require a lot of energy (aquagear, 2021).. Chemical methods use chemical substances such as ferric salts or sulfide to produce a sludge with ionic mercury (U.S. Environmental Protection Agency Office of Superfund Remediation and Technology Innovation, 2007). This method is inexpensive but is not sustainable as chemicals are industrial products that require energy and raw materials to be produced and they create waste.
Yet, none of these solutions filter methylmercury. The bond between the ionic mercury and the methyl molecule has to be broken in order to collect the mercury. We need a sustainable, inexpensive and efficient solution to purify toxic methylmercury from our contaminated waters.
To battle this challenge, we have come up with a practically free-of-charge -solution that is also a carbon sink!
As our host organism, we use photoautotrophic microorganisms called cyanobacteria. These microbes use only light and carbon dioxide to function, which makes our solution sustainable and scalable.
Let us introduce our solution
In our solution, MercuLess, water is purified from methylmercury pollution with the means of synthetic biology.
We break the bond between the methyl group and the mercury with a MerA protein.
Then using a MerB protein, the remaining ionic mercury is transformed into less toxic elemental mercury,
which can be collected from the bioreactor and then upcycled for new appliances.
Cyanobacteria
As these photoautotrophic bacteria use only light as their energy and carbon dioxide as their source of
carbon
to function, they hold endless possibilities for sustainable solutions in all sectors of industry. For
industrial scale use, there are still multiple technical details to be solved.
Nevertheless the strength of the cyanobacteria is that no biological carbon sources or energy have to be
added, which offers economic
scalability. Neither complex mediums are needed as they naturally can grow in both saline or freshwater.
Finally cyanobacteria are carbon sinks therefore contributing in the fight against climate change.
Our Goals
Our goal is to purify natural and processed waters from methylmercury pollution by using genetically modified cyanobacteria. Removing methylmercury from these waters will support ecological balances, enable the safe use of fish and provide clean habitats, while upcycling mercury. Our solution would be perfect to restore contaminated bodies of water or to purify industrial sewage. This means that various groups of people from industrial companies to nature conservationist organizations and individual forest owners may use MercuLess and make our water safer.
Clean Habitats
Animals, wildlife and humans, suffer from mercury. Methylmercury accumulates to various tissues and interferes with the metabolic activities causing necrosis and degeneration in them
Ecological balances
The wellbeing and safety of organisms has a direct influence on entire ecosystems: every organism has its own role and harming just one can have major effects on the whole system. Also by protecting ecosystems we preserve biodiversity.
Safe use of fish
We know that the future holds threats to food security therefore it’s important to ensure that our waters are clean from mercury so that we can use fish and other seafoods safely.