We’ve Polluted the Oceans With Mercury for Centuries. Could Genetic Engineering Be the Solution?

Volcanic eruptions, oil burning, waste incineration, chemical production, and gold mining all share one thing: They release mercury into the environment. This toxic element ends up in the water, where millions of microorganisms convert it into methylmercury. It then moves up the food chain, eventually reaching our homes at mealtime.

The problem with methylmercury is clear, but solving it isn’t easy. Now, researchers are looking elsewhere for answers.

What’s methylmercury? Mercury is a global concern due to its persistence in the environment, its ability to bioaccumulate, and its serious health risks. But methylmercury, the most common organic form in marine environments, is the worst of all.

This wouldn’t be a crisis if methylmercury weren’t known for its “strongest toxicity to humans, showing a high rate of human residues.”

How dangerous is it? At high doses, methylmercury is extremely toxic to the central nervous system, particularly to the developing brain of fetuses and young children. A high blood mercury concentration in pregnant women “may cause irreversible damage to children, including developmental disorders.”

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Previous measures. In 2013, governments worldwide adopted the Minamata Convention to control “anthropogenic releases of mercury and other mercury-derived compounds.” Over the past decade, stricter global criteria have been introduced for foods at risk of mercury exposure.

But controlling mercury pollution isn’t easy, and for now, the best option is to minimize risks.

A bold new solution. With this challenge in mind, Australian scientists believe they’ve found a groundbreaking way to clean up methylmercury. A research team from Macquarie University and Australia’s CSIRO has genetically modified fruit flies and zebrafish to convert methylmercury into a much less harmful gas that disperses into the air.

The team altered these animals’ DNA to insert bacterial gene variants that produce two enzymes capable of transforming methylmercury into elemental mercury. Essentially, they deactivate it. While it doesn’t become completely harmless, its toxicity and ability to accumulate in living organisms are significantly reduced.

Too good to be true? “It still seems like magic to me that we can use synthetic biology to convert the most environmentally harmful form of mercury and evaporate it out of an animal,” Kate Tepper, a synthetic biologist and lead author of the study, said. Indeed, it almost sounds like science fiction.

This research is still in its early stages, and many questions remain. The approach is promising—yet also risky and ethically complex. The bigger question is: Are we willing to go that far?

Image | Harris Vo (Unsplash)

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