It might seem like a counterproductive tactic at first blush, but environmental activists in France have poured a bright green colored substance into rivers throughout the country to raise awareness about water pollution, reports Le Local.

Rivers in at least 12 regions of France have been flowing with toxic-looking fluorescent green water, an effect caused by a colorant called fluorescein. The color is so striking it almost looks radioactive.

“We used a colorant called fluorescein that’s totally harmless,” said Yannick Pognart, an activist involved in the stunt. “It’s to show the path pollution takes in the water. It’s a strong visual, but it’s completely safe. The fish don’t even notice.”

It's true that fluorescein is nontoxic; it's an organic compound often used by researchers to trace the flow of water, and it even has applications in the field of biomedicine. But it's never used in such large quantities. Transforming the color and opaqueness of whole river systems probably has some effect on marine life, even if it's not toxic — though this aspect of the stunt may have been overlooked by activists. The good news is, rivers didn't take long to return to their normal color.

Aside from showing just how rapidly pollution can spread through an entire river system from just a small spill, the action also intends to highlight shrinking funds in France for certain environmental services.

"You can't say ecology is the priority of the country when we see that our resources are down 10 percent," said French environmental worker Patrick Chopin. "We want to alert the public about the need to preserve and strengthen this public service."

The event also coincides with France's domestic environment conferences, which started this same week in Paris.

At the very least, it's an eye-catching stunt with a visual that's hard to ignore. Most pollutants are invisible to the eye, so they often go unnoticed as they disperse throughout a river. It's a reminder that we must remain vigilant about keeping our waterways clean.