Storm runoff can be toxic to aquatic life, but a new study suggests a simple solution: Filter the water through dirt.

Researchers collected runoff from a busy four-lane highway in Seattle during six storms in 2011 and 2012. They tested the toxicity of water from the first five storms and found that coho salmon fry could not survive in it, nor could the mayfly and water flea larvae they feed on.

Then they collected water from the sixth storm. The samples were also highly toxic to the insects, and all of the fish were dead within 12 hours of exposure. But in samples run through the dirt filters, the salmon and the insects flourished. In some of the filters, the researchers included plants as well. As it turned out, the soil mix alone was so effective that plants provided no additional protection. The study was published online in the journal Chemosphere.

Soon, a new look at mysterious Pluto

After traveling nine years across more than 3 billion miles of space, a spacecraft the size of a grand piano is about to give humanity its first high-resolution view of Pluto.

Nobody knows what the rendezvous will reveal. Pluto’s icy surface may resemble an extreme version of Antarctica, with snow-capped mountains, steep crevasses and towering ice cliffs. The dwarf planet could be surrounded by rings of tiny ice particles, like its giant neighbor Neptune. There may even be evidence that once, long ago, there was an ocean beneath the frozen crust of its largest moon, Charon.

Sunday, the spacecraft’s long-range cameras began snapping pictures of Pluto and its moons against a backdrop of stars. More data will be collected during the months leading up to the mission’s big moment this summer: A close approach on July 14.

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