Did you know that toxic chemicals that mess up our groundwater are Highway’s Big Brother? Recent research peeks above our heads, showing that perchlorates form high up in the Earth’s atmosphere.
Perchlorates are chlorine-based chemicals that can seriously throw off your thyroid. They form on bits of smoke and organic materials, hanging out in the stratosphere from about 6 to 31 miles (10 to 50 kilometers) above the planet’s surface. This juicy revelation comes from a new study!
While scientists were always aware that perchlorates had a high-altitude birth, the exact hows and wheres were still hazy. Previous evidence pointed to the fact that these chemicals were zapped by cosmic rays out there in outer space, but the specifics had eluded experts.
The team of researchers discovered that, when going up into the stratosphere, perchlorates steer clear of sulfuric acid particles, which are usually all over the place up there. Instead, they found these nasty chemicals mostly stuck to nitrogen-rich particles or smoke particles—stuff that doesn’t often hang out that high in the atmosphere.
This leaves us wondering: Could more pollution in the stratosphere thanks to us increase the chances of perchlorates making their way back down to pollute our groundwater?
As Daniel Murphy from the NOAA Chemical Sciences Laboratory points out, we’re in the dark about whether changing the atmosphere’s particle makeup could lead to more perchlorates. He emphasizes the need for further research on this topic enough to catch our attention.
Related: A recent study suggests sprinkling diamond dust into the atmosphere could combat climate change but comes with a whopping $175 trillion price tag.
So where do we find perchlorates in the real world? They’re in explosives, batteries, airbags, and rocket fuel. Manufacturing processes might occasionally lead to groundwater contamination. Still, the majority of perchlorates out there are simply naturally occurring. Also, stay tuned for new perchlorate drinking water regulations by the EPA coming in November.
Getting into the nitty-gritty, Murphy and his colleagues stumbled upon the perchlorate formation during a bigger mission exploring stratospheric aerosol particles. They used data primarily gathered from NASA’s WB-57 aircraft—a plane that soared high at around 62,000 feet (19,000 meters). In contrast, commercial flights usually fly between 30,000 and 42,000 feet (about 9,100 to 12,800 m).
“These measurements gave us the closest look at perchlorates that we’ve ever had,” Murphy continued. “They provided insights that no one had before on their natural origins in the stratosphere.”
The research, published on July 28 in the journal PNAS, compares the perchlorates they discovered to those from rocket fuel and finds them to be distinctly different entities. This indicates that what’s cooking up there is purely a product of nature, not our spacecraft!
It’s unclear if the fact that perchlorates only cling to organic materials or smoke particles is just a quirky detail of the chemical’s nature, or if there’s a bigger pattern at play. If these particles help perchlorates form, human-caused shifts in the atmosphere could inadvertently pump them out in greater numbers, which could be concerning. After all, perchlorates can stick around for a long time—over 10,000 years in dry areas, according to 2010 research.
Murphy also mentioned that with wildfires becoming more frequent worldwide, the possibility of an uptick in those natural perchlorate sources might be something to keep an eye on.
And here’s where it gets theoretical: some geoengineering ideas have folks thinking about injecting particles into the stratosphere to reflect sunlight. But this could bring risks if those particles end up leading to perchlorate formation.
On the bright side, the research community is saving time as perchlorate has been identified on Mars. Scientists are already gearing up to probe this chemical further. “Some labs might have the tools from studying it on Mars and could pivot their focus to Earth-based impacts,” Murphy mentions. These kinds of lab studies could help determine whether human pollution exasperates perchlorate formations way up there.
