CHI-TOWN AIRBORNE COMPOUNDS: With elevated levels of cyclic siloxanes in Chicago’s air, it's possible that wildlife in the world's largest freshwater source–the Great Lakes–are contaminated with these chemicals. Image: Flickr/Steve G
On the brink of federal regulatory review, chemicals in deodorants, lotions and conditioners are showing up in Chicago’s air at levels that scientists call alarming.
The airborne compounds – cyclic siloxanes – are traveling to places as far as the Arctic, and can be toxic to aquatic life.
“These chemicals are just everywhere,” said Keri Hornbuckle, an engineering professor at the University of Iowa and senior author of a new study.
Concentrations were 10 times higher in Chicago’s air than in the air of West Branch, Iowa, and four times higher than in Cedar Rapids, Iowa.
Hornbuckle said the findings are worrisome because the compounds are ubiquitous and have been detected at much higher levels than other common environmental contaminants. "These are big concentrations and, truthfully, are concerning to me," she said.
But whether there are any risks from breathing the chemicals is unknown. There have been no studies to measure people’s exposures or investigate potential health risks.
In Chicago’s air, the most prevalent compound, known as D5, was at levels three times greater than what polychlorinated biphenyl (PCBs) typically are there. PCBs are persistent chemicals banned in the 1970s. D5 is most commonly used in soaps, lotions, shampoos and conditioners.
The compounds also are probably in high concentrations in the air of many cities, but no one has looked elsewhere yet. The United States produces or imports between 200 million and one billion pounds of cyclic siloxanes annually, according to U.S. Environmental Protection Agency estimates.
Many people rub the compounds all over their bodies every day. They are in about half of all personal care items, comprising up to two-thirds of the product’s mass in some cases, according to a 2008 study by the New York Department of Public Health and a 2009 Health Canada study. They’re used in such products because they are odorless, colorless and feel smooth.
The new study did not track where the airborne chemicals came from, but it suggests that personal care products are a major source since D5 was the dominant compound in both indoor and outdoor air samples.
Indoor air concentrations in University of Iowa labs and offices were 30 and 75 times higher than those in the outdoor air of Cedar Rapids and West Branch, and D5 made up 97 percent of mass of the indoor samples.
“It’s population based,” said Rachel Yucuis, a masters student at the University of Iowa and lead author of the new study. “And indoors you have both personal products sitting out, and what’s on people, in a concentrated space.”
At night, levels of cyclic siloxanes were about 2.7 times higher than in the daytime, which is probably due to changes in the atmosphere at night, Yucuis said.
D4 – used in polishes, detergents, sealants, adhesives and plastics -- is toxic to wildlife, according to the EPA. Previous lab studies found the compound toxic to certain species – small rainbow trout and water fleas – at concentrations that are expected in the environment.
In addition, D4 causes tumors, reproductive problems, altered organ size and acts like a weak estrogen in studies of lab animals. D5 has caused changes in the nervous systems, livers and immune systems of lab animals.
D4 and D5 are not currently regulated anywhere in the world. But the EPA announced last year that it would evaluate whether D4 should be regulated under the Toxic Substances and Control Act. However, the agency is less concerned about outdoor air concentrations than it is about the risks to water-dwelling creatures, an EPA spokesperson said in an email.