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| The kind of news that makes guys automatically do this |
Common ingredients in the cleaning sprays for your kitchen and bathroom make mice less fertile, suggesting the compounds could do the same to humans, according to a new study.
Health
researchers are concerned about specific chemicals used in cleaners—including
popular brands like Lysol, Clorox and Simple Green—called quaternary ammonium
compounds, used to kill microorganisms.
Recent laboratory work from Virginia
Tech University scientists found that when mice are exposed, both males and
females have some unsettling impacts, such as weaker sperm and decreased
ovulation.
Industry
representatives have pushed back on the research, saying federal agencies deem
the chemicals safe and that mice were exposed to unrealistically high levels.
The study, published in Reproductive Toxicology, comes as U.S. infertility rates appear to be rising. A growing body of evidence suggests that environmental chemicals are playing a role.
“When
we see effects in mice we should be concerned about effects in humans,” said
Tracey Woodruff, a professor at the University of California, San Francisco,
who specializes in reproductive health and the environment.
Even
if you don’t clean, you might be at risk of exposure. Quaternary ammonium
compounds are also used in algae-killing swimming pool chemicals, lumber
treatments, anti-static laundry products and some cosmetics.
In
the study, researchers exposed male and female mice to two common types of the
compounds—alkyl dimethyl benzyl ammonium chloride and didecyl dimethyl ammonium
chloride—through their water. Exposed female mice had reduced ovulation and
spent less time in “heat”, when they’re most fertile.
Exposed
male mice had less concentrated sperm. Also their sperm was less effective at
moving through female mice to fertilize eggs.
Terry
Hrubec, senior author of the study and associate professor of anatomy and
embryology at Virginia Tech University, last year
reported that mice exposed to these compounds took longer to
get pregnant, had fewer pregnancies and gave birth to smaller litters. The
current study aimed to tease out gender-specific problems identified in that
earlier research.
The
compounds are very effective at keeping houses, hospitals, restaurants and
other industries free of microbes and other contamination and are widely used.
There
aren’t any human studies monitoring exposure, but the chemicals’ ubiquity has
“likely resulted in widespread human exposure,” Hrubec and colleagues wrote in
the current study.
“You’re
going to get populations with higher exposures … men and women working in
janitorial services, or for cleaning companies,” Woodruff said.
Paul
DeLeo, associate vice president, environmental safety at the American Cleaning
Institute, which represents cleaning product manufacturers, said the study
raises “unjust concerns.”
He
pointed out that both the U.S. Environmental Protection Agency and the Food and
Drug Administration have tested the chemicals and deemed them safe.
“The
researchers also overdosed the mice tested in their study with levels of the
ingredient at a rate hundreds of times greater than what would be consider a
safe use level (based on EPA standards),” DeLeo said in an email.
A
task force representing the Consumer Specialty Product Association echoed
DeLeo's criticism, adding that the study’s conclusions “ignore 'real world'
experience and scientific scrutiny over more than 30 years,” in an email.
Some
of the mice were dosed at very high levels, Hrubec acknowledged. But male mice
given low doses still had reproductive problems, she said.
In
addition, some male mice weren’t dosed at all but rather lived in a cage and
room where the compounds were used to clean cages and floors and still had
impacted sperm, she said.
Proper
functioning hormones are vital for reproduction, and much research recently has
focused on endocrine disrupting chemicals, which mimic and alter hormones.
It
is too early to speculate why these cleaning chemicals are causing problems for
the mice, Hrubec said.
But
some of the impacts—such as the reduction in number of “heat” cycles for the
females—are “hormonally driven,” raising suspicion of endocrine disruption, she
said.
There
are many potential causes for infertility, and tracing population trends can be
problematic. However, as Hrubec notes in the study, from 2001 to 2010 the
artificial insemination rate in the U.S. increased 37
percent.
Meanwhile
sperm counts across the world have significantly decreased over
the past 70 years.
Dr.
Jeanne Conry, an obstetrician and past president of the American Congress of
Obstetricians and Gynecologists, said most physicians do not understand how
little research is done on chemicals prior to being released into the
environment. These studies, she said, should be taken into account.
“We
walk a fine line between being alarming and being aware,” Conry said. "I
tell women eat healthy, live a healthy lifestyle and keep your cleaning as
simple as possible, maybe use something like vinegar and water.”