they are washed down the drain, synthetic
fragrances in soaps and shampoos are damaging the ability of aquatic
wildlife downstream to eliminate toxics from their systems, according to
a new Stanford University study published by the National Institutes of
The first study to
show that some personal care products in water have an effect, even in
low concentrations, suggests that humans may be harmed too. The
synthetic fragrances can block the ability of human cells to clear
themselves of other substances that could be much more toxic than the
exposed to synthetic musks -- chemicals used to enhance the smell of
detergents, soaps, shampoos, air fresheners, deodorants, cosmetics and
other personal care products -- cause biological damage that is long
lasting and may be irreversible, the scientists demonstrated.
"Synthetic musks can
be easily produced and are very cheap," said Stanford postdoctoral
fellow Till Luckenbach, lead author of the study. "They get into the
environment through sewers and drains, but wastewater treatment plants
are not equipped to handle them."
These chemicals are
found in aquatic environments where they are persistent and accumulate
in the organisms.
Stanford biologist David Epel tested six synthetic musk compounds used
by industry to determine if these artificial fragrances affected the
animals' "xenobiotic defense system," a biochemical process that allows
cells to get rid of poisons and other foreign substances.
"This is the first
line of defense used by all cells," said Epel, a Stanford professor of
marine sciences. "It consists of a special protein, called an efflux
transporter, that's embedded in the cell membrane and pumps out toxins
that get into the cell."
For the experiment,
described in the NIH journal "Environmental Health Perspectives," gills
were sliced from living mussels and placed in water containing very low
concentrations of synthetic musks -- 300 parts per billion or less.
After two hours, the gills were removed and washed.
To see if this short
term exposure affected the animal's defense system, the gills were
placed in musk free water with a red fluorescent dye.
Usually, an efflux
transporter will recognize the dye as a foreign substance and remove it.
But if something interferes with the transporter, the dye will
accumulate inside the cell, which causes it to appear brighter. The
researchers found that even two days after the mussel gills had been
washed clean, they could not remove the dye.
"What we found is
that musks are harmful in the sense that they compromise the defense
system and let other chemicals in that could be more harmful," Epel
said. "The amazing thing is
that, even if you wash the chemical fragrance away, there's a long term
effect up to 48 hours after removal," he said. These results
indicate that even short term events, such as chemical spills and
stormwater runoffs, could have long term effects, Luckenbach said. Human health is also
at risk, the scientists believe. "People have these same transporters in
the blood-brain barrier, the placenta and the intestines," Luckenbach
"Perhaps exposure to
chemical fragrances could compromise the transporters, making it easier
for pollutants to enter the brain, for example," he suggested.
One problem for
consumers trying to avoid synthetic fragrances is that only the word
"fragrance" appears on the label as a rule. The actual chemical compound
is rarely listed.
"One of the
assumptions about these chemicals is that they are regarded as
environmentally low risk compared to pesticides and oil products," Epel
"This is the first
study to show that some personal care products in water do have an
effect, even in low concentrations. Our results indicate that the
effects on the first line of defense might be irreversible or continue
long after the event. It's a warning sign. It's a smoking gun. Are there
other chemicals out there that have similar long-term effects? Could
these be harming these defense systems in aquatic organisms? And could
they be having similar effects in humans?"
"The musks are an
example, but this group of pharmaceuticals and personal care products
consists of thousands of different chemicals," Luckenbach said.
The experiment was
conducted in Epel's laboratory at Stanford's Hopkins Marine Station in
Pacific Grove, California and was funded by the German Academic Exchange
Service, the National Oceanographic and Atmospheric Administration, the
California Sea Grant College and the California State Resources Agency.
of synthetic musks increased from about 7,000 to 8,000 tons a year
between 1987 and 1996, the authors wrote.
Concerns about the
environmental impact of synthetic fragrances first surfaced about 10
years ago in Japan and Europe. "They were picking up pharmaceutical and
personal care products in the wastewater flowing into rivers," Epel
said. "In Japan they found them in mussels and fish and discovered they
are somewhat persistent -- they don't break down."
Use of musk xylene,
the most common industrial fragrance, was banned in Japan several years
ago after traces of the compound were found in human body fat, breast
milk and blood.
Germany has placed a
voluntary ban on musk xylene, although it is still widely used in the
United States, except in lipsticks and other products that are applied
These findings extend
those of a National Research Council report commissioned by the EPA and
published in July 2002 that reassesses the environmental disposition of
sewage biosolids, particularly odorants, such as synthetic musk.
"For odorants," the
NRC report states," the need for further evaluation is driven by he high
level of public concern, as well as very limited characterization of the
odorants present in biosolids and their toxicity."
commonly present in biosolids, the NRC committee wrote, "EPA should move
aggressively to develop acute toxicity values for use in assessing the
risks posed by these chemicals and should support research on the
interaction between these chemicals and pathogens in causing human
Environmental Protection Agency has information about exposure to
chemicals in personal care products at the
National Exposure Research Lab.
products without synthetic fragrance, click here