TOPICS > Science

Human Exposure to Chemicals

June 24, 2005 at 12:00 AM EDT


BETTY ANN BOWSER: Jo Rupert Behm lives a healthy lifestyle. She shops at local farmers markets in Marin County, California, always searching out organic foods that are free of chemicals.

JO RUPERT BEHM: No sprays — OK, good —

BETTY ANN BOWSER: But Behm also wants to know about the toxins in her environment that she can’t control.

JO RUPERT BEHM: I’ve got a son with learning disabilities. I began to wonder what caused … what is the potential cause of this? What are we not seeing here?

BETTY ANN BOWSER: So she joined a study that tested her blood for industrial chemicals found in everyday products like cosmetics, furniture, and electronics, chemicals such as phthalates, PFCs, and PBDEs. Her results arrived in early June.

JO RUPERT BEHM: I have them all. I have every single chemical that I was tested for, and it’s a concern. I don’t know, and no one can tell me, what the health impacts will be, but I wonder how an average citizen going about their daily life can have carcinogenics, mutagenics, endocrine disrupters harboring in my body involuntarily.

BETTY ANN BOWSER: Behm was part of a study that screened the general population in California. It was conducted by environmental advocacy group Commonweal. Such testing is popping up around the country as groups like Commonweal try to bring attention to everyday chemical exposures.

Commonweal’s Davis Baltz says there are 85,000 chemicals registered for use in the U.S., with 1,000 to 2,000 new chemicals entering the marketplace each year.

DAVIS BALTZ: Most of these chemicals did not exist in the 1920s. That was the decade when my parents were born. So some people would say that we have embarked on a chemistry experiment without adequate controls.

SPOKESWOMAN: Members, I would respectfully ask for an “aye” vote.

BETTY ANN BOWSER: Commonweal has teamed up with California state Sen. Deborah Ortiz to pass legislation that would make California the first state to test volunteers for industrial chemicals inside their bodies.

SEN. DEBORAH ORTIZ: They would agree to have either urine, blood, other tissues sampled, and agree to find out what their body is carrying, what their body burden is.

BETTY ANN BOWSER: “Body burden” is a term used by environmental advocates. It describes a person’s cumulative amount of industrial chemicals, often ones they’ve picked up from everyday life, likening them to a bag of chemicals you might carry on your back.

With new advancements bio-monitoring, researchers around the country are now able to detect very low levels of chemicals, and Senator Ortiz wants Californians to benefit from the new science.

SEN. DEBORAH ORTIZ: Californians should have the right to know what their bodies are carrying, and this is that first step.

BETTY ANN BOWSER: The next step, says Ortiz, is to search for links between exposure and health risks.

SEN. DEBORAH ORTIZ: We may indeed see an explanation that cannot be explained simply by genetic or familial factors of this huge increase in certain chronic diseases. Autism is at a huge and alarming rate across the country, particularly in California.

We’re seeing types of cancers that are so rare and so uncommon and that are not linked in individuals to family or genetics that the conclusion is, by default, it has to be some environmental changes.

BETTY ANN BOWSER: But that line of thinking has put the chemical industry on alert.

TIM SHESTEK, American Chemistry Council: Taking a snapshot of bio-monitoring data and then leaping to some sort of conclusions about linking that exposure information to some sort of public health concern, chronic disease, long-term illness, is really not the full picture.

BETTY ANN BOWSER: Tim Shestek from the American Chemistry Council worries that California’s proposed program is based on ideology, not sound science.

TIM SHESTEK: And that ultimately could lead to some new regulations, hindrance of new products coming to the market, the removal of products that may or may not necessarily have any justified reason to be off the market.

BETTY ANN BOWSER: In fact, two years ago, California did ban two common household flame retardants after this California EPA lab found extremely high levels of the contaminate in bay area women. Epidemiologist Myrto Petreas:

MYRTO PETREAS: What we found in our California patients was 30 times higher than anything that was reported from Europe and Japan at the time.

BETTY ANN BOWSER: The California action led furniture manufacturer Ikea to stop using the flame retardants, referred to as Penta and Octa PBDE, which are commonly found in foam mattresses, drapes, and furnishings. Five other states have also banned the chemicals.

SHOPPERS: It’s 149…

BETTY ANN BOWSER: But how do the chemicals make their way from household products into our bodies?

MYRTO PETREAS: That’s a good question. Some of these chemicals may volatilize or be part of the dust, and we can inhale it; or it can settle on our fingers or our food, and we can eat it. So it’s an indoor air exposure.

BETTY ANN BOWSER: The lab has also pioneered the use of breast milk for bio-monitoring. Environmental scientist Kim Hooper has found soaring levels of Penta and Octa PBDEs in mothers’ milk.

Hooper says breast milk gives a perfect snapshot of a critical time in human development, a time when chemical exposure can have the greatest impact.

KIM HOOPER: The most sensitive part of our sort of organism is the fetus. It’s sort of the — most scientists agree that, for chemical insult, the fetus is the one that you need to protect the most. It’s difficult to monitor the fetus.

Probably, the second-most sensitive is the infant — also difficult to monitor the infant. You need to take blood or something like that, and it’s hard, and it’s not pleasant. You can do the same thing by collecting breast milk soon after the pregnancy.

ROSEANNE GEPHARDT: The reason why we measure what’s called your fundal height is so that we can see how the baby’s growing.

BETTY ANN BOWSER: Midwife Roseanne Gephardt helps recruit patients for Hooper’s research. She is quick to point out that even if toxins are found in breast milk, breast feeding is still the best form of nutrition.

ROSEANNE GEPHARDT: Breast feeding protects the baby in so many different ways, and it protects that particular baby from the toxins that the mother was exposed to during that pregnancy. So that milk is specifically designed for that baby.

BETTY ANN BOWSER: Toxicologist Sean Hays, who works with industry to determine safe chemical exposure limits, says the mere presence of chemicals shouldn’t lead to panic.

SEAN HAYS: You need to compare the risks throughout your whole daily life. When you compare the minuscule theoretical risks associated with these chemicals in our products and in your salad, they pale in comparison to your risks associated with driving your car, your occupation, your lifestyle, associated with obesity or exercise or secondhand smoke.

BETTY ANN BOWSER: Those widely respected and in the forefront of bio-monitoring have experienced limitations to the science as well. Epidemiologist Brenda Eskenazi is a professor at the University of California’s Berkeley School of Public Health.

Her six-year study tracks brain development of children born to farm laborers in California’s Monterey County who work with organophosphate pesticides, the most widely used pesticide today.

BRENDA ESKENAZI: The animal evidence suggests that animals have difficulty in learning and attention, memory, and there’s a potential that there would be the same impact on humans, but we don’t know.

BETTY ANN BOWSER: It’s not easy work. People quickly expel organophosphates.

BRENDA ESKENAZI: So an exposure that occurred three days ago may no longer be detectable in the human body. That doesn’t mean it didn’t have an impact on the health of the body when it occurred three days ago, but we may not be able to pick up the occurrence of that pesticide.

BETTY ANN BOWSER: And identifying the effect of each chemical can be tricky.

BRENDA ESKENAZI: They may also have exposure to other chemicals in their environment. How you tease out the independent effects of any one chemical is difficult, not only difficult statistically, but difficult toxicologically, since chemicals may interrelate and affect each other in terms of how they affect the human body.

BETTY ANN BOWSER: Early results of her study show an association with premature birth and abnormal reflexes in newborns, but years of analysis are ongoing. In the meantime, Eskenazi works on exposure prevention.


BETTY ANN BOWSER: Like in this exercise, where laborers are asked to hold an apple, then a baby doll, then are shown with the aid of black light how unseen chemicals can leave residue.

BRENDA ESKENAZI: We don’t just look at and study, but we try to teach people how to prevent exposure, and we do that not knowing whether the exposure actually causes harm; but knowing that there is exposure, we want to prevent. We’re in public health; we’re in the business of prevention of disease.

BETTY ANN BOWSER: Later this month a lot more may be known about the general population’s exposure. That’s when the Centers for Disease Control will publish its third national report on human exposure to environmental chemicals.