National Geographic  [Printer-friendly version]
October 1, 2006

THE POLLUTION WITHIN

[Rachel's introduction: Author David Duncan had his blood tested for
toxic chemicals, then set off on a journey of discovery to learn how
all those toxicants ended up inside him.]

By David Ewing Duncan

My journalist-as-guinea-pig experiment is taking a disturbing turn,

A Swedish chemist is on the phone, talking about flame retardants,
chemicals added for safety to just about any product that can burn.
Found in mattresses, carpets, the plastic casing of televisions,
electronic circuit boards, and automobiles, flame retardants save
hundreds of lives a year in the United States alone. These, however,
are where they should not be: inside my body.

Ake Bergman of Stockholm University tells me he has received the
results of a chemical analysis of my blood, which measured levels of
flame-retarding compounds called polybrominated diphenyl ethers. In
mice and rats, high doses of PBDEs interfere with thyroid function,
cause reproductive and neurological problems, and hamper neurological
development. Little is known about their impact on human health.

"I hope you are not nervous, but this concentration is very high,"
Bergman says with a light Swedish accent. My blood level of one
particularly toxic PBDE, found primarily in U.S.-made foam pads,
mattresses, and furniture, is 10 times the average found in a small
study of U.S. residents and more than 200 times the average in Sweden.
The news about another PBDE variant -- also toxic to animals -- is
nearly as bad. My levels would be high even if I were a worker in a
factory making the stuff, Bergman says.

In fact I'm a writer engaged in a journey of chemical self-discovery.
Last fall I had myself tested for 320 chemicals I might have picked up
from food, drink, the air I breathe, and the products that touch my
skin -- my own secret stash of compounds acquired by merely living. It
includes older chemicals that I might have been exposed to decades
ago, such as DDT and PCBs; pollutants like lead, mercury, and dioxins;
newer pesticides and plastic ingredients; and the near-miraculous
compounds that lurk just beneath the surface of modern life, making
shampoos fragrant, pans nonstick, and fabrics water-resistant and
fire-safe.

===================================================

Sidebar: Home sick home

Learn about the toxins we encounter every day in an interactive
graphic, and eeplore related links at ngm.com.0610.

===================================================

The tests are too expensive for most individuals -- National
Geographic paid for mine, which would normally cost around $15,000 --
and only a few labs have the technical expertise to detect the trace
amounts involved. I ran the tests to learn what substances build up in
a typical American over a lifetime, and where they might come from. I
was also searching for a way to think about risks, benefits, and
uncertainty -- the complex tradeoffs embodied in the chemical "body
burden" that swirls around inside all of us. Now I'm learning more
than I really want to know.

Bergman wants to get to the bottom of my flame-retardant mystery. Have
I recently bought new furniture or rugs? No. Do I spend a lot of time
around computer monitors? No, I use a titanium laptop. Do I live near
a factory making flame retardants? Nope, the closest one is over a
thousand miles away. Then I come up with an idea.

"What about airplanes?" I ask.

"Yah," he says, "do you fly a lot?"

"I flew almost 200,000 miles last year," I say. In fact, as I spoke to
Bergman, I was sitting in an airport waiting for a flight from my
home-town of San Francisco to London.

"Interesting," Bergman says, telling me that he has long been curious
about PBDE exposure inside airplanes, whose plastic and fabric
interiors are drenched in flame retardants to meet safety standards
set by the Federal Aviation Administration and its counterparts
overseas. "I have been wanting to apply for a grant to test pilots and
flight attendants for PBDEs," Bergman says as I hear my flight
announced overhead. But for now the airplane connection is only a
hypothesis. Where I picked up this chemical that I had not even heard
of until a few weeks ago remains a mystery. And there's the bigger
question: How worried should I be?

The same can be asked of other chemicals I've absorbed from air,
water, the nonstick pan I used to scramble my eggs this morning, my
faintly scented shampoo, the sleek curve of my cell phone. I'm
healthy, and as far as I know have no symptoms associated with
chemical exposure. In large doses, some of these substances, from
mercury to PCBs and dioxins, the notorious contaminants in Agent
Orange, have horrific effects. But many toxicologists -- and not just
those who have ties to the chemical industry -- insist that the
minuscule smidgens of chemicals inside us are mostly nothing to worry
about.

"In toxicology, dose is everything," says Karl Rozman, a toxicologist
at the University of Kansas Medical Center, "and these doses are too
low to be dangerous." One part per billion (ppb), a standard unit for
measuring most chemicals inside us, is like putting half a teaspoon of
red dye into an Olympic-size swimming pool. What's more, some of the
most feared substances, such as mercury, dissipate within days or
weeks -- or would if we weren't constantly re-exposed.

Yet even though many health statistics have been improving over the
past few decades, a few illnesses are rising mysteriously. From the
early 1980s through the late 1990s, autism increased ten-fold, one
type of leukemia was up 62 percent, male birth defects doubled, and
childhood brain cancer was up 40 percent. Some experts suspect a link
to the manmade chemicals that pervade our food, water, and air.
There's little firm evidence. But over the years, one chemical after
another that was thought to be harmless turned out otherwise once the
facts were in.

The classic example is lead. In 1970 the U.S. Surgeon General declared
that lead levels of 40 micrograms per deciliter of blood were safe.
It's now known that any detectable lead can cause neurological damage
in children, shaving off IQ points. From DDT to PCBs, the chemical
industry has released compounds first and discovered damaging health
effects later. Regulators have often allowed a standard of innocent
until proven guilty in what Leo Trasande, a pediatrician and
environmental health specialist at Mount Sinai Hospital in New York
City, calls "an uncontrolled experiment on America's children:"

Each year the U.S. Environmental Protection Agency reviews an average
of 1,700 new compounds that industry is seeking to introduce. Yet the
1976 Toxic Substances Control Act requires that they be tested for any
ill effects before approval only if evidence of potential harm exists
-- which is seldom the case for new chemicals. The agency approves
about 90 percent of the new compounds without restrictions. Only a
quarter of the 82,000 chemicals in use in the U.S. have ever been
tested for toxicity.

Until recently, no one had even measured average levels of exposure
among large numbers of ordinary Americans. No regulations required it,
the tests are expensive, and technology sensitive enough to measure
tiny levels didn't exist.

Last year the Centers for Disease Control and Prevention took a step
toward closing that gap when it released data on 148 substances that
ranged from DDT and other pesticides to metals, PCBs, and plastic
ingredients, measured in the blood and urine of several thousand
people. The study said little about health impacts on the people
tested or about how they might have encountered the chemicals. "The
good news is that we are getting real data about exposure levels,"
says James Pirkle, the study's lead author. "This gives us a place to
start."

I began my own chemical journey on an October morning at the Mount
Sinai Hospital in New York City, where I gave urine and had blood
drawn under the supervision of Leo Trasande. Trasande specializes in
childhood exposures to mercury and other brain toxins. He had agreed
to be one of several expert advisers on this project, which began as a
Sinai phlebotomist extracted 14 vials of blood -- so much that at vial
12 I felt woozy and went into a cold sweat. At vial 13 Trasande
grabbed smelling salts, which hit my nostrils like a whiff of fire and
allowed me to finish.

From New York my samples were shipped to Axys Analytical Services on
Vancouver Island in Canada, one of a handful of state-of-the-art labs
specializing in subtle chemical detection, analyzing everything from
eagle's eggs to human tissue for researchers and government agencies.
A few weeks later, I followed my samples to Canada to see how Axys
teased out the tiny loads of compounds inside me.

I watched the specimens go through multiple stages of processing,
which slowly separated sets of target chemicals from the thousands of
other compounds, natural and unnatural, in my blood and urine. The
extracts then went into a high-tech clean room containing mass
spectrometers, sleek, freezer-size devices that work by flinging the
components of a sample through a vacuum, down a long tube. Along the
way, a magnetic field deflects the molecules, with lighter molecules
swerving the most. The exact amount of deflection indicates each
molecule's size and identity.

A few weeks later, Axys sent me my results -- a grid of numbers in
parts per billion or trillion -- and I set out to learn, as best I
could, where those toxic traces came from.

Some of them date back to my time in the womb, when my mother
downloaded part of her own chemical burden through the placenta and
the umbilical cord. More came after I was born, in her breast milk.

Once weaned, I began collecting my own chemicals as I grew up in
northeastern Kansas, a few miles outside Kansas City. There I spent
countless hot, muggy summer days playing in a dump near the Kansas
River. Situated on a high limestone bluff above the fast brown water
lined by cottonwoods and railroad tracks, the dump was a mother lode
of old bottles, broken machines, steering wheels, and other items only
boys can fully appreciate.

This was the late 1960s, and my friends and I had no way of knowing
that this dump would later be declared an EPA superfund site, on the
National Priority List for hazardous places. It turned out that for
years, companies and individuals in this corner of Johnson County had
dumped thousands of pounds of material contaminated with toxic
chemicals here. "It was started as a landfill before there were any
rules and regulations on how landfills were done," says Denise Jordan-
Izaguirre, the regional representative for the federal Agency for
Toxic Substances and Disease Registry. "There were metal tailings and
heavy metals dumped in there. It was unfenced, unrestricted, so kids
had access to it." Kids like me.

Now capped, sealed, and closely monitored, the dump, called the
Doepke-Holliday Site, also happens to be half a mile upriver from a
county water intake that supplied drinking water for my family and
45,000 other households. "From what we can gather, there were
contaminants going into the river," says Shelley Brodie, the EPA
Remedial Project Manager for Doepke. In the 1960s, the county treated
water drawn from the river, but not for all contaminants. Drinking
water also came from 21 wells that tapped the aquifer near Doepke.

When I was a boy, my corner of Kansas was filthy, and the dump wasn't
the only source of toxins. Factories owned by Ford, Colgate-Palmolive,
the Kansas Power and Light Company, Bayer CropScience, and many others
lined the river a few miles away. When we drove past the plants toward
downtown Kansas City, we plunged into a noxious cloud that engulfed
the car with smoke and an awful chemical stench. Flames rose from
fertilizer plant stacks, burning off mustard-yellow plumes of sodium,
and raw sewage poured into the river. In the nearby farm-land, trucks
and crop dusters sprayed DDT and other pesticides in great, puffy
clouds that we kids sometimes rode our bikes through, holding our
breath and feeling very brave.

Today the air is clear, and the river free of effluents -- a visible
testament to the success of the U.S. environmental cleanup, spurred by
the Clean Air and Clean Water Acts of the 1970s. But my Axys test
results read like a chemical diary from 40 years ago. My blood
contains traces of several chemicals now banned or restricted,
including DDT (in the form of DDE, one of its breakdown products) and
other pesticides such as the termite-killers chlordane and heptachlor.
The levels are about what you would expect decades after exposure,
says Rozman, the toxicologist at the University of Kansas Medical
Center. My childhood playing in the dump, drinking the water, and
breathing the polluted air could also explain some of the lead and
dioxins in my blood, he says.

I went to college at a place and time that put me at the height of
exposure for another set of chemicals found inside me -- PCBs, once
used as electrical insulators and heat-exchange fluids in transformers
and other products. PCBs can lurk in the soil anywhere there's a dump
or an old factory. But some of the largest releases took place along
New York's Hudson River from the 1940s to the 1970s, when General
Electric used PCBs at factories in the towns of Hudson Falls and Fort
Edward. About 140 miles downstream is the city of Poughkeepsie, where
I attended Vassar College in the late 1970s.

PCBs, oily liquids or solids, can persist in the environment for
decades. In animals, they impair liver function, raise blood lipids,
and cause cancers. Some PCBs -- there are 209 of them -- chemically
resemble dioxins and cause other mischief in lab animals: reproductive
and nervous system damage, as well as developmental problems. By 1976,
the toxicity of PCBs was unmistakable; the United States banned them,
and GE stopped using them. But until then, GE legally dumped excess
PCBs into the Hudson, which swept them all the way downriver to
Poughkeepsie, one of eight cities that draw their drinking water from
the Hudson.

In 1984, a 200-mile stretch of the Hudson, from Hudson Falls to New
York City, was declared a superfund site, and plans to rid the river
of PCBs were set in motion. GE has spent 300 million dollars on the
cleanup so far, dredging up and disposing of PCBs in the river
sediment under the supervision of the EPA. It is also working to stop
the seepage of PCBs into the river from the factories.

Birds and other wildlife along the Hudson are thought to have suffered
from the pollution, but its impact on humans is less definitive. One
study in Hudson River communities found a 20 percent increase in the
rate of respiratory diseases, while another, more reassuringly, found
no increase in cancer deaths in the contaminated region. But among
many of the locals, the fear is palpable.

"I grew up a block from the Fort Edward plant," says Dennis Prevost, a
retired Army officer and public health advocate, who blames PCBs for
the brain cancers that killed his brother at age 46 and a neighbor in
her 20s. "The PCBs have migrated under the parking lot and into the
community aquifer," which Prevost says was the source of Fort Edward's
drinking water until municipal water replaced wells in 1984.

Ed Fitzgerald of the State University of New York at Albany, a former
staff scientist at the state department of health, is conducting the
most thorough study yet of the health effects of PCBs in the area. He
says he has explained to Prevost and other residents that the risk
from the wells was probably small because PCBs tend to settle to the
bottom of an aquifer. Eating contaminated fish caught in the Hudson is
a more likely exposure route, he says.

I didn't eat much Hudson River fish during my college days in the
1970s, but the drinking water in my dorm could have contained traces
of the PCBs pouring into the river far upstream. That may be how I
picked up my PCB body burden, which was about average for an American.
Or maybe not. "PCBs are everywhere," says Leo Rosales, a local EPA
official, "so who knows where you got it,"

Back home in San Francisco, I step into my shower, which is loaded
with a newer generation of industrial chemicals -- compounds that are
not banned, and, like flame retardants, are increasing year by year in
the environment and in my body. Lathering my hair, I'm probably
exposing myself to bisphenol A, an ingredient in plastics from shampoo
containers to shower curtains. Bisphenol A causes reproductive system
abnormalities in animals. My levels were so low they were undetectable
-- a rare moment of relief in my toxic odyssey.

And that faint lavender scent as I wash out the suds? Credit it to
phthalates, molecules that dissolve fragrances, thicken lotions, and
add flexibility to PVC, vinyl, and some intravenous tubes in
hospitals. The dashboards of most cars are loaded with phthalates, and
so is some plastic food wrap. Heat and wear can release phthalate
molecules, and humans swallow them or absorb them through the skin.
Because they dissipate after a few minutes to a few hours in the body,
most people's levels fluctuate during the day.

Like bisphenol A, phthalates disrupt reproductive development in mice.
An expert panel convened by the National Toxicology Program recently
concluded that although the evidence so far doesn't prove that
phthalates pose any risk to people, it does raise "concern,"
especially about potential effects on infants. "We don't have the data
in humans to know if the current levels are safe," says Antonia
Calafat, a CDC phthalates expert. I scored higher than the mean
[average] in five out of seven phthalates tested. One of them,
monomethyl phthalate, came in at 34.8 ppb, in the top 5 percent for
Americansperhaps, says Leo Trasande, because I gave my urine sample in
the morning, just after I had showered and washed my hair.

My inventory of household chemicals also includes PFAs -- tough,
chemically resistant compounds that go into making non-stick and
stain-resistant coatings. 3M also used them in its Scotchgard
protector products until it found that the specific PFA compounds in
Scotchgard were escaping into the environment and phased them out. In
animals these chemicals damage the liver and thyroid and cause birth
defects and perhaps cancer, but not much is known about them in
humans.

Long-range pollution left its mark on my results as well: My blood
contained low, probably harmless, levels of dioxins, which escape from
paper mills, certain chemical plants, and incinerators. Out in the
environment, dioxins settle on soil and in the water, then pass into
the food chain. They build up in animal fat, and most people pick them
up from meat and dairy products.

And then there is mercury, a neurotoxin that can permanently impair
memory, learning centers, and behavior. Coal-burning power plants are
a major source of mercury, sending it out their stacks into the
atmosphere, where it disperses in the wind, falls in rain, and
eventually washes into lakes, streams, or oceans. There bacteria
transform it into a compound called methylmercury, which moves up the
food chain after plankton absorb it from the water and are eaten by
small fish. Large predatory fish at the top of the marine food chain,
like tuna and swordfish, accumulate the highest concentrations of
methylmercury -- and pass it on to seafood lovers.

For people in northern California, mercury exposure is also a legacy
of the gold rush a century and a half ago, when miners used
quicksilver, or liquid mercury, to separate the gold from other ores
in the hodgepodge of mines in the Sierra Nevada. Over the decades,
streams and groundwater washed mercury-laden sediment out of the old
mine tailings and swept it into San Francisco Bay.

I don't eat much fish, and the levels of mercury in my blood were
modest. But I wondered what would happen if I gorged on large fish for
a meal or two. So one afternoon I bought some halibut and swordfish at
a fish market in the old Ferry Building on San Francisco Bay, both
caught in the ocean just outside the Golden Gate. That night I ate the
halibut with basil and a dash of soy sauce; I downed the swordfish for
breakfast with eggs (cooked in my non-stick pan).

Twenty-four hours later I had my blood drawn and retested, and the
effect of those old mines was plain to see: My level of mercury had
more than doubled, from 5 micrograms per liter to a higher-than-
recommended 12. Mercury at 70 or 80 micrograms per liter is dangerous
for adults, says Leo Trasande, and much lower levels can affect
children. "Children have suffered losses in IQ at 5.8 micrograms." He
advises me to avoid repeating the gorge experiment. It's a lot harder
to dodge the PBDE flame retardants responsible for the most worrisome
of my test results. My world -- and yours -- has become saturated with
them since they were introduced about 30 years ago.

Scientists have found the compounds planetwide, in polar bears in the
Arctic, cormorants in England, and killer whales in the Pacific.
Bergman, the Swedish chemist, and his colleagues first called
attention to potential health risks in 1998 when they reported an
alarming increase in PBDEs in human breast milk, from none in milk
preserved in 1972 to an average of four ppb in 1997.

The compounds escape from treated plastic and fabrics in dust
particles or as gases that cling to dust. People inhale the dust;
infants crawling on the floor get an especially high dose. Bergman
describes a family, tested in Oakland, California, by the Oakland
Tribune, whose two small children had blood levels far higher than
mine. When he and his colleagues summed up the test results for all
PBDE forms, they found total levels of 390 ppb in the five-year-old
girl and 650 ppb -- twice my total -- in the 18-month-old boy.

In 2001, researchers in Sweden fed young mice a PBDE mixture similar
to one used in furniture and found that they did poorly on tests of
learning, memory, and behavior. Last year, scientists at Berlin's
Charite University Medical School reported that pregnant female rats
with PBDE levels no higher than mine gave birth to male pups with
impaired reproductive health.

Linda Birnbaum, an EPA expert on these flame retardants, says that
humans would probably start seeing detrimental effects at about four
times the baby boy's level. She says I shouldn't worry. Bergman isn't
so sure, and he says that in a pregnant woman my levels would be of
concern. "Any level above 100 parts per billion is a risk to
newborns," he guesses. Neither he nor Birnbaum really know for sure.

Any margin of safety may be narrowing. In a review of several studies,
Ronald Hites of Indiana University found an exponential rise in people
and animals, with the levels doubling every three to five years. Now
the CDC is putting a comprehensive study of PBDE levels in the U.S. on
a fast track, with results due out late this year. Pirkle, who is
running the study, says my seemingly extreme levels may no longer be
out of the ordinary. "We'll let you know," he says.

Given the stakes, why take a chance on these chemicals? Why not
immediately ban them? In 2004, Europe did just that for the penta- and
octa-BDEs, which animal tests suggest are the most toxic of the
compounds. California will also ban these forms by 2008, and in 2004
Chemtura, an Indiana company that is the only U.S. maker of pentas and
octas, agreed to phase them out. Currently, there are no plans to ban
the much more prevalent deca-BDEs. They reportedly break down more
quickly in the environment and in people, although their breakdown
products may include the same old pentas and octas.

Nor is it clear that banning a suspect chemical is always the best
option. Flaming beds and airplane seats are not an inviting prospect
either. The University of Surrey in England recently assessed the
risks and benefits of flame retardants in consumer products. The
report concluded: "The benefits of many flame retardants in reducing
the risk from fire outweigh the risks to human health."

Except for some pollutants, after all, every industrial chemical was
created for a purpose. Even DDT, the arch-villain of Rachel Carson's
1962 classic book Silent Spring, which launched the modern
environmental movement, was once hailed as a miracle substance because
it killed the mosquitoes that carry malaria, yellow fever, and other
scourges. It saved countless lives before it was banned in much of the
world because of its toxicity to wildlife. "Chemicals are not all
bad," says Scott Phillips, a medical toxicologist in Denver. "While we
have seen cancer rates rise;' he says, "we also have seen a doubling
of the human lifespan in the past century."

The key is knowing more about these substances, so we are not
blindsided by unexpected hazards, says California State Senator
Deborah Ortiz, chair of the Senate Health Committee and the author of
a bill to monitor chemical exposure. "We benefit from these chemicals,
but there are consequences, and we need to understand these
consequences much better than we do now." Sarah Brozena of the
industry-supported American Chemistry Council, thinks safeguards are
adequate now, but she concedes: "That's not to say this process was
done right in the past."

The European Union last year gave initial approval to a measure called
REACH -- Registration, Evaluation, and Authorization of Chemicals --
which would require companies to prove the substances they market or
use are safe, or that the benefits outweigh any risks. The bill, which
the chemical industry and the U.S. government oppose, would also
encourage companies to find safer alternatives to suspect flame
retardants, pesticides, solvents, and other chemicals. That would give
a boost to the so-called green chemistry movement, a search for
alternatives that is already under way in laboratories on both sides
of the Atlantic.

As unsettling as my journey down chemical lane was, it left out
thousands of compounds, among them pesticides, plastics, solvents, and
a rocket-fuel ingredient called perchlorate that is polluting
groundwater in many regions of the country. Nor was I tested for
chemical cocktails -- mixtures of chemicals that may do little harm on
their own but act together to damage human cells. Mixed together,
pesticides, PCBs, phthalates, and others "might have additive effects,
or they might be antagonistic," says James Pirkle of the CDC, "or they
may do nothing. We don't know."

Soon after I receive my results, I show them to my internist, who
admits that he too knows little about these chemicals, other than lead
and mercury. But he confirms that I am healthy, as far as he can tell.
He tells me not to worry. So I'll keep flying, and scrambling my eggs
in Teflon, and using that scented shampoo. But I'll never feel quite
the same about the chemicals that make life better in so many ways.

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