BOSTON -- My nose is clamped and I'm trying not to choke on a tube a scientist at Harvard University has stuffed in my mouth. I am blowing into a clear plastic bag, which is sealed and later studied for what it contains.

 

Sure, everyone suffers occasionally from a little bad breath. But what they found in mine was enough to keep my wife away for a week.

 

Besides my breath, researchers at Harvard's School of Public Health examined my blood, hair, urine, toenails and bones. It's all in the name of the emerging science of body burden, a concept referring to the amount of chemicals that accumulate in the human body.

 

As it turns out, I am polluted. Everyone is to some degree. But as the list of toxic chemicals identified in people continues to grow, scientists are trying to figure out what the implications are for human health.

 

"It is alarming," Professor John Spengler says. "This is not meant to be settling information. I think if more people wake up to this fact, the better we are going to be . . . and the more demanding we're going to be of our governments and our industries."

 

An estimated 35,000 chemicals are in commercial use in Canada and more than twice as many in the United States. The national American government registers an average of 2,000 newly synthesized chemicals each year.

 

Cosmetics have at least 5,000 chemicals; more than 3,200 are added to food. As many as 1,010 chemicals are used in the production of 11,700 consumer products, and about 500 chemicals are used as active ingredients in pesticides, according to Environmental Protection Agency data cited by the Environmental Working Group, based in Washington, D.C.

 

Many chemicals end up in the environment, even thousands of kilometres from industry.

 

Despite being banned years ago, PCBs are still found in Arctic wildlife. Biologists are also finding rising levels of polybrominated diphenyl ethers (PBDEs), flame retardants used in foam, textiles and plastics, as well as chlorinated paraffins, chemicals used in paints, sealants and rubber-processing.

 

Scotchgard, which is part of a family of chemicals used to make clothes, carpets and furniture stain-resistant, has been found in polar bears in Alaska and bald eagles around the Great Lakes.

 

If chemicals are showing up in wildlife and the environment, it's no surprise that many are being discovered in people.

 

"Pretty much from the minute you wake up to the moment you go to bed, you're exposed to hundreds and hundreds of chemicals," says Jane Houlihan, vice-president of research for the Environmental Working Group. "...In most cases, they're in minuscule quantities. But that fact is it's hundreds [of chemicals] and they're adding up."

 

What's disturbing, Prof. Spengler says, is how the majority of the chemicals have been approved for use without any research being done on their potential impact on human health, except mainly for those that end up in drugs or food.

 

What's more, little is known about what our chemical body burden truly is. "So measurements like we're doing on you, and myself, and our research subjects are really part of a new frontier because it's really trying to understand ... what effects these might have on disruption of human function," Prof. Spengler says.

 

No extensive study has considered the chemical body burden of Canadians, although separate studies have reported the presence of individual compounds -- for example, research documenting a dramatic rise of PBDEs in breast milk.

 

More wide-ranging studies have been done in the United States.

 

In one, researchers found at an average of 91 "industrial compounds, pollutants and chemicals" in the blood and urine of nine volunteers and a total of 167 chemicals in the group. According to the research, conducted by Mount Sinai School of Medicine in New York with the Environmental Working Group, "76 cause cancer in humans or animals, 94 are toxic to the brain or nervous system, and 79 cause birth defects or abnormal development." None of the people tested worked with chemicals or lived near an industrial facility.

 

"I expected to find many different chemicals," Ms. Houlihan says. "But to actually see the numbers roll out that show that one person has 100 chemicals in their blood at one time. It's pretty powerful."

 

The most comprehensive research on body burden to date was conducted by the U.S. Centers for Disease Control and Prevention and released in 2003. As part of the $6.5-million (U.S.) report, the agency tested the blood and urine of 2,500 volunteers for 116 compounds, including PCBs, pesticides, dioxins, furans and metals.

 

It found many of the contaminants in at least half of the people they tested. As well, researchers discovered elevated levels of lead in the blood of children and the ubiquitous presence of phthalates, chemicals widely used in plastics that are linked to cancer and reproductive problems in studies on rats.

 

Meanwhile, they also discovered that chemicals such as DDT and PCBs, which are banned or restricted, appear to be going down.

 

"Just because they can [detect it] doesn't mean it's at a dangerous level or a level that causes health effects. It mostly reflects the fact that we've improved our ability to measure," says Jim Pirkle, deputy director of science for the CDC, referring to new technology that allows scientists to identify compounds in amounts that would have gone unnoticed a decade earlier.

 

Dr. Pirkle notes that most of the chemicals being found are in infinitesimally small amounts of parts per million and parts per billion, equivalent to a grain of rice in an Olympic-sized swimming pool.

 

"There are going to be small levels of many things in people. That's because they're dispersed in low levels all over the environment. What you really have to do is stop and look at them one by one and go through them and say, 'Is that a level that's likely to cause disease? Is that a level that's so trivially small, we have good instruments that can measure it, but it's so small it's not of any concern?' You have to do that one chemical at a time."

 

All this brings us back to Harvard and my own results.

 

After bombarding my knee for half an hour with a small amount of radiation, the technician in the bone lab gives me the news: My skeleton is contaminated with lead.

 

Lead is an acute toxin. It's poisonous at higher levels. But even at low concentrations, research has linked it to an increased risk of hypertension, kidney disease, impaired neurological development in children, even cataracts.

 

The good news is my lead levels place me well within the average range for someone my age with no appreciable health risk, says Howard Hu, a professor of occupational and health medicine at Harvard's School of Public Health.

 

Others are less fortunate. Dr. Hu has measured lead amounts five to 10 times higher in many women, posing potential harm to their unborn babies.

 

"There's so many different exposure routes that just living and breathing can provide exposures today," he says. "Lead is in many different consumer products. It was in gasoline. ... It was in food cans, pipes and solder. ... It was in toys and plastics."

 

In another lab across the street, scientists have clipped a lock of my hair and are analyzing it. It will tell them how much mercury my body contains.

 

Although it occurs naturally in the environment, mercury is also a byproduct of coal-fired power plants and waste incinerators. When it enters the water and reacts with bacteria, it is transformed into methyl mercury and it accumulates in fish, and people when they eat it.

 

It's a neurotoxin and the human fetus is particularly vulnerable. At low doses, it can cause subtle changes to the developing brain; at larger doses, it can cause blindness and other birth defects. At high levels, it can kill nerve cells, causing blurred vision, lack of co-ordination and slurred speech.

 

Fortunately, my mercury level is .411 parts per million, about half the EPA guideline of 1 ppm.

 

Next came my blood results. As it turns out, my blood contains PCBs and pesticides, including DDT, an insecticide banned in North America decades ago. But for many people my age, my results are considered well within the low-to-average range.

 

Unfortunately, as Russ Hauser of Harvard's School of Public Health points out, his research is finding that men exposed to similar doses have problems with semen quality, which is associated with infertility.

 

"PCBs and DDT were banned decades ago, but they're still present in the environment," Dr. Hauser says. "You're exposed primarily through intake of food because they accumulate as we move up the food chain. ... So consuming fish, dairy products, meats, that's primarily how you're exposed."

 

Although the Harvard scientists were looking for arsenic, a highly poisonous metal, in my toenails, they found virtually none. Prof. Spengler wasn't surprised, saying it's something they typically find in people who drink water from a well and mine comes from a lake.

 

But he was amazed by something in my breath, the content of which is an indicator of relatively recent exposure to chemicals in the air. It wasn't the list of solvents, such as benzene, that are often associated with vehicle exhaust. It was MTBE, a fuel additive that is not supposed to be widely used in Canada (less than 2 per cent of gas in this country contains it, according to Environment Canada). Prof. Spengler speculates I breathed in MTBE on the way to Harvard in a taxi.

 

In total, the scientists found 76 chemicals in my body, including PCBs, pesticides, solvents and metals. Even though my body contains extremely small amounts of them, I can't help but ask Prof. Spengler whether I should be worried.

 

"I would say you're not very toxic compared to people we've measured all over the world, even compared to me," he says.

 

He points out that his own DDT levels place him in the top fifth of Americans. I'm in the bottom fifth.

 

"On the one hand, you might say, 'Well, I'm normal. I might be a little high on one thing and low on another.' But that's not the way we should look at it."

 

Prof. Spengler says the issue is not whether one has an average amount of chemicals in his body. Rather, it's why the average person is carrying around so many chemicals in the first place.

 

There has been little scientific inquiry into the net effect of being exposed to many chemicals at the same time, the so-called "toxic soup effect."

 

Complicating the toxicology is the counterintuitive concept of hormesis, a phenomenon in which a small dose of an otherwise toxic substance can be helpful. Studies on plants and animals have documented it in alcohol, antibiotics, hydrocarbons and pesticides.

 

Nevertheless, Prof. Spengler and many other scientists believe that exposure to a range of chemicals in the environment may be behind a host of emerging health problems in addition to those already well documented. "We're concerned about the growing rates of cancer in our society, the growing rates of autism," he says. "In most developed countries, asthma has grown substantially over the past 20 years, particularly in children"

 

As for myself, Prof. Spengler says there's very little I can do to reduce the contamination that is already in my body. Aside from eating different types of fish to lower my mercury level, the PCBs and pesticides are there for the long haul while the solvents will continue to show up in my breath as long as I'm exposed to cars and trucks, which are kind of difficult to avoid.

 

Prof. Spengler says the solution is targeting chemicals we don't want in our bodies in the first place. He points to PBDEs, which has been referred to as the "PCBs of the 21st century."

 

Research commissioned by The Globe and Mail and CTV News found that many everyday foods consumed by Canadians -- such as salmon, ground beef, cheese and butter -- are laced with PBDEs.

 

In Sweden, the flame retardants were banned after rising levels were noticed in the breast milk of women. "They said to the industry, 'We don't want them in our plastics. We don't what them in our materials' -- and they started to see the levels come down," Prof. Spengler says.

 

"Now, you see the similar data out of North American women. . . . The levels are already 50 times higher in our populations and nobody is saying, 'Ban that product.' ... So I think this really has to do with how we've come to judge what is beneficial to the population," he says. "[But] at what point do we invoke some precaution?"

 

- Mark Stevenson is an independent producer and a regular contributor to the Discovery Channel's Daily Planet. A version of this feature has aired on the show.

 

MARK'S BODY

 

Test results show low levels of 76 chemicals.

 

Metals in blood*
metal	  Normal levels (ppb):	Mark's levels (ppb):
Lead	         <100	               19.13
Manganese     4.2-16.5              	969
Cadmium	         <5                     0.06

Mercury in hair
EPA reference level: 1.0 ppm
Mark's level: 0.411 ppm

Arsenic in toenails
Normal level: below 0.2 ppm
Mark's level: 0.032 ppm

Solvents in breath (nanogram/litre)
solvent	       Mark
MTBE	       6.22**
Hexane	       2.71
Benzene	       4.23
Toluene	       4.05
Xylene	       1.38
Pinene	       4.30
Limonene     108.42***

 

Pesticides in blood

Mark has 0.879 ppb of DDT (low to average)

 

PCBs in blood

Mark has 0.82 ppb (low to average)

 

Lead content in bone

Mark has 4.67 ppm (average)

 

*Lead, cadmium and mercury are not considered "natural" elements in the body. Manganese, on the other hand, is an essential element at very trace amounts.

 

**MTBE, a fuel additive to improve emissions, could have been inhaled in the United States where it is much more common than in Canada.

 

***The high limonene level could be attributed to orange juice or air freshener.

 

© Copyright 2005 Bell Globemedia Publishing Inc. All Rights Reserved.

 

http://www.theglobeandmail.com/ser