More toxin risks found with perchlorate

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More toxin risks found with perchlorate

11:36 AM PDT on Thursday, October 5, 2006

By DAVID DANELSKI

The Press-Enterprise

http://www.pe.com/localnews/inland/stories/PE_News_Local_B_perch05.fab2c0.html

More than a third of U.S. women are more vulnerable to the harmful effects

of a rocket-fuel chemical found in hundreds of water supplies and various

foods nationwide, federal researchers found in a study released on

Wednesday.

The researchers discovered that women with low levels of iodine in their

bodies had reduced thyroid function from consuming perchlorate, most

probably in their water and food.

The scientists said they were surprised because the thyroid changes were

detected even when perchlorate exposure was very low.

An estimated 36 percent of the nation's female population have low levels

of iodine, the researchers said.

Perchlorate contamination is widespread in Inland groundwater supplies,

forcing water agencies to shut down some wells. They also treat the water

or blend it with cleaner sources before sending it to customers.

The study, published in the federal journal Environmental Health

Perspectives, is expected to be a bombshell in a years-long debate over

how much perchlorate should be allowed in drinking water and food,

observers said.

With more than 2,000 research subjects, the study by scientists at the

Centers for Disease Control and Prevention in Atlanta is the most

comprehensive to date on the human health effects of perchlorate, an

oxidizer used in rockets, munitions, road flares, fireworks, matches and

car airbag propellants.

A California health official said the new research could prompt the state

to could reconsider a recommended drinking water standard.

The federal scientists measured perchlorate in the urine of 2,299 people

12 and older from 30 locations nationwide; 1,111 of them were female. The

thyroid changes were not observed in men.

Among 348 women with low iodine, higher perchlorate levels correlated with

reduced thyroid function, researchers found.

It was measured by the amount of thyroid hormones in their blood.

Thyroid hormones control the body's metabolism and, in pregnant women,

guide fetal brain and nerve development.

Mild hypothyroidism -- reduced thyroid function -- during pregnancy has

been linked to " subtle cognitive deficits in children, " the researchers

said.

Rene Sharp, an analyst with the Environmental Working Group research and

advocacy organization, said the group will demand tough state and federal

standards for food and drinking water because of the CDC research.

California and federal officials are moving toward standards that wouldn't

protect people's health, she said. " They were wildly off. "

Ben Blount, a CDC research chemist, and his colleagues found that

low-iodine women with as little as 2.9 parts per billion of the chemical

in their urine were affected by perchlorate. Two parts per billion is

equivalent to about a teaspoon in an Olympic-size swimming pool.

It's unclear how much perchlorate the women were consuming in their food

and water during the study, which took place in 2001-2002

The study did not make clear the relationship between perchlorate in urine

and the amount consumed; but the CDC group found that perchlorate levels

in 62 colleagues were much higher in their urine than in the city's

drinking water.

Water agencies didn't routinely test for perchlorate until the late 1990s,

when a technique was developed that could detect tiny amounts. Some Inland

wells have been found to contain perchlorate in hundreds of parts per

billion, but the water is not served to consumers.

Perchlorate has been found in cow's milk, human breast milk, grain, fruit,

lettuce and other foods.

California health officials have proposed a drinking water limit of 6

parts per billion. Most Inland water agencies say they serve water with 0

to 4 parts per billion.

The U.S. Environmental Protection Agency, based on a National Academy of

Sciences review, last year declared that 24.5 parts per billion is safe

for drinking water.

Both California and National Academy officials relied heavily on an

industry-sponsored study, published in 2002, that exposed 37 people to

different levels of perchlorate and concluded that 245 parts per billion

had no effect on humans.

That study did not look specifically at women with low iodine levels. Some

scientists criticized the research because the raw data showed that some

of the subjects appeared to affected by the chemical at levels the authors

said had no effect.

Pleus, a Seattle toxicologist who co-authored the industry study,

could not be reached for comment Wednesday.

LOW THYROID FUNCTION

Symptoms may include:

Tiredness

Difficulty losing weight

Dry skin

Constipation

Hair loss, especially the outer third of the eyebrows

Difficulty concentrating

Difficulty carrying pregnancy to full term

In women, irregular menstrual periods

Fetuses can have neurological deficiencies

Baby may have goiter at birth. State law requires thyroid testing of

newborns, so underactive thyroid can be treated and corrected.

Source: Dr. Suvesh Chandiok, endocrinologist who teaches in UC Riverside's

bio-medical program; National Institutes of Health

Staff writer Sharon McNary contributed to this report.

*

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