By J.R. Pegg

WASHINGTON, DC, March 4, 2003 (ENS) - The final draft of revised U.S. federal guidelines for cancer risk assessment assumes that children are more vulnerable to the effects of certain carcinogens than adults. It is the first time the U.S. government has officially accepted this position.

The move could change the way the federal government devises rules and policies to limit the American public's exposure to environmental pollutants.

"This is a really big step and has far reaching implications for protecting children's health," said Jane Houlihan, vice president of research for Environmental Working Group, a non profit environmental research organization.

"The government's message is simple. Children are at greater risk from exposure to carcinogens than adults."

The U.S. Environmental Protection Agency's (EPA) final draft of new guidelines for cancer risk assessment, released yesterday, "explicitly recognizes that variation exists among people in their susceptibility to carcinogens."

The final draft considers children age two and younger to have 10 times the cancer risk of adults when exposed to mutagenic carcinogens, which cause cancer through direct damage to DNA.

Children age two through 15 would be considered to have three times the risk of adults.

Mutagenic carcinogens include arsenic, benzene, formaldehyde, mutagen X, brominated organics and polycyclic aromatic hydrocarbons.

EPA's guidelines for carcinogen risk assessment are the framework for agency scientists to assess possible cancer risks from exposures to environmental pollutants. They are used throughout the federal government to evaluate risks from environmental pollutants.

These guidelines have not been updated since they were first issued in 1986 and the current review is intended to make greater use of the increasing scientific understanding of risks from carcinogens.The proposed updates to these guidelines could prompt reevaluation of existing standards.

For its review, EPA analyzed 23 peer reviewed studies of cancer incidence from the past 50 years.

There is increasing scientific evidence that children face much higher cancer risks from exposure to environmental pollutants than adults. (Photo courtesy The National Children's Cancer Society)

Environmentalists and public health advocates said the new guidance is a good first step, but some are concerned it does not consider gender differences in cancer risks and worried that it could allow new guidelines for adult risks to carcinogens to be weakened.

And EPA has evidence that supports increasing the risk standard for children even further, Houlihan said.

The figure of 10 times used by EPA for children under two years of age is the average of its analysis, but some mutagenic carcinogens have been shown to be some 65 times more potent when exposure occurs during childhood.

EPA data shows that half of lifetime cancer risk accumulates in the first two years of life, Houlihan said, and the agency should extend its guidance to cover carcinogens that act through other mechanisms than mutagenicity, such as phthalates and atrazine.

"The guidelines need to extend to all carcinogens," said Houlihan.

EPA's review finds not enough available data to determine cancer risk assessment from non mutagenic carcinogens for specific segments of the population. It suggests that a variety of approaches still need to be developed and additional research is required.

Some mutagenic carcinogens are 65 times more potent when exposure occurs during childhood. (Photo courtesy Hugs and Hope)

The increasing scientific evidence that children face higher risks from exposure to carcinogens prompted the agency to release for public review and comment draft supplemental guidance for assessing early life exposure to carcinogens.

The supplemental guidance is part of the agency's response to a 1994 recommendation by the National Research Council that "EPA should assess risks to infants and children whenever it appears that their risks might be greater than those of adults."

The final draft guidelines on risk assessment, according to EPA, reflect many of the comments and suggestions provided to EPA by public and independent scientific peer reviews.

The public can submit comments on the proposed guidelines through May 1, 2003. They will take effect after a final review by an independent scientific advisory board.

More information on the proposed guidelines can be found at: http://epa.gov/ncea/raf/cancer2003.htm