The study determined that a tolerable threshold for human exposure to this toxic chemical would be 500 to 1,500 times higher than is outlined by the Environmental Protection Agency. And in other work, which is still in preliminary stages, studies seem to be showing that previous studies about aflatoxins, another common carcinogen, are reasonably accurate.
"The EPA levels of exposure for both the PAH compound and aflatoxins were determined using essentially the same methodology based on rodent studies," Bailey said. "But our research suggests that the findings for aflatoxins are pretty accurate, while for the PAH compound we're off by a factor of about 1,000."
In addition, the OSU study determined that use of "biomarkers" such as DNA adducts to determine carcinogenic potential can also be flawed. That was a "huge surprise" and very significant, Bailey said, since much of the carcinogen research around the world is based on this.
Together, the findings suggest that past methodology to assess the danger of some of the most common carcinogens in the world may be questionable. They may, or may not, be accurate.
"In the past, our regulatory agencies have done the best they can with the data they have available," Bailey said. "The key is that now we have animal models that can far more accurately determine the real cancer risk some compounds pose, and in biochemical detail that's more valuable than the kill-them-and-count-them approaches of the past."
"It may be time for government agencies and medical researchers to reconsider the way we approach carcinogen research," he said.
|Contact: George Bailey|
Oregon State University