The Week That Was
March 22, 2003

1. New on the Web: WITH THE COLUMBIA ACCIDENT STILL UNDER INVESTIGATION, WE SHOULD RECALL THAT THE CHALLENGER SHUTTLE DISASTER CAN BE TRACED TO ENVIRONMENTAL ZEAL: the 1977 Consumer Products Safety Commission ban on retail asbestos products and the ban on all asbestos use by the Environmental Protection Agency.







2. CDC Releases Second "Biomonitoring" Report:

In its Second National Report on Human Exposure to Environmental Chemicals, the U.S. Centers for Disease Control and Prevention (CDC) measured levels of 116 chemical substances in the blood and urine of more than 2,500 volunteers. Major findings included declines in exposures to lead, environmental tobacco smoke and pesticides. Although the study included information on dioxins and related compounds, as CCC noted, "…the CDC data represent good news for the American public: average dioxin blood levels are so low that they are below the limits of analytical detection." More information is available at


3. Pperc Editorial Argues for Lengthy Phaseout of Perc:

A Newsday editorial by Peter Sinsheimer, director of the Pollution Prevention Education and Research Center (PPERC), and Robert Gottlieb, professor of urban and environmental policy, both at Occidental College in Los Angeles, argues for ending the use of perchloroethylene (perc) by dry cleaners. The piece argues for a switch to alternatives such as wet cleaning, with a phaseout over 10 to 15 years. Sinsheimer and Gottlieb say that the phaseout is a better solution than installing equipment to reduce perc emissions. Gottlieb is co-author of the recent book "Deceit and Denial:

The Deadly Politics of Industrial Pollution." For full text of the article, please click on the following link: story.


4. Massachusetts Developing Influential Mercury Emissions Standard:

Massachusetts is developing new state standards that could reduce mercury levels by as much as 90 percent, significantly beyond reductions expected in EPA's soon-to-be-released national standard. The Massachusetts plan, to be released June 1, is being closely observed as a trendsetter since it will constitute the first proposed standards in light of an international agreement. Chemical Policy Alert says that industry officials have pointed out that regulators must acknowledge, "that there are challenges because each plant has a unique set of circumstances." Industry is urging Massachusetts to continue gathering information before making new rules because efforts there will have "far-ranging implications.".


5. EPA Dioxin Reassessment by NAS:

The federal appropriations bill for fiscal year 2003 addressed EPA's draft Dioxin Reassessment, with a provision directing the Interagency Working Group (IWG) to complete its review of the draft reassessment within 60 days. The National Academy of Sciences (NAS) review is to begin immediately after the IWG review is completed, or after 60 days if the IWG review remains uncompleted. The health policy issues that the IWG and NAS are to resolve include: the evidence to classify dioxin as a human carcinogen; the basis for a using a linear, non-threshold model for the cancer risk estimate; the validity of the toxic equivalency factor (TEF) approach absent specific data for each dioxin-like chemical; and the use of body burdens as the appropriate dose metric.

6. Dioxins May Have Beneficial Effects:

A new study shows that dioxins may have beneficial effects at low doses. Toxicologists at the University of Massachusetts found that animals had a "profoundly lower tumor risk" when exposed to low levels of dioxin. One researcher theorized that small amounts of chemicals may increase cells' natural defenses by "exercising" them. The study concluded that while certain chemicals are always harmful in large doses, there may be a consistent low range when the chemicals are helpful. According to New Scientist, "if [the study's] model supplants today's gospel, it could mean a radical shake-up in the way we measure the hazards chemicals pose to humans and the environment, and the way drug doses are worked out."

Dangerous levels of toxins miscalculated: Potential pollutants and poisons may be beneficial in low doses. We may be putting too much effort into cleaning our environments.

By HELEN R PILCHER 13 February 2003
© Nature News Service / Macmillan Magazines Ltd 2003

The levels at which potentially toxic substances such as mercury and lead are classified as dangerous may have been miscalculated, two US scientists are warning. Risk assessments and regulations on safe limits for these substances in medicine and the environment may have to be rethought, they warn.

There are safe levels below which potential pollutants and poisons may actually be beneficial, say Edward Calabrese and Linda Baldwin of the University of Massachusetts in Amherst. For the past 30 years, cancer-causing chemicals and X-rays have been viewed largely as dangerous whatever their level. "The field of toxicology has made a terrible blunder," says Calabrese. "A lot of high-powered people need to take the time to explore this."

For example, dioxins, which are industrial by-products that at certain doses can cause cancer, can actually reduce tumor growth in some species. Similarly, small amounts of the toxic trace metal cadmium can promote plant growth.

"What we call 'toxic chemicals' is a misnomer," says cell biologist and UK government advisor Anthony Trewavas from Edinburgh University. "Mild chemical stress is beneficial."

Having identified over 5,000 similar examples, Calabrese and Baldwin are among a growing number of researchers who feel that the hazardous nature of toxic substances has been overstated. The levels used in studies are not comparable to those normally experienced by humans, Calabrese says. "This provides an interesting challenge for the clinical and pharmaceutical industries as they develop new medicines."

The point of toxicological testing is to determine the drug exposure at which undesired effects are observed

Britain's Medicines Control Agency (MCA) is more cautious. "The point of toxicological testing is to determine the drug exposure at which undesired effects are observed," a spokesperson said, adding that the new criticisms are, "unlikely to change the way in which the MCA or other regulatory agencies conduct product risk-benefit analysis."

The debate also raises the question of how clean our environment really needs to be. Some argue that billions of dollars are being wasted ridding the world of substances that are dubbed 'hazardous', when low levels could actually be a good thing.

"We don't need to spend large amounts of money on removing chemicals from the environment," says Trewavas. "Food contains lots of natural chemicals that are as damaging as synthetics. We consume lots of these all the time without harm. The public need re-educating in this."

But convincing people that 'safest' is a more meaningful description of risk than 'safe' and 'dangerous' is notoriously difficult.

Calabrese, E.J. & Baldwin, L.A. Toxicology rethinks its central belief. Nature ,421, 691 -321 , (2003).

7. The demise of frogs and amphibians: Not ozone-related after all

Faithful readers of TWTW know of our fixation on frogs - ever since a noted professor of zoology at Oregon State University (yes… the same institution that houses the notorious Jane Lubchenco) blamed their demise on ozone depletion caused by CFCs. [Follow the frog trail with ]

His "finding" created quite a stir at the time - although not as much as the "blind sheep" stories that hyped the Antarctic Ozone Hole. When told that there was no evidence for any increase in solar ultraviolet radiation, he opined: "Well, maybe it's a fungus."

Now a graduate student from the University of Washington has discovered a leading cause: non-native trout that like to eat frogs and frog eggs. Delicioso!



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