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New Class of Chemicals Accumulating in People, Land Animals

By Jack Kaskey
July 16 2007;  bloomberg.com

July 12 (Bloomberg) -- Pesticides and fragrances are accumulating in people and Arctic land animals, part of a class of thousands of chemicals that need to be assessed for the potential to collect in the food chain, a study said.

Risk assessments currently look for chemical accumulations in fish. That misses substances that people and land animals retain and fish remove by breathing in water, according to a study by researchers at Simon Fraser University in Burnaby, British Columbia.

About one-third of the 12,000 organic chemicals in production fall into this category, constituting a previously unidentified class of potentially bio-accumulative substances, according to the journal Science, where the paper will be published tomorrow. New regulatory assessments are needed to prevent harm to the ecosystem and humans, the study said.

"As a society, we would be stupid not to feel the urgency of this paper's call," Sonya Lunder, a senior analyst at Environmental Working Group, a Washington-based watchdog, said in a telephone interview from Oakland, California. "This underscores the importance of making good decisions on the chemicals we are using in commercial products."

Substances the study found concentrating in terrestrial organisms include the pesticides lindane, dicofal, endosulfan and trifluralin; musk xylene, a synthetic fragrance used in soaps and perfumes; and the intermediate chemicals tetradifon and tetrachlorobenzene.

Tyson, ConAgra

Makers and handlers of trifluralin, a broadleaf herbicide used to control weeds in grass, cotton and soybeans, include Tyson Foods Inc., ConAgra Foods Inc. and The Andersons Inc., according to the Environmental Protection Agency's 2004 Toxic Release Inventory. Tyson was unable to comment immediately. The other companies didn't return calls for comment.

International Flavors & Fragrances Inc. made or imported at least 10,000 pounds of xylene musk in 1998, according to a U.S. Environmental Protection Agency database. Company spokeswoman Melissa Sachs said International Flavors has never produced the chemical.

Researchers found high concentrations of these chemicals in land animals, including wolves, seals and polar bears, and native Inuit people, and no accumulation was found in Arctic fish. Chemicals that don't vaporize easily and dissolve readily in water have been overlooked because they don't build up in fish and were assumed to be safe, the study said.


Toxins that can't be excreted easily become concentrated in body fat as they move up the food chain, a process called biomagnification. Such was the case with DDT, a pesticide that contributed to a sharp drop in the population of bald eagles before it was banned.

Governments around the world are evaluating all commercial chemicals to identify substances that concentrate in food chains to levels that harm people and the environment, according to the paper.

More than 120 nations have agreed to eliminate PCBs, dioxins, furans and nine pesticides under the Stockholm Convention on Persistent Organic Pollutants, which took effect in 2004.

Fewer than 10 percent of chemicals in use are fully screened for human health effects, Lunder of the Environmental Working Group said. The study should help focus regulators' attention on the chemicals most likely to cause harm, she said. Many chemicals, such as brominated flame retardants, were discovered to be accumulating in people by accident, she said.

"People in the U.S. still have chemicals in their bodies that were banned from commerce three decades ago," Lunder said. "We've made some really big mistakes, and anything we can do to prevent learning that lesson with our own bodies and our own health is a really important tool."

Study co-author Frank Gobas did not respond to requests for comment.

To contact the reporter on this story: Jack Kaskey in New York at jkaskey@bloomberg.net .