High levels of chemicals discovered in moms, babies
IU researchers say there is little data on health risks from flame-retardant PBDEs

By Steve Hinnefeld, Herald-Times Staff Writer

Indiana University researchers have found relatively high levels of potentially harmful flame-retardant chemicals in the blood of Indiana mothers and their infants.

The chemicals, called polybrominated diphenyl ethers or PBDEs, were found at levels 20 times higher than those reported in Sweden and Norway.

"Why is the U.S. high? We don't really know," said Ron Hites, a professor at IU's School of Public and Environmental Affairs in Bloomington.

Hites worked with faculty at the IU School of Medicine and chemistry department on the study. Their findings were published this week in the online edition of Environmental Health Perspectives.

A companion study from California, also published this week, found similar levels of the chemicals, which are used to prevent fires in computers, TVs and other electronic products and in polyurethane foam.

The findings bring to mind the discovery 30 to 40 years ago of the pesticide DDT and the industrial chemicals PCBs in the tissues of birds, fish and humans. Environmental levels of those chemicals have dropped significantly since their uses were restricted, Hites said. But levels of PBDEs, which are still in use, are increasing exponentially, he said.

Hites said the findings are troubling, but it's not clear how troubled people should be. Lab studies have shown PBDEs to cause health problems in rats, but relatively little is known about their effects on humans.

"We don't know," he said. "Reasoning by analogy with PCBs, there are probably some (health risks). But it took us 25 years to figure out what the health effects of PCBs were, and there's still controversy about it."

The study involved analyzing blood samples taken from 12 Indiana mothers and their babies' umbilical cords immediately after birth. The analysis used sophisticated techniques called gas chromatography and mass chromatography.

Researchers found PBDEs at levels ranging from 15 to 580 parts per billion in the blood fat of the mothers and from 14 to 460 parts per billion in the umbilical cords.

Hites said there was nothing in the experience or lifestyles of the women to explain the different levels, or the reasons their levels were higher than those found in northern Europe.

He said it's not obvious whether human exposure is chiefly from consumer products or industrial wastes. He knows of three factories that manufacture PBDEs, two in Louisiana and one in Israel.

The chemicals, sometimes called brominated flame retardants, are soluble in fat and accumulate in the fatty tissues of humans and other animals.

Much of the early work in detecting and measuring them has been done in Europe, particularly Sweden and Denmark. The European Union has considered trying to regulate their use and disposal, including a requirement that used computers be returned to manufacturers and the chemicals recycled. U.S. authorities have been slower to talk about regulation.

"Most of this work, I've got to tell you, is in Europe," Hites said.

He first heard about the chemicals at a conference in Stockholm in 1997. A Swedish researcher had studied archived samples of human breast milk and found increasing levels of PBDEs over a 25-year period.

"I got interested and started wondering what was going on around the Great Lakes region," said Hites, who has done important studies of environmental levels of PCBs, dioxins and furans for 20 years.

He worked with Robert Bigsby, an IU Medical School researcher, to set up and conduct the study.

Hites said they plan additional studies of PBDE levels in mothers and babies. He has U.S. Environmental Protection Agency funding to look for the chemicals in archived fish samples from the Great Lakes. And he plans to work with the IU Medical School on studies of the toxicology of the chemicals.