A paper presented at Toronto’s “Dioxin 2005” conference suggests that levels of PBDEs in humans are overtaking levels of long-banned chemicals PCBs

Toronto – An analysis of persistent chemicals in the breastmilk of Pacific Northwest mothers, including ten mothers from British Columbia, was released today at an international scientific conference in Toronto, “Dioxin 2005.” The analysis found that levels of the toxic flame retardants PBDEs may be overtaking those of PCBs, an industrial chemical banned in the late 1970s. PBDEs, which are structurally similar to PCBs, are accumulating rapidly in humans and the environment and may present similar health threats to those of PCBs, which have been linked to developmental delays and cancer.

Thirty percent of the mothers tested in the study—which was coordinated by Seattle-based research center Sightline Institute—had higher levels of PBDEs than PCBs. The breastmilk samples for the study were analyzed in the Hazardous Materials Laboratory of Cal/EPA’s Department of Toxic Substances Control (DTSC) in Berkeley, California. The Northwest study is one of several being conducted by DTSC scientists at the Department’s Berkeley lab—including one underway involving analyses of California women’s breastmilk—indicating that levels of PBDEs in humans may be overtaking those of PCBs.

“The comparison suggests that PBDEs have emerged as a major environmental health concern,” said Clark Williams-Derry, research director for Sightline. “PBDEs could be as potent a problem as PCBs, which are still polluting people and the environment 30 years after they were banned.”

“Canada needs to ban these substances immediately,” said Paul Muldoon, executive director of the Canadian Environmental Law Association. “Such hazards fall between the cracks of Canada’s environmental and consumer product laws. The forthcoming review of the Canadian Environmental Protection Act must address this gap.”

The PBDE data from the study was originally released in 2004 by Northwest Environment Watch (now Sightline Institute), but the PCB data and the comparison between the chemicals are new. The 40 mothers in the study—who are from British Columbia, Montana, Oregon, and Washington—had levels of PBDEs 20 to 40 times higher than levels found in individuals from Europe and Japan. PBDEs are widely used as flame retardants in furniture foams, industrial textiles, and consumer electronics.

Williams-Derry emphasized that mothers should continue breastfeeding. Research shows that despite the presence of contaminants, breastfeeding is the healthiest choice. Benefits include reducing the risk of many illnesses in infants, as well as the incidence of anemia and some cancers in women. NEW chose breastmilk as a measure because it is the most convenient body fluid to obtain and study, and because it provides a good proxy for contamination levels in fetuses, pregnant and nursing women, and the general population.

Specific findings from the CAL/EPA analysis and the original NEW study include:

Some PBDE levels surpassing those of PCBs: The CAL/EPA scientists analyzed levels of 12 types of PBDEs, and 80 types of PCBs in the 40 mothers studied by NEW. Of the mothers, 13 had higher levels of PBDEs than PCBs. For the most abundant forms of the chemicals, PBDE-47 and PCB-153, the average PBDE level was higher, and 65 percent of the mothers had more PBDE-47 than PCB-153 in their breastmilk, a trend that could become more common if PBDE levels in people continue to rise.

Results for British Columbia: All 40 women in the study had measurable levels of PBDEs and PCBs in their bodies. The 10 British Columbian women in the study had the lowest average level of PBDEs (60 parts per billion, or ppb), compared to 121 ppb for Oregon, which had the highest average. Further testing is needed to clarify whether these variations are representative of each region’s population. (See NEW’s regional fact sheet for results for each Northwest region.)

PBDE levels rising: The CAL/EPA analysis notes that previously, in most biological samples, total levels of PBDEs were less than PCBs, but, “as a consequence of the increasing PBDE levels, this may be changing.” Over the past 20 years, rising levels of PBDEs have been found by almost every study that has examined time trends, especially studies in North America.

Exposure through food and house dust: The CAL/EPA scientists found no correlation between PBDE and PCB levels in the women, suggesting that the two chemicals enter people in different ways. PCBs are believed to enter the body through food, particularly from consuming fish. Several recent studies suggest that house and office dust may be a significant exposure pathway for PBDEs.

Health effects of the chemicals: PCBs are a known carcinogen and have been linked to developmental delays, including significant IQ deficits that persist at least through age 11. PBDEs are structurally similar to PCBs and while no studies have been done on humans, laboratory studies have shown that PBDEs can impair memory and learning, alter behavior, delay sexual development, and disturb thyroid hormone levels. Research indicates that the two chemicals may be more harmful in combination than individually.

Some action on PBDEs has been taken. Sweden was the first country to phase out some forms of PBDEs in the 1990s, followed by the European Union, and US states including California, Washington, and Oregon. But while the federal government in Canada has conducted an initial assessment of the risk of PBDEs, it has not yet banned the chemical. The Canadian Environmental Law Association (CELA) recommends a PBDE ban using regulatory tools instead of waiting for voluntary actions.

“I don’t like the fact that we have these chemicals in our bodies,” said Erin McAllister, a Vancouver, BC, mother who participated in the study. “Why are countries like Sweden on the leading edge of all these innovations? Canada should be as well.”

Sightline Institute also recommends that programs be established to help consumers dispose of PBDE-laden products; and that governments adopt a prove-safety-first approach with new chemicals. Roughly 80,000 different synthetic compounds have been introduced since the 1940s, yet only a relative handful have been tested for their potential health effects in humans.

“PBDEs are sometimes called ‘the next PCBs,’ for good reason,” said NEW research director Williams-Derry. “It’s time to stop using the chemicals, especially since safer alternatives exist.”

A paper describing the results of the Cal/EPA analysis by Jianwen She, Arthur Holden, Margaret Sharp, Clark Williams-Derry, and Kim Hooper will be presented today at the Dioxin 2005 conference in Toronto. Sightline Institute is a Seattle-based research center that monitors regional progress. More information on the CAL/EPA analysis and the Sightline study is available here.

More information

Main study page

Regional fact sheet with results for each Northwest region

August 25, 2005