Studies find remarkably high levels of flame retardants in California's children.

May 03, 2010

Rose, M, DH Bennett, A Bergman, B Fangstrom, IN Pessah and I Hertz-Picciotto. 2010. PBDEs in 2- 5-year-old children from California and associations with diet and indoor environment. Environmental Science and Technology http://dx.doi.org/10.1021/es903240g.

Windham, GC, SM Pinney, A Sjodin, R Lum, RS Jones, LL Needham, FM Biro, RA Hiatt and LH Kushi. Body burdens of brominated flame retardants and other persistent organo-halogenated compounds and their descriptors in U.S. girls. Environmental Research http://dx.doi.org/10.1016/j.envres.2010.01.004.



Synopsis by Ami Zota, Sc.D

2010-0427californiachildren
San Jose Library/flickr
Two new studies show remarkably high levels of PBDE flame retardants in the bodies of California children. PBDE body burden levels in two separate populations of California children were 10 to 1,000 times higher than European children, 2 to 10 times higher than other U.S. children and adults, and approached levels measured in occupationally-exposed adults.
The studies are the first to report PBDEs in a large group of California children. While the findings are surprising, they are consistent with previous studies that have demonstrated elevated PBDE exposures in California and in children compared to adults.
 

Context

Polybrominated diphenyl ethers, (PBDEs) are chemical flame retardants that have been added ubiquitously to consumer products, such as polyurethane foam in furniture and electronics, since the 1970s. PBDEs are persistent organic pollutants (POPs) that do not readily break down in the environment. They can bioaccumulate in the food chain.

Three major PBDE commercial mixtures have been commonly used in consumer products: deca-BDE, octa-BDE and penta-BDE. Penta-BDE has been most often mixed into polyurethane foam (PUF) used in furniture, while octa and deca-BDE are used in electronics and other plastic products.

Concern over human exposure to PBDEs stems from their structural similarity to PCBs, another class of POPs, which has been shown to impair brain development and disrupt endocrine function in humans. PBDEs can disrupt the thyroid system and have been linked to neurodevelopmental problems in children following prenatal exposure.

PBDEs are not chemically bound to products and can easily migrate into the indoor air and dust. House dust is one of the primary routes of human exposure to PBDEs. Young children are especially vulnerable due to their close contact with the floor and frequent hand-to-mouth behavior. Diet can also contribute to exposure, especially contaminated meat and dairy.

Concentrations in environmental and human samples vary internationally. The United States has much higher reported blood, breast milk and house dust levels compared to Europe. This is consistent with the greater use of these chemicals in the United States.

There is also regional variation in PBDE exposure within the United States. Elevated exposures are measured in California as compared to the rest of the country. A study by Silent Spring Institute found that PBDE levels in the dust of California homes were 4 to 10 times higher than levels found elsewhere in the United States. Californians have twice the level of PBDE in their blood than people in the rest of the country.

The higher exposures in California are likely an unintended consequence of Technical Bulletin 117. The performance-based furniture flammability standard requires furniture to be fire resistant to an open flame for 12 seconds. Compliance with this standard was historically achieved with PBDEs. This standard is unique to California.

Penta- and octa-BDE production in the United States halted in 2004 following bans in several states including California. Deca-BDE is being phased out. However, due to the slow turnover of treated furniture and other products, the chemicals will be present in our environment for a long time. Additionally, PBDEs are being replaced with alternative flame retardants, such as Firemaster 550, which may pose new health and safety concerns due to their similarity to PBDEs.

What did they do?

Rose et al. measured circulating levels of PBDE in 100 children between 2 to 5 years old from California as part of an ongoing study of environmental influences on neurodevelopment and autism. They measured 11 different PBDE chemicals from the penta-, octa-, and deca- BDE formulations. They also collected information in a telephone interview about breastfeeding history, diet, potential sources of PBDEs and demographic characteristics so they could identify factors that may influence body burden levels.

Windham et al. measured and compared body burden levels of PBDEs and other POPs (for example, PCBs and DDE) in 600 girls aged 6 to 8 years old from California and Ohio. The PBDE chemicals in this study were representative of the penta- and octa-BDE formulations but not deca-BDE. They focused on pre-puberty to investigate if chemicals that affect the endocrine system might potentially alter the reproductive development that occurs through puberty and into adolescence. They collected information on social factors, breastfeeding history, body mass index (BMI) and other potentially important biological factors.

Unfortunately, neither study measured PBDE levels in the participant’s diet or household dust, a more direct measure of indoor exposures.

What did they find?

Rose and colleagues reported that in comparison to other studies, the PBDE levels, characteristic of penta-BDE, in 2- to 5-year-old California children is 10 to 1,000 fold higher than European children, 5 times higher than other U.S. children and 2 to 10 times higher than U.S. adults. The levels in this population approach and often exceed the levels measured in occupationally exposed U.S. adults working as polyurethane foam recyclers and carpet installers. Chemicals from deca-BDE (BDE-209) were also elevated, but there were fewer studies available for comparison.

They also found that diet, indoor environment and social factors influenced children’s body burden levels. Eating poultry and pork contributed to elevated body burdens for nearly all types of flame retardants. Presence of new mattresses or furniture was associated with higher levels of deca-BDE chemicals only, which may reflect the phasing out of penta- and octa-BDE. Additionally, lower socioeconomic status – as measured by the educational level of the mother – was associated with higher PBDE levels in the child. Hispanic children and children of foreign-born mothers had lower levels of some but not all chemicals.

Windham and colleagues found significantly higher levels of PBDE flame retardants in girls from California compared to Ohio. Levels among school-aged girls in California were higher than other U.S. children and adults but slightly lower than those measured in the 2- to 5-year-olds in the Rose study.

Windham et al. also observed a difference in exposure by race and ethnicity. Black girls had significantly higher levels of PBDEs compared to white girls, and Hispanics had intermediate values. Interestingly, PBDEs were not correlated with levels of PCBs or pesticides, suggesting different exposure pathways. Blacks had the lowest levels of PCBs compared to other race and ethnic groups.

Similar to the Rose et al. findings, the Windham study also observed that higher PBDE levels were found in children with caregivers who were less educated. Reasons for the racial and socioeconomic disparity in exposure are unknown, but may reflect differences in exposure pathways, housing factors or furnishings.

What does it mean?

This is the first set of studies to measure PBDEs in a large group of children who live in California. Taken together, these studies confirm that California's children have higher body burdens of PBDEs than children in other parts of the world – including Europe and Mexico – and most adults who do not work with the chemicals.

These high levels were linked to the children's exposure through diet and indoor air, as well as through socioeconomic factors. The studies are some of the first to identify an association of higher PBDE body burden with lower educational status, which may reflect differences in housing stock or furniture quality.

The studies are also some of the first to identify which racial groups have the highest exposures. Reasons for racial/ethnic differences in PBDE body burden are likely complex and influenced by where people live (presently and formerly), income and education, as well as potential differences in diet or metabolism.

The results support previous studies that demonstrate elevated PBDE exposures in California adults compared to the rest of the country and the world. The high levels are likely due to the unique furniture flammability standard in the state.

Because of these elevated exposures, the children may be more vulnerable to the adverse health effects associated with PBDE flame retardants. Studies in people and animals show the chemicals can disrupt thyroid hormones. These hormones are important regulators and influence many systems, including reproduction and metabolism. Prenatal exposure to PBDEs has also been shown to affect brain development in ways that may interfere with learning, memory, and physical development.


Resources

Agency for Toxic Substances and Disease Registry. Toxicological fact sheet for polybrominated diphenyl ethers.

Betts, KS 2008. New thinking on flame retardants. Environmental Health Perspectives 116:A210-A213.

Blum, A. 2007. The fire retardant dilemma. Science 318(October 12):194-195 (PDF).

Herbstman, JB, A Sjodin, M Kurzon, SA Lederman, RS Jones, V Rauh, LL Needham, D Tang, M Niedzwiecki, RY Wang and F Perera. 2010. Prenatal exposure to PBDEs and neurodevelopment. Environmental Health Perspectives http://dx.doi.org/10.1289/ehp.0901340.

U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics. Polybrominated diphenyl ethers (PBDEs).

Zota, AR RA Rudel, RA Morello-Frosch and JG Brody. 2008. Elevated house dust and serum concentrations of PBDEs in California: Unintended consequences of furniture flammability standards? Environmental Science and Technology 42: 8158–8164.

 

 

 

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