GOALS: This study investigated the role of immigration to California on PBDE levels in Latino children.

METHOD: The research group compared serum PBDE concentrations in a population of first generation Mexican-American 7-year old children (n=264), who were born and raised in California, with 5-year old Mexican children (n=283), who were raised in the states in Mexico where most mothers, having participated in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, had originated.

RESULTS: On average PBDE serum concentrations in the California Mexican-American children were three times higher than their mothers’ levels during pregnancy and seven times higher than concentrations in the children living in Mexico. The PBDE serum concentrations were higher in the Mexican-American children regardless of length of time their mother had resided in California or the duration of the child’s breastfeeding. These data suggest that PBDE serum concentrations in these children resulted primarily from postnatal exposure.

CONCLUSION: In the first study to assess the relationship between environmental levels of BTEX and NTDs, we found an association between benzene and spina bifida. Our results contribute to the growing body of evidence regarding air pollutant exposure and adverse birth outcomes.

Policy Implications

Two of the three commercially produced preparations of PBDEs have been phased out in the U.S. and Europe since 2004. However, the semi-volatile compounds continue to be released from old furniture, materials and equipment, and are bioaccumulative, persisting in humans and the environment for years. In addition, one preparation, decaBDE, is still used in consumer electronics and wire insulation, among other applications. This study found that the high PBDE body burdens in the 7 year olds in California were primarily due to postnatal exposure sources, including house dust and food. Previous biomonitoring studies indicated that children living in California have some of the highest documented PBDE serum levels worldwide, and exposure studies have revealed higher PBDE levels in house dust collected in California compared with other parts of the U.S. and Canada. These findings may be an unintended consequence of California’s furniture flammability standards, some of which were developed in the 1970’s. The regulations resulted in the addition of millions of pounds of flame retardants to various product materials during manufacturing. Attempts in other regions of the U.S. to meet California’s flammability standards have resulted in the spread of products containing high levels of PBDE throughout the U.S. Some studies indicate that PBDE levels may be higher in lower-income homes due to the presence of poorly manufactured products, aging and deteriorating products, and poorer ventilation.

PBDE crosses the blood-brain barrier and negatively impacts brain development, interferes with thyroid hormone levels, and may cause liver toxicity. Strict regulations of decaPBDEs at the federal and state levels are needed, and local consumer outreach, especially targeted to vulnerable populations, should provide information on potential sources of continuing exposure. Mandatory toxicological testing of other halogenated flame retardants or replacement chemicals should be required of chemical manufacturers prior to commercial use.

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Full article available courtesy of Environmental Health Perspectives here.

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GOALS:  To conduct a case–control study assessing the association between ambient air levels of benzene, toluene, ethylbenzene, and xylene (BTEX) and the likelihood of NTDs to occur among offspring.

METHOD: The Texas Birth Defects Registry provided data on NTD cases (spina bifida and anen­cephaly) delivered between 1999 and 2004. The control group was a random sample of unaffected live births, frequency matched to cases on year of birth. Census tract–level estimates of annual BTEX levels were obtained from the U.S. Environmental Protection Agency 1999 Assessment System for Population Exposure Nationwide.

RESULTS: Mothers living in census tracts with the highest benzene levels were more likely to have off­spring with spina bifida than were women living in census tracts with the lowest levels. No significant associations were observed between anen­cephaly and benzene or between any of the NTD phenotypes and toluene, ethylbenzene, or xylene.

CONCLUSION: In the first study to assess the relationship between environmental levels of BTEX and NTDs, we found an association between benzene and spina bifida. Our results contribute to the growing body of evidence regarding air pollutant exposure and adverse birth outcomes.

Policy Implications

Benzene is known to cross the placenta. Previous studies found significant associations between maternal occupational exposure to benzene and other organic solvents and birth defects, including NTDs. This study found an association between prenatal exposure to benzene in ambient air and spina bifida, suggesting that adverse birth outcomes may not be limited to those whose mothers are occupationally exposed. Most of human exposure to benzene, aside from tobacco smoke, is from automobile exhaust and industrial emissions. Stricter industrial and motor vehicle emissions policies and regulations at the federal level are called for to reduce the general population’s exposure to benzene. In addition, adoption of innovative transportation policies, such as investment in sustainable transit programs, the creation of walkable neighborhoods and cities, and integrated bike paths, represent proactive approaches in reducing human exposure to benzene and other hazardous compounds from motor vehicle exhaust.