Superfund Toxic Wastes
In May 1997, the California Birth Defects Monitoring Program reported findings which suggest that women who lived within a quarter-mile of a federally defined Superfund site during her first trimester of pregnancy may have a higher risk of having a baby with neural tube or heart defects.

The US Environmental Protection Agency (EPA) has identified 1,430 hazardous waste sites on its National Priority List for cleanup. These are often call Superfund sites. Such sites include inactive pesticide and chemical manufacturing plants, wood processing facilities, drum storage sites, contaminated ground-water areas, sanitary landfills, and mines.

The CBDMP had conducted this review of babies born near the 105 EPA named hazardous waste sites which are located within California in order to determine if living near one of these sites would raise the risk for birth defects. The researchers interviewed 2,000 mothers for this study, including mothers of children with specific birth defects.

The average woman living in California has a 1 in 1,000 chance of having a baby with a neural tube defect. That rate increased to 1 in 500 if she lived near a contaminated site, according to the findings of the study.

Similarly, the average chance of a woman in this state having a child with a serious heart defect is also about 1 in 1,000 live births. If the woman lived near one of the Superfund sites during the first three months of her pregnancy (when the fetus is physically growing and developing), her chance of having a baby with a heart defect increased to 1 in 250, the study found.

Of the mothers interviewed during this study, only 0.6% of them lived within 1/4 mile of a Superfund side during the early part of her pregnancy. It was noted in the study that almost half of these women lived on military bases. This was considered to be an important point as military bases make only up 20% of California’s Superfund sites.

The very small number of birth defect cases around hazardous waste sites may mean the study’s findings do not have strong statistical power, but the data was drawn from a population of over 1 million births, and to date, it is the largest study of this type. Considering the difficulty of studying hazardous waste sites, this study may be relevant to community planning and especially so if a community is considering the re-use of known contaminated sites.

(Journal of Epidemiology, July 1997)