During the fall of 1984, we conducted a survey of umbilical cord blood lead levels of 723 live births that occurred at 5 hospitals located in 5 cities in California. Historical ambient air lead levels were used as a qualitative surrogate of air and dust exposure. The area-specific cord blood means (all means approximately 5 micrograms/dl), medians, deciles, and distributions did not vary among locations. The California distributions included means that were lower than the 6.6 micrograms/dl reported in Needleman et al.'s Boston study in 1979. Indeed, the entire California distribution was shifted to the left of the Boston study distribution, even though 3% of the California cord lead levels exceeded 10 micrograms/dl--the level above which Needleman et al. have documented psychoneurological effects in children during the first few years of life. Fourteen percent of premature babies had cord blood lead levels above 10 micrograms/dl. The association between prematurity (i.e., less than 260 d gestation) and elevated (greater than 5 micrograms/dl) cord blood lead was observed in all hospitals and yielded a relative risk of 2.9 (95% CI: .9, 9.2) and a population attributable risk of 47%. Further research is needed to confirm this association and to explore the roles of endogenous and exogenous sources of lead exposure to the mothers who give birth to premature infants.

We recently concluded that exposure to solvent-contaminated drinking water was an unlikely explanation for observed excesses of adverse pregnancy outcomes during 1980-1981 in the Los Paseos neighborhood of Santa Clara County, California, because these excesses were not observed in an adjacent exposed area. The validity of this conclusion depends on the assumption that the two areas had comparable exposure. Using quantitative methods to model movement of the solvent leak plume and water flow within the distribution system, we estimated that women with adverse outcomes were no more likely to have received contaminated water than women with normal live births. These results strengthen the conclusion that exposures to water from the contaminated well were not responsible for the excess of adverse outcomes observed in the Los Paseos area.