An aggregate analysis of kriged residential soil arsenic and lead concentrations and mother-child measures in low-income populations

Background: We undertook an aggregate analysis of mother-child variables at the United States Census 2000 block group level, using low-income populations, and comparing spatially interpolated residential soil arsenic (As) and lead (Pb) concentrations with race/ethnicity of the mother, child's gestational age, and baby birth weight. Methods: Three areas with higher prevalence of intellectual disabilities in children than the state average (case areas), and one control area were identified. Arsenic and Pb, both neurotoxic metals, were measured in residential surface soils from the four locations, and concentrations were kriged across each sampling location and averaged by block group. Potential community-level sources of Pb including median year home built, and road coverage were identified. Results: Both As and Pb concentrations were significantly negatively correlated with weeks of gestation in one case area (rs = -0.28 and -0.26, and p = 0.01 and 0.017, respectively), which also had significantly lower weeks of gestation than the two other case areas (p < 0.05). There was a racial disparity with respect to mother's race; higher concentrations of As and Pb were associated with higher proportions of black mothers in two case and the control location (for Pb, all rs > 0.41 and p < 0.02), and lower Pb concentrations were associated with higher proportions of white mothers in all four locations (all p < 0.01). Pb concentrations were also associated with higher percent road coverage and older homes by block group. Conclusions: Higher soil metal concentrations were associated with mother-child measures, and racial differences and community characteristics may impact this relationship.