Metals in Tap Water Across Childcare and Home Environments

Abstract

Background: Metals, including lead, are frequently detected in tap water. Biomarker-based studies link elevated levels of lead with poorer child cognitive outcomes, including executive function (EF) skills. Nevertheless, few studies have characterized metal exposures in childcare center and home water samples or examined whether tap water concentrations of lead alone are associated with child EFs.
Objective: We aimed to 1) characterize metal concentrations in tap water from childcare kitchens, classrooms, and homes, 2) identify sociodemographic and environmental predictors of waterborne lead, and 3) test associations between lead and child EF outcomes.
Methods: Tap water from 51 North Carolina (NC) childcare kitchens, 120 classrooms, and 138 homes of 297 children (2-6 years old) were collected and analyzed for 15 metals via EPA Method 200.8. Child EF was assessed through a performance-based assessment and parent questionnaire. Regression models related waterborne lead to sociodemographic characteristics and water source. Path models evaluated associations between lead from samples in each setting and EF outcomes.
Results: Lead was detected in 67% of childcare kitchen, 34% of classroom, and 57% of home kitchen drinking water samples. While 8% of childcare kitchen, 3% of classroom, and 7% of home kitchen water samples exceeded the American Academy of Pediatrics reference level of 1 part per billion (ppb) for lead, none exceeded the NC state action level and U.S. Environmental Protection Agency standard of 10 ppb. Lead concentration in childcare kitchen water was negatively associated with inhibitory control.
Significance: Metals were frequently detected in childcare center and home water samples. Although waterborne lead concentrations were below the state action level, childcare kitchen lead was negatively associated with child EF skills.
Impact Statement: Key metals, including lead, were frequently detected in water samples collected from childcare kitchens (N=51), classrooms (N=120), and homes (N=138) of children ages 2-6 years old. Though lead levels were below state and federal guidelines, childcare center waterborne lead was negatively associated with children’s executive function skills (N=297). The absence of a link between home water lead and children's executive function skills may stem from selection bias, as families at higher risk for lead were underrepresented in home sample collection. The results underscore the frequency of exposure to, and potential impact of, neurotoxic contaminants in children’s daily environments.