Children who drink private well water in US at 25% increased risk of high blood lead, may cause damage: Study
In the US, 13% of households depend on an unregulated private well for their water. Researchers have now found that compared with children in houses served by a regulated water utility, children in these homes have a 25% increased risk of elevated blood lead. Since lead is a neurotoxin that contributes to permanent cognitive and developmental impairment in exposed children, these children are at greater risk of experiencing irreversible cognitive damage, which can decrease their performance in school and increase their risks of behavioral problems, says the research team. “Little attention has been paid to lead (Pb) in private wells, which provide drinking water for 13% of the US population. This study evaluates the risk of lead exposure in children in households relying on private wells. It is based on a curated dataset of blood Pb records from 59,483 North Carolina children matched with household water source information,” say researchers from Indiana University, Bloomington; The University of North Carolina at Chapel Hill; University of Pennsylvania, Philadelphia; and Duke University, Durham.
According to the authors, lead exposure before age 7 has been associated with decreased IQ, poor performance in school, and increased risks of behavioral problems such as attention-deficit/hyperactivity disorder (ADHD), and juvenile delinquency. They emphasized that a largely overlooked route of lead exposure in water is unregulated private water systems, on which 42.5 million US residents (13% of the population) rely for their drinking water. Approximately 3.2 million children under age 7 (13% of this age group) live in such households. The vast majority of private water systems are wells serving a single household. The Safe Drinking Water Act’s requirements for lead monitoring and control do not cover private wells. “Households relying on private wells must be stewards of their own water quality, monitoring for lead on their own and, when necessary, installing and managing their own corrosion-control systems or replacing lead-containing well components and plumbing materials,” says the study published in Proceedings of the National Academy of Sciences (PNAS).
The team says that despite the evidence that private well water can pose high risks of lead exposure and that awareness of this risk is low, the extent to which private well water contributes to the persistent burden of elevated blood lead in some children is unknown. Accordingly, the authors analyzed the dataset for statistical associations between children’s blood lead and household drinking water source. “To our knowledge, no prior studies have investigated whether measured blood lead concentrations in US children obtaining their water from private wells are higher than those of children whose homes are served by community water systems that are regulated by the Safe Drinking Water Act. Determining whether children getting their water from private wells are at increased risk is critical to ongoing initiatives to= ensure that all US children are sufficiently protected from the lifelong adverse consequences of exposure to environmental lead,” they write.
The analysis shows that blood lead concentrations were significantly (20%) higher, on average, among children relying on private well water, compared with those served by a regulated water utility. The odds of elevated blood lead (5 μg/dL or greater) were 25% higher among children relying on private wells, compared with children served by a regulated water utility. Compared with children under 9 months, older children had higher blood lead, with the highest concentrations in those aged 16 to 20 months. However, the child’s age was not significantly associated with the risk of elevated blood lead, say researchers. Boys, on average, had slightly higher blood lead concentrations. However, their odds of elevated blood lead were not higher than for girls. Children in homes built after 1950 had lower blood lead concentrations than those in older homes.
The experts say the significant decline in concentrations among children living in homes built after 1978 highlights the effectiveness of the 1978 lead paint ban. Children’s blood lead concentrations decreased as the value of the child’s home increased, and the risk of elevated blood lead likewise decreased as the home value increased. Children’s blood lead concentrations also increased with the proportion of non-Hispanic Blacks in the neighborhood. Every 10% increase in the non-Hispanic Black “census block group population proportion” was associated with a 29% increase in the blood lead concentration in children living in that neighborhood.
“Children relying on private wells had blood lead concentrations that were 20% higher, on average, than children with community water service. These children also had 25% higher odds of having elevated blood lead compared with children in houses served by a community water system. These children are at significantly increased risk of exposure to lead in water, compared with their peers with community water service. Blood lead concentrations and risks of elevated blood lead were also higher among children in older or lower-valued homes, in areas with a higher percentage of non-Hispanic Black residents, and neighborhoods excluded from nearby municipal services,” the findings state.
The researchers explain that this lead exposure is likely a result of corrosion of household plumbing and well components because homes relying on private wells rarely treat their water to prevent corrosion. In contrast, corrosion control is required in regulated community water systems. “These findings highlight the need for targeted outreach to prevent lead exposure for the 42.5 million Americans depending on private wells for their drinking water,” they add.
Multiple types of policy interventions could help prevent exposure to lead in drinking water from private wells, says the team. According to them, legislation may be needed to ensure that all components in new wells, as well as in plumbing and fixtures connecting private wells to houses, are lead-free. The experts suggest interventions to control lead corrosion from plumbing and well components such as drop pipes, pump parts, and valves and fittings in households depending on private wells. Questions about water sources could be added to lead risk screening questionnaires, suggest authors. “For example, North Carolina recommends the administration of a blood lead risk screening questionnaire for all children at 12 and 24 months of age. The screening questionnaire asks about multiple potential risk factors for lead exposure — including whether the child lives in or regularly visits a home built before 1950, lives in or visits a home built before 1978 that has ongoing renovations, lives in a house with vinyl miniblinds, has a sibling who has had a high blood Pb level, lives in a high-risk zip code, or is a refugee — but does not ask about the child’s drinking water source,” they explain.
The research team also recommends that resources to support outreach to private well owners by local health departments could be increased. “At a minimum, health departments could use this additional support to promote water testing (through media platforms, mailers, pediatricians’ offices, childcare centers, and other venues frequented by families with young children),” say authors. They add, “They could also increase their capacity to provide guidance on selection and implementation of control measures such as replacement of confirmed or suspected lead-containing water system components, installation and maintenance of corrosion-control systems, and/or point-of-use or point-of-entry water filters capable of removing lead, in cases where high lead concentrations in drinking water are detected or suspected. To implement such outreach campaigns, local health departments are likely to need targeted financial support to hire and train personnel.”