By: Matthew Gribble, PhD
Although an effort is being made now to prevent further elevated lead exposures for children in Flint, the recent exposure is likely to linger in affected children’s bodies for a while. Research by geophysicist William Manton and colleagues (6) estimated the elimination half-life of lead to be 8-11 months for young children with transient exposures (e.g., professional home remodeling) and 20-38 months for children with ongoing exposure (e.g., parents doing remodeling). Although for the most severe cases of childhood lead poisoning, it is possible to accelerate the elimination of lead through a medical treatment called chelation, this treatment is not appropriate for the situation of most children in Flint and does not guarantee better outcomes. A trial of chelation in children ages 12-33 months with blood lead 20-44 μg/dL showed decreases in blood lead with chelation, but this did not correspond with differences in cognitive outcomes at age 7 (7). In summary, the contamination of young bodies and damage to young brains from a transient exposure to higher lead may be an ongoing problem.
In summary, extrapolating from previous studies of children exposed to low levels of lead, the population of children in Flint may have worse cognitive developmental outcomes in the wake of this exposure than they would have had otherwise. However, evidence is very limited for the implications of lead specifically for persons with such low baseline lead exposure that blood concentrations are <5 μg/dL. Epidemiological research in partnership with Flint communities may help provide additional insights into the health implications for children of exposures within the very-low-exposure range. Lastly, although this commentary has emphasized the health relevance of an increase in lead exposure for the children of Flint who may have been exposed after birth, lead exposure during pregnancy is also a hazard (9) and lead has toxicity for adults as well (10-13). People of all ages exposed to lead are at risk for lead toxicity, and the potential public health harms in Flint may be multifaceted.
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