Usefulness of lead isotopes analysis in a pediatric case of chronic lead poisoning

Identifying the source of lead is a key measure in the management of childhood lead poisoning. In cases with multiple potential sources or with unusual circumstances, this identification can be complex. By comparing the lead isotopic ratios (IRs) between the potential sources and the blood sample from the patient, it is possible to identify which source caused the poisoning. We report here the case of a 13-years-old girl, screened for lead poisoning as she was known to eat paint chips from two walls in her apartment. Her blood lead level was 395 µg/L, and the environmental investigation came back negative. X-ray fluorescence found lead concentration in paints to be below the regulatory threshold of 1 mg/cm². As there was no other potential source of lead exposure in this case, a comparative analysis of the IRs of lead between the child's blood and two presumed sources (bathroom and kitchen paints) was performed. This analysis confirmed the source of lead intoxication to be the paints in the apartment, mostly from the bathroom wall.