Measurement of 239Pu in keratinous materials: A potential non-invasive bioassay for monitoring human exposure

The use of hair, toenail, and fingernail as non-invasive monitors of occupational and environmental exposure to 239Pu are reported. Volunteers from US national laboratories and individuals with suspected environmental exposure to Pu were recruited to participate in the study. The exposure history of cases was assessed using a short questionnaire. Levels of Pu in keratinous materials collected from the exposed individuals were above the limit of detection in 5 of 7 cases with concentrations ranging from 0.055 to 0.78 ng/kg. To our knowledge, this is the first time that Pu has been measured in hair and nail samples collected from actinide workers in the United States. The 239Pu levels in the hair and nails collected from the exposure group are comparable to individuals from Minsk, Belarus and Dubna, Russia and lower than individuals living near the Semipalatinsk region of Kazakhstan and in the Gomel region of Belarus.