To the Editor: In their study on persons aged 50 to 70 years,1 Dr Weil and colleagues found no association between blood mercury levels and neurobehavioral function. We believe that some limitations in this study need to be considered.
First, as the authors note, blood mercury levels represent only recent exposure to methylmercury. Therefore, they have not considered exposure to other chemical forms of mercury like inorganic mercury or mercury vapor, which are normally measured in urine. Exposure to low levels of mercury vapor has been associated with impairment of neurobehavioral function.2