Correspondence Comment On “Occurrence of Butyltin Compounds in Human Blood” SIR: The occurrence of butyltin compounds in blood samples from 32 human volunteers, and the possible implications of these findings with respect to the general population, was recently reported by Kannan et al. (1). The compounds in question include mono- (MBT), di- (DBT), and tributyltin (TBT). Comments are offered here on issues that could affect the author’s interpretation of their findings. Several analytical uncertainties were noted that could have a significant impact on the butyltin results reported, including the following: (i) Use of methods developed for mammal blubber, not blood. To our knowledge, butyltins have not been reliably analyzed in blood samples. Developing accurate methods has been hampered by the low volumes of sample available (e.g.,
