Environ. Sci. Technol. 2009, 43, 5547–5548
Comment on “Speciation Analysis of Gadolinium Chelates in Hospital Effluents and Wastewater Treatment Plant Sewage by a Novel HILIC/ICP-MS Method” In their recent article, Ku ¨ nnemeyer et al. (1) present an innovative method to determine the chemical speciation of anthropogenic Gadolinium in wastewaters. However, we question their conclusions related to the behavior of the contrast agents during wastewater collection and treatment, which are derived from a limited set of nonrepresentative samples. We outline our concerns below. (1) Hospital Towers. “The large concentration difference in the effluent samples from the two tower buildings most likely is a result of the different sampling time.” Highly variable concentrations are reported in the two hospital towers (