Pharmaceutical Ingredients in Drinking Water: Overview of Occurrence and Significance of Human Exposure

A comprehensive examination is presented of the data published through 2009 on the active pharmaceutical ingredients (APIs) that have been reported in finished drinking water (FDW). A synoptic review reveals that quantitative occurrence data for FDW exists for 64 APIs and miscellaneous transformation products, reported in 48 publications. Significantly, however, for these 64 substances only 17 have quantitative data from more than two reports each; only 36 have corroborative data from a second study. Almost all of the available data has been published since the year 2000. The occurrence data are organized around the Anatomical Therapeutic Chemical (ATC) classification system. The top four ATC classes for which the most API data have been reported are: N, C, V, and M. APIs have been reported for 7 of the 14 main ATC classes; no API has been reported for ATC classes A, B, H, L, R, or S. Some emphasis is also placed on negative data - those APIs with either data of absence or absence of data. The six most frequently reported APIs in FDW (in descending order) are: carbamazepine, ibuprofen, sulfamethoxazole, clofibric acid, gemfibrozil, and iopromide. The six APIs with roughly the most consistent highest reported concentrations are: ibuprofen, triclosan, carbamazepine, phenazone, clofibric acid, and acetaminophen. With only one exception (ibuprofen and its methyl ester metabolite), no API exceeded a concentration of 1 ppb (1 mu g/L). Also covered are some of the reported transformation products and disinfection by-products unique to APIs. Some of the less-discussed aspects of the potential ramifications for human health are also included. A clearer picture is emerging as to the extent and scope of API occurrence in drinking water, some preliminary generalizations can be drawn, and a better sense is emerging of where future research should be directed.