Blood:air partition coefficients of individual and mixtures of trihalomethanes

The objective of the present study was to determine the rat blood:air partition coefficients (Pb:a) of chloroform, bromodichloromethane, dibromochloromethane and bromoform present in vitro individually or as mixtures. The experimentally determined Pb:a of chloroform, bromodichloromethane, dibromochloromethane and bromoform present individually corresponded to (mean±SD, n=8) 21.3±1.8, 41.8±6.2, 97.5±4.1, and 187±7.4, respectively. The Pb:a of these trihalomethanes (THMs) showed a decreasing trend during mixed in vitro exposures to 0.138±0.002 or 0.273±0.002 μmol of each of the four THMs. In general, the Pb:a determined during mixed exposures differed by less-than-or-equals, slant15% of the average Pb:a determined for THMs present individually. The results of this study suggest that an alteration of Pb:a of the individual THMs is unlikely to occur at the blood concentrations of THMs observed during mixed exposures in rats.