Experimental Examination of Organic Toxicity for Trihalomethane.

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There are numerous surveys concerning TRI toxicity to animals and humans. In recent years, two carcinogenicity bioassays have indicated that the daily administration of high oral doses of TRI leads to an increased incidence of hepatocellular carcinoma in B6C3Fl mice.TRI pollution of surface water as well as ground water is increasing year by year, creating serious problem in many advanced nations. In contrast, relatively little is known about its absorption from the gastrointestinal tracts. In our previous paper, we administered TRI solutions at three concentrations to the three segments of intestinal tracts of the circulation loop system in dogs, and measured TRI and its metabolites in serum or blood, urine, bile and circulating solution However, the amounts of administered solution was so large (about 500 ml) that we could not clarify the detail of the small volume of TRI absorption from the intestinal tracts. From these reason, we administered TRI solutions at three concentrations (0.1, 0.25 and 0.5%, about 20ml each) to the three segments of intestinal tracts (jejunum, ileum and colon) of the closed loop system in dog. We measured TRI and its metabolites, F-TCE, TCA and Conj-TCE, in the serum or blood, urine, bile and remaining solutions. The fraction of TRI absorbed from the intestine were 85-90% of the administered volume of TRI two hours after administration in all groups, and all parts of intestine readily absorbed TRI. Moreover, there were no significant differences between results from the three parts of the intestine. The combined biliary and urinary excretion ratios of TRI and its metabolitesto the total amounts absorbed from intestine were very low (0.6-1.6%) two hours after administration in all groups.There were no significant differences between the Tween 80 added groups and the non-added groups in the 0.1% TRI administered group.