AWWA WQTC69472

This powerpoint presentation begins by presenting the research strategy that includes the following: develop Physiologically Based Pharmacokinetic (PBPK) Model to quantify organ dose from ingestion at low doses; and, mechanism of toxic response at low doses. This leads to a reexamination of the basis for health goal, and a revision of risk assessment at low doses. A summary of bromate health risk is presented, along with critical risk assessment issues, pharmacokinetic issues with bromate ingestion, bromate chemistry and kinetics, cellular effects, and metabolism kinetics experiments. Study progress and conclusions indicate the following: developed sampling, storage and analytical procedures for bromate in body fluids @ 1ng/ml; rapid reduction by sulfide simulated gastric juice at low pH and with reducing agents, e.g. ferrous, iodide, nitrite; minor effect of chlorine on reduction rate; liver cells are resistant to bromate toxicity vs kidney; liver is not a target organ for cancer; rapid elimination from blood by iv and ingestion (first pass GI/liver metabolism); half life in minutes vs perchlorate half life ~12 hours; exploring possibility of endogenous formation; and, elucidating, partitioning parameters, organ distribution, bromide effects, PBPK model, risk assessment. Includes tables, figures.