Superfund Research Program

Perchloroethylene (PCE) in Drinking Water and Cancer Risk

Project Leader: Ann Aschengrau
Grant Number: P42ES007381
Funding Period: 1995 - 2000

Project-Specific Links

Final Progress Reports

Year:   1999  1998  1997  1996  1995 

Project investigators continue to examine the relationship between risk estimation and formation of macro-molecular biomarkers of exposure so that the human health risk due to exposure to low levels of the carcinogens benzene and trichloroethylene (TCE) can be characterized. One of the accomplishments of the past year has been the development of [³H] accelerator mass spectrometry (AMS) to complement [¹⁴C] AMS and provide the capability for additional studies. [³H] AMS is being developed in order to measure the [³H] content of milligram-sized biological research samples. Lawrence Livermore National Laboratory (LLNL) has already successfully applied [¹⁴C] AMS to a variety of problems in the area of biomedical research and the development of [³H] AMS will complement these studies.

In order to investigate the accuracy of [³H] AMS compared to [¹⁴C] AMS for the detection and quantification of tracers in biological systems, mice were dosed with equimolar quantities of 0.01-10 ug/kg [³H] and [¹⁴C] labeled 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) by gavage. Liver tissue samples were analyzed by [¹⁴C] AMS in parallel to preparation for [³H] AMS analysis. The data indicated a good correlation between [³H] and [¹⁴C] AMS for the measurement of PhIP in liver tissue (by regression analysis, p<0.05, r²=0.999), although the [³H] AMS revealed standard deviations greater than observed with [¹⁴C] AMS (an average of 34% of the mean compared to less than 10% with ¹⁴C AMS). Recent experiments have concentrated upon reducing these uncertainties by optimization of sample preparation parameters. The methodology will also be used shortly in the first double-labeling experiment utilizing two different compounds.