2-BUTOXYETHANOL: HAZARD CHARACTERIZATION AND EXPOSURE–RESPONSE ANALYSIS

Abstract

2-Butoxyethanol has been assessed as a Priority Substance under the Canadian Environmental Protection Act. Based primarily on investigations in experimental animals, the critical health effects associated with exposure to 2-butoxyethanol are alterations in hematological parameters associated with hemolysis and lesions of the forestomach in mice. A tolerable concentration of 11 mg/m³ has been derived, based upon the benchmark concentration for hematological effects in rats, quantitatively taking into account experimental data on interspecies variations in kinetics and dynamics. A tolerable concentration of 0.04 mg/m³ has also been derived based on the benchmark concentration for hyperplasia of the forestomach in mice. There is less confidence in this value, however, due to the paucity of information on mode of induction and, hence, relevance to humans.

ACKNOWLEDGMENTS

Under the mandate of CEPA, Health Canada assesses substances in the environment with respect to their potential for adverse effects upon human health. These assessments are each published as a Priority Substances List Assessment Report. Supporting documentation providing more detailed study descriptions is available upon request for each Assessment Report. Data obtained after October 1999 were not considered for inclusion in this assessment.

H. Atkins (Ottawa Hospital, General Campus) provided advice on the biological significance of hematological effects. A. Renwick (University of Southampton) provided advice on the adequacy of data as a basis for replacement of default components of uncertainty factors. Input on this aspect was also received at a workshop of the International Programme on Chemical Safety on uncertainty and variability in risk assessment, held in Berlin, Germany, on May 9–11, 2000. Comments primarily on the adequacy of coverage in the sections of the supporting documentation related to health effects were provided in a written review by members of the Canadian Manufacturers' Association Ethylene Glycol Ethers Panel, including R. Boatman, Eastman Kodak (for Eastman Chemical); R. Gingell, Shell Chemical; S. Lewis, Canadian Manufacturers' Association; A. Schumann, Dow Chemical; and T. Tyler, Union Carbide Corporation. Comments on accuracy of reporting, adequacy of coverage and defensibility of conclusions with respect to hazard characterization were provided in written review by BIBRA International and H. Atkins (Ottawa Hospital, General Campus). Accuracy of reporting, adequacy of coverage and defensibility of conclusions with respect to hazard characterization and exposure–response analyses were considered in written review of the completed Assessment Report by H. Clewell, K.S. Crump Group, Inc., ICF Kaiser International, Inc.; J. Delic, U.K. Health and Safety Executive; J. Gift, National Center for Environmental Assessment, U.S. Environmental Protection Agency; and J. Roycoft, National Institute for Environmental Health Sciences.