Effects of 2-chlorodibenzofuran on fetal development in mice
- National Institute of Hygienic Sciences, Tokyo (Japan)
2-Chlorodibenzofuran (2-MCDF), a monochlorinated derivative of dibenzofuran, has been detected as a contaminant in chlorinated tap water in Japan. Shiraishi et al. (1985) analyzed polynuclear aromatic hydrocarbons in Tsukuba tap water and detected 0.04-1.4 ng/L of 2-MCDF. This means that unintended human exposure to 2-MCDF has occurred, and therefore safety evaluation of 2-MCDF is needed. Toxicological information on 2-MCDF is limited and available only on mutagenicity and metabolic fate. In the Ames test, 2-MCDF showed weak mutagenic activity on Salmonella typhimurium strain TA 98 above 0.4 {mu}mol/plate, but not on strain TA 100 even at 10 {mu}mol/plate, and this activity was diminished by the addition of S9 mix. After intravenous or oral administration to rats, 2-MCDF is rapidly metabolized and excreted in bile and urine. Major metabolites in the rate bile fluid were 2- and/or 7-hydroxylated forms of 2-MCDF. For developmental toxicity, we previously examined the embryotoxicity of 2-MCDF by using post-implantation rat embryo culture. When day 9 embryos were continuously exposed throughout 48 hr culture period either in the presence or in the absence of a metabolic activation system, 2-MCDF at 1 mM was embryotoxic and caused morphological abnormalities of the embryos. However, dosing of up to 1000 mg/kg/day of 2-MCDF to pregnant rats during days 9 to 11 of gestation, corresponding to the culture period, had no effects on the embryo-fetal growth. It was tentatively concluded from these results that 2-MCDF had weak-inactive teratogenicity in rats. In the present study, we further examined fetal effects of 2-MCDF by a teratogenicity test in which the dosing period covers the major organogenic period. We used mice, since they have been used for the evaluation of teratogenicity of polychlorinated congeners of 2-MCDF, because of their higher susceptibility than that of rats. 16 refs., 1 fig., 3 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 35724
- Journal Information:
- Bulletin of Environmental Contamination and Toxicology, Vol. 51, Issue 5; Other Information: PBD: Nov 1993
- Country of Publication:
- United States
- Language:
- English
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