Male Fertility, Sister Chromatid Exchange, and Germ Cell Toxicity Following Exposure to Mixtures of Chlorinated Phenoxy Acids Containing 2,3,7,8-tetrachlorodibenzo-p-dioxin

Fertility and sperm number, motility, and morphology were analyzed in male C57BL/6 mice exposed to various mixtures of 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlor-ophenoxyacetic acid (2,4,5-T), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the diet for 8 wk. Somatic cell (bone marrow) sister chromatid exchange frequencies were also evaluated in mice injected with similar chemical mixtures. The concentration of the test chemicals was such that the average daily feeding dose in the three mixtures or control was 40 mg/kg 2, 4-D, 40 mg/kg 2,4,5-T, and 2.4 micrograms/kg TCDD; 40 mg/kg 2,4-D, 40 mg/kg 2,4,5-T and 0.16 microgram/kg TCDD; 20 mg/kg 2, 4-D, 20 mg/kg 2,4,5-T, and 1.2 micrograms/kg TCDD; or no chemical added (control). No significant dose-related effects were observed in the treated mice compared to the control group.