Disposition and metabolism of 2,3-[14C]dichloropropene in rats after inhalation

Abstract

2,3-Dichloropropene (2,3-DCP) is a constituent of some commercially available preplant soil fumigants for the control of plant parasitic nematodes. Human exposure potential exists during manufacture of the chemicals or during bulk handling activities. The purpose of this investigation was to determine the disposition and metabolism of 2,3-[14C]DCP in rats after inhalation. Male Fischer-344 rats were exposed nose-only to a vapor concentration of 250 nmol 2,3-[14C]DCP/liter air (7.5 ppm; 25 degrees C, 620 Torr) for 6 hr. Blood samples were taken during exposure, and urine, feces, expired air, and tissues were collected for up to 65 hr after exposure. Urinary excretion was the major route of elimination of 14C (55% of estimated absorbed 2,3-DCP). Half-time for elimination of 14C in urine was 9.8 +/- 0.05 hr (means +/- SE). Half-time for elimination of 14C feces (17% of absorbed 2,3-DCP) was 12.9 +/- 0.14 hr (means +/- SE). Approximately 1 and 3% of the estimated absorbed 2,3-[14C]DCP were exhaled as either 2,3-[14C]DCP or 14CO2, respectively. Concentrations of 14C in blood increased during 240 min of exposure, after which no further increases in blood concentration of 14C were seen. 14C was widely distributed in tissues analyzed after a 6-hr exposure of rats to 2,3-[14C]DCP. Urinary bladder (150 nmol/g), nasal turbinates (125 nmol/g), kidneys (84 nmol/g), small intestine (61 nmol/g), and liver (35 nmol/g) were tissues with the highest concentrations of 14C immediately after exposure. Over 90% of the 14C in tissues analyzed was 2,3-DCP metabolites. Half-times for elimination of 14C from tissues examined ranged from 3 to 11 hr. The data from this study indicate that after inhalation 2,3-DCP is metabolized in tissues and readily excreted.