Submitted to: American Chemical Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 5/31/2006
Publication Date: 9/10/2006
Citation: Smith, D.J., Hakk, H., Larsen, G.L. 2006. Tissue distribution, elimination, and metabolism of sodium 36cl-perchlorate in lactating goats. American Chemical Society Abstracts. San Francisco, CA, Sept. 10-14, 2006.
Technical Abstract: Perchlorate has contaminated water sources throughout the US, but particularly in the arid Southwest, an area containing large numbers of people and few water sources. Recent studies have demonstrated that perchlorate is present in alfalfa and that perchlorate is secreted into the milk of cows. Only a small portion of a perchlorate dose could be accounted for by elimination in milk, feces, or urine of orally administered cows. The purpose of this study was to determine the fate and disposition of 36Cl-perchlorate in lactating dairy goats. Two goats (60 kg) were each orally administered 3.5 mg (16.5 microCi) of 36Cl-perchlorate. Blood, milk, urine, and feces were collected incrementally until slaughter at 72 hours. Total radioactive residues (TRR) and perchlorate were measured using radiochemical techniques and LC-MS MS. Peak blood levels of TRR occurred at 12 h (~195 ppb); peak levels of parent perchlorate, however, occurred after only 2 h suggesting that perchlorate conversion to chloride occurred rapidly in the rumen. By 24 h perchlorate was not detectable in blood, but TRR remained elevated (160 ppb) through 72 h. Milk perchlorate levels peaked at 12 h (157 ppb) and were not detectable by 36 hr, even though TRR remained (69 ppb) through 72 h. Perchlorate was not detectable in skeletal muscle or liver at slaughter (72 h). Chlorite and chlorate were not detected in any matrix. Bioavailability of perchlorate was poor in lactating goats; perchlorate that was absorbed was rapidly eliminated in milk and urine.