ISSN:
1432-0800
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Medicine
Notes:
Conclusions DCPD is subjected to rapid and extensive metabolism after oral exposure to a lactating cow. Of the total radiolabeled dose administered to the animal, about 86% was recovered in the urine and feces, and only trace amounts were secreted into milk. The portion of the dose not accounted for in the excreta may reflect, in part, experimental error; but quite probably, because of the relatively high volatility of DCPD, some of the administered material may have been eliminated through gases eructated from the rumen or perhaps even through respiration. The fact that more than 80% of the administered dose was ultimately excreted in the urine and only about 4% in feces indicates that the orally adminstered compound was extensively absorbed from the gastrointestinal tract. The extent of radiocarbon elimination through the feces was possibly greater than that indicated in Table I because any intact DCPD that might have been eliminated in the feces would almost certainly have suffered some volatility loss before collection and possibly more extensive loss during analysis. Also, even though radiocarbon was not detected in any tissue samples analyzed, the possibility that such residues were indeed present cannot be ruled out because of the volatility of DCPD. Little was learned about the chemical nature of DCPD metabolites during this study except that, in urine, they are primarily in the form of glucuronide conjugates. It may well be that these metabolites in the cow arose, at least in part, through epoxidation of one or both of the DCPD double bonds, followed by hydrolysis of the epoxides to diols (or possibly epoxy diols or tetraols), then ultimately conjugation with glucuronic acid. The current studies suggest that low-level exposure of ruminants to DCPD will not result in appreciable retention of residues by edible tissues or their secretion into milk. Although the retention of some DCPD residues by tissues cannot be absolutely ruled out, the relatively high volatility of the compound makes it almost certain that normal food preparation procedures will prevent residues from reaching the human food supply. Recent studies in this laboratory have shown that DCPD is not appreciably toxic to cattle (PALMER 1979), thus the exposure of these animals to low levels of DCPD in the environment will not likely result in any significant toxicological hazard.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01608171
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