Bioavailability to rats and toxicity of bound residues in bean seeds fumigated with 14C-methyl bromide.
Fumigation of Vicia faba seeds with 14C-methyl bromide for two weeks followed by four-week aeriation period resulted in the formation of bound residues equivalent to 33% of the terminal residue or approx. 30 ppm. Of this amount, 3.4% was incorporated into the seed DNA. The effect of cooking on the treated-aerated beans showed that 50% of the initial dose remained bound to seed tissues. A bioavailability study of 14C-bound residues showed that over 70% of the ingested dose was bioavailable to the rat. The major radioactivity was eliminated in urine (36.6%), feces (24.1%) and CO2 (19.3%). Analysis of the urine showed that 36% of the radioactivity was in the purine fraction; one fifth of this amount was associated with 7-14C-methylguanine. Subacute feeding of bound residues to mice for 8 weeks at a dietary level of 30 ppm resulted in a significant decrease in the number of white blood cells and an increase in the activity of SGOT and SGPT of the treated mice. Blood urea nitrogen was also increased while blood creatinine remained unaltered. The data indicate that seed-bound 14C-methyl bromide residues are highly bioavailable to the rat. The bound residue also possesses a toxicological potential, as manifested by hepatic and glomerular injuries in mice.
Mostafa
I Y
IY
Middle Eastern Regional Radioisotope Centre for the Arab Countries, Cairo, Egypt.
Zayed
S M
SM
Hazzaa
N I
NI
Hegazi
B
B
D000818:Animals; D001682:Biological Availability; D007887:Fabaceae; D005506:Food Contamination / Q000032:analysis; D006842:Hydrocarbons, Brominated / Q000032:analysis / Q000493:pharmacokinetics* / Q000633:toxicity; D008111:Liver Function Tests; D008297:Male; D010573:Pesticide Residues / Q000032:analysis / Q000493:pharmacokinetics* / Q000633:toxicity; D010946:Plants, Medicinal; D051381:Rats; D015430:Weight Gain / Q000187:drug effects
D006842:Hydrocarbons, Brominated; D010573:Pesticide Residues; C005218:methyl bromide