The effect of long-term feeding of Aroclor 1254 to female rhesus monkeys on their polychlorinated biphenyl tissue levels.

The result of feeding Aroclor 1254 to female Rhesus monkeys at doses of 0, 5, 20, 40 and 80 micrograms/kg body weight/day for a period of 37 months was measured in terms of polychlorinated biphenyl (PCB) levels in blood, adipose tissue, and feces. PCB concentrations in whole blood increased more rapidly during the first 10 months of the study than in the remaining 27 months for all dose groups. On a blood-lipid basis, however, another rapid increase in PCB levels was observed after 27 months of dosing, which could not be explained on the basis of an overall decrease in blood-lipid levels. Concentrations in adipose tissue and adipose fat increased continuously during the 37 months of dosing. These observations were reflected in the ratio profiles of PCB levels in blood/PCB levels in adipose tissue, which remained relatively static between the 2nd and 27th month of continuous feeding. Expressing the data in terms of relative concentrations (concentration/dose) suggests that bio-accumulation or retention of PCBs may be dose-dependent, particularly for adipose tissue, with the higher relative concentrations of the lowest dose group significantly (p less than 0.001) different from all other dose groups. Similarly, the limited feces data available suggests a dose-dependent PCB absorption. The distribution of PCB peaks in the gas chromatographic elution pattern of all analyzed substrates showed considerable deviation from that of administered Aroclor 1254. Only minor changes in the percent distribution pattern were observed between dose groups.