Copper, iron, manganese, and zinc content of hair from two populations of rhesus monkeys.

The concentrations of the elements copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in hair of caged (in Maryland) and free-ranging (in Puerto Rico) rhesus monkey populations were determined. Significant chronological age-related decreases were evident for the trace elements Mn and Zn in both populations (P < or = 0.01) and for Cu and Fe in free-ranging monkeys (P < or = 0.005). The only overall gender difference was higher hair Mn concentration in free-ranging males than in females (P < 0.03). There were no significant differences in hair Cu, Fe, or Mn related to pregnancy status. Hair Zn was lower in samples from pregnant than from nonpregnant monkeys from the caged monkeys (P < or = 0.05), but did not differ in the free-ranging monkeys. Comparison of the two populations revealed that hair Zn levels were significantly higher in caged vs free-ranging animals (P < 0.001). We attribute this higher hair Zn in the caged monkeys to contact and ingestion of Zn from their galvanized enclosures. Hair iron levels were significantly higher (P < 0.001) in free-ranging monkeys, possibly as a result of Fe-rich soil ingestion from their environment. These data support continued investigation of the use of hair as an indicator of the exposure of large groups or populations to potentially high levels of specific minerals, and the use of nonhuman primates as models for the study of trace element deficiency and/or toxicity in humans.