Trace elements in hair: a study of residents in Darjeeling (India) and San Diego, California (U.S.A).

Trace element contents of scalp hair from randomly selected, ethnically homogeneous subjects of Darjeeling (India) were compared with those of the residents of San Diego, California (U.S.A.). The differences between mean concentrations of Ca, Mg, Cu, Na and Cd in the two groups were not significant, and the concentrations of K, Fe, Mn and Zn were significantly higher (P less than 0.01), and that of Al was significantly lower (P less than 0.01), in hair of the residents of Darjeeling. Concentrations of lead in four of the Darjeeling hair samples were very high (greater than 30 micrograms g-1) and in the remaining samples the mean concentration was similar to San diego hair samples. In two mentally retarded Darjeeling subjects, abnormally high values of aluminum (50 and 70 micrograms g-1) and iron (155 and 196 micrograms g-1) were observed. The mean aluminum concentration (2.4 micrograms g-1) in the remaining Darjeeling hair samples was significantly lower than the mean aluminum concentration (10.6 micrograms g-1) in the San Diego hair samples (P less than 0.01). The mean manganese concentration in Darjeeling hair was 20 times higher than the mean manganese content in San Diego hair samples.