Age- and sex-based comparative distribution of selected metals in the scalp hair of an urban population from two cities in Pakistan

Concentrations of Cu, Zn, Pb and Ni in the scalp hair of male and female donors, with an age range of 6–60 years, were determined by ICP atomic emission spectroscopy. The donors were drawn from the densely populated city of Lahore and the relatively less-populated capital city of Islamabad for comparative evaluation of the metal levels in relation to age, sex and location. Linear regression analyses and correlation between paired metals indicated a positive correlation between Cu and Zn for both sexes (r > 0•600) and between Pb and Ni (r > 0•484) for males and females of Lahore. Metal concentrations varied between the two cities and the two sexes. The highest mean concentration was found for Zn at 180•5 μg g−1 for males and 202•4 μg g−1 for females from Lahore, while for counterparts from Islamabad the values were 105•2 μg g−1 and 206•6 μg g−1. Copper showed an identical mean concentration (20•8 μg g−1) in the hair of both males and females from Lahore; however, relatively lower mean concentrations (7•7 and 10•8 μg g−1) were observed for donors from Islamabad. Mean Pb concentrations in hair of male donors from Lahore and Islamabad were 9•4 and 7•0 μg g−1, respectively; in female groups the concentrations were 14•3 and 5•7 μg g−1, respectively. Ni showed the lowest concentration range (4•3–4•5 μg g−1) of all the four metals for subjects from Lahore, and this was higher than the corresponding range (2•0–3•2 μg g−1) for subjects from Islamabad. The findings are discussed in relation to the available data from the literature.