Analysis of some heavy metal concentrations in selected human hair dye products and their effects on human female users in Lafia Metropolis, Nasarawa State

Regulatory agencies have established reference values to limit human body exposure to heavy metals due to their significant health risks. In this work, the concentration of selected heavy metals in selected hair dye products in Lafia Metropolis was investigated using standard procedures. Statistical analysis of triplicate values of mean concentration standard deviation was calculated and compared with reference ranges, and values P<0.05 were considered significant. The results revealed significantly higher concentrations (P<0.05) of heavy metals across the samples. The presence of all heavy metals was detected in the samples, following the trend Zn > Se > Cd > Pb > Fe > As. In the female study group, the mean concentration of Cd in dyed hair was 0.07±0.01 mg/L, which fell within the reference range (<0.1 mg/L). However, Cd levels in dyed hair increased to 0.24±0.20 mg/L, exceeding the reference value. The mean concentration of Fe in dyed hair (0.04±0.01 mg/L) and grey hair (0.02±0.01 mg/L) was significantly lower than that in undyed hair (0.36±0.11 mg/L), although it remainedbelow the reference range (0.6–1.5 mg/L) (P>0.05). The mean concentration of Pb in dyed and grey hair was 0.03±0.02 mg/L, which was within the reference range (<0.6 mg/L). Despite the use of hair dye and care products, the results of the triplicate analysis indicated that heavy metal concentrations in undyed, dyed, and grey hair in the female study group generally remained below the reference values established by regulatory bodies. However, an exception was noted for the Cd concentration in dyed female hair, which slightly exceeded the reference value (<0.1 mg/L) with a measured concentration of 0.24±0.20 mg/L. Smoking, hair dyes marketed as permanent solutions, bleach, and certain hair sprays were identified as contributing factors to Cd contamination.