Comparison of Trace Elements between Dyed and Non-Dyed Head Hair Samples among Females from Different Ethnic Groups in Malaysia Using Icp-Oes

Abstract

Hair dye is a commonly used cosmetic product applied directly on the scalp which exposes the users to possible harmful elemental dye components, via absorption especially through skin pores to body organs. Essential elements such as Zn and Fe play significant roles in proper human development while non - essential elements for example Cd and Pb are harmful even at low concentrations. The objective of this study is to investigate the presence and the concentration of heavy metals such as iron (Fe), zinc (Zn), cadmium (Cd), copper (Cu) and lead (Pb) in dyed and non-dyed hair samples among females from different ethnic groups (Malay, Chinese and Indian) in Malaysia using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The sample group used for this research compromise of 90 female individuals (45 with dyed hair and 45 with non-dyed hair). The identification of heavy metals in the hair samples was analysed by using microwave digestion method with ICP-OES. The analysis of calibration curve for each heavy metal showed a good linear regression with coefficient of determination (R2) of 0.999 with a low limits of detection (LOD) and quantification (LOQ). The results indicate that the raised levels of heavy metals in dyed hair may be attributed to hair dye use while high levels in non-dyed hair highlights environmental exposure, largely caused by industrialization and urbanization. The statistical findings also indicate that both hair dyeing and ethnic background have significant effects on the buildup of heavy metals in hair (p ≤ 0.05). There is no globally standardised “normal” range for heavy metals in hair due to large variability influenced by geography, age, sex, ethnicity, hair treatments and analytical methods. Therefore, the comparisons should ideally be with population data of similar geographical location, ethnicity, gender, lifestyle and working environment to get more comprehensive results on the presence of heavy metals in hair samples.