PPD is found in over thousands hair dye formulations sold across the world. Epidemiologic researches revealed that workers within the textile dye and rubber industries, also hair colors users and barbers, were shown to have a significant risk of bladder cancer, non-hodgkin's lymphoma, multiple myeloma, and hematopoietic malignancies (Saranya et al., 2014).
In developed countries, standard hair dye formulations contain no more than 2% PPD in 100 ml dye solution making it less toxic if accidental poisoning occurs (Hamdouk et al., 2011). Due to lack of standard regulations in developing countries, these concentrations range from 2–90% (Jain et al., 2011).
A variety of analytical techniques were used to measure PPD as gas chromatography coupled mass spectrometry (GC/MS) (Wang and Krynitsky., 2011), inductively coupled plasma mass spectrometry (ICP/MS) (Ahmed et al., 2013), high-performance liquid chromatography (HPLC), and capillary electrophoresis (CE) (Ko et al., 2019).
In previous studies, the determination of PPD was carried out by GC and many peaks were found in the GC chromatograms using a flame ionization detector (Coligan et al., 1996), but in our experiment, PPD was detected as one peak using GC/MS in splitless mode. This method is simple, rapid, reproducible technique, sensitive and accurate analytical method and can be used to determine PPD in commercial hair dyes.
In our results, it was found that 99.706% of SHD and 99.80% of Tancho HD was PPD, and this means that SHD and tacho HD mainly PPD. This agreed with previous results done by Coligan et al., (1996) who reported that the conentration of PPD in SHD was 99.85%. Also, the result of our study was in accordance with the result of Ahmed et al., (2013) who reported that 99.66% of SHD was PPD.
The concentration of PPD of other commercial HDs in our results was shown in Table 1 as follow: 0.492% in bigen HD powder and 5.563% in bigen HD cream.
Heavy metals (HMs) are metals with a specific density of more than 5 g/cm3 that harm the environment and living beings (Monisha et al., 2014).Some of them may be harmful to human health even at extremely low concentration since they have prolonged biological half-lives and are non-biodegradable, allowing them to persist in the body for long time (Djahed et al., 2018).
Many cosmetic items contain heavy metals such as lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), and nickel (Ni) (Abdul et al., 2017). They can enter the body through ingestion or absorption through the skin. Because the majority of cosmetics are applied topically, dermal exposure is thought to be the most important route for hair dyes (Arshad et al., 2020). Individual metals absorption is influenced by variety of parameters, including physical and chemical properties of the mixtures (Sani et al., 2016).
Heavy metals as arsenic (As), Aluminium (Al), cadmium (Cd), chromium (Cr), mercury (Hg), nickel (Ni), lead (Pb), copper (Cu) and zinc (Zn) can build up within the body over time and have been linked to a wide range of health issues as headaches, vomiting, nausea, diarrhea, contact dermatitis, loss of hair, malignancies, reproductive and developmental disorders, amnesia, mood disturbances, neurological, skeletal, blood, immune and renal problems, Many of them are hormone disruptors and respiratory toxins (Palpandi and Kesavan, 2012).
There are currently no global limits for pollutants such as heavy metals in cosmetics, with the exception of 20 g/g for lead and 5 g/g for cadmium (Al-Dayel et al., 2011). While the regularity limits for certain metals in cosmetics in Canada are 10 g/g for Pb, 3 g/g for As, Cd, and Hg, and 5 g/g for Sb (Ullah et al., 2017).
The elemental composition of the sample is determined using Energy dispersive X-ray spectroscopy (E.D.X) (Mujeeb and Zafar., 2017).
In our study, we found that the amount of Aluminum (Al) in the hair dye samples studied varied greatly. Bigen cream HD had the greatest Al level (29.63%), followed by SHD (29.215%), and finally Bigen HD powder (3%), while absent in tancho H and this agreed with previous study done by Ahmed et al., (2013) who reported that Aluminum represented the highest component of stone hair dye (55.12 %). This could be due to a discrepancy in the dye's origin or a difference in the sensitivity of the devices.
Another study was done by Shihata., (2018) to assess the concentration of heavy metals in SHD and showed that the highest level in black stone hair dye were: Aluminum (45.44mg/l), Lead (45mg/l), zinc (32.2mg/l), iron (29.76mg/l), cupper (24.26mg/l) and Magnesium (52.24mg/l).
Sample of bigen HD powder had highest concentration percentage of lead (Pb) at (74.49%) whereas Bigen HD cream and SHD contain least amount of Pb (8.995%) and (6.265%) respectively and absent in Tancho HD.
This agreed with another study done by Benzeid et al., (2021) on Morroco who reported that thirteen samples of hair dyes out of total 16 samples, were with extremely high lead level ranged from 448.43 to 3617.02 ppm. Also, the result of our study was in accordance with the result of Hussein., (2015) carried out on the Baghdad market in Iraq who reported a maximum lead level of 0.92 ppm in hair dyes. Another study of Ozbek and Akman reported the same outcome (Ozbek and Akman., 2016).
Many researchers investigated the heavy metal content of cosmetic products from various countries. (Ullah et al., 2017, Farrag et al., 2015 and Iwegbue et al., 2016).