Safety evaluation of metal exposure from commonly used hair dyes and tattoo inks in Nigeria.
Tattoos and dying of hair have been practiced for several centuries worldwide. Tattoos have been used as a simple fashionable body ornament as well as to express membership of a particular sociocultural group (Forte, Petrucci, Cristaudo, & Bocca, 2009).
In permanent tattoos, the pigments are deposited into the dermis by means of a needle, which ensures that pigments are permanent. The person is directly exposed to the ingredients in the tattoo color. Tattoo colors are metal based; for instance, dichromate, cobalt, cadmium, and mercury salts are used as the base for green, blue, yellow and red colors, while iron oxide, titanium dioxide, cobalt, and manganese are prevalent in brown, white, black, and violet (Forte et al., 2009; Kaatz, Elsner, & Bauer, 2008). Organics and metals are sometimes combined to create a different hue, brightness, lightness, and shade of colors (Duke, Urioste, Dover, & Anderson, 1998). The direct contact of the skin with the metal components of these pigments can cause metal-related skin inflammation such as allergic, eczematous, lichenoides, psudolymphomatous, or granulomatous reactions in sensitized persons.
The assessment of metal concentrations in personal care products is a public health concern since the use of these products could represent a possible source of human exposure to a variety of chemicals (Piccinini, Piecha, & Torrent, 2013). Most of these products are applied directly to human skin. While skin provides a good protective barrier, some of the ingredients in cosmetic products can penetrate the skin and reach vital internal organs via the circulatory system (Gondal, Seddigi, Nasr, & Gondal, 2010) where they can exhibit acute or chronic toxicity.
Exposure to low concentrations of lead can cause disorders such as behavioral abnormalities, decreased learning and hearing, and permanent neurological damage and can have adverse effects on the reproductive, hepatic, and renal systems. The International Agency for Research on Cancer (IARC) has categorized cadmium as a group 2A carcinogen because it is a cell poison, which causes different types of damage including cell death or increased cell proliferation (World Health Organization, 2004).
Other metals such as nickel, chromium, iron, manganese, zinc, and aluminum are essential to humans since they are involved in many biological processes, even though some controversy still exists surrounding chromium. Despite the importance of these metals to humans and other organisms, the presence of these metals in personal products may constitute a serious health risk, e.g., allergic reactions. Nickel, chromium, and cobalt are well-known allergens, while copper, manganese, and zinc are seen as weak allergens. The objective of our study was to evaluate the concentrations of metals (cadmium, copper, chromium, aluminum, lead, nickel, zinc, cobalt, manganese, and iron) in hair dyes and tattoo inks with a view to providing information on the hazards associated with use of these products.
Materials and Methods
Samples of commonly used hair dyes and tattoo inks were purchased from markets in Abraka, Warri, Asaba, Benin-City, and Lagos, Nigeria. A total of 24 brands were collected, including some manufactured in Nigeria and some imported from other countries. The choice of brands was carefully made to reflect the brands used by different income classes.
Within each type or brand, a total of three samples with different batch numbers and date of manufacture were collected in order to study the variation in elemental concentrations within a particular brand. All samples collected were within their specified usage periods (shelf life). Information about the brand names, country of origin, and active ingredients of these products is displayed in Table 1.
All reagents, nitric acid (69%), hydrogen peroxide (30%), and perchloric acid, were ultra-pure quality. The calibration standards were prepared by diluting 1,000 mg/L commercial standards of cadmium, copper, chromium, aluminum, lead, nickel, zinc, cobalt, manganese, and iron with 0.25 mol/L nitric acid.
A mass of 1.0 g of each sample was placed in a Teflon vessel, to which 20 mL of concentrated nitric acid, 10 mL of perchloric acid, and 5 mL of hydrogen peroxide were added and the mixture (sample + acids) was left to stand overnight. The following day, the sample was heated on a hotplate to 125[degrees]C for two hours. The sample solution was allowed to cool, and was then filtered and made up to 25 mL with 0.25 mol/L nitric acid. Four blanks were prepared in an identical manner, but omitting the samples.
All digested samples were analyzed in triplicate for cadmium, copper, chromium, aluminum, lead, nickel, zinc, cobalt, manganese, and iron by using flame atomic absorption spectrometry. Calibration standards and blank solutions were analyzed in the same way as the samples. In each analysis at least three to four blanks were analyzed. The average blank signal was subtracted from the analytical signal of the sample before statistical analysis.
Quality Control and Statistical Analysis
All glassware used in the study was previously soaked in 10% (v/v) nitric acid solution for 24 hours and rinsed with deionized water. The instrument was calibrated after every 10th run. The accuracy of the analytical procedure was verified by using a spike recovery method. A known amount of the test element was introduced into an already analyzed sample and the sample was reanalyzed. The percentage spike recoveries for metals were between 89.0% and 98.9%. The limits of detection for the metals were 0.05, 0.01, 0.03, 0.01, 0.08, 0.01, 0.01, 0.01, 0.02, and 0.03 [micro]g/g while the limits of quantification were 0.15, 0.03, 0.10, 0.25, 0.03, 0.03, 0.03, 0.03, 0.05, and 0.10 [micro]g/g for cadmium, copper, chromium, aluminum, lead, nickel, zinc, cobalt, manganese, and iron, respectively. Analysis of variance (ANOVA) and Tukey's multiple comparison tests were used to determine whether the concentrations of metals varied significantly within the same brand and among the different brands of hair dyes and tattoo inks.
Results and Discussion
The concentrations of metals measured in the selected types of hair dyes and tattoo inks are displayed in Table 2. The concentration of the metals varied significantly (p < 0.05) among the different types, although the concentrations of chromium in the different types of hair dyes were similar. The metallic concentrations varied from manufacturer to manufacturer and from one color to another, even among like-colored pigments. As a general trend, iron, manganese, and zinc were the dominant metals in the hair dyes, while iron, manganese, zinc, copper, and aluminum were the dominant metals in the tattoo inks.
The concentrations of cadmium in these samples were below the limit of detection except for HD-11 (16.8 [micro]g/g), which is higher than the 3.0 [micro]g/g regulatory limit for cadmium in cosmetic products (Health Canada, 2012). Human exposures to cadmium from the use of these products are very low except in the case of HD-11.
Copper was detected in all samples analyzed except in HD-10. The concentrations of copper in these products ranged from <0.03 to 20.5 and 2.25 to 2,480 pg/g for hair dyes and tattoo inks, respectively. The tattoo inks had higher concentrations of copper than the hair dyes. In our study, HD-16 had a higher concentration of copper than the other hair dyes analyzed, while TT-6 and TT-7 had significantly higher copper levels than the other tattoo inks. The higher concentrations of copper were observed in the blue- and green-colored tattoo inks. The high concentrations of copper in TT-6 and TT-7 may be due to the use of blue pigments from materials such as copper (II) carbonate, calcium copper silicate, and copper phthalocyanine. Copper phthalocyanine and malachite are used to produce green pigments (Forte et al., 2009). Forte and co-authors (2009) reported similar high concentrations of copper in blue- and green-colored tattoo inks (8,329 and 5,887 [micro]g/g, respectively). The red-colored hair dye had a higher copper concentration than the other colors.
Chromium was found in all samples of the hair dyes and tattoo inks except in HD-10. The concentrations of chromium ranged from <0.10 to 9.00 [micro]g/g and 8.00 to 27.0 [micro]g/g in the hair dyes and tattoo inks, respectively. On average tattoo inks had higher concentrations of chromium than the hair dyes. The highest chromium concentrations were observed in the green-colored tattoo inks, which may be due to the use of dichromate pigments in the manufacture of these products. The concentrations of chromium found in this study were lower than 0.315 to 147.0 [micro]g/g reported for tattoo inks in Italy (Forte et al., 2009).
Nickel concentrations ranging from <0.03 to 1.33 and 0.60 to 8.40 [micro]g/g were found in hair dyes and tattoo inks, respectively. The tattoo inks had elevated levels of nickel when compared with the hair dyes. TT-6 had a higher nickel concentration than the other tattoo inks. The concentrations of nickel found in our samples were higher than those reported in tattoo inks in Italy (Forte et al., 2009), but were lower than nickel concentrations of henna in the Palestinian market (AlQutob, Alatrash, & Abol-Ola, 2013).
The concentrations of cobalt in the majority of the hair dye samples were below the limit of detection except in HD-12 and HD-17. The cobalt concentrations in the tattoo inks ranged between 0.50 and 2.25 [micro]g/g. The highest concentration of cobalt was found in a blue tattoo ink, which is due to the presence of cobalt aluminum oxides. Cobalt-based tattoo inks are more toxic than copper-based inks and are linked with urticarial, granulomatous, and pseudolymphomatous reactions (Bagnato et al., 1999; Bjornberg, 1961; Blumental, Okun, & Pontich, 1982; Smith, Odom, & Maibech, 1975). Nickel, chromium, and cobalt are metals of allergological relevance and the levels of nickel, chromium, and cobalt found in our samples can be compared with published maximum levels defined as allergologically safe for consumers exposed to products containing these metals. In this context, Basketter and co authors (2003) have shown that the presence of the irritant or following repeated
exposures to cobalt, chromium, and nickel, individuals rarely react below 10 [micro]g/g. For this reason, Basketter and co-authors (2003) recommended that consumer products should not contain more than 5 [micro]g/g of cobalt, chromium, or nickel as "good manufacturing practice" while the "target" value to minimize the risk of sensitization in particularly sensitive subjects should be as low as 1 [micro]g/g.
The results of our study indicated that hair dyes and tattoo ink samples contained chromium at concentrations above safe limits while cobalt and nickel were within the safe limit, except for nickel in TT-2 and TT-6. The concentrations of nickel and cobalt found in a henna tattoo mixture ranged from less than 2.5 to 3.96 [micro]g/g and 2.96 to 3.54 [micro]g/g, respectively, while lead and copper were less than their respective detection limits (Kang & Lee, 2006).
Aluminum was found to be less than 0.25 [micro]g/g in all the samples of hair dyes examined, whereas aluminum concentrations of 42 to 878 [micro]g/g were found in five of the tattoo inks examined. The highest aluminum concentration was observed in a yellow-colored tattoo ink. Our samples contained lower concentrations of aluminum than those reported in tattoo ink in Italy (Forte et al., 2009). Al-Qutob and co-authors (2003) reported an aluminum concentration of 142.1 [micro]g/g in henna in the Palestinian market. Aluminum exposure, apart from causing cholinotoxicity, can induce changes in other neurotransmitter levels since neurotransmitter levels are closely related (AlAshban, Aslam, & Shan, 2004).
The concentrations of lead in the hair dyes and tattoo inks ranged from <0.03 to 3.50 [micro]g/g and 0.50 to 34.0 [micro]g/g, respectively. Tattoo ink samples TT-3 and TT-5 (black colored) had much higher concentrations of lead than other samples investigated. The United States Food and Drug Administration (FDA) maximum limit for lead in color additives in cosmetics for external use formulated following good manufacturing practice is 20 [micro]g/g, while a 10 [micro]g/g limit for lead in cosmetics was specified by the Canadian Health Authority (Health Canada, 2012). In our study, only TT-3 and TT-5 had lead concentrations above the FDA and Canadian Health specified limits for lead in cosmetics. Apart from these two samples (TT-3 and TT-5), all other samples analyzed had lead concentrations in the range reported by Forte and co-authors (2009). Al-Qutob and co-authors (2013) found lead concentrations of 5.35 [micro]g/g in henna from a Palestinian market.
Zinc concentrations of <0.03 to 298 [micro]g/g and 31.5 to 138 [micro]g/g were detected in the hair dyes and tattoo inks, respectively. Higher concentrations of zinc were observed in HD-11, HD-14, HD-15, HD-16, TT-3, and TT-5 than in other samples investigated. Zinc used in anti-dandruff shampoos has been shown to cause allergenic contact dermatitis (Salvador, Pascual-Marti, Arago, Chisvert, & March, 2000) and high levels of exposure to zinc can cause brittle hair and nails, neurological abnormalities, and gastrointestinal disorders and convulsions (Ayenimo, Yusuf, Adekunle, & Makinde, 2010).
The concentrations of manganese in these samples were in the range of <0.05 to 41.5 [micro]g/g and 17.8 to 37.3 [micro]g/g for hair dyes and tattoo inks, respectively. Higher manganese concentrations were found in blue-, green-, and red-colored tattoo inks than in the other colors. The concentrations of manganese observed in our samples were higher than levels reported for tattoo inks in Italy (Forte et al., 2009). Skin diseases associated with manganese seem to be quite rare. Manganese has been reported as a possible cause of swelling and itching, scaling, and cutaneous granuloma in the purple region of a tattoo (Nguyen & Allen, 1979; Schwartz, Mathias, Miller, Rojas-Corona, & Lambert, 1987).
Iron was not detected in two samples of the hair dyes (HD-10 and HD-11), while iron concentrations of 76.1 to 331 [micro]g/g were detected in the other samples of hair dyes. The highest concentration of iron was found in a purple hair dye. Also, the coral brown and wine red hair dyes had significantly higher concentrations of iron than the other colors investigated. Iron concentrations of 69.8 to 454 [micro]g/g were detected in the samples of tattoo inks. High concentrations of iron in a blue tattoo ink may be due to the presence of ferro-ferricyanide (Prussian blue). The lemon yellow, bright red, and black tattoo inks contained high amounts of iron. Iron in a black tattoo ink is associated with the use of magnetite and wustite (iron oxides) as components of the ink. The concentrations of iron in our samples were higher than concentrations of iron found in tattoo inks in Italy (Forte et al., 2009).
The results of our study revealed that iron, manganese, and zinc are the main components of hair dyes while iron, manganese, zinc, copper, and aluminum are the main components of tattoo inks. Our study indicated that the tattoo ink samples contained allergenic metals such as nickel, chromium, and cobalt at concentrations above the suggested limit of 1 [micro]g/g for greater skin protection in most samples. The toxic metals (cadmium and lead) were below their respective specified limits in cosmetic products in the majority of these samples. The results of our study demonstrate the need for the establishment of regulatory guidelines for metals in these kinds of cosmetic products.
Chukwujindu M.A. Iwegbue
Delta State University University of KwaZulu-Natal
Sunday O. Onyeloni
Faculty of Pharmacy Delta State University
Francisca I. Bassey
Department of Chemistry University of Calabar
Godswill O. Tesi
Rachael O. Ogboru
Department of Chemistry Delta State University
Bice S. Martincigh
School of Chemistry & Physics University of KwaZulu-Natal
Acknowledgements: CMAI thanks the University of KwaZulu-Natal for the award of a Postdoctoral Scholarship. BSM is grateful for the award of a South African Medical Research Council Self-initiated Research (SIR) grant.
Corresponding Author: Chukwujindu M.A. Iwegbue, School of Chemistry & Physics, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa. E-mail: email@example.com.
Al-Ashban, R.M., Aslam, M., & Shan, A.H. (2004). Kohl (surma): A toxic traditional eye cosmetic study in Saudi Arabia. Public Health, 118(4), 292-298.
Al-Qutob, M.A., Alatrash, H.M., & Abol-Ola, S. (2013). Determination of different heavy metals concentrations in cosmetics purchased from the Palestinian markets by ICP/MS. Advances in Environmental Sciences Bioflux, 5(3), 287-293.
Ayenimo, J.G., Yusuf, A.M., Adekunle, A.S., & Makinde, O.W. (2010). Heavy metal exposure from personal care products. Bulletin of Environmental Contamination and Toxicology, 84(1), 4-14.
Bagnato, G.F., De Pasquale, R., Giacobbe, O., Chirico, G., Ricciardi, L., Gangemi, S., & Purello d'Ambrosio, F (1999). Urticaria in a tattooed patient. Allergologia et Immunopathologia, 27(1), 32-33.
Basketter, D.A., Angelini, G., Ingber, R.A., Kern, P.S., & Menne, T. (2003). Nickel, cadmium, and cobalt in consumer products: Revisiting safe levels in new millennium. Contact Dermatitis, 49(1), 1-7.
Bjornberg, A. (1961). Allergic reaction to cobalt in light blue tattoo marking. Acta Dermato-Venereologica, 41, 259-263.
Blumental, G., Okun, M.R., & Pontich, J.A. (1982). Pseudolymphomatous reaction to tattoo. Journal of the American Academy of Dermatology, 6(4 Pt. 1), 485-488.
Duke, D., Urioste, S.S., Dover, J.S., & Anderson, R.R. (1998). A reaction to a red lip cosmetic tattoo. Journal of the American Academy of Dermatology, 39(3), 488-490.
Forte, G., Petrucci, F., Cristaudo, A., & Bocca, B. (2009). Market survey on toxic metals contained in tattoo inks. Science of the Total Environment, 407(23), 5997-6002.
Gondal, M.A, Seddigi, Z.S., Nasr, M.M., & Gondal, B. (2010). Spectroscopic detection of health hazardous contaminants in lipstick using laser induced breakdown spectroscopy. Journal of Hazardous Material, 175(1-3), 726-732.
Health Canada. (2012). Guidance on heavy metal impurities in cosmetics. Retrieved from http://www.hc-sc.gc.ca/cps-spc/pubs/indust/heavy_metals-metaux_lourds/index-eng.php
Kaatz, M., Elsner, P., & Bauer, A. (2008). Body modifying concepts and dermatologic problems: Tattooing and piercing. Clinical Dermatology, 26(1), 35-44.
Kang, I.J., & Lee, M.H. (2006). Quantification of para-phenylenediamine and heavy metals in henna dye. Contact Dermatitis, 55(1), 26-29.
Nguyen, L.Q., & Allen, H.B. (1979). Reactions of manganese and cadmium in tattoos. Cutis, 23(1), 71-72.
Piccinini, P., Piecha, M., & Torrent, S.F. (2013). European survey on the content of lead in lip products. Journal of Pharmaceutical and Biomedical Analysis, 76, 225-233.
Salvador, A., Pascual-Marti, M.C., Arago, E., Chisvert, A., & March, J.G. (2000). Determination of selenium, zinc, and cadmium in antidandruff shampoos by atomic spectrometry after microwave assisted sample digestion. Talanta, 51(6), 1171-1177.
Schwartz, R.A., Mathias, C.G.T., Miller, C.H., Rojas-Corona, R., & Lambert, W.C. (1987). Granulomatous reaction to purple tattoo pigment. Contact Dermatitis, 16(4), 198-202.
Smith, J.D., Odom, R.B., & Maibech, H.I. (1975). Contact urticarial from cobalt chloride. Archives of Dermatology, 111(12), 1610-1611.
World Health Organization. (2004). Guidelines for drinking water quality, Vol. 1: Recommendations. Third Edition, Geneva.
TABLE 1 Hair Dyes and Tattoo Inks Sampled Country of Active Brand Name Color Origin Ingredients Hair dyes Above Nature Black India Nil Above Floweriness Red India Nil Above Violet Red India Nil Cruset Deep black China Cetearyl alcohol, hydrogen peroxide Orino Black China Nil Orino Wine China Nil Orino Gold China Nil Orino Purple China Nil Orino Coral brown China Nil Orino Chestnut brown China Nil Orino Purplish wine China Nil Sabary Wine red India Nil Sabary Chestnut brown India Nil Sabary Grape red India Nil Sabary Splendid purple India Nil Sabary Splendid red India Nil Native Dye Black Nigeria Nil Tattoo inks Intenze Lemon yellow USA Nil Intenze Bright red USA Nil Intenze True black USA Nil J.Y. Red China Nil J.Y. Black China Nil J.Y. Blue China Nil J.Y. Green China Nil Note. Nil = not specified. TABLE 2 Metal Concentrations ([micro]g/g) in Hair Dyes and Tattoo Inks Purchased in Nigeria Sample Codes Cadmium Copper Hair dyes HD-1 <0.15 2.00 [+ or -] 0.16 HD-2 <0.15 7.00 [+ or -] 1.05 HD-3 <0.15 8.50 [+ or -] 0.85 HD-4 <0.15 4.25 [+ or -] 0.72 HD-5 <0.15 3.25 [+ or -] 0.39 HD-6 <0.15 1.50 [+ or -] 0.27 HD-7 <0.15 3.25 [+ or -] 0.24 HD-8 <0.15 2.00 [+ or -] 0.29 HD-9 <0.15 9.50 [+ or -] 0.57 HD-10 <0.15 <0.03 HD-11 16.8 [+ or -] 2.47 7.75 [+ or -] 0.93 HD-12 <0.15 4.75 [+ or -] 0.33 HD-13 <0.15 2.25 [+ or -] 0.18 HD-14 <0.15 2.50 [+ or -] 0.20 HD-15 <0.15 4.00 [+ or -] 0.68 HD-16 <0.15 20.5 [+ or -] 2.46 HD-17 <0.15 4.25 [+ or -] 0.55 Tattoo inks TT-1 <0.15 775 [+ or -] 38.8 TT-2 <0.15 5.50 [+ or -] 0.66 TT-3 <0.15 2.25 [+ or -] 0.32 TT-4 <0.15 3.00 [+ or -] 0.45 TT-5 <0.15 57.8 [+ or -] 6.93 TT-6 <0.15 2480 [+ or -] 173 TT-7 <0.15 1680 [+ or -] 151 Sample Codes Chromium Aluminum Hair dyes HD-1 7.50 [+ or -] 0.45 <0.25 HD-2 8.00 [+ or -] 0.64 <0.25 HD-3 7.75 [+ or -] 1.40 <0.25 HD-4 7.75 [+ or -] 1.24 <0.25 HD-5 8.25 [+ or -] 0.83 <0.25 HD-6 8.25 [+ or -] 0.99 <0.25 HD-7 8.75 [+ or -] 1.49 <0.25 HD-8 8.50 [+ or -] 1.11 <0.25 HD-9 8.25 [+ or -] 1.07 <0.25 HD-10 <0.10 <0.25 HD-11 9.0 [+ or -] 1.53 <0.25 HD-12 7.25 [+ or -] 1.09 <0.25 HD-13 8.00 [+ or -] 0.48 <0.25 HD-14 7.25 [+ or -] 0.58 <0.25 HD-15 7.25 [+ or -] 0.65 <0.25 HD-16 8.25 [+ or -] 0.73 <0.25 HD-17 8.50 [+ or -] 0.94 <0.25 Tattoo inks TT-1 16.5 [+ or -] 2.64 878 [+ or -] 105 TT-2 18.0 [+ or -] 3.24 42.0 [+ or -] 2.52 TT-3 14.3 [+ or -] 0.86 78.5 [+ or -] 7.07 TT-4 8.00 [+ or -] 0.48 <0.25 TT-5 9.50 [+ or -] 1.24 <0.25 TT-6 27.0 [+ or -] 0.02 245 [+ or -] 14.7 TT-7 14.8 [+ or -] 1.18 353 [+ or -] 28.2 Sample Codes Lead Nickel Hair dyes HD-1 3.00 [+ or -] 0.15 0.73 [+ or -] 0.04 HD-2 2.00 [+ or -] 0.24 0.95 [+ or -] 0.08 HD-3 0.50 [+ or -] 0.07 0.78 [+ or -] 0.05 HD-4 2.25 [+ or -] 0.38 0.78 [+ or -] 0.07 HD-5 1.25 [+ or -] 0.23 0.78 [+ or -] 0.11 HD-6 1.50 [+ or -] 0.17 0.20 [+ or -] 0.01 HD-7 <0.03 0.43 [+ or -] 0.04 HD-8 4.50 [+ or -] 0.72 0.08 [+ or -] 0.02 HD-9 1.25 [+ or -] 0.19 0.78 [+ or -] 0.15 HD-10 0.75 [+ or -] 0.09 <0.03 HD-11 2.75 [+ or -] 0.36 1.33 [+ or -] 0.17 HD-12 0.75 [+ or -] 0.04 0.75 [+ or -] 0.11 HD-13 0.25 [+ or -] 0.26 0.58 [+ or -] 0.06 HD-14 1.75 [+ or -] 0.21 0.73 [+ or -] 0.04 HD-15 3.50 [+ or -] 0.42 0.63 [+ or -] 0.08 HD-16 2.00 [+ or -] 0.26 1.05 [+ or -] 0.17 HD-17 1.25 [+ or -] 0.15 0.70 [+ or -] 0.05 Tattoo inks TT-1 0.50 [+ or -] 0.08 4.78 [+ or -] 0.76 TT-2 1.25 [+ or -] 0.23 5.28 [+ or -] 0.79 TT-3 31.8 [+ or -] 2.86 3.65 [+ or -] 0.33 TT-4 1.50 [+ or -] 0.08 0.60 [+ or -] 0.03 TT-5 34.0 [+ or -] 5.10 1.73 [+ or -] 0.42 TT-6 1.75 [+ or -] 0.16 8.40 [+ or -] 0.40 TT-7 0.50 [+ or -] 0.03 3.25 [+ or -] 0.46 Sample Codes Zinc Cobalt Hair dyes HD-1 32.5 [+ or -] 4.23 <0.03 HD-2 32.0 [+ or -] 4.80 <0.03 HD-3 30.0 [+ or -] 1.80 <0.03 HD-4 30.0 [+ or -] 2.40 <0.03 HD-5 34.8 [+ or -] 3.75 <0.03 HD-6 20.0 [+ or -] 1.70 <0.03 HD-7 26.8 [+ or -] 2.56 <0.03 HD-8 34.0 [+ or -] 3.82 <0.03 HD-9 32.0 [+ or -] 2.80 <0.03 HD-10 <0.03 <0.03 HD-11 155 [+ or -] 24.8 <0.03 HD-12 62.5 [+ or -] 4.38 0.50 [+ or -] 0.07 HD-13 27.8 [+ or -] 3.89 <0.03 HD-14 275 [+ or -] 19.3 <0.03 HD-15 298 [+ or -] 17.9 <0.03 HD-16 133 [+ or -] 10.6 <0.03 HD-17 37.3 [+ or -] 4.84 1.00 [+ or -] 0.04 Tattoo inks TT-1 38.5 [+ or -] 4.24 1.00 [+ or -] 0.17 TT-2 31.5 [+ or -] 4.41 0.75 [+ or -] 0.14 TT-3 138 [+ or -] 19.3 0.75 [+ or -] 0.16 TT-4 70.0 [+ or -] 10.5 0.50 [+ or -] 0.08 TT-5 110 [+ or -] 5.50 0.75 [+ or -] 0.09 TT-6 85.0 [+ or -] 5.95 2.25 [+ or -] 0.12 TT-7 60.0 [+ or -] 8.40 0.50 [+ or -] 0.02 Sample Codes Manganese Iron Hair dyes HD-1 22.3 [+ or -] 3.34 76.1 [+ or -] 13.7 HD-2 25.8 [+ or -] 2.32 105 [+ or -] 6.28 HD-3 24.0 [+ or -] 1.20 81.6 [+ or -] 4.08 HD-4 41.5 [+ or -] 3.32 188 [+ or -] 20.7 HD-5 26.5 [+ or -] 2.39 86.6 [+ or -] 12.1 HD-6 21.3 [+ or -] 1.49 76.4 [+ or -] 6.11 HD-7 23.0 [+ or -] 4.14 77.2 [+ or -] 6.95 HD-8 25.3 [+ or -] 4.04 331 [+ or -] 46.4 HD-9 27.5 [+ or -] 2.48 243 [+ or -] 26.8 HD-10 <0.05 <0.10 HD-11 <0.05 <0.10 HD-12 18.8 [+ or -] 2.44 286 [+ or -] 25.7 HD-13 26.0 [+ or -] 3.38 157 [+ or -] 25.1 HD-14 20.8 [+ or -] 1.87 133 [+ or -] 15.9 HD-15 26.3 [+ or -] 3.64 77.6 [+ or -] 3.88 HD-16 29.3 [+ or -] 3.22 99.2 [+ or -] 6.94 HD-17 18.5 [+ or -] 0.93 128 [+ or -] 14.1 Tattoo inks TT-1 23.8 [+ or -] 1.19 188 [+ or -] 22.6 TT-2 29.8 [+ or -] 2.38 136 [+ or -] 8.15 TT-3 17.8 [+ or -] 1.07 168 [+ or -] 10.1 TT-4 30.8 [+ or -] 2.77 69.8 [+ or -] 5.58 TT-5 28.5 [+ or -] 3.71 74.7 [+ or -] 11.2 TT-6 37.3 [+ or -] 1.86 454 [+ or -] 59.1 TT-7 32.5 [+ or -] 2.28 113 [+ or -] 12.4
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||INTERNATIONAL PERSPECTIVES|
|Author:||Iwegbue, Chukwujindu M.A.; Onyeloni, Sunday O.; Bassey, Francisca I.; Tesi, Godswill O.; Ogboru, Rac|
|Publication:||Journal of Environmental Health|
|Article Type:||Cover story|
|Date:||Jan 1, 2016|
|Previous Article:||Did you know?|
|Next Article:||Assessment of the physicochemical quality of drinking water resources in the central part of Iran.|