Metal Concentrations In Hair Research Articles

Hair-Metal Binding

Extensive ambient extraction of several metals from human hair compromises some assumptions concerning the binding of metals to hair and the biochemical process of metal incorporation into hair. Hair metal concentrations can reveal metal intoxications and metal deficiencies. The scalp hair selected for investigation included specimens of different colors from both sexes for various donor ages and from different geographic exposure areas. The hair samples were washed by agitation for 30 min with a 1% solution of sodium lauryl sulfate in a pH 7.2 buffer, rinsed repeatedly with deionized water, and oven-dried at 110°C before 2-g portions were taken for extraction and digestion. Extraction involved agitation of the washed hair samples for 21 hr with 40 ml of 1% nitric acid at room temperature (23°C). The extracted hair was digested in order to quantitate the amount of metal that was not extracted. Metal measurements were made by conventional flame atomic absorption spectroscopy. Potential interferences were investigated. Extraction varied between 82 and 100% for Na, Mg, K, Ca, Mn, Zn, Cd, and Pb. Removal of Fe, Ni, and Cu was 33–54%. Anatomical location, binding chemistry, biochemical incorporation, and mass screening are discussed.

Trace metal content of hair. I. Zinc and copper content of human hair in relation to age and sex.

Cadmium and lead content of hair of males and females was found to he age-dependent. Regression analysis showed two male groups with respect to cadmium, namely those under and those over 12 years of age, while the data revealed only one male group with respect to lead. Analysis of the data also indicated that hair cadmium distribution for females delineated one group below, and one above, 50 years. Females showed hair lead which fell into two groups, one below and the other above 30 years of age. Cadmium and lead in the hair of both sexes showed a high degree of association of the metals (r= 0.4052 (P = .001) for males and r = 0.2563 (P = .02) for females). The data indicate that comparisons of metallic content of hair in humans must be limited to a narrow age range and to one sex.

Iron, copper, and zinc content of human hair

Determination of trace elements in human hair has been studied as a possibly highly effective procedure to facilitate the diagnosis of various metal poisonings. For this, it is necessary to know in detail metal content of hair among average persons. For the content of iron, copper, and zinc, quite a few studies have been published, but most of them examined very small samples and the distribution of the analyzed values was not referred to. In this study, therefore, the iron, copper, and zinc content of hair from many healthy persons was determined and the data obtained were statistically investigated in regard to sex and age.174 men and 164 women, healthy, 5 to 79 years in age, living in five cities of Fukuoka Prefecture served as subjects. Hair samples collected from them were cut into small pieces and about 1.5g of each was washed twice using a nonionic detergent solution, and rinsed with distilled water. It was then once washed with an 1per cent EDTA solution and again rinsed twice with distilled water. Such treated hair samples were dried at 100°C in an electric oven for 10 hours, and weighed. They were then each transferred to porcelain crucibles and incinerated at 450-500°C in the muffle furnace for 16 hours. The resulting ash was dissolved in 10ml of 6N-HCl with a few drops of HNO3 and subjected to analysis of the three mineral elements. The 6N-HCl solution was extracted by methylisobutylketone, and iron in the extract was determined by the ortho-phenanthroline method after the reextraction from the methylisobutylketone solution by distilled water. After deviding the 6N-HCl solution into halves, copper and zinc were analyzed separately. Copper was determined by the bathocuproine method as recommended by Borchardt and Butler. After extracted by sodium diethyldithiocarbamate, zinc was determined by the D. C. polarographic method.Results obtained were as follows:1) Distribution of iron content was shown to be logarithmic-normal for both the entire male and female subjects. (Fig. 7) Logarithmic mean of iron content of hair samples from 174 male subjects was 1.136μg/g, while that from 164 females 1.408μg/g. It was also noted that female hair contained a significantly greater amount of iron than male hair. The hair from males of 10-19 years of age contained a relatively little amount of iron, while that of 5-9 and more than 20 years contained a greater amount. In female subjects, the iron content of under 14 years of age was rather little and that of over 15 years was greater. (Table 5-1)2) Copper content of male and female hair showed an approximately logarithmic-normal distribution. (Fig. 8) Logarithmic mean of copper content of hair from all male subjects was 1.018μg/g, and the corresponding figure for females 1.099μg/g. Female hair contained a significantly greater amount of copper than male hair. As to the mean copper content by age, the same tendency as noted for the mean iron content was observed for both males and females. (Table 5-2)3) Zinc content of male hair also showed an approximately logarithmic-normal distribution, and that of female hair clearly showed a logarithmic-normal one. (Fig. 9) Logarithmic mean of zinc content of hair from male subjects was 2.121μg/g, while that from female subjects 2.202μg/g, being much greater than the corresponding iron and copper contents for both sexes. Female hair contained a significantly greater amount of zinc than male hair. For age distribution of zinc content, hair from those under 19 years of age was shown to be rather little, while that from over 20 years was great in male subjects. Similarly, content of those under 14 years was relatively little, while that from over 15 years of age was great in female subjects. (Table 5-3)4) No significant correlations were observed between the iron content and the copper content, between the iron content and the zinc content, or between the copper content and the zinc