Hair analysis is a powerful tool for assessing human exposure to metals and metalloids (MM). The basis for interpreting laboratory results lie on the use of coverage intervals (CI), computed between the 0.025 and 0.975 fractiles, from a well-defined group of reference individuals reflecting normal and healthy people. A critical point in efficient use of CI, when used for comparative decision-making processes, forensic and clinic considerations, is constituted by confounding factors as the specific living site of study population and gender of participants. Our study aims to demonstrate that hair levels of trace elements are site specific and also gender specific. We have taken into account the levels of 20 trace elements in hair samples from children of the same age (11-14 years old) residing in Sicilian sites characterized by different environmental conditions. The dataset consisted of hair samples collected within the urban area of Palermo, in several small towns located around the volcanic area of Mt. Etna and close to the industrial area of Gela. The study was organized as follow: (a) the first part was addressed to establish whether coverage intervals for MM in human scalp hair are to be considered site specific reflecting local environmental conditions; (b) the second part was intended to provide more information about the gender effect on MM distribution in human scalp hair. The obtained main results can be summarized as follows: a) for many elements, the computed CIs are clearly not equivalent for the different sites, but rather the interval of an element for a site extends far beyond that one calculated for another site, suggesting that what is normal for one site may not be normal for another site. Therefore CIs are valid only for a well defined area and can hardly be extended to other areas with different characteristics. b) CIs of several elements computed for hair samples from female subjects are statistically different from those computed for male subjects. For example, Cd, Li and Rb male coverage intervals extend far beyond those calculated for females, instead, those of Cu, Mn, Ni, Sr, V and Zn are wider for females than males. The Mann-Whitney test (p < 0.01) showed statistically significative differences, between males and females, for Al, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Rb, Sb, Se, Sr, V and Zn. Linear Discriminant Analysis indicated a clear-cut separation in terms of Sr, Ni, Zn, V, Cd, Cu, Mn, Mo and Pb levels for females and Se, Cr, As, Li, Rb and Sb levels for males. We have concluded that CI computed for human hair are to be considered gender specific and they reflect the different basal metabolism between boys and girls. Therefore, the levels of trace elements in hair cannot strictly comparable between different areas and between subjects of different sex. This issue is particularly relevant when identification of anomalous (peculiar) environmental exposures are requested or even in detecting physiological disorders.

Tamburo, E., Varrica, D., & Dongarrà, G. (2015). Coverage intervals for trace elements in human scalp hair are site and also gender-specific. RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA, 35(2S), 317-317.

Coverage intervals for trace elements in human scalp hair are site and also gender-specific

TAMBURO, Elisa;VARRICA, Daniela;DONGARRA', Gaetano
2015

Abstract

Hair analysis is a powerful tool for assessing human exposure to metals and metalloids (MM). The basis for interpreting laboratory results lie on the use of coverage intervals (CI), computed between the 0.025 and 0.975 fractiles, from a well-defined group of reference individuals reflecting normal and healthy people. A critical point in efficient use of CI, when used for comparative decision-making processes, forensic and clinic considerations, is constituted by confounding factors as the specific living site of study population and gender of participants. Our study aims to demonstrate that hair levels of trace elements are site specific and also gender specific. We have taken into account the levels of 20 trace elements in hair samples from children of the same age (11-14 years old) residing in Sicilian sites characterized by different environmental conditions. The dataset consisted of hair samples collected within the urban area of Palermo, in several small towns located around the volcanic area of Mt. Etna and close to the industrial area of Gela. The study was organized as follow: (a) the first part was addressed to establish whether coverage intervals for MM in human scalp hair are to be considered site specific reflecting local environmental conditions; (b) the second part was intended to provide more information about the gender effect on MM distribution in human scalp hair. The obtained main results can be summarized as follows: a) for many elements, the computed CIs are clearly not equivalent for the different sites, but rather the interval of an element for a site extends far beyond that one calculated for another site, suggesting that what is normal for one site may not be normal for another site. Therefore CIs are valid only for a well defined area and can hardly be extended to other areas with different characteristics. b) CIs of several elements computed for hair samples from female subjects are statistically different from those computed for male subjects. For example, Cd, Li and Rb male coverage intervals extend far beyond those calculated for females, instead, those of Cu, Mn, Ni, Sr, V and Zn are wider for females than males. The Mann-Whitney test (p < 0.01) showed statistically significative differences, between males and females, for Al, Ba, Cd, Co, Cr, Cu, Mn, Ni, Pb, Rb, Sb, Se, Sr, V and Zn. Linear Discriminant Analysis indicated a clear-cut separation in terms of Sr, Ni, Zn, V, Cd, Cu, Mn, Mo and Pb levels for females and Se, Cr, As, Li, Rb and Sb levels for males. We have concluded that CI computed for human hair are to be considered gender specific and they reflect the different basal metabolism between boys and girls. Therefore, the levels of trace elements in hair cannot strictly comparable between different areas and between subjects of different sex. This issue is particularly relevant when identification of anomalous (peculiar) environmental exposures are requested or even in detecting physiological disorders.
Settore GEO/08 - Geochimica E Vulcanologia
Il Pianeta Dinamico: sviluppi e prospettive a 100 anni da Wegener
Firenze
2-4 settembre 2015
Tamburo, E., Varrica, D., & Dongarrà, G. (2015). Coverage intervals for trace elements in human scalp hair are site and also gender-specific. RENDICONTI ONLINE DELLA SOCIETÀ GEOLOGICA ITALIANA, 35(2S), 317-317.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/145483
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