Distribution of trace elements in the lipid and nonlipid matter of hair

Abstract

We studied the effect of lipid removal on the concentrations of 13 trace elements measured in human hair. We used a pooled specimen of hair from a barber shop, initially washed with de-ionized water, with ultrasonic cleaning, then analyzed for Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Si, Sr, and Zn with use of an inductively coupled plasma emission spectrometer. The lipid was removed by Soxhlet extraction with ethanol, and the hair was re-analyzed. We found several elements present in a relatively large proportion (greater than 20%) in the lipid fraction, mainly Na, K, Ca, Mg, Ni, and Sr. We suggest that removal of part or all of the lipids from hair by using detergents or other lipid-removing solvents for washing may account for the variability in data on elements in hair reported by different laboratories, and that those elements largely present in the lipid fraction are the result of environmental exposure, whereas those retained in the hair fiber after lipid removal can be attributed to nutritional and clinical aspects. We believe that such determination of the distribution of elements may help validate the use of hair in assessing trace elements in the body.

Provenance of Ancient Textiles—a Pilot Study Evaluating the Strontium Isotope System in Wool*

“…The distribution of several trace elements, including Sr, in human hair has been studied in detail by Attar et al (1990). They found several elements (Na, K, Ca, Mg, Ni and Sr) to be present in a relatively large portion (>20%) in the lipid fraction.…”

“…The implication of this study is that it would be essential to remove lipid-sourced Sr in hair before using the Sr for isotopic origin tracing, as it is likely that this fraction is sensitive to post-mortem contamination by environmental signatures (in the case of ancient wool fibre contamination by, for example, percolating fluids during the burial period, interaction of pore waters with the fibres in peat bog finds etc.). In their contribution, Attar et al (1990) presented release spectra of certain elements in a procedure that apparently is capable of extracting lipid matter of hair by an ethanol exposure. In order to quantify the effect of our HF pretreatment, we have analysed a number of trace elements in the rinse solution and the residual fraction of our hair/wool treatment.…”

“…It is today widely accepted 'that hair can be considered a minor excretory organ, supporting its use as a biopsy material representing the body' (Attar et al 1990). The elevated trace element concentrations make hair a suitable specimen for epidemiological studies and potentially for diagnostic considerations (e.g., Attar et al 1990).…”

“…It is today widely accepted 'that hair can be considered a minor excretory organ, supporting its use as a biopsy material representing the body' (Attar et al 1990). The elevated trace element concentrations make hair a suitable specimen for epidemiological studies and potentially for diagnostic considerations (e.g., Attar et al 1990). Consequently, trace element analyses of human and animal hair have become a powerful tool in environmental impact history studies, veterinary medicine and forensic investigations (Ahmed and Elmubarak 1991;Folin et al 1991;Alhashimi 1994;Batzevich 1995;Bertazzo et al 1996;Ali et al 1997;Dong et al 1998;Abugassa et al 1999;Sakai et al 2000;Asano et al 2002;Hasan et al 2004;Menezes et al 2004;Rashed and Soltan 2005).…”

“…Despite these promising prerequisites, applications of the stable Sr isotope system to hair are virtually non-existent. Among different reasons, a particular one might be the very low concentrations of Sr in animal and human hair-Sr concentrations in recent human and animal hair are of the order of less than one ppm to a few ppm (Morita et al 1986;Attar et al 1990;Christian et al 1997;Miekeley et al 1998;Rosborg et al 2003), which makes the recovery of sufficient amounts of Sr for precise mass spectrometric analyses a complex undertaking. The results of a recently conducted pilot study (von Carnap-Bornheim et al 2007) aiming at determining Sr isotopic ratios from Iron Age wool textile and leather pieces from a peat bog in Schleswig-Holstein (Germany) were in support of using this tracer to potentially determine the place of origin of these archaeological finds.…”