Brief communication: Choice of washing method of hair samples for trace element analysis in environmental studies

Abstract

Determination of inseparable exogenous and endogenous levels of toxic trace elements such as lead in human scalp hair has been used to understand and assess population exposure to such elements. For any such analysis, washing of the hair samples to remove superficial contamination is the foremost requirement. However, the use of such washing methods prior to elemental analysis removes minute quantities of trace elements from the hair strands. This degree of loss is dependent on the washing method employed. In the present study, the element lead has been determined in human scalp hair after three methods of hair washing. It is apparent that the nonionic detergent-acetone method is best suited for securing valid lead analysis results in human scalp hair.

A Comparative Evaluation of Three Washing Procedures for Minimizing Exogenous Trace Element Contamination in Fetal Scalp Hair of Various Obstetric Outcomes

“…In addition to fluctuations in temperature, humidity, and water salinity levels, elemental contaminants in adult hair would tend to be of heterogeneous origins and chemical speciation, giving rise to binding affinities and mechanisms that are likely different from those in fetal hair. Such differences probably account for the marked variations often observed in the response of adult hair samples to currently used washing methods [2,7,29]. The reason for exogenous copper and zinc contamination levels being higher than those of the other elements in all the samples analyzed is unclear.…”

Assessment of environmental and occupational exposure to heavy metals in Taranto and other provinces of Southern Italy by means of scalp hair analysis

“…Hairs were taken near the scalp from different points of the nape and temple areas; then, from each hair, a 3-cm length was cut from near the root end. The samples' weight ranged from 0.2 to 1.0 g (Hinners et al 1974;Sen and Das Chaudhuri 2001).…”

Town and Gender Effects on Hair Lead Levels in Children from Three Sardinian Towns (Italy) with Different Environmental Backgrounds

“…The treatment steps were: overnight predigestion with 10 mL of high-purity concentrated (68%) HNO 3 , a 30-min stage at microwave power of approximately 180 W, a 30-min stage at microwave power of approximately 240 W, a 10-min cooling stage, addition of 1 mL H 2 O 2 (30%) and 1 mL hydrofluoric acid (50%), a further 30-min stage at microwave power of 300 W, a 1-h stage at microwave power of 360 W, quantitative transfer into polypropylene tubes, and dilution up to 20 mL with double-distilled water. It should be emphasized that standardization of the methods of hair lead (PbH) determination remains an unresolved problem [47] and the washing method adopted to remove surface contaminants may produce large differences in PbH values [43,48]. The method used for quantification of Pb consists of inductively coupled plasma atomic absorption spectrometry with a Thermon Electron Corporation, model M6MK2.…”