Lifestyle influence on trace element contents in human scalp hair of young residents in different urban contexts. Preliminary results.

Abstract

A causal relationship between earth material and human health, although not always proven, is highly plausible because many chemical elements in rocks and soils are directly inhaled by respiration or transmitted, via air, water and vegetation, into food chain and then to human body. It is well known that metals and metalloids may result essential to biochemical and physiological functions, but it is also well known that health problems may derive from either dietary deficiencies or excesses. Among the techniques employed to assess the exposure of living organisms to metals and metalloids present in the environment, the human biomonitoring has attracted the attention of investigators over the past decades. More specifically, the human biomonitoring is a method for assessing human exposure to chemicals by measuring the searched chemicals or their metabolites in human tissues or specimens, such as blood, plasma, serum, breast milk, urine, teeth and also hairs. However, some of these specimens may not always be the best indicators of element intake because of the homeostatic system of control in the human body. Human hairs seem to be particularly appropriate as they offer several advantages. Hair are stable and their composition does not change over short time period. Furthermore, sampling procedure is very easy, requires no specific professional skills, is painless and non-invasive. The present study deals with the trace elements content of hair samples from the scalp of 136 young students, between 11 and 14 years of age, of female and male gender, resident in the metropolitan area of Palermo (80 samples) and in a small rural town, Altavilla (56 samples), 20 km far from Palermo. The concentrations of 18 elements (Al, As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Sb, Se, Sr, U, V, Zn) in hair were determined by ICP-MS. In order to eliminate external contamination, each hair sample was firstly properly washed. The obtained results were in line with the ranges of values published in other studies. The most abundant elements resulted Zn, Cu, Al, Sr, Ba, Pb in Palermo as well as in Altavilla, although with different abundance orders. All the remaining analyzed elements were below 1 ppm. Zn is known to be an essential element recognized in more than 300 enzymes depending on this element for catalytic, structural, and regulatory functions. Cu is considered an indispensable catalytic cofactor in redox chemistry for proteins. Al and Sr are typical geogenic elements; their different abundances in the Palermo and Altavilla samples are related to the different lithological site, carbonate rocks in Palermo and calcarenites-clays at Altavilla. Sr is also strictly related to calcium content in bones. The highest levels of most elements were found in Altavilla samples: this may indicate a possible different exposure due to different lifestyles, as evidenced by Al and Pb. In fact, children living at Altavilla spend more time outdoors than those living in Palermo. The higher Ba concentration in children from Altavilla may be also related to the Ba content of local drinkable water. Significant gender-related differences were found for certain elements. This was the case of Sr and Zn, more abundant in female subjects, and Cr, Li, Pb, Sb and U which were more abundant in males. When the elements are subdivided in essential and not essential, and their ratios with respect to aluminum are compared with those in air particulate matter and road dust, it appears evident that some elements typical of anthropogenic sources (Cd, Pb e Sb) are taken by PM10-2.5, PM2.5 and the finest fractions of road dust. Data concerning subjects exposed and not exposed to passive smoke are also reported. Further, it has been examined the relationship between exposure to passive smoke and concentration of nicotine (and its metabolite cotinine) in hairs. A first result of this work is that the reported data and concentration ranges can be used as guidelines for to evaluate envir