Trace Elements in Hair: Relevance to Air Pollution

Abstract

Elemental concentrations of single hair samples taken from 2003 to 2012 had been evaluated by X-ray fluorescence for the assessment of the relation between calcium and cancer. Early results implied a mechanism linking hair and serum element concentrations with a shift in element levels over time. After 2009, pollution-attributable differences were seen in the levels of Ca, Sr, P, Cl, Br, K, S, elements under renal control by parathyroid hormone (PTH), as well as Cu, Zn, Ti. Especially, hair taken from February to March 2011 showed low [Cu] and [Zn] indicating about half of the normal serum level and often three orders of magnitude higher [Ti] than typical. These specimens also showed higher serum [S] than usual, and except for one patient with PTH-related disease, all the subjects had the normal or lower hair calcium than typical for earlier years. Almost all the subjects showed store-operated Ca channel gating. The pollution era is associated with an increase in hair Na, a decrease in K, and abnormally low P, suggesting a functional deterioration of Na + /K +-ATPase. These results can be attributed to increases in serum Ca and S coincident with breathing the polluted air; the incorporated Ca closes the ion channels of hair matrix cells but may be moved with P to bone, resulting in the abnormal P deficiency, likely producing an ATP shortage in serum. This insufficient ATP supply may result in inactivated molecular pumps and hypokalemia contributing to fatal ventricular fibrillation in patients with myocardial infarction. The pollution increase [S] in serum may be excreted by forming sulfide compounds with Cu and Zn, resulting in Cu deficiency necessary for making elastin to repair damage in blood vessels. The K and Cu deficiencies observed appear to account for the reported increase in infarction mortality after high-pollution days.