# Weekly and Longitudinal Element Variability in Hair Samples of Subjects Non-Occupationally Exposed
## 3 Results and Discussion
### Element Content in Human Hair Samples
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Element Concentration (Mean \(\pm\) s.d. 1)**} \\ \hline \multicolumn{4}{c}{**Scalp Location**} & \multicolumn{4}{c}{**Longitudinal Variability**} \\ \hline  & **Left Zone** & **Central Zone** & **Right Zone** & **Proximal** & **Distal** \\ \hline Ag & 0.882 \(\pm\) 0.250 & 1.15 \(\pm\) 0.295 & 0.830 \(\pm\) 0.095 & 0.953 \(\pm\) 0.172 & 0.527 \(\pm\) 0.133 \\ Au & \textless{LOD} & \textless{LOD} & 0.037 \(\pm\) 0.009 & 0.037 & 0.015 \(\pm\) 0.006 \\ Ba & \textless{LOD} & \textless{LOD} & 1.30 \(\pm\) 0.19 & 1.30 & 1.49 \(\pm\) 0.26 \\ Br & 27.1 \(\pm\) 2.1 & 23.7 \(\pm\) 0.5 & 28.8 \(\pm\) 1.7 & 26.5 \(\pm\) 2.6 & 26.5 \(\pm\) 4.9 \\ Ca & 1363 \(\pm\) 619 & 1933 \(\pm\) 331 & 1998 \(\pm\) 214 & 1765 \(\pm\) 349 & 2255 \(\pm\) 594 \\ Co & 0.033 \(\pm\) 0.001 & 0.034 \(\pm\) 0.004 & 0.042 \(\pm\) 0.012 & 0.036 \(\pm\) 0.005 & 0.046 \(\pm\) 0.018 \\ Cr & 0.081 \(\pm\) 0.004 & 0.086 \(\pm\) 0.005 & 0.092 \(\pm\) 0.090 & 0.056 \(\pm\) 0.047 & 0.116 \(\pm\) 0.058 \\ Cu & 26.3 \(\pm\) 6.4 & 27.8 \(\pm\) 1.8 & 6.12 \(\pm\) 1.91 & 20.1 \(\pm\) 12.1 & 10.1 \(\pm\) 6.8 \\ Eu & \textless{LOD} & \textless{LOD} & 0.00070 \(\pm\) 0.00035 & 0.01 & \textless{LOD} \\ Fe & 14.2 \(\pm\) 0.1 & 13.5 \(\pm\) 0.8 & 20.8 \(\pm\) 3.8 & 16.2 \(\pm\) 4.0 & 19.2 \(\pm\) 8.0 \\ K & 211 \(\pm\) 16 & 234 \(\pm\) 6 & 282 \(\pm\) 41 & 242 \(\pm\) 36 & 255 \(\pm\) 97 \\ La & 0.288 \(\pm\) 0.626 & 0.351 \(\pm\) 0.453 & 1.35 \(\pm\) 0.67 & 0.663 \(\pm\) 0.595 & 1.40 \(\pm\) 0.20 \\ Mn & 4.30 \(\pm\) 1.21 & 3.20 \(\pm\) 1.61 & 4.20 \(\pm\) 0.48 & 3.90 \(\pm\) 0.61 & 3.52 \(\pm\) 2.30 \\ Na & 102 \(\pm\) 7 & 105 \(\pm\) 4 & 103 \(\pm\) 19 & 103 \(\pm\) 1 & 114 \(\pm\) 26 \\ Rb & 0.129 \(\pm\) 0.011 & 0.270 \(\pm\) 0.049 & 0.200 \(\pm\) 0.170 & 0.199 \(\pm\) 0.070 & 0.338 \(\pm\) 0.219 \\ Sb & 0.064 \(\pm\) 0.009 & 0.096 \(\pm\) 0.014 & 0.072 \(\pm\) 0.019 & 0.077 \(\pm\) 0.017 & 0.073 \(\pm\) 0.040 \\ Sc & 0.012 \(\pm\) 0.005 & \textless{LOD} & 0.007 \(\pm\) 0.004 & 0.008 \(\pm\) 0.007 & 0.007 \(\pm\) 0.006 \\ Se & 0.352 \(\pm\) 0.004 & 0.414 \(\pm\) 0.045 & 0.430 \(\pm\) 0.035 & 0.397 \(\pm\) 0.042 & 0.430 \(\pm\) 0.070 \\ Tb & \textless{LOD} & \textless{LOD} & 0.020 \(\pm\) 0.010 & 0.020 & \textless{LOD} \\ Th & \textless{LOD} & \textless{LOD} & 0.001 \(\pm\) 0.017 & 0.001 & 0.012 \(\pm\) 0.020 \\ W & 0.012 \(\pm\) 0.000 & 0.013 \(\pm\) 0.002 & 0.019 \(\pm\) 0.012 & 0.015 \(\pm\) 0.04 & 0.024 \(\pm\) 0.016 \\ Zn & 68.6 \(\pm\) 4.1 & 87.0 \(\pm\) 2.7 & 66.3 \(\pm\) 5.8 & 74.0 \(\pm\) 11.3 & 85.3 \(\pm\) 7.3 \\ \hline \hline \end{tabular} \({}^{1}\) s.d. standard deviation.  
\end{table} 
Table 3: Element concentrations (\(\mu\)g g\({}^{-1}\)) in the nape different areas and along the hair (proximal and distal zones), (five independent measurements). good health conditions and in \"anomalies\" caused by occupational and/or environmental exposure. On the other hand, the concentration of elements of environmental origin (i.e., La, Rb, Sc, Th, and W) is less stable: their CVs vary between 38.4%, tungsten, and 126.9%, thorium. The hypothesis that can be advanced is that their presence in the environment, and therefore their levels in the hair, is connected to the variation of local climatic conditions: wind direction, wind speed, temperature, humidity, etc. A trend similar to that of the elements of environmental origin is also shown by two chemicals considered essential, i.e., Cr and Cu, and, albeit to a lesser extent, by Fe (CV% 45%, 53.2%, and 23.5%, respectively). For these three elements, the hypothesis of a double origin could be put forward; i.e., there is an overlapping between the element basal levels (i.e., the concentration levels naturally present in the human body) and the concentrations deriving from environmental pollution.