Analysis of metal content in soils near abandoned mines of Bashkir Trans-Urals and in the hair of children living in this territory.

The aim of this study was to investigate the metal content in the hair of children living near abandoned nonferrous metal mines located in the rural settlements Tubinsk, Ishmurzino and Semenovsk the South Urals (Russia), and in the soils obtained from the same area. The hair and soils samples were examined for the presence of the following metals: copper (Cu), zinc (Zn), iron (Fe), cobalt (Co), nickel (Ni), manganese (Mn), lead (Pb) and cadmium (Cd). The results of this study showed that soil from this territory contained an increased level of Cu, Fe, Zn, Mn, Pb, Cd, exceeding the maximum permissible concentration (MPC) 38.3, 16.8, 4.5, 1.5, 1.4, 1.5 - fold, respectively. These values are indicative of severe soil pollution in the studied locality, thus calling for further detailed investigations. Mineral analysis of the hair samples was performed using a combination of atomic emission spectrometry and inductively coupled plasma mass spectrometry. In the hair samples, positive correlations between the following pairs of the studied metals were observed (p < 0.05): Pb-Cd (r= 0.73), Mn-Cd (r= 0.79), Fe-Cd (r= 0.56), Fe-Co (r= 0.85), Mn-Co (r= 0.65), Ni-Co (r= 0.67), Mn-Fe (r= 0.78), Ni-Fe- (r= 0.45), Pb-Fe (r= 0.46); Pb-Mn (r= 0.58). The comparison between Zn and Pb showed a negative linear correlation for the hair samples (r= -0.50; p<0.05) and for the soil samples (r= -0.68; p<0.05) suggesting that the presence of Zn and Pb in the hair could correlate with the content of these two metals in the soil. Comparison of the data on hair from this study with the average reference data for Russia showed the presence of an excess of Fe, Mn and Zn in the hair samples of the majority of the studied population: 100, 72.5 and 54.5 percent, respectively. We also observed an excess of Ni, Cd and Pb in a small number of children (in 18.2, 13.6 and 9.1 percent of the studied population, respectively). A deficiency of Cu and Co, the essential microelements for human health, was found in 27.3 percent of the studied population. The results of this study could be used to analyze the internal toxic metal burden in contaminated areas of Bashkortostan and could also serve as reference for further studies.