Concentrations of Heavy Elements in the Hair of Sudanese Gold Miners as Indicators of Environmental Pollution using Three XRF Techniques

Abstract

The aim of this study is to determine the concentration of Ca,Fe, Cu, Zn, Pb, Br and Sr in scalp hair of Sudanese exploration (gold) workers in Al-Ubaidiyya town and healthy volunteers from Khartoum, using x-ray fluorescence techniques (XRF). The accuracy and precision of the method for the elements were evaluated through the analysis of a standard hair sample. Workers hair samples were classified corresponding to age, work duration, year of work and the area of work place of the participants. The results showed that the studied trace toxic and heavy elements in both of workers and control groups were positively skewed. In comparison with the control group, lower Fe, Cu, Zn and Pb were found in all studied exploration workers. The result in control group of the analysis shows that mean concentrations (ppm) of heavy metals (Ca, Zn, Br, Sr ) obtained were as follows: Ca = 291 ; Zn = 59.88 ; Br = 0.76 and Sr is 0.488 .While the mean concentrations of all trace elements detected were higher in the exploration workers, that is in exploration workers the main concentration reported in (ppm) to be for Ca = 294.6 ; Zn = 178.78; Br = 0.816 and Sr is 0.651. The relationships between age and heavy trace elements concentrations were also investigated. Statistical analysis of the results indicates that for both groups shows significant difference for Ca and Zn that Ca concentration has direct proportionality with age and Zn decrease with age increasing while Br and Sr showed there was no correlation between the age and trace element concentration in hair. Zn showed the highest deviation among other elements in most samples for the exploration workers groups which reflect the probability of high exposure to contamination at the workplace. These toxic metals have relationship with duration of work since the effects indicate the distribution for concentration of heavy metals under investigation Ca, Zn, Br showed increasing in concentration (ppm) during the duration increment. While Sr had lower value as the duration of work increasing. This data is a good start, but more data characterizing and correlate to other studies including the contamination in water, food, fish, soil and over all environments is needed. It is also noted that Br element appears in most samples in our work, when compared to other studies made locally or abroad. This may be attributed to the preparation procedures as the samples did not exposed to heat. The drying process was made by using liquid nitrogen (LN2). This technique is known as freeze drying. Since Br has low evaporation temperature it follows that they evaporate from the hair thus does not present. A comparison of the common elements has been made using different X-ray fluorescence analysis (Canbera 35 plus (MCA), Energy Dispersive (EDX7000,EDX 8000), scanning electron microscope (SEM). It was found that the concentration of these elements in EDX and SEM is lower compared to XRF. This is due to the presence of more elements in them. The recalibrating of the readings in the three techniques reduced the difference between them and become more reliable.