Geochemical and electrical characterization of heavy metals in contaminated soils

Mohamed M Gomaa; Ahmed Melegy; Hussein Metwaly; Salwa Hassan

doi:10.1016/j.heliyon.2020.e04954

Geochemical and electrical characterization of heavy metals in contaminated soils

Heliyon. 2020 Sep 17;6(9):e04954. doi: 10.1016/j.heliyon.2020.e04954. eCollection 2020 Sep.

Authors

Mohamed M Gomaa¹, Ahmed Melegy², Hussein Metwaly², Salwa Hassan²

Affiliations

¹ Geophysical Sciences Department, Head of Geophysical Exploration Group, National Research Centre, El-Behoos St., Dokki, Cairo, Egypt.
² Geological Department, National Research Centre, El-Behoos St., Dokki, Cairo, Egypt.

Abstract

The present work is conducted in the industrial district south of greater Cairo (ElTabbin area). Some heavy metals like Mn, Co, Ni, Cu, Zn, Pb, Cr, Ba, Cd, Mo were determined in polluted soils during May, 2018. At the study area, results displayed that average heavy metals concentrations differ considerably. They are decreased from Mn to Cd (Mn > Ba > Zn > Cr > Ni > Co > Pb > Cu > Mo > Cd). The average ranges as follows: Mn (255.8-31448.2 ppm); Ba (145.2-17545.6 ppm); Zn (53.3-1589.9 ppm); Cr (26.7-311.3 ppm); Ni (29.7-114.1 ppm); Co (13.2-39.8 ppm); Pb (5.7-77.4 ppm); Cu (7.6-35.2 ppm); Mo (0.1-15.9 ppm) and Cd (0-1.5 ppm), respectively. ElTabbin area has heavy manufacturing activity at Egypt. ElTabbin area was chosen as a model for that contamination. Electrical characteristics of some specimens from El- Tebbin area, Egypt, were taken and measured electrically at frequency range (10^-3 to 100 kHz). Major and heavy elements were measured at specimens. Specimens were classified to three categories according to electrical properties. The changes were the consequence of change in minor and major mineral composition in the specimens. Electrical properties were able to recognize different specimens according to different levels of contaminants in the specimens. Texture, tortuosity and minor elements of heavy elements are the controlling factors that control electrical properties at specimens. High values concentration of Mn, Ni, and Zn heavy elements increases conductivity while the high concentration of Pb and Cu heavy elements decreases the conductivity. The mixing up of these different minor and major minerals and elements at specimen may lead to the change of conductivity values. The main controlling factors of the major elements are the Fe₂O₃ and SiO₂, while the main controlling factors of the minor elements are the Mn and Pb. Our main objective is to study mixing up of the different minor and major minerals and elements on electrical properties of rocks.

Keywords: Condensed matter physics; Dielectric constant; Earth sciences; Geochemistry; Geology; Geophysics; Hydrology; Impedance; Mineralogy; Physical chemistry; Physics methods electrical conductivity.