Soil pollution studies of Takum, Nigeria: The use of environmental magnetic properties, elemental analysis and geostatistical tools

Abstract

The study examined the pollution status of Takum town, Nigeria using environmental magnetic, geochemistry and geostatistics. The environmental magnetic approach included measurement of concentration, grain size and magnetic mineral dependent parameters. Magnetic susceptibility (χ), saturation and anhysteric remanent magnetizations were highly variable having values that ranged from 32.11–1118.57 × 10−8 m3kg−1, 95.03–1206.59 × 10−8 m3kg−1 and 199.87–16,002 × 10−5 Am2kg−1 respectively. These values reflect top soil enhancement due to the dominance of secondary ferrimagnetic minerals, revealed by thermomagnetic runs to be mainly magnetite. The frequency dependent susceptibility χfd% had an average value of 10.63% implying that the samples were dominated by pedogenic superparamagnetic grains, however, the presence of multi-domains grains from vehicular sources were also present. The mean concentration of the measured heavy metals decreased in the order: Fe > Ti > Mn > Zn > Pb > Cu > Ni > Hg. Based on various indices, Hg and Pb has been identified as elements constituting the greatest risk to the area. Significant positive correlation were obtained between magnetic concentration parameters and Cr, Fe, Zn, Pb and PLI, supporting the use of environmental magnetic properties for quick assessment and monitoring of pollution levels in the Takum soils. The sources of heavy metal pollution have been identified to originate from vehicular, agricultural, pedogenic and weathering activities. Different degrees of significant correlation were obtained between magnetic parameters, heavy metals and particle size classes, indicating potential of using magnetic techniques as proxy for textural parameters.