Assessment of Heavy Metals and Physiocochemical Quality of Soil around Auto Mechanic Workshops in Mararaba, Nasarawa State

Analysis of soils for the physicochemical properties from 9 selected auto mechanic workshops in Mararaba, Nasarawa State was carried out according to standard methods. Soil samples were analysed for pH, organic matter, salinity and cationic exchange capacity. The level of heavy concentration in the soil samples obtained from the workshops were determined using Atomic Absorption Spectroscopy (AAS). The results obtained for the physicochemical properties and concentration of heavy metals varied according to the sampling locations and the type of metals. The pH of the soil ranged from 7.46 to 8.91, Organic matter; 5.20 to 7.30 %, Soil salinity; 28.80 to 73.03 μS/cm, and Cation exchange capacity of soil ranged from 0.80 to 2.49 meg/100g It was observed that the ranges of concentration of the assessed heavy metals were: Pb: 0.9719-0.2154 mg/kg, Cd: 0.03491 – 0.8991 mg/kg, Ni: 1.2521-1.1762 mg/kg, Cu: 4.6997-0.7291 mg/kg, Cr: 5.6063-1.8736 mg/kg, and Zn: 4.5142-0.6733 mg/kg. The I-geo, Cf and QoC values were also calculated and reported. The results obtained for heavy metals revealed that the soils from some of the sampling locations are impacted negatively as observed in significant concentrations of some heavy metals which are above threshold limit for agricultural soil, indicating potential environmental and health risks. The study highlights the need for regular monitoring and remediation of soils in auto mechanics workshops to prevent environmental pollution and ensure sustainable land used practices.