Environmental Risk Assessment of Some Selected Heavy Metals in Soil Among Small Scale Automobile Repair Workshops in Brownfields Urban of Damaturu Lga, Yobe State, Nigeria

In this study, the environmental risk of some selected heavy metals in soil among small-scale automobile repair workshops in brownfields urban of Damaturu LGA, Yobe state, Nigeria was assessed. The specific objectives of the study were to assess the presence of selected heavy metals in the soil; compared the concentration of heavy metals with European council for European communities (EC), World Health Organization (WHO) and Food and Agricultural Organization (FAO) standards for soil quality. Soil samples were collected from selected automobile workshops site along Maiduguri, Gujba, Potiskum and Gashua roads respectively at the depths of 0-5, 5-10, 10-15, 15-20 and 20-25cm. A simple random sampling method was adopted for the study. Analysis were carried out using mean, standard deviation and ANOVA. Mean concentrations of heavy metals in soil samples (mgkg-1) ranged from 24.49+4.18-58.18+2.60, 3.32+1.12-7.85+0.42, 19.29+2.42-40.09+1.74, 53.54+20.08- 173.74+8.51, 20.95+0.83 – 46.93+2.28 for Pb, As, Se, Fe and Cd respectively. All the values recorded for the selected heavy metals in the samples were within the permissible limit recommended by WHO/FAO except selenium (Se) and cadmium (Cd) which were found to be above the permissible limit. The concentration of lead (Pb) was found to be significant (P˂0.05) at depth 5-10cm (36.26b). So also, the concentration of Cd and As in Maiduguri road was found to be significant (P˂0.05) at a depth 20-25cm (32.72b) and 10-15cm (7.13b) respectively while no significant difference was observed in Gashu’a road between the whole soil depth (P˃0.05) recorded respectively. There is a significant differences (P >0.05) in the concentration of Se in both road at some certain soil depth. The concentration of Fe was found to be significant (P˂0.05) at both road except in Potiskum road. The results indicated that soil qualities varied between slightly contaminated to highly polluted status. This showed that the heavy metal contamination of the soils do not call for any alarm; however, it is recommended that, proactive measures must be taken to minimize accumulation of these metals in the soil; health and environmental talks should also be given occasionally to automobile operators to be more safety conscious and embrace environmentally friendly practices that will enhance their performance and work operations