Risk Assessment of Heavy Metals and Soil Qualities from Different Motor Parks Around Ekiosa Market in Benin City, Nigeria

1*Imarhiagbe, Esosa Emmanuel and 2Ovie, David Omokefe

1Department of Environmental Management and Toxicology, Faculty of Life Sciences, University of Benin, Benin City
2Applied Environmental Bioscience and Public Health Research Group (AEBPH RG), University of Benin, Benin, Edo State, Nigeria

Corresponding author: esosa.imarhiagbe@uniben.edu


Soil samples from five motor parks around Ekiosa market in Benin
City, Edo State were assessed for physicochemical, microbiological
qualities, pollution and health risks due to heavy metals exposure.
Standard analytical procedures; Atomic Absorbance Spectrophotometry, pour plate method were utilized in the determination of the physicochemical, heavy metals and heterotrophic microbial flora of the top soils. The pH range from 7.28 ± 5.14 to 7.48 ± 5.14; electrical conductivity (µS/cm) of 138.15 ± 97.69 to 234 ± 165.46. The particle size results were 95.83 ± 67.76 to 98.33 ±69.53 % (sand), 1.09±0.77 to 4.40±3.11 % (silt) and 0.002 to 0.9±0.26% (clay). The mean concentrations of metals recorded were found to be in the range (mg/g) of 0.025 to 1.05; 0.035 to 1.06; 0.05 to 0.15 and 24.05 to 31.10 for lead, cadmium, chromium and iron respectively, which are higher than world soil average abundance of metals except for iron which was lower. Total heterotrophic bacterial and fungal enumeration yielded values that ranged from 0.8 to 1.9 x (105 cfu/g) and 0.3 to 2.7 x (105 cfu/g) respectively, which were lower than the control soil (2.3 x 105 cfu/g and 2.7 x 105 cfu/g) for THB and THF respectively. The pollution assessment indices results indicated low ecological risk and moderate contamination for all metals except cadmium, which showed high ecological risk. Pollution assessment indices results indicated a polluted soil, the current safety of this site would be jeopardized over time due to continuous vehicular activities, therefore it should be suggested that motor parks be kept away from market environment.

Keywords: Motor Park, Physicochemical, Microbiological qualities, Pollution and health risks