Assessment of Cd and Zn in Roadside Surface Soils and Vegetations along Some Roads of Kaduna Metropolis, Nigeria

• Published in: Research journal of environmental sciences 2008-04, Vol.2 (4), p.266-274
• Main Authors: Okunola, O J, Uzairu, A, Ndukwe, GI, Adewusi, S G
• Format: Article
• Language: English
• ISSN: 1819-3412
• DOI: 10.3923/rjes.2008.266.274

To identify the concentrations of heavy metals in roadside environment, samples of roadside soils and vegetation were collected from 30 sites of 24 minor and major roads in Kaduna metropolis across two seasons. Subsequently, the concentrations of Cadmium (Cd) and Zinc (Zn) in the samples were analyzed using atomic absorption spectrophotometer. The mean concentration of Zn (mg kg super(-1) d.w.) in soil ranged from 45.37-237.96 and 24.21-123.14 for dry and wet season, respectively. While Cd mean concentration (mg kg super(-1) d.w.) in soil ranged from 1.96-6.80 and 0.38-2.44 for dry and season, respectively. Concentration of Zn in plant (mg kg super(-1)) ranged from 27.78-185.19 and 15.43-138.89 for dry and wet season, respectively while concentration (mg kg super(-1) d.w.) of Cd ranged from 4.88-14.63 and 4.88-9.76 for dry and wet season, respectively. The Zn concentrations in both soil and plant leaves were found to be within ICRCL and FAO/WHO recommended limits, respectively. While Cd concentrations were found in excess of ICRCL and FAO/WHO recommended limits, respectively, this indicates potential health risk for human through the food chain. Comparative study showed that Cd and Zn values for soil and plant leaves were found high in the study area than the control area. This suggests that automobiles are a major source of these metals in roadside environment.