Temporal variability of heavy metal content in the atmosphere of Ketu- mile 12 area of Lagos - State, southwestern - Nigeria using moss plant Polytrichum juniperum as bioindicator

Abstract

The concentrations of the five heavy metals; Zinc (Zn), Lead (Pb), Cadmium (Cd), Nickel (Ni) and Copper (Cu) were determined using Atomic Absorption Spectrophotometer (AAS). Results of the analysis, shows that the average concentration of the heavy metals at Ketu - Mile 12 were : Zn 7.175mg/L; Pb 1.288mg/l; Cu 0.531mg/l; Ni 0.223mg/l and Cd 0.021mg/l which reflects Zn 77.67; Pb 13.94; Cu 5.75; Ni 2.41 and Cd 0.22 % with the most abundant pollutant heavy metal being Zn in all the sites while the least abundant was Cd. It was found that the highest concentration of each heavy metals in all the sites were as follow; Zn 14.93mg/l - Alapere; Pb 1.720mg/l - Ketu garage; Cd 0.118mg/l - Mile 12 market; Ni 0.458mg/l - Mile 12 and Cu 0.956mg/I - Ketu garage while the least concentration of heavy metals in all the sites were as follows: Zn < 0.005mg/l, Pb < 0.001mg/l), Cd < 0.001mg/l and Cu 0.106mg/l - Oniru, Ni 0.108mg/ - Iyana school. The most polluted site was Ikosi road 4.441 mg/l while the least polluted was Iyana School 0.327mg/l. The sequence of bioaccumulation and distribution follows the pattern thus: Zn>Pb>Cu>Ni >Cd.

Keywords: Bioaccumulation, Pollution, Spectrophotometer, Bioindicator, Anthropogenic, Concentrations