The level of heavy metals in the atmosphere of a macroenvironment, Lagos State, Southwestern - Nigeria using moss plant (Dicranium scorparium) as bioindicator

Abstract

The major objective of this study is to investigate the concentrations of some metals (Zn, Pb, Cd, Ni and Cu) content in moss plant (Dicranum scoparium) collected at different locations within Yaba College of Technology, Campus Lagos state, Southwestern - Nigeria. The samples of the plant were collected randomly between September and November, 2016 at 10 different locations at the Campus between 2 - 2.5 meters high from unplastered buildings in Lagos state. The samples were properly cleaned from all the debris, weighed and digested with a mixture of HN0₃ and H₂O₂ for 35 min. The concentrations of heavy metals were analyzed using Atomic Absorption Spectrophotometer (AAS) Perkin Elmer AA 200. Results obtained, showed that the average concentrations of the heavy metals at Yaba College of Technology Campus were: Zn 8.63574mg/l, 1.12618mg/l, Cu 0.51249mg/l, Ni 0.43252mg/l and Cd 0.02563mg/l which reflects 80.46; 10.49; 4.78; 4.03 and 0.24% respectively with the most abundant pollutant heavy metal being Zn in all the sites while the least abundant was Cd. Similarly, the most polluted site was Bakassi Hostel while the least polluted was the Staff Quarters. The levels of Zn and Pb were present in concentrations greater than the WHO threshold limiting values. There was a significant difference in the level of each heavy metal in the atmosphere of Yaba College of Technology Campus (PV < 0.05).The sequence of bioaccumulation and distribution follows the pattern thus: Zn > Pb > Cu > Ni > Cd.

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