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  (P_V < 0.05).The sequence of  bioaccumulation  and distribution  follows  the  pattern  thus:  Zn > Pb > Cu > Ni > Cd.