Biomonitoring of atmospheric heavy metals in Agbara Industrial Area of Ogun - State, South –Western, Nigeria using <I>Sphagnum compactumas</I> biomonitor

Abstract

The presence of heavy metals in the environment beyond the acceptable limits is a serious concern to the environmentalists.The present research reports the results of some heavy metal content (Zn, Pb, Ni, Cu and Cd) in Agbara Industrial area of Ogun - State using the moss plant Sphagnum compactum as bioindicator. The samples of the Moss plant were collected randomly from September to November, 2018 at ten different locations inAgbara Industrial Area between 2 to 2.5 metres high from unplastered buildings in Ogun - State and analysed for their heavy metal contents as at the time of sampling. The samples were properly cleaned from all the debris then weighed and digested with a mixture of HNO3and H2O2 for 35 min. The concentrations of the five heavy metals were determined using Atomic Absorption Spectrophotometer (AAS) PG-990. Results of the analysis, show that the average concentration of the heavy metals at Agbara Industrial area is: Zn 69.71mg/l,68.89%; Pb 16.502mg/l,16.3%; Ni 7.78mg/l,7.7%; Cu 6.869mg/l, 6.8% and Cd 0.395mg/l,0.41%, with the most abundant pollutant heavy metal being Zn(69.71mg/l) in all the sites while the least abundant was Cd(0.395mg/l).The most polluted site is Eko Supreme Limited (29.871mg/l) while the least polluted is Elphitina (2.269mg/l). The sequence of bioaccumulation and distribution follows the pattern thus: Zn> Pb>Ni>Cu>Cd . There is a significant difference in the levels of each heavy metals in the atmosphere of Agbara Industrial area (pvalue< 0.05). Moreover, the concentrations of heavy metals obtained exceeded the recommended limits of the Federal Ministry of Environment (FME), European Communities (EC) and United Nations Environmental Programme (UNEP) permissible level for heavy metals in the atmosphere, which suggests that the study area is polluted with heavy metals.

Keywords: Anthropogenic, bioaccumulation, bioindicator, concentrations, pollution, spectrophotometer.