Pattern of distribution and concentration of selected heavy metals in farmlands near roadsides in Owerri, Nigeria
Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
University of Oradea Publishing House
Abstract
Vehicular traffic has been implicated in increasing heavy metals concentrations in nearby soils. Notably, severe environmental and health challenges have been associated with elevated concentrations of these heavy metals, hence the need to monitor them in adjoining farmlands to forestall entry into food chains. The distribution patterns of Pb, Cd, Mn and Cu on Owerri Onitsha and Owerri-Aba expressways were studied. Soil and Panicum maximum leaf samples were collected at 3 locations on each road at 5m, 10m and 15m away from the roadsides. Samples were processed and analysis for heavy metal concentrations was done with atomic absorption spectrophotometer (AAS). Results obtained indicated the presence of all the selected heavy metals at almost all the locations and points studied. The order for heavy metals in samples from Owerri-Aba expressway was Pb>Cu>Cd>Mn, while
that of Owerri-Onitsha was Mn>Pb>Cu>Cd. Although the concentrations generally fluctuated with increasing distance away from the roadsides at most locations, in some grass samples it increased with distance. There was also a decline in their concentrations with increasing distance away from the road for some soil samples. Owerri-Onitsha expressway gave higher concentrations of heavy metals in both samples than Owerri-Aba expressway. Meanwhile, the concentrations of Mn and Cu in plant extracts were generally below the maximum allowable levels while Pb and Cd far exceeded it. Similarly, their concentrations in soil samples were below the EU limits except Cd. Results of metal bioaccumulation factor revealed that Panicum maximum moderately bioaccumulated most heavy metals from the soil. There was weak or no correlation between heavy metal contents of soil and P. maximum samples.
Atmospheric deposition also contributed to the heavy metals in plant samples. Since some heavy metals studied exceeded their recommended limits, it is advisable to discourage farming activities upto 15m from the roadsides, especially on sloped roadsides.
Description
The article has tables and figures
Keywords
exhaust fumes, roadside, heavy metals, bioaccumulation, distribution, Owerri-Aba road, Owerri-Onitsha road, Department of Microbiology
Citation
Anuforo, H. U., Akujobi, C. O., Umeh, P. K. & Ejimadu, P. I. (2020). Pattern of distribution and concentration of selected heavy metals in farmlands near roadsides in Owerri, Nigeria. Analele Universităţii din Oradea, Fascicula Biologie, XXVII(1), 32-38