Floristic Distribution and Heavy Metal Levels Around Auto-Mechanic Workshop Clusters in the Yenagoa Metropolis, Bayelsa State, Nigeria

摘要

A floristic survey of plant species encountered around auto-mechanic workshop clusters in the Yenagoa Metropolis was conducted using stratified sampling technique and following standard methods in this study. Sampling was done at three intervals; reference point (0m), 50m and 100ms from 5 auto-mechanic workshop clusters and a control site. Results were expressed in simple percentages X±STD. The distributional patterns, frequency of occurrence and Sorensen's Similarity Index of plant species around auto-mechanic workshop clusters were used to determine prevalence levels and variations from one sample site to another. It was observed that distance decay concept manifested conspicuously as plant species' diversity increased with increasing distances from the reference points (0m) of the auto-mechanic workshop clusters. Overall plant species diversity at the reference point (0m) was 5±1, 25±23 at 50m and 36±12 at 100m around the automechanic workshop clusters while 37±32 was observed at the control site, respectively. However, the control site showed highest species' frequency distribution and diversity as compared to the auto-mechanic workshop clusters in this study. Heavy metal levels were generally observed to be higher in soils around auto-mechanic workshop clusters than at the control site showing evidence of anthropogenic effects in samples encountered at the auto-mechanic workshop clusters. Zn, Cu, Cd, Cr, Hg and Mn were noticed to have decreased with increasing distances suggesting distance decay while Ni and Fe increased with increasing distances in soils of the auto-mechanic workshop clusters. These had tremendous effects on the distributional patterns of most plant species in this study. This study has shown that plant species like Sc. dulcis (Scrophuriaceae), C. digitalis (Cyperaceae), Py. Polystachyos (Cyperaceae), A. tectorum (Poaceae), P. foetida (Passifloraceae), S. paramidalis (Rubiaceae), as well as C. mucunoides (Febaceae) remain better choices for use as bio-indicators for heavy metal studies around auto-mechanic workshop cluster in the Yenagoa Metropolis since despite exposure to prevailing natural and anthropogenic conditions, they still showed heavy metal tolerance and remediation potentials.