Soil Based Heavy Metals Originating from Anthropogenic Activities on Floristic Composition of Some Selected Sites in Kaduna Northern Guinea Savanna of Nigeria

Abstract

Soil based heavy metals originating from anthropogenic activities on floristic composition of some selected sites in Northern Guinea savanna of Nigeria were investigated.   50m x 50m plots were laid in each of the three (3) selected sites with 30m espacement between each plot. This is replicated three (3) times to make a total of nine (9) plots in all.  Soil samples were collected at a depth of 25m with a soil auger and heavy metal analysis was carried out with the use of atomic absorption spectrophotometer. The floristic compositions were evaluated using line transect method. Flora were enumerated in all the sites irrespective of the growth form, (i.e. trees, shrubs and herbs). The data collected were subjected to descriptive statistic, Anova using SPSS while the diversity index was calculated using Shannon Weiner method. The study revealed the presence of six (6) soil based metals in the selected sites, Cd; Cu; Mn; Ni; V and Zn.  Significance differences (P<0.05) exist in soil based heavy metal between sites.  A total of two thousand two hundred and sixty one (2,261) floral species were evaluated. The population densities of the floristic composition are higher in site A than all the other sites while species diversity decrease significantly (P<0.05) from Site A to C.  It is concluded that population densities and diversity of the floristic composition in the selected sites are influenced as a result of soil based heavy metals originating from anthropogenic activities in the sites. It is however recommended that there should be provision of guidelines for the abatement of pollution establishing standard for the control of fuel additives with respect to heavy metals.  Also, there should be prescribed standard for the level of emission from automobile exhaust and energy generating plants and stations.