Accumulation of heavy metals and minerals in soil rhizosphere and organs of Parkia biglobosa and Butryospermum paradoxum growing at the lead polluted site in Niger State, Nigeria

Abstract

Anthropogenic activities inducing the accumulation of trace elements in Madaka village (between latitudes 6°00' E and 7°00' E, and 10°00' N and 10°04' N longitudes) of Rafi Local Government Area (Kagara, Niger State, Nigeria) have claimed many lives in the past. This study evaluated the accumulation of heavy metals and minerals in Butryospermum paradoxum and Parkia biglobosa and their soil rhizosphere at the lead polluted site around Madaka village of Rafi Local Government Area (Kagara, Niger State, Nigeria). Lead, arsenic, pH, nitrogen (%), organic carbon (%), organic matter (%), P, K, Na, Ca, Mg, N and cation exchange capacity were determined. Results showed significant differences (p < 0.05) between the Pb content in the soil from control (3.13 ± 1.010 mg/kg) and polluted sites (12.71 ± 1.010 mg/kg), and in the seeds of Butryospermum paradoxum from control (3.80 ± 0.09 mg/kg) and polluted sites (13.10 ± 0.10 mg/kg). A significant (p < 0.05) difference was also observed between the Pb content in Parkia biglobosa seeds from the control site (2.50 ± 0.10 mg/kg) and from the polluted site (14.10 ± 1.10 mg/kg). Overall, no significant differences (p > 0.05) were observed in the nutrient contents among all samples analysed. A significantly high concentration of Pb and As in these plants around the lead polluted site poses a great health concern. This calls for the public’s attention, both go- vernmental and non-governmental organisations, to intervene by creating awareness of the likelihood of their bioconcentration in humans and animals that consume these plants