Heavy metal concentrations and distribution in surface soils of the Bassa industrial zone 1, Douala, Cameroon

Abstract EN

Partial extraction was carried out on thirty-three (33) soil samples collected from the Bassa industrial zone 1 of Douala, Cameroon.

From the samples analyzed the following metal concentrations (range) were obtained (in ppm): Ag (0–1.3), As (0–64), Cd (0–7.3), Co (0–31), Cr (34–423), Cu (12–909), Mn (55– 3282), Mo (0–81.6), Ni (9–284), Pb (0–3320), Sb (0–30), Sc (0.6–7.5), V (26– 110), Zn (30–3782), and Fe (in wt %) (1.50–47.31).

Results obtained reveal background and anomalous populations for most of the metals except Sc and V, which only have background populations.

Multi-element geochemical anomalies occur within the vicinity of industries, waste dump sites, metal workshops, and mechanical workshops.

R-mode factor analysis reveals three element associations and two singular elements (As, Cd) accounting for 94% of the total data variance.

The three associations are: Ag–Cu–Cr–Fe–Mn–Mo–Ni–Sb; Co–Cu–Pb–Sb–Zn; and Sc–V.

The geoaccumulation indices show that soils in the Bassa industrial zone are moderately to very highly polluted.

These metal-laden soils constitute a major health risk to the local population and a cause for concern.

This study successfully relates the concentration and distribution of toxic metals in the soils of the Bassa industrial zone to urban effluents generated mainly from industrial activities.