Environmental risk assessment of potentially toxic elements of sediments from Massili river, Burkina Faso

Abstract

A study of selected potentially toxic elements (PTE) contamination levels (As, Cr, Cu, Ni, Pb, Zn) which can produce harmful effects to the benthic organisms and sediments environmental quality from  Massili River,  has been done in Burkina Faso. The study design has been use as Latin square of three (03) treatments (Station 1, Station 2, Station 3) in three (03) replications. Some samples (three per station for each parameter) have been collected. The r physico-chemical parameters (pH, electrical conductivity, organic matter and grain size) and a series of metals and As including Al, Fe, Ti, Zr, Cr, Cu, Ni, Pb and Zn have been determined. The magnitude of target PTE (As, Cr, Cu, Ni, Pb, and Zn) contamination was investigated by applying the enrichment factor (FE) and the geoaccumulation index (I_geo), whereas the environmental quality of the sediments was assessed by comparing the PTE concentrations of the samples to those of mono-elemental ecotoxicity criteria: consensus toxic effects threshold and consensus of probable effects and the average multi-elementary PEC quotient. Both EF and I_geo suggested non-existent or low enrichment and zero contamination of the sediments. In contrast, the assessment of the environmental quality of the sediments indicated that Cr and Ni concentrations in all the stations and those of Cu in the samples collected from S2 and S3 were greater than the toxicity threshold, and thus these elements may occasionally produce harmful biological effects on the benthic organisms. However, the average PEC suggested that the target PTE were unlikely to pose serious threats to the benthic organisms.