Assessment of contaminated sediment by phosphate fertilizer industrial waste using pollution indices and statistical techniques in the Gulf of Gabes (Tunisia)

Abstract

On July 2010, 26 surface sediments of the Gulf of Gabes, Tunisia were sampled at depth ranging from 0.5 to 10 m. These specimens were analyzed to determine Al, Cd, Cr, Cu, Pb, Zn, F, P, and N concentrations and total organic carbon contents. The distribution map shows that the high amounts of pollutants are principally located between the commercial harbor and the fishing harbor of Gabes. Measurements of heavy metal contents were carried out using (absorption atomic spectrometer), where the enrichment factor (EF), the geoaccumulation index (Igeo), and the contamination index (CI) are determined. The EF values of all metals were >1.5, corroborate anthropogenic impact on the metal levels in this studied area. However, the Igeo and CI values of Cd and Zn elements indicated that sediments collected from sites at the vicinity of the commercial harbor are very contaminated, although for Pb, Cr, and Cu elements these indices indicated that the same sediments are uncontaminated. Statistical analyses (principal component analysis/factor analysis and matrix correlation) show that heavy metals, fluoride, and phosphorus are resulting from the same anthropogenic source.