Enrichment and geoaccumulation of heavy metals and risk assessment of sediments from coast of Ain Temouchent (Algeria)

摘要

The present study was undertaken for assessing the level of heavy metals such as iron, copper, zinc, lead, and cadmium in surface sediment samples of the coast of Ain Temouchent (north-western of Algeria). Sediment samples were obtained from Zouanif, Rachgoun, Beni saf, and Sidi ali during a period between March 2012 and February 2013. The samples were digested using a mixture of acids and the metal content determined using atomic absorption spectrophotometer (AAS). Heavy metal concentrations in sediments show significant variability and ranges from 16.30 to 32.15 mg/g for Fe, 12.49-31.25 mg/kg for Cu, 120.17-193.31 mg/kg for Zn, 25.94-57.27 mg/kg for Pb, and 1.45-16.84 mg/kg for Cd. The results revealed relatively high metallic concentrations of Zn, Pb, and Cd in sediments at the four stations and exceed the background values. The sediment pollution assessments were carried out using a geoaccumulation index (I-geo) and enrichment factor (EF). The results of geoaccumulation index reveal that sediments are uncontaminated with Fe and Cu, uncontaminated to moderately contaminated with Zn and Pb, and moderately contaminated with Cd. The calculation of enrichment factors showed that Cu is depleted, whereas Zn and Pb are moderately and Cd is severely enriched. Metal concentrations were significantly high between stations. Industrial and agricultural activities and a nearby municipal dumpsite were associated with the higher elemental concentrations particularly at Rachgoun and Beni saf. ANOVA test was used to compare the levels of the metals in different stations (inter-station comparison). Principal component analysis (PCA) was applied to investigate the sources affecting surface sediment samples at the stations.