Trace metal contamination by phosphogypsum discharge in surface and core sediments of the Gabes coast area (SE of Tunisia)

• Published in: Arabian journal of geosciences 2018-05, Vol.11 (9), p.1-15, Article 207
• Main Authors: Amor, Rim Ben, Abidi, Myriam, Gueddari, Moncef
• Format: Article
• Language: English
• Subjects: Anthropogenic factors; Area; Barriers; Bottom sediments; Cadmium; Calcium; Calcium sulfate; Commercial fishing; Contamination; Copper; Cores; Discharge; Distribution; Earth and Environmental Science; Earth science; Earth Sciences; Fertilizers; Fishing; Fluorides; Fluorine; Heavy metals; Human influences; Industrial areas; Industrial wastes; Lead; Metal concentrations; Metals; Mineralogy; Original Paper; Phosphates; Phosphogypsum; Piers; Pollutant load; Pollutants; Pollution index; Pollution load; Principal components analysis; Sediment; Sediments; Spatial distribution; Statistical analysis; Statistical methods; Sulfates; Sulfur trioxide; Trace metals; Vertical distribution; Zinc
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-018-3521-7

The purpose of the present study is to ascertain the extent of the effect that phosphate fertilizer industrial waste has on the surface and bottom sediments of the Ghannouch-Gabes coast, off the Tunisian Mediterranean Sea. To achieve this, 44 surface sediments and 3 core sediments were studied for mineralogy, trace metals (Cd, Cu, Pb, and Zn), F, CaO, and SO 3 . For all the analyzed elements, the spatial distribution in surface sediments showed that the area located between the commercial and the fishing port of Gabes is the most polluted zone. The ranking of metal contents was found to be Zn > Cd > Cu > Pb. The vertical distribution of trace metals indicated that the highest levels were found in the uppermost segment of the sediment cores compared to the lower depth subsurface due to a continuous input of phosphogypsum (PG) release and confirmed that the area between the two harbors suffered from several types of pollutants compared to reference core C1, collected from other non-industrialized areas. This spatial and vertical distribution is probably due to the harbor piers which acted as barriers and limited the dispersion of PG discharge. The contamination factor, the geoaccumulation index, and the pollution load index were determined. The results obtained confirm the anthropogenic impact on the levels of metal, on the fluorine, calcium, and sulfate concentrations in the area, located between the commercial harbor of Ghannouch and the fishing harbor of Gabes, whereas the concentrations of elements analyzed tends to decrease on both sides of this sector. Statistical analyses (principal component analysis) showed trace metals, fluoride, sulfate, and a large amount of calcium resulting from the same anthropogenic source.