Spatial Distribution and Source Identification of Heavy Metals in Surface Waters of Three Coastal Areas of Tunisia
Zaher Drira1, Houda Sahnoun2, Habib Ayadi1
More details
Hide details
1Biodiversity and Aquatic Ecosystems UR/11ES72 Research Unit, Department of Life Sciences, Sfax Faculty of Sciences, University of Sfax, Soukra Road Km 3.5. BP 1171 - PO Box 3000 Sfax, Tunisia
2Coastal and Urban Environment Research Unit, IPEIS , P.C. 3000, Sfax, Tunisia
Online publish date: 2017-05-05
Publish date: 2017-05-26
Submission date: 2016-10-13
Final revision date: 2016-12-03
Acceptance date: 2016-12-04
Pol. J. Environ. Stud. 2017;26(3):1057–1069
The concentrations of selected dissolved trace elements (Ni 446-919 μg L-1, Pb 383-1015, Fe 195-739, Cu 217-318, Cr 156-336, Zn 9-236, Mn 0-187, Co 0-310, and Cd 26-77) were assessed in the surface water of 30 stations belonging to three coastal areas along the Gulf of Gabes, i.e., the southern (stations 1-10) and northern (stations 11-20) coastal areas of Sfax and the Ghannouch area (stations 21-30) during October and November 2014. Results showed that dissolved metals in surface waters, which were analyzed by means of flame atomic absorption spectrophotometry, followed the concentration levels (Pb>Ni>Fe>Cu>Cr>Co>Mn>Cd>Zn) on the southern and (Ni>Pb>Fe>Cu>Cr>Zn>Mn>Co>Cd) on the northern coasts of Sfax, and (Ni> Fe>Pb>Cu>Cr>Zn>Co>Cd>Mn) in the Ghannouch area. In the southern and the northern coasts of Sfax, all analyzed metals were detected in 100% of sampled stations except Co, which was revealed in 90 and 80% of stations, respectively. However, in the Ghannouch area all analyzed metals were detected in 100% of sampled stations except Mn, which was revealed in 70% of stations. These trace elements, except for Fe and Mn, exceeded the safety limit of the USEPA water quality criteria for the protection of aquatic fauna and flora survival and their uses. The Sfax and Ghannouch coastal areas should be considered relatively polluted with metals (Zn, Ni, Pb, Co, Cr, Cd, and Cu). The elevated metal contents were attributed to anthropogenic waste inputs around the study area. The main sources of Ni and Co loading in the seawater were the SIAPE phosphoric acid and fertilizer plant and a waste water treatment plant located close to station 1. Whereas the fishing harbor of Sfax, which is situated on the southern coast (station 9), is the second source of high amounts of Cd, Mn, Cr, and Pb. This situation has led to serious human health risks and chronic toxicity caused by their potential bioaccumulation in some aquatic fauna such as shrimp, fish, crab, shellfish, mollusk, and cephalopoda.