Organic and heavy metal pollutants in dredged sediment of Oran Harbor, Algeria.

Abstract

Harbors on all coasts regularly silt up, receiving sedimentary inputs that progressively reduce the water depths available for navigation. Consequently, they are routinely dredged to guarantee the depths necessary for navigation. Sediments act as a reservoir for anthropogenic contaminants such as heavy metals and persistent organic pollutants (POPs) that enter the aquatic system associated with particles or in solution. The objective of this study is to assess the state of pollution by POPs and heavy metals such as copper and zinc, used in large quantities in antifouling paints, in the sediments of the port of Oran. These were characterized by different methods: size, XRD, calcination, FTIR, NMR, GC-MS, and AAS, in order to determine their main characteristics and heavy metals and POPs content. The particle size is determined by laser particle size distribution. Thus, sediments from Oran port are composed of means and end sands, silt, and clay. The XRD analysis shows that the sediments consist mainly of silicates and calcite. The organic matter was determined by ignition loss at 450 and 550°C; it is about 7%. Analysis by FTIR, 1H and 13C NMR, and GC-MS of POPs excerpts shows that the sediments are highly polluted by aliphatic and aromatic hydrocarbons (3372mg/kg). Finally, metals were determined by AAS method. The results show significant pollution of Zn (313.5mg/kg) and moderate pollution by Cu (75.6mg/kg).