Environmental Effects of A Marine Fish Farm of Sea Bass and Sea Bream in The Eastern Mediterranean Sea on Water Column and Sediment

Abstract

Concentration of selected Metallic Element Contaminants (MECs) (Cd, Pb, Hg,Cu, Fe, Zn, Mn, Mg, Ca, Na and K), Total Organic Carbon (TOC) and Total Nitrogen (TN) in the superficial layer of sediments from four fish farms in the Eastern Mediterranean Sea were studied in order to evaluate the environmental effects of marine aquaculture and to establish correlations between aquaculture and accumulation of selected Metallic Elements Contaminants (MECs)(Cd, Pb, Hg, Cu, Fe, Zn, Mg, Mn, K, Na and Ca). The levels of nutrients (Nitrate (NO3, Nitrite (NO2), Ammonium (NH4), Phosphate (PO4), Silicate (Si), Total Nitrogen (TN) and Total Phosphorus (TP) in the water column was evaluated.
 The concentrations of Cd, Pb and Cu were determined by atomic absorption spectrophotometry with graphite furnace and Zeeman correction (Varian 220 Z). The Metallic Element Fe, Zn, Mg, Mn, K, Na and Ca were measured by the flame atomic absorption spectrophotometry (Varian AA 10). Hg was analyzed by Direct Analyzer of Mercury.
 Nutrients analyses were carried out by Autoanalyzer using the standard colorimetric methods according to Strickland and Parsons.
 The results suggested that MECs enrichment in the sediments may be attributed to the fish farm effluents, although metal concentrations are not likely to cause harmful effects in the marine ecosystem. Continuous monitoring and further studies of the area are recommended to determine long-term effects.
 The nutrient levels in the water column can be due to sources arising from various anthropogenic activities within the study area. Moreover, the spatial variability was due to increasing nutrient concentrations at the localities close to nonpoint sources.