Effect of Heavy Metals and Nutrients Levels of Ballast Waters in Commercial Ships on Chemical Quality Status of Seawater of the Tobruk-libya Gulf

Abstract

Marine transportation still generates negative impacts on the marine environment, including releases of ballast water containing aquatic invasive species; historical use of antifoulants; oil and chemical spills; dry bulk cargo releases; garbage; underwater noise pollution; ship-strikes on marine megafauna; risk of ship grounding or sinkings; and widespread sediment contamination of ports during trans-shipment or ship breaking activities. Commercial vessels that do not conduct ballast water exchange, in accordance with International Convention Ballast Water Management, will endager the environment of ports. In this study, investigation of heavy metal (Cd, Cu, Fe, Mn, Pb and Zn) and nutrients (NO3, NO2, NH4, PO4 and SiO4) contents in ballast waters of three commercial ships entering the Tobruk port, along the Tobruk Gulf. High concentration levels were observed in all samples which were the main source of high heavey metals concentration of coastal waters of Tobruk Gulf. These results were confirmed by determination of nutrients concentration which were also found in high concentrations levels compared with reference sample. Results showed that in a long term the ballast water has the potential to change the chemical quality in marine environments, and it should treated before discharge in coastal areas, as well as the unpolluted of ballast waters should be loaded.