Investigation of heavy metals in the ballast water of ship tanks after and before the implementation of the ballast water convention: Bushehr Port, Persian Gulf.

In this study, the amount of heavy metals such as Ni, Cd, Pb and Cu and some physiochemical factors including pH, temperature and total organic carbon (TOC) in the ballast water of the ships entering the Bushehr Port were measured for two years (cold and hot seasons) before and after the ballast water convention was enforced. The mean concentrations of Ni, Cd, Pb and Cu, before and after implementation of the convention were 46.55, 3.93, 5.36, 58.83 and 26.41, 2.12, 2.59, 23.54 ppb. It became clear that the concentrations of heavy metals after the implementation of the convention was lower in comparison and there was a significant difference (p < .05). It seems that continuous monitoring of the quality of the ballast water and determination of locations free of pollution and contamination in the Persian Gulf are necessary for ships that intend to exchange their ballast water in this Gulf.