Heavy metal levels of ballast waters in commercial ships entering Bushehr port along the Persian Gulf

Highlights: • Levels of Cu and Fe in all ballast water samples were higher than the coastal water. • 76.47% of samples had higher level of Cd compared with the coastal water. • Ballast waters discharged by ship may change chemical contents in long time period. - Abstract: In this study we report the concentration levels of heavy metals (including Pb, Cd, Hg, Cr, Ni, Fe, Mn, Cu) in ballast water of commercial ships, entering Bushehr port for the first time in the region of the Persian Gulf. The concentration levels of Cu and Fe in all samples of the ballast water were higher compared with the coastal waters of Bushehr port. In the case of Cd, 76.47% of samples had higher concentration level compared with the coastal waters of Bushehr port. Results showed that in a long term the ballast water has the potential to change the chemical quality in marine environments and also may affect the human health and marine ecosystem where ships discharge their ballast water. Therefore, permanent monitoring as well as treatment of ballast water before discharging is crucial to keep the marine environment health.