Levels of heavy metals in sediments in the vicinity of Chabahar Bay desalination plant

Abstract

Desalination plants are potentially capable of having impacts on coastal marine environments due to the production of wastewater with high concentrations of salts (brine discharge) and some heavy metals. The aim of this study was to examine the concentration of accumulated metals (Ni, Cu, Cd, Fe, Zn, Pb) in the sediments near the brine discharge point in the Chabahar Bay. Twenty one sediment samples were collected from seven stations in summer pre-monsoon and post-winter monsoon, in April and October 2011. The results showed that stations closer to brine discharge points had higher concentrations of metals in the sediment than other stations. Metal contamination in sediment samples was below a critical level with the exception of cadmium with higher values than MAFF, ANZECC and FDEP standards at a maximum of 5.76 mg/kg dry weight. There was a clear decreasing gradient in heavy metal concentrations from station 2 to station 7, especially for Cd, Pb, Fe and Zn. The probable reason for this is the water circulation in the Chabahar Bay.