Mikdad Abdol elah Taheer - Faculty of Science / University of Kufa
Amal Jalil Hashim - Faculty of Science/ University of Baghdad

This study was conducted to assess the concentrations of cadmium and mercury in Najaf Sea at Najaf city through the accumulation of Cd and Hg in the soft tissue and in the shell for The benthic invertebrates which collected were: Bivalves: Corbiculla and Unio, Gastropods: Melanopsis and Bellamya, The samples were collected bimonthly from December 2016 to October 2017, from four different select sites from sea of Najaf in Najaf city. The annual concentration of Cd in Corbiculla soft tissue was 0.094µg/g, while in the shell was 0.055µg/g. While Hg concentration in soft tissue was 0.0341µg/g, while in the shell was 0.0069µg/g. In Unio soft tissue the Cd concentration was 0.142µg/g, while in shell was 0.053µg/g. Hg concentration in soft tissue was 0.057µg/g, while in the shell was 0.021µg/g. Melanopsis soft tissue had Cd concentration of 0.052µg/g, while the shell was 0.038µg/g, for Hg concentration in soft tissue was 0.0454µg/g, and in the shell was 0.0031µg/g. The concentrations of Cd and Hg in all the collected benthos were found to be higher in spring and autumn than in summer and winter. Unio had the highest concentration of Hg among the collected benthos, while Corbiculla had the highest Cd concentration. The soft tissues of bivalves and gastropods have higher concentrations of Cd and Hg than the concentration in the shell. In general the Cd concentrations in all collected organisms were higher than Hg concentrations.