Investigating the heavy metals in soil is important to the life of humans and living organisms. Diyala River Lower Reaches was chosen due to the changes in environmental characteristics that took place in recent years. Twelve sediment samples were collected from four different sites. The physical, and chemical properties and the concentrations of nine heavy metals were indicated. The results showed that the average concentrations of arsenic, copper, chromium, cobalt, iron, manganese, nickel, lead, and zinc are 8.5, 45.7, 538.5, 12.2, 5.07, 991.7, 183.5, 16.07, 136.5 ppm, respectively. They reflect contamination with arsenic, chromium, and nickel, while they are free of lead, and zinc contamination, according to the Environmental Protection Agency's (EPA) sediment quality guidelines. The measured contamination indices (the enrichment factor (EF), contamination factor (CF), degree of pollution (Cdeg), geographical accumulation index (Igeo), and pollution load index (PLI)), reflected high contamination factor for arsenic and chromium, and medium for manganese, nickel, lead, and zinc, while low for copper and cobalt. Based on all the results in all sampling sites indicate the presence of heavy element contamination in the sediments of the Diyala River Lower Reaches.
