Comparison between biotic (Gammarus sp.) and abiotic (Coastal sediment) absorption performances in Caspian Sea Coast

The crustacean Gammarus sp. lives in sediment at coastal zones having an important role on food chains. It also transfers energy to higher trophic levels i.e. fishes and birds. The littoral zone of the Caspian Sea receives many pollutants from the sea and the land. Cadmium can be found naturally in low concentrations in the environment but human intervention, anthropological discharge connected to the urban and industrial activities raise the concentration of heavy metals in costal sediment and aquatic ecosystems. In the present study, Gammarus sp. was selected as a test organism because it is the abundant in southern coast of the Caspian Sea. This crustacean absorbs metals from food or water. The concentration of cadmium in the present experiment was lower than LC50. Samples were collected from the submerged mesocosm different times, i.e. 0 (control), 30, 60, 90, 150, 210 and 270 minutes. After preparing the sediment and Gammarus samples, cadmium concentration were determined using an ICP-OES. Significant differences (using ANOVA) were observed among exposure times. A t-test indicated that there was a significant difference between Gammarus and sediment in cadmium uptake. In conclusion, the present study indicated that cadmium absorption by Gammarus and sediment was a function of the exposure time and accumulation of this metal, increases over time.