Biota-sediment accumulation factor and concentration of heavy metals (Hg, Cd, As, Ni, Pb and Cu) in sediments and tissues of Chiton lamyi (Mollusca: Polyplacophora: Chitonidae) in Chabahar Bay, Iran

Heavy metals and some organic substances which are drained into the aquatic environments and cannot be decomposed or eliminated will sink into sediments or find their way into different levels of food chain. Bioaccumulation is the process of continuous deposition and aggregation of these substances into the body tissue of living organisms. Mollusks are remarkably appropriate to be used as bio-indicators because of their motionless or almost sessile nature, relatively high abundance, selective absorption of certain ions, and worldwide distribution in marine and inland aquatic habitats. Chiton lamyi is a sedentary species from the phylum, Polyplacophora, which is usually abundant on the rocky shores and intertidal zone of marine environments. Sediment and Chiton samples were taken from four stations of Chabahar Bay in autumn 2013. After acid digestion of samples, the concentration of heavy metals (mercury, cadmium, arsenic, nickel, lead and copper) were measured by the graphite furnace atomic absorption apparatus, and the bioaccumulation factor in relation to sediment was calculated. The highest concentration value was calculated as 3.28 for cadmium in the Hafte Tir station. The results of this study indicated that chitons can be used as an appropriate bio-indicator for heavy metals particularly cadmium pollution in the marine environment

Assessment of chiton lamyi mollusk as a biological indicator of heavy metals such as Cd, Cu, As and Hg in the coast of Chabahar Bay

Mollusks are remarkably appropriate as a bio-indicator due to their wide geographical distribution, high abundance in benthic environments, selective absorption of certain ions and their motionless nature. Chiton, a mollusk of the phylum of Polyplacophora, and of its lamyi species is abundant in Chabahar Bay coastal rocks. Based on previous studies, this animal can be introduced as a potential indicator of Ecosystem Health; hence Chiton was chosen to be investigated rate of accumulation of metals, Cd, Cu, As and Hg in Chabahar Bay. After sampling four major stations, the samples were prepared and Cold Vapor Atomic Absorption apparatus were used for measurement of mercury and graphite furnace method was used for measuring other metals. Then, using the obtained data, bioaccumulation factor was calculated for each metal separately in the maximum amount of cadmium bioaccumulation factor at station 4 (Great sea) (136.34±0.02) and the lowest mercury at station 2 (Coast of Maritime University) (1.88±0.02), respectively. After statistical analysis of the results, it was found that Chiton can be introduced as a bio-indicator of the mentioned contaminants in the coast of Chabahar Bay