Sediment and Organisms as Marker for Metal Pollution

Pollution caused by metal elements has drawn increasing attention worldwide due to the increase of anthropogenic contaminants to the marine ecosystems. Pollution of the natural environment by metals is a serious problem because these elements are indestructible and most of them have toxic effects on living organisms, when they exceed a certain concentration. Sediments are widely used as geo-marker for monitoring and identifying the possible sources since sediment can act as sink for the pollutants. Most metals are bound in fine-grain fraction because of its high surface area-to-grain size ratio where they have a greater biological availability compared to those in larger fraction. Lying in the second trophic level in the aquatic ecosystem, shellfish species have long been known to accumulate both essential and non-essential metals. Many researchers have reported the potentiality of using mollusks, especially mussel and oyster species, as bioindicators or biomarkers for monitoring the metal contamination of the aquatic system.