Marine Invertebrates as Bioindicators ofHeavy Metal Pollution

Atmosphere, earth and water compose the environment. The presence of heavy metals in the environmenthas grown because of their large employment in some industrial and agricultural activities.Although these metals are terrestrial products, they flow into the sea through effluents andsewage or are directly discharged from industries placed on the seawater front. It should be consideredthat metals concentrations vary widely according to different seawater latitudes anddepths and can be strongly influenced by fresh water discharges from heavily polluted rivers. Inthis review recent studies on heavy metal pollution in marine ecosystems and their organisms willbe presented. Metal speciation, bioaccumulation in biota, as well as abiotic and biotic factors affectingtheir bioavailability will be reviewed. Moreover, the use of bioindicator organisms for thebiomonitoring of heavy metal toxicity and their ecological effects will be defined. Many marineinvertebrate species fulfill the following criteria: Sensitivity to a wide range of chemicals (especiallyto heavy metals), cost-effectiveness for repeatable tests, readily interpretable biological consequencesof pollution. Among the most important marine invertebrates used as bioindicators, thesea urchin embryo is one of the most suitable, especially to assess metal/heavy metal pollution.