Marine Invertebrates as Bioindicators of Heavy Metal Pollution

The marine environment presents a range of anthropogenic contaminants. According to the World Health Organization, more than 100,000 chemicals are released into the global environment every year as a consequence of their production, use and disposal. The fate of a chemical substance depends on physical-chemical properties, in combination with the characteristics of the environment where it is released. Among the substances that accumulate in the sea, for anthropogenic activities, metals/metalloids have a leading position. Some of these have a biological role but their bioaccumulation is injurious. Chemical pollutants can cause effects on organisms, biodiversity and human health. Various effects induced by chemicals on marine organisms have been examined, but the main problem is that the marine environment contains several chemical pollutants for which it is hard to carefully determine the effect induced by an each one. Considering these aspects, it is essential to find a system that effectively reflects the health of the sea and accurate markers of pollution, such as bioindicator organisms. In this monograph, recent studies on heavy metal pollution in marine ecosystems and their effects on organisms are presented. In particular the book focuses on some types of chemical pollution: after a generic description of the heavy metals, for each of them, the main physical-chemical characteristics and the relationship on environmental pollution is described. Data acquired by several researchers on the relationship between heavy metal pollution and the use of marine invertebrates as bioindicators are reported. About 20 marine invertebrates were mainly used for this purpose. In this manuscript, the following characteristics for each organism are reported: scientific classification, biology, habitat and effects caused by exposure to heavy metals. Furthermore, an analysis on the emergence and evolution of marine organisms during the evolution of the earth is made, suggesting that these organisms have had a significant evolutionary success and developed a capacity to adapt to different conditions of stress. All these features have led, in science, to consider the validity of these organisms as bioindicators.