Metal(loid)s in Macrophytes from the Americas

Pollution from metals and metalloids is a major concern due to the persistence of these elements in the environment and the impacts on ecological and human health. Evaluation of the distribution, bioaccumulation and toxicity of metal(loid)s in aquatic organisms has been studied for many years. In consequence, research on plants with a high tolerance to metals, and therefore, of use as bioindicators of theses contaminants, has become a subject of interest in recent years. This chapter presents a brief analysis of the bioaccumulation patterns and physiological responses of aquatic plants to pollution from metals and metalloids, with a focus on describing what we have learned from our studies conducted in the laboratory and in the field with the emergent macrophyte, Potamogeton pusillus and with the mangrove species, Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle, all of which are native to South America. Furthermore, the capacity of P. pusillus to be used for active and passive biomonitoring in aquatic ecosystems highly impacted by environmental degradation is discussed. In addition, there is a discussion of the bioaccumulation and translocation of metals from interstitial water and sediment to the roots and leaves of mangroves inhabiting estuaries in Brazil with different levels of pollution, correlating metal bioaccumulation with differences in macrophyte anatomy. Finally, the use of stable isotopes in mangroves as biomarkers of environmental pollution is demonstrated.