Revisión sistemática para la evaluación de moluscos bivalvos como bioindicadores de metales pesados en ecosistemas marinos

Abstract

Aquatic ecosystems are complex environments where organisms continuously interact with environmental factors that determine their ecological balance. Heavy metal pollution, largely resulting from industrial and mining activities, poses one of the most critical threats to these systems due to the high toxicity, persistence, and bioaccumulation potential of these elements throughout the food chain. In this context, bivalve mollusks have emerged as potential bioindicators due to their wide geographical distribution, sedentary lifestyle, and remarkable filtration capacity. In the marine ecosystems of Ecuador, species such as Anadara tuberculosa and Mytella guyanensis stand out for their ability to reflect environmental quality through the accumulation of heavy metals in key organs such as the hepatopancreas and gills. This study focuses on a systematic review of the potential use of these species as environmental monitoring tools, considering their distribution along the Ecuadorian coast. From the bibliometric analysis, 490 articles were obtained in the initial search, of which 9 of them met the established criteria and managed to answer the research questions. The analysis reveals that in the province of Guayas, more than 70% of the sampled areas exhibit concentrations of cadmium (Cd), lead (Pb), and mercury (Hg) that exceed national regulatory limits (0.5 mg/kg, 0.1 mg/kg, and 19 mg/kg, respectively). The ability of these species to synthesize metallothioneins, proteins associated with the regulation of toxic metals, reinforces their value as reliable bioindicators. This review highlights the importance of bivalve-based biomonitoring not only for contaminant detection but also for identifying accumulation patterns over time, providing fundamental information for the formulation of environmental policies, conservation strategies, and contamination mitigation measures in Ecuadorian aquatic ecosystems.