Health Status Assessment of Panamanian Pacific Coastal Areas Using Multi-Level Biomarkers in the Mangrove Cockle Anadara tuberculosa

Tropical coastal ecosystems are highly productive but increasingly threatened by anthropogenic pressures, making environmental monitoring tools essential to determine the health status of the environment. In this study, the health status of three sites along the Pacific coast of Panama (Río Santa María, Cuchilluyo, and Montijo) was assessed using the bivalve mollusc Anadara tuberculosa as a sentinel species. A multilevel biomarker approach was employed, combining chemical analyses with biochemical and histological biomarkers. Metal concentrations in whole soft tissues were generally low-to-moderate, except for arsenic, and polycyclic aromatic hydrocarbon (PAH) concentrations were low in all sites, being dominated by low-molecular-weight compounds. Biomarker responses were consistent with the chemical data, with cockles from Montijo exhibiting lower glutathione S-transferase (GST) activity and reduced oxidative DNA damage. Histological analyses revealed only mild alterations, including hemocytic infiltration in the connective tissue of digestive glands and atrophy, with no major reproductive impairments. Overall, results indicate low to moderate pollution levels in the studied areas, with Montijo representing the least impacted site. The study supports the suitability of A. tuberculosa as a sentinel species and the relevance of a multilevel biomarker approach for assessing environmental health in tropical coastal ecosystems.