Environmental evaluation of the Reloncaví estuary in southern Chile based on lipophilic shellfish toxins as related to harmful algal blooms

• Published in: The Science of the total environment 2024-06, Vol.928, p.172374-172374, Article 172374
• Main Authors: Fuenzalida, Gonzalo, Yarimizu, Kyoko, Norambuena, Luis, Fujiyoshi, So, Perera, Ishara Uhanie, Rilling, Joaquin-Ignacio, Campos, Marco, Ruiz-Gil, Tay, Vilugrón, Jonnathan, Sandoval-Sanhueza, Alondra, Ortiz, Mario, Espinoza-González, Oscar, Guzmán, Leonardo, Acuña, Jacqueline J., Jorquera, Milko A., Maruyama, Fumito
• Format: Article
• Language: English
• Subjects: Algal toxins; Aquaculture; Environmental toxicology; Reloncaví; Toxin monitoring
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.172374

The Reloncaví estuary in southern Chile is famous for its aquaculture. However, recurring harmful algal blooms have adversely affected mussel production. Therefore, regular monitoring of algal toxins is urgently needed to better understand the contamination status of the estuary. In this study, we quantified 15 types of lipophilic shellfish toxins in Metri Bay in the Reloncaví estuary on a biweekly basis for 4 years. We identified algal species using microscopy and metabarcoding analysis. We also measured water temperature, salinity, chlorophyll-a, and dissolved oxygen to determine the potential relationships of these parameters with algal toxin production. Our results revealed the presence of a trace amount of pectenotoxin and the causal phytoplankton Dinophysis, as well as yessotoxin and the causal phytoplankton Protoceratium. Statistical analysis indicated that fluctuations in water temperature affected the detection of these toxins. Additionally, metabarcoding analysis detected the highly toxic phytoplankton Alexandrium spp. in some samples. Although our results suggest that the level of lipophilic shellfish toxins in Metri Bay during the study period was insignificantly low using our current LC-MS method, the confirmed presence of highly toxic algae in Metri Bay raises concerns, given that favorable environmental conditions could cause blooms. [Display omitted] •First long-term monitoring of lipophilic shellfish toxin at Reloncaví estuary•Simultaneous detection of pectenotoxin and causal alga Dinophysis in Metri Bay•Simultaneous detection of yessotoxin and causal alga Protoceratium at Metri•Confirmation of Alexandrium in Metri, the most prominent algae in Chile•Water temperature correlated yessotoxin and Protoceratium production