Accumulation of marine biotoxins including saxitoxin and domoic acid in shellfish during harmful algal bloom events

Abstract

While shellfish consumption provides nutritional benefits, harmful algal blooms (HABs) can render these seafood resources toxic through biotoxin bioaccumulation. This research quantified the accumulation of saxitoxin (STX), domoic acid (DA), okadaic acid (OA), Dinophysistoxin (DTX), and yessotoxin (YTX) in blue mussels (Mytilus edulis) during a 28-day monitoring period encompassing a major HAB event in Argentine coastal waters. The research was conducted at monitoring stations along the Buenos Aires coastline between October 2022 and March 2023. Phytoplankton enumeration confirmed peak bloom intensities of 4.8 × 10⁶ cells/mL dominated by Alexandrium catenella and Pseudo-nitzschia seriata. LC-MS/MS analysis revealed rapid biotoxin uptake, with STX reaching 287 μg/100g tissue and DA reaching 184 μg/100g tissue by day 14 of the bloom. STX represented 42.3% of total biotoxin burden, followed by DA (31.7%), OA (14.2%), DTX (7.4%), and YTX (3.8%). Strong positive correlations existed between bloom cell density and both STX (r = 0.87, p