Prevalence, Variability and Bioconcentration of Saxitoxin-Group in Different Marine Species Present in the Food Chain

Abstract

The saxitoxin-group (STX-group) corresponds to toxic metabolites produced by cyanobacteria and dinoflagellates of the genera Alexandrium, Gymnodinium, and Pyrodinium. Over the last decade, it has been possible to extrapolate the areas contaminated with the STX-group worldwide, including Chile, a phenomenon that has affected ≈35% of the Southern Pacific coast territory, generating a high economic impact. The objective of this research was to study the toxicity of the STX-group in all aquatic organisms (bivalves, algae, echinoderms, crustaceans, tunicates, cephalopods, gastropods, and fish) present in areas with a variable presence of harmful algal blooms (HABs). Then, the toxic profiles of each species and dose of STX equivalents ingested by a 60 kg person from 400 g of shellfish were determined to establish the health risk assessment. The toxins with the highest prevalence detected were gonyautoxin-4/1 (GTX4/GTX1), gonyautoxin-3/2 (GTX3/GTX2), neosaxitoxin (neoSTX), decarbamoylsaxitoxin (dcSTX), and saxitoxin (STX), with average concentrations of 400, 2800, 280, 200, and 2000 µg kg−1 respectively, a species-specific variability, dependent on the evaluated tissue, which demonstrates the biotransformation of the analogues in the trophic transfer with a predominance of α-epimers in all toxic profiles. The identification in multiple vectors, as well as in unregulated species, suggests that a risk assessment and risk management update are required; also, chemical and specific analyses for the detection of all analogues associated with the STX-group need to be established.

Fatal Canine Intoxications Linked to the Presence of Saxitoxins in Stranded Marine Organisms Following Winter Storm Activity

“…PST in starfish was considered to originate as a consequence of feeding on detritus [ 11 ], whilst [ 9 ] reported A. amurensis was contaminated directly through feeding on bivalves. In Chile, the PSP toxicity in the starfish ( Stichaster striatus ) was also attributed to the capturing of toxins through feeding on PST-contaminated clams and mussels [ 12 ]. [ 10 , 22 ] described the presence of primarily TTXs in A. scoparius , together with low concentrations of some PST [ 10 ].…”

“…Toxin occurrence in fish has been reported in the United Kingdom (UK) previously, including species of flatfish such as Dab, as well as in seals [ 8 ]. To date, there are only a few reports of PST in starfish, with all occurrences detected outside of Europe [ 9 , 10 , 11 , 12 ]. No testing has been conducted for marine toxins in starfish in Europe to date, presumably given that these animals are considered unsuitable for consumption in European countries.…”

Paralytic Toxin Producing Dinoflagellates in Latin America: Ecology and Physiology

“…The case of M. chilensis is relevant since in the adductor muscle 99% (in molar basis) NEO was found, whereas in the mantle and digestive glands, GTX1/4 were detected. In a recent study of the PSTs content in regulated and non-regulated aquatic organisms from regions with a variable presence of A. catenella (Oyaneder-Terrazas et al, 2017), the analogs GTX1/4, GTX2/3, NEO, dcSTX, STX were detected. Dominant analogs in rocky strata-dwelling species were 58.8 mol% STX, followed by 15.4 mol% GTX2/3, 4.8 mol% NEO, and 3.3 mol% dcSTX; while in sandy bottom-dwelling species, 77.7 mol% of GTX2/3 were detected, 19.3 mol% STX, 2.1 mol% NEO and 0.9 mol% dcSTX.…”

“…Paralytic toxins have affected ∼35% of the Southern Pacific coast of Chile (Oyaneder-Terrazas et al, 2017). In 1996, samples of the mussel M. chilensis from the regions XI and XII, were analyzed, and in general they showed a molar dominance of GTX analogs, with a dominance of GTX2/3 in samples collected in the XI region, whereas GTX1/4 were the major analogs in the XII region (Lagos et al, 1996).…”

“…NEO, STX, dcGTX2/3 and dcSTX were found in trace levels. Cell toxicity was estimated in ≈15 pg STXeq cell −1 (Oyaneder-Terrazas et al, 2017). The authors pointed out that this was a characteristic toxin profile for species blooming during January and March in the austral fjords of Chile.…”