Global Distribution of Freshwater Paralytic Shellfish Poisoning Toxins (“Saxitoxins”) 1967–2025: Implications, Limitations, and Application to Risk Assessment

Our exposure assessment was inhibited by this subset of studies having study-specific limitations, severely restricting the use of these data for risk assessment. Toxicological uncertainty further hampered risk assessment – dose–response data for acute consumption of PSPTs has been generated and assessed, but questions remain about the accuracy of the no-observed-adverse-effect-level. Chronic/sub-chronic PSP toxicity data has been collected in animal models but there are no regulatory guidelines that utilize these for guidance values.

The evidence indicates that PSPT production potential is widespread in freshwater environments, but most existing data do not accurately assess environmental concentration. Given these uncertainties, there is significant potential for harm from exposure to freshwater PSPTs.