Characteristics and potential human health risks of Paralytic Shellfish Toxins identified in eight species of bivalves from South Yellow Sea Mudflat

The consumption of bivalves contaminated with paralytic shellfish toxins (PSTs) poses a serious risk to human health. However, the presence of PSTs in bivalves from the South Yellow Sea Mudflat remains unclear. This study comprehensively examined the characteristics and potential health risks of PSTs in eight species of bivalves from the South Yellow Sea Mudflat across four seasons. Typical PSTs, including STX, dcNeoSTX, GTX1, GTX2, GTX3, and GTX4, were detected in white clams, clams, short-necked clams, blue mussels, razor clams, mussels, scallops, and oysters. Significant differences of PSTs concentrations among bivalves across different seasons were detected using Kruskal-Wallis tests (p < 0.05), with the highest PSTs concentrations found in mussels (20.46 μg/individual) during autumn. Furthermore, Pearson tests revealed significant positive correlations between PSTs concentrations and shell length, shell height, shell width, and soft tissue wet weight, indicating that larger bivalves contain higher PSTs levels. The highest dietary toxin intake (DTI) of PSTs across the four seasons was found in mussels (2.138 μgSTX eq. kg⁻¹ bw day⁻¹) during autumn. Notably, the exposure risk index (ERI) from bivalve consumption for male consumers was 1.23 ± 0.819, which was higher than that for female consumers (1.102 ± 0.735). The ERI of PSTs for children aged 2–7 and the elderly over 65 were 1.448 ± 0.957 and 1.316 ± 0.874, respectively, which were higher than those for other age groups, indicating that children and the elderly are more sensitive to PSTs. It is important to note that most ERIs of PSTs from total tissues were higher than 1 (potential risk), while ERIs of PSTs from non-digestive tissues were lower than 1, suggesting that potential health risks could be reduced by removing the digestive tissues of bivalves before consumption. This study provides valuable information for mitigating health risks associated with bivalve consumption.