Contamination status of paralytic shellfish toxins in shellfish from Southeastern China in 2017-2021

Harmful algal blooms is a widespread problem in aquatic ecosystems, in particular dinoflagellates that produce PSTs which are harmful to animal and human health. To explore the contamination status of PSTs in shellfish in the Southeastern China, a total of 2355 shellfish samples were analyzed by ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to study the toxin profiles of the 10 PSTs collected from the southeast coast of China from 2017 to 2021. From 2355 shellfish samples, 257 were detected (10.91%), with the highest value in samples of Perna viridis. Among the six source areas in China, the samples from Fujian recorded the highest detected rate (15.28%). PSTs were found in Fuzhou, Ningde, Quanzhou, Putian, Zhangzhou, and Xiamen, with Quanzhou and Fuzhou having the highest and lowest detection rates of 15.28% and 4.23%, respectively. Saxitoxin (STX), neosaxitoxin (neoSTX), gonyautoxin (GTX1, GTX2, GTX3, GTX4), N-sulfocarbamoyl toxin (GTX5), and decarbamoyl toxin (dcSTX, dcGTX2, dcGTX3) were detected, and GTX5 and dcGTX2 were dominant. In addition, the samples containing PSTs were mostly concentrated in May to August. The study confirms the risks of PSTs to shellfish consumers in the region. It will offer a great foundation for future monitoring of marine toxins and protecting the health of seafood consumers in China. This is the first detailed evaluation of PSTs occurrences and their profiles in shellfish from the Southeastern China over a period of multiple years. HIGHLIGHTS: 2355 mussels from China were analyzed by UPLC-MS/MS for PSTs in 2017-2021. The predominant PSTs were GTX5, neoSTX and dcGTX2. Arca granosa and Crassostyea gigas exhibited higher levels than other shellfish. Shellfish containing PSTs were mostly concentrated in May to August. Maximum detected level in shellfish was 2137.10 ug STXeq/kg.