Early detection of toxin contamination in shellfish (i.e., prior to harvest) would be of considerable advantage to fish farmers, researchers and food safety administrators. In 2004, a solid-phase adsorption toxin tracking (SPATT) technique was developed to study algal toxins in New Zealand shellfish harvesting areas. In subsequent years, the basic idea have been further developed. Using a SPATT method, an investigation into diarrhetic shellfish toxins (DSTs) was conducted over a 10.5-month period in 2012 in shellfish farming areas in Lingshan Bay (Yellow Sea, China). This paper discusses the relationship among DSTs in toxic algae, seawater and contaminated shellfish. OA, DTX1 and PTX2 toxins were found in this shellfish farming area from summer to autumn. In shellfish the maximum concentrations of OA and DTX1 were 81 and 41 ng g(-1) respectively. PTX2 was very low. The maximum levels of OA and DTX1 in seawater were 165 and 56 ng g(-1) respectively, and were detected on June, separated by a 14-day period. Shellfish had accumulated the highest levels of OA and DTX1 recorded in this study. Comparison of the variations in DST levels in seawater showed there to be about 2 weeks for administrators to warn of the potential for toxin contamination in shellfish. Further research to explore the relationship between the variables of seawater temperature, sunlight and salinity, and DSTs in shellfish may help to establish a more suitable model for forecasting DST contamination in shellfish.
Keywords: DTX1; Diarrhetic shellfish toxins (DSTs); OA; PTX2; SPATT.