渤海海域唐山贝类养殖区腹泻性和麻痹性贝类毒素的监测与风险评估

Surveillance and risk assessment of diarrhetic and paralytic shellfish toxins in the Tangshan shellfish culture areas of Bohai Sea, China

中文关键词: 渤海  腹泻性贝类毒素  麻痹性贝类毒素  风险评估

英文关键词: Bohai Sea  Diarrhetic shellfish poisoning  Paralytic shellfish poisoning  Risk assessment

中文摘要:

      为监测渤海海域唐山贝类养殖区贝类毒素的污染情况，防止食用贝类中毒事件发生，于2019年10月—2020年9月间，每月持续在渤海海域唐山贝类养殖区采集四角蛤(Mactra veneriformis)、菲律宾蛤仔(Ruditapes philippinarum)、脉红螺(Rapana venosa)、牡蛎(Crassostrea gigas)、青蛤(Cyclina sinensis)、文蛤(Meretrix meretrix)和硬壳蛤(Mercenaria mercenaria) 7种经济贝类样品，采用高效液相色谱–串联质谱(HPLC-MS/MS)法测试了5种腹泻性贝类毒素(diarrhetic shellfish poisoning, DSP)和14种麻痹性贝类毒素(paralytic shellfish poisoning, PSP)。结果显示，在7种经济贝类样品中均未检出DSP。检出的PSP成分包括石房蛤毒素(Saxitoxin, STX)、膝沟藻毒素1 (Gonyautoxin 1, GTX 1)、膝沟藻毒素2 (Gonyautoxin 2, GTX 2)和脱氨甲酰基膝沟藻毒素3 (Ddecarbamoy l gonyautoxin 3, dcGTX 3)，其中，GTX 1含量最高且最高值为537.95 μg/kg。不同季节贝类毒素蓄积含量有一定差异，PSP主要集中在4月检出。菲律宾蛤仔、牡蛎、文蛤和硬壳蛤中PSP的检出率分别为11.76%、47.06%、5.90%和8.82%，其他贝类均未检出。PSP总量均低于欧盟及中国的食用安全限量标准800 μg STXeq/kg。应用风险熵值法和点评估法进行食用安全风险评估，显示风险熵值和暴露风险指数均在安全范围内，结果表明，渤海海域唐山贝类养殖区7种经济贝类不存在食用安全风险。

英文摘要:

      Shellfish are filter feeders that can accumulate toxic algae and their related toxins, increasing risk when consumed. Shellfish toxins can directly affect the physiological activities of marine organisms and threaten the stability of marine ecosystems. Ultimately, these toxins pass through the food chain and can endanger human health and economic security. Globally, shellfish poisoning incidents have occurred in many countries. The Bohai Sea is a semi-enclosed inland sea, where severe eutrophication of the seawater has occurred in recent years, leading to harmful algal blooms. To date, no simultaneous surveillance of diarrhetic shellfish poisonings (DSP) and paralytic shellfish poisonings (PSP) have been reported in the Tangshan shellfish culture area. To better understand shellfish toxin pollution in the shellfish culture areas of Tangshan and the dietary and health risks to residents, Mactra veneriformis, Ruditapes philippinarum, Rapana venosa, Crassostrea gigas, Cyclina sinensis, Meretrix meretrix, Mercenaria mercenaria, and Azumapecten farreri were collected for toxin monitoring from the Tangshan shellfish culture areas in Bohai Sea from October 2019 to September 2020. A total of 34 samples were collected for each shellfish species. Each sample weighed approximately 3 kg. All samples were transported to the laboratory on ice. In the laboratory, samples were flushed with tap water to remove sand and silt and shucked to collect the soft tissue. The tissue was thoroughly homogenized with a household blender, and approximately 50 g of tissue from each sample was stored at –20 ℃ until required for analysis. Five DSP including okadaic acid (OA), dinophysistoxin 1 (DTX1), dinophysistoxin 2 (DTX2), yessotoxin (YTX), and azaspiracid 1 (AZA1), and 14 PSP including saxitoxin (STX), neosaxitoxin (NEO), gonyautoxin 1/4 (GTX1/4), gonyautoxin 2/3 (GTX2/3), decarbamoylsaxitoxin (dcSTX), decarbamoylneosaxitoxin (dcNEO), decarbamoylgonyautoxin 2/3 (dcGTX2/3), gonyautoxin 5 (GTX5), gonyautoxin 6 (GTX6), and N-sulfocarbamoyl toxin 1/2 (C1/2) were tested using high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The detection limit of the DSP method was 5 μg/kg, and the detection limit of the PSP method was 10–20 μg/kg. The DSP toxins were not detected in any of the samples. Several PSP toxins were detected, including saxitoxin (STX), gonyautoxin 1 (GTX1), gonyautoxin 2 (GTX2), and decarbamoylgonyautoxin 3 (dcGTX3). The GTX1 levels were the highest overall PSP toxin at 537.95 μg/kg in April. The results revealed positive rates of PSP for R. philippinarum, C. gigas, M. meretrix, and M. mercenaria, which were 11.76%, 47.06%, 5.90%, and 8.82%, respectively. Of the toxins tested, none were detected in the remaining samples. The highest PSP toxin levels in the positive samples from R. philippinarum, C. gigas, M. meretrix, and M. mercenaria were 414.26, 532.57, 452.77 and 195.46 μg STXeq/kg, respectively. We ranked the species in order of highest to lowest PSP toxin levels as: C. gigas > M. meretrix > R. philippinarum > M. mercenaria. In general, the toxin content of the shellfish in this area was lower than the EU limit of 800 μg STXeq/kg. The composition of shellfish toxins is related to many factors, including the sampling location and collection time. The toxin accumulation capacity by shellfish is also affected by many factors, including water pollution, salinity, ligh整渠獩畮牴敥瑳桩整⁹搬攠癡敮汤漠灭浯敳湴琠⁩潭晰瑲桴敡獴桬敹氬氠晴楨獥栠⁳慰煥畣慩捥畳氠瑡畮牤攠⁤楥湮摳畩獴瑹爠祯⁦愠湴摨⁥琠潴獸畩灣瀠潡牬瑧⁡捥漠湩獮甠浴敨牥†桳敵慲汲瑯桵⹮੤ing waters. The ecological risk assessment methods used in this study were the risk quotient method (RQ) and the point assessment method. The RQ method is primarily used for semi-quantitative risk assessments to determine whether the pollutant concentrations have harmful effects. The point assessment model is a dietary exposure assessment tool. We applied risk quotient and point assessment methods to determine risk. There was no safety risk in the consumption of shellfish harvested from the Tangshan coastal study area during the study period. According to the point assessment method, at this specific time it was safe to consume the shellfish as the toxin levels were low. This analysis indicated that the safe single intake quantity of shellfish during months with high levels of shellfish-enriched toxins was reduced. As the toxin levels accumulating in different shellfish tissues can vary greatly, each sampled tissue was analyzed separately. The results indicate when there is a high accumulation of shellfish toxins present, consumers should restrict their consumption to a single serving rather than regularly consuming shellfish as part of their daily diet. The safety risk assessment results indicate that the seven shellfish species posed no food safety risk during the study period. This study provides a scientific basis for improving shellfish management practices to ensure shellfish are safe for consumption. This study analyzed the effects of toxin residues in shellfish species; different seasons and different locations vary in toxin content and components. We recommended consumers regulate their consumption to avoid potential poisoning events. This study provides social, economic, and ecological benefits in promoting green and healthy aquaculture of shellfish products, by ensuring the safety of shellfish products for consumer health. However, continuous long-term monitoring of both phytoplankton and biotoxins are recommended to