钦州湾海水和香港牡蛎体内脂溶性贝类毒素污染特征

POLLUTION OF LIPOPHILIC SHELLFISH TOXINS IN QINZHOU BAY:SEAWATER AND CRASSOSTREA HONGKONGENSIS

近年中国沿海普遍受到脂溶性贝类毒素(lipophilic shellfish toxins,LSTs)的污染。钦州湾是国内外闻名的牡蛎养殖基地,目前仍不了解该海域海水和主要养殖品种香港牡蛎(Crassostrea hongkongensis)沾染LSTs毒素情况与食用安全性。本文于2015年10月至2016年9月,在钦州湾香港牡蛎养殖区海水交换口处,通过固相吸附毒素跟踪技术(solid phase adsorption toxin tracking,SPATT)吸附收集海水中的脂溶性贝类毒素,同时每月采集香港牡蛎样品,应用液相色谱串联质谱法分析海水和香港牡蛎体内的LSTs毒素含量与组成,并对香港牡蛎食用安全性进行评估。结果表明:(1)海水共检出GYM、OA和PTX2三种组分,平均浓度分别为0.44、14.20和1.67μg/(kg resin·30d)。香港牡蛎共检出DTX2、GYM、SPX1、Homo-YTX四种组分,其中Homo-YTX为定性结果,DTX2、GYM、SPX1三者平均浓度分别为0.95、18.86和0.95μg/kg。(2)GYM毒素均值在海水中和香港牡蛎体内含量变化趋势呈正相关,Pearson相关系数为0.70;OAs毒素在海水中和香港牡蛎体内变化趋势类似,Pearson相关系数为0.35。(3)毒素存在一定季节变化。海水OA和PTX2夏季高,其他季节低,均值最高值分别发生在7月和6月;香港牡蛎体内GYM冬季和夏季较高,DTX2春季和夏季较高;但海水中的GYM和香港牡蛎体内的SPX1全年变化均不明显。总体而言,钦州湾海水和香港牡蛎已受到多个LSTs毒素组分污染,海水LSTs毒素含量较国内其他海域低,参考欧盟LSTs毒素标准,本海域的香港牡蛎脂溶性贝类毒素仍未超标,可放心食用。

In recent years,coastal areas of China were contaminated with lipophilic shellfish toxins(LSTs).Qinzhou Bay in Beibu Gulf,Guangxi,South China,is an oyster breeding base.However,study on LSTs in the bay water and in oyster Crassostrea hongkongensis,the main farming species in the bay,remains blank.From October 2015 to September 2016,C.hongkongensis and seawater were sampled simultaneously monthly at three seawater exchange sites,for which SPATT(solid phase adsorption toxin tracking)technology was deployed in the Qinzhou Bay.The content and composition of LSTs in the seawater and C.hongkongensis were analyzed using LC-MS/MS.In addition,the seafood safety of C.hongkongensis was evaluated.Three components of GYM,OA,and PTX2 were detected out in seawater,on average concentrations of 0.44,14.20,and 1.67μg/(kg resin·30d),respectively.Four components of DTX2,GYM,SPX1,and Homo YTX were detected in C.hongkongensis.Except for Homo-YTX showing as a qualitative result,the average concentrations of DTX2,GYM,and SPX1 were 0.95,18.86 and 0.95μg/kg,respectively.A positive correlation was observed between the mean value of GYM toxin in seawater and that in the oyster,and the Pearson correlation coefficient was 0.7.A similar trend for OAs toxins was also found between seawater and the oyster,but the coefficient was small(0.35).Seasonal pattern of LST in Qinzhou Bay was presented.In the seawater,OA and PTX2 peaked in summer(July and June,respectively),while in C.hongkongensis,GYM reached the maximum in winter and summer,and DTX2 in spring and summer.However,GYM in seawater and SPX1 in C.hongkongensis showed no obvious seasonal change during the investigation.Therefore,the seawater and the cultured oyster were contaminated by LSTs toxins in Qinzhou Bay,and the toxin level was below that in other sea areas of China.When referring to European Union regulatory limits,the LSTs toxins in C.hongkongensis from Qinzhou Bay did not exceed the benchmark,thus they can be consumed safely.