Concentrations of total mercury (THg) and methyl mercury (MeHg) were determined in seawater,sediments and marine organisms collected from Shenhu Bay,Fujian.THg concentrations in seawater ranged from 1.16 ～ 7.29 ng/dm3 with an average of 3.32 ng/dm3.The concentrations of THg in sediments were between O.006 and 0.066 μg/g and MeHg contributed 4.7％ to 38.6％ of THg.Besides,the concentrations of THg in sediments were negatively correlated with the percentage of MeHg(r =-0.840,p ＜0.05),suggesting that higher THg concentrations,which inhibits MeHg synthesis,lead to lower,even negative methylation rates.Analysis results showed THg concentrations in marine organisms were 0.037 ～ 0.353 μg/g (dw),MeHg concentrations,1.01 ～ 42.50 ng/g (dw),with MeHg accounting for 1.5％ ～ 40.4％ of the total.Moreover,the concentrations of THg and MeHg were significantly correlated(r =0.484,p ＜0.10).However,the percentage of MeHg were slightly correlated with THg concentrations(r =-0.293,p ＜ 0.10) and correlated little with MeHg concentrations (r =0.061,p ＞ 0.05).Therefore,it was speculated that THg and MeHg in the organisms were extraneous and the THg/MeHg rate varied greatly in different organisms.Based on the MeHg reference dose of 0.1 μg/(kg · d) regulated by EPA of the Unite State,estimation for human consumption for residents in Shenhu Bay has been assessed.Results showed that it would be safe to consume 600 g fish per week from Shenhu Bay.For further study,MeHg concentrations in seawater samples are needed for the calculation of bioaccumulation factor in order to indicate the biomagnification of MeHg in different organisms.Additionally,evaluating the trophic levels of fish using stable isotopes (δ13C and δ15N)is necessary to study the relationships of bioaccumulation effects and trophic level.%测定了福建省泉州深沪湾海水、沉积物和生物体中的总汞含量,测定了沉积物、生物体中的甲基汞含量.海水总汞含量范围是1.16 ～7.29 ng/dm3,平均值为3.32 ng/dm3.沉积物中总汞含量为0.006～0.066 μg/g,甲基汞占总汞的比例为4.7％ ～38.6％,该比例与总汞含量呈负相关关系(r=-0.840,p＜0.05),这可能是因为总汞含量的升高使甲基汞合成反应受到抑制,导致反应速率降低甚至为负,即甲基汞的分解.生物体中总汞含量为0.037 ～0.353 μg/g(干重),甲基汞含量为1.01 ～42.50 ng/g(干重),甲基汞占总汞的比例为1.5％ ～40.4％.甲基汞含量与总汞含量显著相关(r =0.484,p＜0.10)；总汞含量与甲基汞占总汞比例略有相关(r=-0.293,p＜0.10)；甲基汞含量与其占总汞比例无相关性(r=0.061,p＞0.05).可以推测,生物体中的总汞和甲基汞都是外源性的,不同生物体甲基汞占总汞的比例变化很大.对深沪湾居民进行海产品摄入量评估,以美国EPA规定的甲基汞参考计量0.1 μg/(kg·d)为标准,计算得深沪湾周边居民每周食用3次(600g)湾内的海产品是安全的,不会产生汞中毒.未来还需要测定海水中甲基汞的含量,用以计算生物富集因子,表征不同生物对甲基汞的富集程度；通过测定鱼体中的δ13C、δ15N比值来确定不同鱼类的营养级,进而研究甲基汞的生物累积效应与营养级的关系.
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