Methylmercury (MeHg) concentrations in three different species from different trophic levels with different amounts of Hg exposures were determined for the first time in the EEZ of Qatar. Sampling was conducted during autumn 2017 in two nearshore (Palm Tree and Al-Besheriya Islands) and two offshore locations (Sherawoo and Ishat Islands). Fish muscle and liver tissues were analyzed according to the US Environmental Protection Agency Method 1630. The lowest mean MeHg concentration was found to be 42.3 ppb wet weight in the lower trophic level fish Gerres oyena due to small fish size and trophic level; whereas, the highest MeHg concentration was found in higher trophic level sharks Rhizoprionodon oligolinx and Chiloscyllium arabicum with mean wet weight concentrations of 712 ppb and 166 ppb, respectively. Linear relationships were found between fish body size (weight, length, age) and MeHg concentrations. MeHg bioaccumulation was found to be higher in liver than in muscle tissue; however, there was no significant difference in tissue MeHg accumulation as well as, the concentrations between the four locations. The present study concludes that MeHg in most of the fish tissues is within the allowable limits and pose no threat to public health. Only the higher trophic level shark Rhizoprionodon oligolinx was found to have a MeHg concentration higher than the US EPA advisory level of 0.3 ppm. However, consumers should still be encouraged to eat smaller sized younger fish from lower trophic levels, which would be safer than larger older species from higher trophic levels.

在卡塔尔EEZ中首次确定了来自不同营养水平和不同汞暴露量的三种不同物种中的甲基汞（MeHg）浓度。采样是在2017年秋季在两个近岸（棕榈树和Al-Besheriya群岛）和两个近海地点（Sherawoo和Ishat群岛）进行的。根据美国环境保护局的方法1630对鱼的肌肉和肝组织进行了分析。由于鱼的大小和营养水平较小，最低营养级鱼类Gerres oyena的最低平均MeHg浓度为42.3 ppb湿重。而，最高浓度甲基汞在高营养水平鲨鱼发现Rhizoprionodon oligolinx和斑竹树胶平均湿重浓度分别为712 ppb和166 ppb。发现鱼体大小（体重，长度，年龄）与甲基汞浓度之间存在线性关系。发现肝脏中的MeHg生物蓄积量高于肌肉组织中的蓄积量。但是，组织中的甲基汞累积以及这四个位置之间的浓度没有显着差异。本研究得出的结论是，大多数鱼组织中的甲基汞含量均在允许范围内，对公共卫生没有构成威胁。仅营养级较高的鲨鱼Rhizoprionodon oligolinx被发现的MeHg浓度高于美国EPA的建议含量0.3 ppm。但是，仍应鼓励消费者食用营养水平较低的小规格小鱼，这比营养水平较高的较大型老鱼更安全。