乌江渡水库网箱鱼汞和有益脂肪酸的分布特征

Distribution character of mercury and fatty acids in cage-cultured fish from Wujiangdu reservoir in Guizhou

目的研究贵州乌江渡水库网箱鱼的汞及脂肪酸的含量。方法于2015年12月,采集养殖量最大的8种鱼类(草鱼、武昌鱼、鲫鱼、白鲢、花鲢、鲶鱼、江团鱼和鲈鱼),测定总汞和甲基汞以及饱和脂肪酸(SFA)、单不饱和脂肪酸(MUFA)、多不饱和脂肪酸(PUFA)等脂肪酸含量。结果乌江渡8种常见网箱养殖鱼的总汞含量在4.16~169.2μg/kg湿重之间,平均含量为(42.02±6.02)μg/kg湿重,甲基汞占总汞的比例为29.6%~53.9%。肉食性与非肉食性鱼类总汞含量间比较,差异无统计学意义(P>0.05)。该8种网箱鱼的总脂肪酸含量范围在5 194.4~38 605.0 mg/kg湿重之间,其中,SFA的含量为754~8 274mg/kg湿重,MUFA的含量为860~20 216 mg/kg湿重,PUFA的含量为2 742.4~8 691.3 mg/kg湿重,PUFA中所含的n3PUFA和n6PUFA含量分别为1 129.8~5 660.8、1 190.7~5 316.8mg/kg湿重。结论本次研究的乌江渡水库养殖的8种鱼均检出总汞和甲基汞,但含量均未超过我国《食品中污染物限量》(GB 2762-2012)规定的限值。

Objective To know the mercury and fatty acid contents of cage-cultured fish in Wujiangdu reservoir in Guizhou province. Methods In December 2015,eight species of fish(grass carp,Wuchang fish,crucian carp,silver carp,bighead carp,catfish,long-snout catfish and bass) with the largest breeding stock were collected. The total mercury,methylmercury and the content of saturated fatty acids(SFA),monounsaturated fatty acids(MUFA) and polyunsaturated fatty acids(PUFA) were determined. Results The total mercury contents of the cage-cultured fish from eight common cage farms in Wujiangdu reservoir were 4.16-169.2 μg/kg with an average contents of(42.02±6.02)μg/kg. The methylmercury contents accounted for29.6%-53.9% of total mercury. There was no significant difference in total mercury between carnivorous and non-carnivorous fish(P>0.05). The total contents of fatty acids in the fish of the eight species ranged from 5 194.4 to 38 605.0 mg/kg,among which the contents of saturated fatty acids ranged from 754 to 8 274 mg/kg,the contents of monounsaturated fatty acids ranged from 860 to 20 216 mg/kg,the contents of polyunsaturated fatty acids ranged from 2 742.4 to 8 691.3 mg/kg.Among polyunsaturated fatty acids,the contents of n3PUFA and n6PUFA in PUFAs were 1 129.8-5 660.8,1 190.7-5 316.8 mg/kg,respectively. Conclusion Total mercury and methylmercury are detected in all investigated fish in Wujiangdu reservoir in Guizhou province,but the contents of which don't exceed the related national standard limits in National Standards for Food Safty-Limits for Pollutants in Food(GB 2762-2012).