台灣地區養殖魚類重金屬之調查

THE INVESTIGATION ON HEAVY METAL CONTENTS OF CULTURED FISHES IN TAIWAN

於民國七十五年七月至七十六年六月在全省魚類養殖量較高的十五個縣市抽購吳郭魚、虱目魚、鯉魚、鰻魚、鱒魚等五種魚類檢體計272件，利用原子吸光光譜儀分析魚類可食部分砷、汞等重金屬含量，利用感應耦含電漿原子發射光譜儀分析其鉛、銅、鎘等重金屬含量。分析結果吳郭魚含銅量0.274～1.713ppm之間，總平均值0.632ppm，含鉛量N.D.～0.720ppm之間，總平均值O.290ppm，含鎘量N.D.～0.075ppm之間，總平均值0.027ppm，含汞量N.D.～0.031ppm之間，總平均值0.012ppm，含砷量N.D.～0.115ppm之間，總平均值0.038ppm。虱目魚含銅量0.100～1.840ppm之間，總平均值0.540ppm，含鉛量0.016～1.208ppm之間，總平均值0.482ppm，含鎘量N.D.～0.068ppm之間，總平均值0.035ppm，含汞量N.D.～0.088ppm之間，總平均值0.019ppm，含砷量N.D.～0.114ppm之間，總平均值0.048ppm。鯉魚含銅量0.130～2.390ppm之間，總平均值0.717ppm，含鉛量0.096～1.520ppm之間，總平均值0.414ppm，含鎘量N.D.～0.093ppm之間，總平均值0.031ppm，含汞量N.D.～0.060ppm之間， 總平均值0.017ppm，含砷量N.D.～0.067ppm之間，總平均值0.024ppm。鰻魚含銅量0.203～1.510ppm之間，總平均值0.604ppm，含鉛量N.D.～1.460ppm之間，總平均值0.308ppm，含鎘量N.D.～0.154ppm之間，總平均值O.033ppm，含汞量N.D.～0.050ppm之間，總平均值0.015ppm，含砷量N.D.～0.091ppm之間，總平均值0.031ppm，鱒魚含銅量O.165～0.704ppm之間，總平均值0.469ppm，含鉛量0.138～0.787ppm之間，總平均值0.306ppm，含鎘量O.009～0.033ppm之間，總平均值0.017ppm，含汞量0.011～0.080ppm之間，總平均值0.025ppm，含砷量0.019～0.042ppm，總平均值0.029ppm，鱒魚係以高冷地區流動之冷水源養殖，其重金屬含量可視為自然含量。重金屬含量在魚種間的差異經變方分析顯示銅、鉛、鎘、汞、砷等五種重金屬在各魚種間均有顯著差異（P<0.05）這表示重金屬之含量會因殖水水質的差異，放養飼料的差異，魚體重金屬累積能力的不同等因素，使不同魚種間重金屬含量有顯著之差異。目前我國僅有衛生署公告之魚蝦類汞的衛生標準，限量在0.5ppm以下，此調查顯示五種魚類汞的含量均遠低於此限量。而鉛、銅、鎘、砷等重金屬的衛生標準尚未訂定，此結果可提供衛生機關訂定衛生標準之參考。

Tilapia, milkfish, common carp, eel and trout of 272 samples were collected from fifteen major aquaculture counties and cities between July 1986and June 1987. Contents of mercury and arsenic in edible porion of cultured fishes were analyzed by atomic absorption spectrophotometry. Contents of lead, copper and cadmium were analyzed by inductively coupled plasma atomic emission spectrometry. The result showed that mean copper, lead, cadmium, mercury and arsenic contents in tilapia were 0.632 ppm, 0.290 ppm, 0.027 ppm, 0.012 ppm and 0.038 ppm respectively. The mean copper, lead, cadmium, mercury, and arsenic contents in milkfish were 0.540 ppm, 0.482 ppm, 0.035 ppm, 0.019 ppm and 0.048 ppm respectively. Ther corresponding conntents in common carp were 0.717 ppm, 0.414 ppm, 0.031 ppm, 0.017 ppm and 0.024 ppm respectively. The contents in eel were 0.60 ppm, 0.308 ppm, 0.033 ppm, 0.015 ppm and 0.031 ppm respectively, in trout were 0.469 ppm, 0.306 ppm, 0.017 ppm, 0.025 ppm, and 0.029 ppm respectively. Ther trout were cultured in ponds located in cool high mountain area, where metal contamination was unlikely. Therefore the metal contents in trout was assumed as natural occuring. According to the analysis of variance, the contents of copper, lead, cadmium, mercury and arsenic among the five fish species were significantly different ( p < 0.05 ). This is probable due to the differences in farming condition, types of feed and the ability of fish to accumulate metals. The mean mercury contents in these five kind of fishes were below the allowable limit being 0.5 ppm of mercury content in fish and shellfish. The allowable limit of copper, lead, cadmium and arsenic have not been determined yet. This result can provide a reference for Health Administration to establish the allowable limit.