Many Marine species are overfished, and some have high levels of mercury and PCBs.

过度捕捞的很多海洋物种中，有许多含有高浓度的汞和多氯联苯。

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For one thing, most companies use species of fish that are lower on the food chain, like cod and sardines, which accumulate less mercury.

原因之一是，大多数公司使用的种鱼类，都降低其食物链，如鳕鱼和沙丁鱼，它们积累及少量的汞。

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There is also different mercury enrichiments among different organs of identical plant. Different organs absorb and cumulate mercury, which is related to mecury species.

不同地区同种植物中总汞含量存在很大差异，同种植物不同器官对汞的富集程度不同，植物各器官吸收并累积汞与汞的形态有关。

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