由于食物链中的生物累积作用，老鹰体内的农药含量比小鱼高得多。

Due to ___bioaccumulation in the food chain, eagles have much higher pesticide levels than small fish.

大型鱼类体内的汞含量较高，这是生物蓄积作用的结果。

Large fish have higher mercury levels due to ___bioaccumulation in the food chain.