Living at the top of the food chain, sharks can accumulate dangerous levels of methylmercury.

因为生活在食物链的顶端，所以鲨鱼可以积累达到危险水平的汞。

Stan O'Neal, Merrill's head, had no idea that his firm had accumulated fatal levels of subprime exposure because he had pushed aside the people who might have warned him.

美林证券的头儿斯坦奥尼尔（Stan O'Neal）把本可能规劝警告他的人都打入冷宫，因此根本没有意识到公司已经累积了致命数额的次级贷。