Much of the harm done by such pollutants is invisible to the eye: it shows up only in the analysis of dead polar bears or in tuna served in New York sushi bars.

• 许多由这些污染物造成的损害是肉眼不可见的：只有通过对死亡的北极熊或纽约寿司店里被享用的金枪鱼的体内分析，才能显示出来。