Over the past few decades,however, scientists have determined that even trace amounts of lead in children's bodies leads to long-term neurological and behavioral problems.

VOA: standard.2009.12.19

I don't know how many know that there are trace, trace amounts, of cyanide in almonds.

我不知道有多少人知道在杏仁中有非常，非常微量的氰化物。

麻省理工公开课 - 化学原理课程节选