Comment by dotancohen

  > Intuitively thinking, I'd imagine higher temps would end up extracting more of those from
  > leaves to the drink than lower temps?

If we're discussing non-volatiles such as heavy metals, boiling acually concentrates them by removing some of the water. This is more of a concern with the water than with the tea, however if one is already bringing up the health aspects then obviosly neither can be ignored.