exactly how much "Caffeine" did Asarco release in the Paso del Norte?

http://www.google.com/hostednews/ap/article/ALeqM5gRNiTtgwAEeIASdS5QDK8fH0NlQAD9AERFPO0  "Effort in NM to keep medications out of Rio GrandevBy SUSAN MONTOYA BRYAN (AP) Sept 1, 2009  ALBUQUERQUE, N.M. — New Mexico's largest water utility announced a plan Tuesday aimed at educating the public and keeping pharmaceuticals out of one of the West's most important water ways, the Rio Grande.  The announcement by the Albuquerque Bernalillo County Water Utility Authority follows a recent discovery in the Rio Grande of caffeine, which scientists often look for as a possible signal for the presence of other contaminants.[ i.e. the "canary in the mine"] An environmental group also reported earlier this summer that it found traces of pharmaceuticals in the Rio Grande Valley's irrigation system."