1. Environmental Science and Engineering Program, Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts 02115, Environmental Chemical Processes Laboratory, Department of Chemistry, University of Crete, 71409 Heraclion, Greece, Department of Instrumental Analysis, University of Concepcion, Casilla 160-C, Barrio University s/n, Concepcion, Chile, and Commission Nacional del Medio Ambiente (CONAMA), Valentin Letelier 13, Santiago, Chile