1. Stable Isotope Research Group, School of ChemistryUniversidad Nacional Heredia Costa Rica
2. Chemistry SchoolUniversidad Nacional Heredia Costa Rica
3. Environmental Protection Research Center, School of ChemistryInstituto Tecnológico Cartago Costa Rica
4. Empresa de Servicios Públicos de Heredia (ESPH) Heredia Costa Rica
5. Natural Resources Laboratory, Agronomical Research CenterUniversidad de Costa Rica San Pedro Costa Rica
6. Department of Geography and Water and Global Change ObservatoryUniversity of Costa Rica San José Costa Rica