The use of an epiphyte (Tillandsia caput-medusae morren) as bioindicator of air pollution in Costa Rica

Tillandsia caput-medusae (Bromeliaceae) is an epiphytic neotropical plant able to absorb water and nutrients directly from the air. For this reason we have selected this species to carry out a monitoring study of air pollution in San José city (Costa Rica) from February 1993 until October 1994. Three trace metals were tested bimonthly in the plant: Pb, Cu and Cd, whose presence indicates different sources of pollution. The results of analysis of Pb, Cd and Cu (in μg/g) carried out with DPASV (differential pulse anodic stripping voltammetry) on the internal and the external Tillandsia leaves, are presented as a function of sampling date. The metal concentrations of the external leaves were compared with the rainfall profile. The results of the investigation show that T. caput-medusae was successfully used as a biomonitoring tester for air pollution. We recommend the use of Tillandsias in all Latin American countries, where some species of these epiphytes are very widespread.