ESTABLISHING A STANDARD SONORAN REFERENCE PLANT AND ITS APPLICATION IN MONITORING INDUSTRIAL AND URBAN POLLUTION THROUGHOUT THE SONORAN DESERT

Using analyses from honey mesquite (Prosopis glandulosa) leaves from n early pristine locations in Arizona, an inorganic plant concentration standard is proposed for use as a 'Sonoran Reference Plant' (SRP). Suc h a standard can be used as a monitoring device for different anthropo genic pollution sources throughout the Sonoran Desert. To test the app lication of the SRP, honey mesquite leaves were collected at different sites in southern Arizona and their 'chemical fingerprints' compared to SRP. Sources of element origin were identified through factor analy sis and correlation matrices. A terrestrial factor was found in leaves from all sites. Anthropogenic factors varied for different sites. Mes quite leaves accumulated significant amounts of elements originating f rom copper smelters (As, Sb) and urban pollution (La, Sm, Ce, V). Thes e pollutants are small-sized and have been linked to human lung diseas es. Mesquite is a deciduous tree; the yearly comparison of mesquite le af element concentration spectra to the SRP standard can be used to de termine seasonal improvement or deterioration of environmental quality in a particular area.