DETERMINATION OF THE LEVELS OF NA, K, CA, MG, FE, ZN AND CU IN AEROSOLS OF THE WESTERN VENEZUELAN SAVANNA REGION

The determination of seven elements in cellulose filters loaded with a ir particulate matter (total and size distributions) was carried out i n two rural western Venezuelan savannah sites during dry and rainy sea sons. After acid digestion of the filter material with high purity nit ric acid, analysis of the metals was carried out by atomic absorption spectroscopy. The level of possible error at the analytical stage was found to be insignificantly small. The K and Ca excess concentrations in relation to sea water were similar to 90%. A large concentration of Ca in coarse particles > 1.5 mu m was observed, probably coming as ca rbonates from soil and cement production emissions, which should have a good potential to neutralize the acidity of the atmosphere. In both dry and rainy seasons, K was present in a large fraction (> 50%) of co arse particles > 1.5 mu m, indicating that the western Venezuelan sava nnah region is little affected by vegetation burning emissions in comp arison with other Venezuelan savannah regions. The release of water so luble K salt particles from vegetation is the most likely additional K source other than sea-salt. A very high concentration was found for C u (233-394 ng m(-3)) in the rainy season, which is up eight times high er than found in other Venezuelan savannah regions. This range of conc entration is well above the range of 3-100 ng m(-3) found in other rur al areas of the world, indicating possible natural and/or anthropogeni c sources for the atmospheric concentration of this element.