Deposition patterns of SO{sub}4{sup}(2-), NO{sub}3{sup}- and H{sup}+ in the Brazilian territory

摘要

SO{sub}4{sup}(2-), NO{sub}3{sup}- and H{sup}+ depositions are estimated in the Brazilian territory based on the existing rainfall chemical data and on annual rainfall distribution over the whole territory. Local and regional depositions are estimated. Rainfall chemical data over the Brazilian territory shows that the average pH values are usually low (between 4.0 and 5.5). These values are observed in the tropical Amazon forest as well as in urban areas. However, the rainwater acidity in the tropical forests are due to organic acids naturally produced by the vegetation while in urban areas the acidity is mainly due to acidic anion deposition (NO{sub}3{sup}- and SO{sub}4{sup}(2-)).In some Amazonian areas, the average input values through rainfall for NO{sub}3{sup}- is about 0.06 keq.ha{sup}(-1).yr{sup}(-1) and for SO{sub}4{sup}(2-) is between 0.23 and 0.54 keq.ha{sup}(-1).yr{sup}(-1). On the other hand, in some urban centers, such as Sao Paulo, values of .072 keq.ha{sup}(-1).yr{sup}(-1) for NO{sub}3{sup}- and 1.16 keq.ha{sup}(-1).yr{sup}(-1) of SO{sub}4{sup}(2-) are found and in sites where sulfate sources (coal mining) are present, as for the area of Florianopolis, values as high as 5.59 keq.ha{sup}(-1).yr{sup}(-1) for SO{sub}4{sup}(2-) are found.