Deposition patterns of SO42-, NO3- and H+ in the Brazilian territory

SO42-, NO3 and H+ depositions are estimated in the Brazilian territory base d on the existing rainfall chemical data arid on annual rainfall distributi on 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 rainw ater acidity in the tropical forests are due to organic acids naturally pro duced by the vegetation while in urban areas the acidity is mainly due to a cidic anion deposition (NO3- and SO42-). In some Amazonian areas, the avera ge input values through rainfall for NO3- is about 0.06 keq.ha.yr(-1) and f or SO42- is between 0.23 and 0.54 keq.ha(-1).yr(-1). On the other hand, in some urban centers, such as Sao Paulo, values of .072 keq.ha(-1).yr(-1) for NO3- and 1.16 keq.ha(-1).yr(-1) of SO42- are found and in sites where sulf ate sources (coal mining) are present, as for the area of Florianopolis, va lues as high as 5.59 keq.ha(-1). yr(-1) for SO42- are found.