Rainwater chemistry at the summit and southern flank of the Itatiaia massif, Southeastern Brazil

Wet deposition and related rainwater chemistry were studied at the Itatiaia massif, on which is settled the Itatiaia National Park (INP). Samples were simultaneously collected on a weekly basis over 12 months, using automated wet and dry samplers, at the INP-Headquarters (INP-Hq; altitude=820 m) and the Itatiaia Plateau (It-Pt; altitude=2460 m). Conductivity, pH, Na+, K+, Mg2+, Ca2+, NH4+, Cl−, NO3− and SO42− were determined in 36 rainwater samples. Volume-weighted mean (VWM) pH was lower at the INP-Hq (4.9) than at the It-Pt (5.3). Very strong correlation between Cl− and Na+ was found for the INP-Hq (r=0.99). At the Itatiaia massif, SO42−, NO3−, and NH4+ comprised together about 60% of the total inorganic ions and appear to exert the major control on rainwater pH. Rainwater chemistry at the Itatiaia massif in SE Brazil is strongly dominated by S and N inorganic species, and influenced by human activities.