Abstract

RODRIGUES, Renato de Aragão Ribeiro; MELLO, William Zamboni de  and  SOUZA, Patricia Alexandre de. Atmospheric deposition of ammonium, nitrate ans sulfate on the montane dense ombrophilous forest in Serra dos Órgãos, RJ. Quím. Nova [online]. 2007, vol.30, n.8, pp. 1842-1848. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40422007000800009.

Wet and dry (dust) deposition was measured in the Serra dos Órgãos National Park. VWM pH was 5.3. Non-sea-salt (nss) SO₄^2- comprised 97% of total SO₄^2-. The molar ratio [2(nss-SO₄^2-) + NO₃^-]/[NH₄⁺ + H⁺] was 1.1, suggesting that pH is predominantly controlled by H₂SO₄, HNO₃, and NH₃. Wet deposition of NH₄⁺, NO₃^-, and nss-SO₄^2- was respectively 0.59, 0.25, and 0.30 kmol ha^-1 yr^-1. Assuming that dry deposition of N can comprise 30-50% of its total (dry + wet) deposition, the latter is estimated to be 1.2-1.7 kmol ha^-1 yr^-1 (17-24 kg N ha^-1 yr^-1).

Keywords : rainwater chemistry; wet deposition; dry deposition.