Organic and inorganic acids in rain from a remote site of the Venezuelan savannah

In this paper, we report the chemical characterization of rain events collected at a remote site in the Venezuelan savannah. The volume-weighted average pH was 4.7. In most of the samples over 60% of the free acidity may be due to formic and acetic acids. Sulphuric and nitric acids only contribute with <= 40%. The potential contribution of HCl is relatively high, up to 16%. Ammonium ion concentrations were lower than the values observed in other natural tropical ecosystems. Rain samples collected during the period of vegetation burning show less free acidity ( pH > 5.3) and higher concentration of all the ions than those collected in the non-burning periods.