Two sampling points were chosen and forty samples were collected between January and December 2006 at Alto Sorocaba basin. The rainwater pH varied from 5.46 to 6.36 (Ibiúna) and 5.26 to 6.81 (Itupararanga), being Ca2+ the main ion responsible for controlling the rainwater pH. The ionic concentrations decreased in the following order: Ca2 +>Na+> Mg2+>K+ for cations and SO4(2-)>HCO3->NO 3->Cl- >PO4(3-) for anions. The annual atmospheric deposition appeared to be controlled mostly by following sources: mining activities and cement factories (Ca2+ and HCO3-), natural soil dust (Na+, Mg2+ and HCO3-), fossil fuel burning (SO4(2-)) and agriculture activities (K+, NO3- and PO4(3-)).
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机译：在2006年1月至2006年12月期间，选择了两个采样点，并在Alto Sorocaba盆地采集了40个样本。雨水的pH值在5.46至6.36（Ibiúna）和5.26至6.81（Itupararanga）之间变化，Ca2 +是负责控制雨水pH值的主要离子。离子浓度按以下顺序降低：Ca2 +> Na +> Mg2 +> K +表示阳离子，SO4（2-）> HCO3-> NO 3-> Cl-> PO4（3-）表示阴离子。年度大气沉积似乎主要受以下来源控制：采矿活动和水泥厂（Ca2 +和HCO3-），天然土壤粉尘（Na +，Mg2 +和HCO3-），化石燃料燃烧（SO4（2-））和农业活动（K +，NO3-和PO4（3-））。
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