Composition of rainwater in the central region of São Paulo city

Química Nova

Pedrotti, Jairo J.¹  Fontenele, Anna P. G.¹  Fornaro, Adalgiza¹  Universidade Presbiteriana Mackenzie, São Paulo¹  Leal, Tatiana F. M.¹  Universidade de São Paulo, São Paulo¹ 

关键词: acid rain;    ionic composition;    air pollution.;   

DOI  :  10.1590/S0100-40422004000600003

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

The chemical composition of rainwater samples collected from March 2002 to February 2003 in downtown São Paulo city (Universidade Presbiteriana Mackenzie) is presented. Potentiometric and conductimetric measurements were used to evaluate the [H+] and the total ionic content. Major anions and cations were determined by ion chromatography with conductivity detection. The rainwater was acidic with a mean pH of 4.99. The volume weighted means, VWM, of the anions nitrate, acetate and sulfate were, respectively, 21.2, 16.9 and 12.4 µmol L-1. Ammonium was the most abundant ion with a VWM of 37.6 µmol L-1. The contribution of each anion to the free acidity potential decreases in the following order: SO42- (28.8%), CH3COO- (24.7%), NO3- (22.8%), Cl- (13.4%), HCOO- (7.7%) and C2O42- (2.5%). The relative contribution of the weak organic acids to the free acidity was significant, 34.9%.

【 授权许可】

Unknown