Composição iônica majoritária de águas de chuva no centro da cidade de São Paulo

Química Nova

Tatiana F. M. Leal²  Anna P. G. Fontenele²  Jairo J. Pedrotti²  Adalgiza Fornaro¹ 

[1] ,Universidade Presbiteriana Mackenzie Departamento de Química São Paulo SP

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

DOI  :  10.1590/S0100-40422004000600003

来源: SciELO

【 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: SO4(2-) (28.8%), CH3COO- (24.7%), NO3- (22.8%), Cl- (13.4%), HCOO- (7.7%) and C2O4(2-) (2.5%). The relative contribution of the weak organic acids to the free acidity was significant, 34.9%.

【 授权许可】

CC BY-NC   
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