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

Autor: Leal Tatiana F. M., Fontenele Anna P. G., Pedrotti Jairo J., Fornaro Adalgiza
Jazyk: English<br />Spanish; Castilian<br />Portuguese
Rok vydání: 2004
Předmět:
Zdroj: Química Nova, Vol 27, Iss 6, Pp 855-861 (2004)
Druh dokumentu: article
ISSN: 0100-4042
1678-7064
Popis: 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%.
Databáze: Directory of Open Access Journals