Chemical composition of rainwater in an urban area of the southeast of Brazil

Özet

from Sep/2013 to Mar/2014, were quantified by ionic chromatography (ICS 90); and $HCO_3^-$was determinedvia Gran titration. Three source apportionment methods, namely Principal Component Analysis (PCA), air masstrajectory clustering and enrichment factor (EF), were used to identify the main sources of pollutants dissolved inrainwater samples. The concentration of ions (μeq $L^{-1}$), of the samples was:$Ca^{2+}$ > $NH^{4+}$> $Na^{+}$ > > $Mg^{2+}$ > $SO_4^{2-}$> $NO3^-$ > $CI^-$ > $K^+$ > $H^+$, and pH = 5.6 inVWM. The first three components obtained via PCA explained 75% of the total variance correlation and indicated a strong contribution of pollutants from agricultural emissions in the studied region, possibly due to theproximity of rural areas. The generated trajectory clusters indicated a 70% contribution from continental sourcesin the studied area. EF showed that $SO_4^{2-}$, $NO3^-$ , $CI^-$, $K^+$, $Mg^{2+}$ and $HCO_3^-$ are from anthropogenic sourceswhereas $Ca^{2+}$ is from crust and $Na^{+}$ is from crust and anthropogenic sources. The anthropogenic sources,possibly associated with the region's agricultural activities, mining, industries and heavy vehicle traffic. In addition, it was verified the negative impact the fire outbreaks in the State of São Paulo had on the quality of the airin Limeira. Finally, the ionic concentrations in rainwater samples collected in the urban area of Limeira werecompared with data from monitored cities in Brazil and throughout the world.