Monitoring of SO2 concentration in the air and physicochemical characteristics of rainwater in the Irazú Volcano

Abstract

Sulfur dioxide and other chemical pollutants can reach nature and the environment through volcanic activity. Due to this, in Costa Rica, the areas near the volcanoes are affected with these pollutants. Therefore, a monitoring of the concentration of sulfur dioxide in air was carried out, and the determination of the pH and concentration of fluoride, chloride, bromide, phosphate and sulfate in rainwater at the Irazú Volcano, in 2019. Initially, Analytical performance parameters were evaluated: linearity, repeatability, intermediate precision, limit of detection and quantification in the method used. Special wet samplers or collectors were used at specific points in the area, then the samples were analyzed in the Laboratory of Atmospheric Chemistry (LAQAT), where the concentration of the anions in water was determined by means of ion chromatography. The pH was determined with a calibrated pH-meter. The results obtained indicate that the sulfur dioxide does not exceed the permitted limits. In addition, the pH results of the rainwater samples (3.55 to 5.33) indicate the presence of acid rain in the areas near the crater of the volcano, therefore, to use it, a treatment that reduces the acidity. Likewise, the results of the anions in the rainwater presented low values ​​(less than 6.58 mg / l), in addition, it was not possible to detect bromide and phosphate in the samples. The concentration of sulfur dioxide present is not considered detrimental to the health of visitors and workers in the area.