SPECIATION ANALYSIS OF ADSORBED ATMOSPHERIC ARSENIC IN POLLEN AND AEROBIOLOGICAL SAMPLES BEFORE AND DURING THE COVID-19 PANDEMIC

ESCUDERO, DANIELA R.; ISAGUIRRE, ANDREA C.; MOYANO, FRANCO M.; HASUOKA, PAUL

Mendoza

Congreso; XL Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2022

Arsenic (As) is a toxic element for humans, which can be released into the environment naturally or by anthropogenic activities. Pollen grains have the ability to adsorb and transport heavy metals such as As, these having become indicators for contamination by As. The toxicity of As depends on the chemical form in which it is present, the inorganic form being more toxic than the organic forms. Therefore, to assess the risk of exposure to As, the individual concentrations of each species must be determined rather than a total elemental analysis. The objective of this research is to evaluate the effects of vehicular traffic on the concentration of As in the atmosphere, for this aerobiological samples were collected in pre-pandemic and pandemic periods in the city of San Luis, Argentina, in the vicinity of the San Luis Regional Hospital. Subsequently, total As was determined in the mentioned samples. Similarly, for a more comprehensive study, As speciation was performed on fresh pollen samples from Vachellia caven. Firstly, an elution of atmospheric As species adsorbed on pollen samples was performed, which was optimized by using 1% v/v acetone, 15 minutes of ultrasonic bath and centrifugation. The eluted As species were determined by LC-ICP MS, with As (III) and As (V) concentrations between 0.08 and 0.62 μg g-1 and 0.33 and 0.89 μg g-1 respectively, these concentrations corresponding to year 2021. Analyzing 0.05 g of pollen, the method reaches a detection limit and quantification limit of 0.01 and 0.04 μg g-1 for As (III); and 0.01 and 0.06 μg g-1 for As (V), respectively. A microscopic analysis of the aerobiological samples was also carried out in order to determine the most abundant pollen species in the periods studied, which was identified as Chenopodiaceae-Amaranthaceae, with a concentration of 38 grains of pollen/m3 of air in 2019 and 36 grains of pollen m-3 of air in 2021. The concentration of this type of pollen, in the years studied, is in the moderate category of the Manual of the Spanish Network of Aerobiology. In addition, other types of pollen were recorded during these periods, such as Poaceae, Plantago, Artemisia and other Asteraceae, but in the “low” categories established by REA. The results obtained in this study showed significant variations in the concentration of total As, in aerobiological samples, which suggests that traffic increases the concentration of atmospheric As