Amostragem e determinação de hidrocarbonetos policíclicos aromáticos e seus derivados nitrados e oxigenados em material atmosférico particulado por cromatografia gasosa acoplada a espectrometria de massas sequencial

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are known by its carcinogenic and mutagenic potential, especially benzo[a]pyrene. Their oxygenated (oxy-PAHs) e nitrated (nitro-PAHs) derivatives is in the concern of the Academia and regulatory boards due to their higher carcinogenic and mutagenic potential than their parent organics. All these compounds are found in the atmosphere from petrogenic sources, as result of fuel combustion, and pyrogenic, trough burning of biomass and coal. Natural processes, biogenic, like the decomposition of leaves and vegetables explain the presence, mainly of the oxygenated derivatives, as well as volcanic ashes releasing also explains the presence of the hydrocarbons. To extract and analyze of PAHs and their oxygenated (oxy-PAHs) and nitrated (nitro-PAHs) derivatives was used an adapted methodology developed in prior works of the Rede Mineira de Cromatografia Avançada (RMCA). The extraction of the analytes from the particulate matter, collected on quartz filters, and gaseous phase, collected on polyurethane foam (PUF), was performed by solid phase microextraction. All the analysis were done by gas chromatography coupled to tandem mass spectrometry. The samples were collected in two samplings rounds at the city of Brumadinho/MG, the first in five different locations, throughout the months of September to November/2021, and the second in two different locations, in the months of April and May/22. At UFMG surroundings, the sampling round occurred at two locations during the months of March and April/2022. The validated method reached lower limits of detection and quantification lower than those reported in the literature, as the limit of detection to the particulate matter varied within the range of de 0,0005ng m–3 to 0,01822 ng m–3 and the limit of quantification varied within the range of 0,0015 ng m–3 a 0,04884 ng m–3. To the gaseous phase the limits of detection and quantification varied within the range of 0,00081 ng m–3 to 0,03850 ng m–3 and 0,00163 ng m–3 e 0,11028 ng m–3, respectively. All the determination coefficients (R²) were higher than 0,9 and repeatability, recovering and precision were satisfactory. Overall PAHs concentrations were higher than oxy-PAHs concentrations which in turn were higher than nitro-PAHs concentrations. The lifetime cancer risk (LCR) was calculated based on the benzo[a]pyrene equivalent (B[a]Peq) concentration calculated from the concentration of the PAHs and their toxic equivalency factor (TEF). The concentrations of (B[a]Peq) varied from 0,33 ng m–3 to 2,07 ng m–3 at the sampling locations at the city of Brumadinho and from 0,32 ng m–3 to 0,33 ng m–3 at the UFMG geographic region. The LCR at the city of Brumadinho varied from 7,61×10–5 to 1,8×10–4, while in the urban region of the university varied between 2,79×10–5 and 2,90×10–5. Diagnostic ratios and principal component analysis were employed to estimate the HPAs source of emissions.