Banca de DEFESA: ALINE SANTOS DE ALMEIDA

Distribution of manganese and other trace elements in particulate matter fractionated by size, 

Total Particulate - PTS and Breathable Particulate - PM2.5 in the area of influence of an Fe-Mn metallurgy.

Atmospheric particulate matter; Manganese; trace elements; metallurgy; exposure risk; ICP-MS.

Manganese ore is essential for the production of manganese-based ferroalloys and steel production in the steel industry. Despite being an essential element for man, acting in the formation of bones and tissues, reproductive function and metabolism of carbohydrates and lipids, chronic exposure to Mn mainly affects the central nervous system. Fe-Mn metallurgy is a potential source of emission of this metal and the knowledge of its distribution, as well as of other trace elements in atmospheric particle size ranges, is of great importance in characterizing the risk to which a population may be exposed. In this work, Mn and other trace elements (Co, Cd, Ni, Cu, Se and Pb) were determined in atmospheric particulate matter fractionated by size, total particulate matter - PTS and breathable particulate matter - PM2.5 at three points located in the municipality where is a metallurgy Fe-Mn (Simões Filho) and at a point located in Salvador-BA, Imbuí neighborhood, an urban area far from industry, in addition to a point in the rural area of Tobias Barreto-SE, considered a background station. Measurements were taken between March and October 2017. The following equipments were used to collect atmospheric particulate matter: cascade impactor, Berner type, with 6 (six) stages; Small Volume Sampler (APV) for particles up to 2.5 micrometers (PM2.5); Portable Medium Volume Sampler for Total Particles – PTS. The trace elements Mn, Ni, Cu, Se and Pb were determined in the particulate material fractionated by size using Inductively Coupled Plasma Mass Spectrometry (ICP-MS), also being determined in the PTS and PM2.5 Co and Cd, in addition to those elements. Mn, as expected, showed higher average concentrations in the particulate matter sampled in the three different ways, at the stations closest to the metallurgy: Simões Filho – Área Urbana (F-AU), Cotegipe (COT) and Mapele (MAP). The fine fraction of particulate matter showed a high Mn percentage for all locations ranging from 71-85%, corresponding to 12 ng m

^-3

 at the IMBUÍ and Tobias Barreto (TB), background station to 561 ng m

^-3

 at the closest (1.4 km), downstream of the metallurgy (COT), exceeding the WHO recommendation (150 ng m

^-3

). At the IMBUÍ stations, in Salvador and TB (background station), Mn showed an average concentration lower than the quantification limit of the method in all size fractions of atmospheric particulate matter. The fine fraction of particulate matter sampled in the impactor (0.06-1.7 µm) showed an average percentage of quantified elements (Mn, Ni, Cu and Pb) in all locations ranging between 65% referring to Ni at the IMBUÍ station and 92 % referring to Pb in COT. With the exception of Ni, the atmosphere of the background station (TB), presented the lowest percentages for the other elements in the particulate matter fractionated by size. Mn presented in the PTS the highest average concentrations in SF-AU (112 ng m

^-3

), MAP (803 ng m

^-3

) and COT (1697 ng m

^-3

), being in the last two stations from 5 to 11 times above the limit recommended by the WHO. Also in PM2.5, this limit was exceeded in SF-AU and COT (155 and 537 ng m

^-3

), which may further aggravate the health of the population, due to the greater ease of penetration of smaller particles into the respiratory tract. Cd was only quantified in PTS and PM2.5 in TOC (5.7 and 6.3 ng m

^-3

, respectively), both above the annual standard of 5 ng m

^-3

 established by the European Union, while Co only was quantified in PTS, MAP and COT with mean concentrations of 0.70 and 1.2 ng m

^-3

. The highest concentrations of Pb in the PTS were found in the stations closest to the metallurgy, which ensures that this is its main source. Both in PTS and in PM2.5 Cu showed higher average concentrations in areas with urban influence (Simões Filho and IMBUÍ) and must also be related to vehicular emissions. The risk contribution profile (LCR) for the different locations showed that Cd is responsible for 100% of the total carcinogenic risk in relation to exposure to PTS, in the area of influence of metallurgy. Regarding PM2.5, Cd and Ni are responsible for 58% and 42%, respectively. Pb, considering PTS and Cd, considering PM2.5, showed a higher non-carcinogenic risk probability for all age groups (infants, children and adults), mainly in the urban area of Simões Filho and in Cotegipe, the closest sampling site and downstream of metallurgy. For Mn, no non-carcinogenic risk was found in any of the locations, despite the average concentrations above the WHO recommendation in PTS and PM2.5. The results also showed that adults are more susceptible to the probable risk of cancer than children and babies, certainly related to the exposure time considered for each age group. The highest average cancer risk calculated for the population was 6.69 x 10-6, found in Cotegipe associated with Cd.