EGU2020-15354
https://doi.org/10.5194/egusphere-egu2020-15354
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Atmospheric aerosol analysis close to the mining area of Aljustrel (SW of Portugal)

Ana Barroso1,2, Sandra Mogo2,3,4, Manuela Silva1,5, Victoria Cachorro4, and Ángel de Frutos4
Ana Barroso et al.
  • 1Department of Earth Sciences, University of Coimbra, Coimbra, Portugal (raquel.barroso65@gmail.com)
  • 2University of Beira Interior, Covilhã, Portugal (smogo@ubi.pt)
  • 3Institute Dom Luiz (IDL), University of Lisbon, Lisbon, Portugal (smogo@ubi.pt)
  • 4Universidad de Valladolid, Facultad de Ciencias, Fisica Teórica Atómica y Óptica, Valladolid, Spain (smogo@ubi.pt)
  • 5Centre for Earth and Space Research of the University of Coimbra, (mmvsilva@dct.uc.pt)

Mining activities are associated with dust emissions and increased contaminant levels in the environment, due to excavation, crushing and transportation of ore and the generation of a high amount of polluting wastes. Therefore, it is crucial to study the particulate matter in these areas to understand their impacts on nearby urban areas and populations (Csavina et al., 2012). Analysis PM10 samples collected near the active mining area of Aljustrel (SW Portugal) allowed to do an individual characterization and to investigate the contaminants levels and aerosols sources. In Aljustrel, the exploitation of volcanogenic massive sulphides (VMS) deposits has been done since pre-Roman times, releasing great quantities of mine wastes, which have contaminated the soils (Candeias, et al. 2011). Now the exploitation is done underground, but even so, the ore processing plant releases dust, which is transported by wind to the village.

The PM10 samples were collected in two points at the southeast of the ore processing plant. The sampling was done in two periods July 10-17 and November 1-10 of 2018. Two different techniques were used: SEM-EDX for the individual characterization and ICP-MS for the elemental concentration of 11 elements (Ca, Na, Fe, Mn, As, Cd, Cu, Sb, Pb, and Zn). PM10 mass concentration observed was 20 to 47 µg m-3 (July) and 4 to 23 µg m-3 (November) which is lower than the limit of 50 μg m-3 established in the European Directive (Directive 2008/50/CE of May 21). The individual characterization of 2006 particles by SEM-EDX shows the presence of oxides (17%) and sulphides (10%) in the aerosols, and the elements Na, Si, Fe, S, Al and Cu are those with the most representativeness in all the analyzed particles. The Principal Component Analysis (PCA) allowed to distinguish the main sources of aerosols. Five factors were extracted (72% of the total variance of the data): CP1 is defined by O, Al, Si and Fe, the geogenic elements; CP2 is defined by As and Pb, CP3 is defined by S, CP4 defined by Cu and Zn; and finally, the CP5 defined by Mn. These factors are related to the ore minerals. The ICP-MS results indicate that daily elemental concentration in the samples collected in July is higher than in those collected in November, for each element. The elements Fe, Cu, Zn, As, Cd, Sb, Pb have strong correlations (α = 0.05, r > 0.93) and are the main constituents of the ore minerals. Therefore, these elements will have an anthropogenic source. Comparing the concentration of some pollutes (As, Cd, and Pb) with their limits in the European legislation only As exceeds its limit in all samples.

This work was the first study about atmospheric aerosols developed in this area and shows a strong relationship between PM10 analyzed and the ore exploited in Aljustrel, indicating implications in the quality of the air for the resident population. Even if some limits are not exceeded, the continuous exposition over many years is a potential hazard.

How to cite: Barroso, A., Mogo, S., Silva, M., Cachorro, V., and de Frutos, Á.: Atmospheric aerosol analysis close to the mining area of Aljustrel (SW of Portugal), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-15354, https://doi.org/10.5194/egusphere-egu2020-15354, 2020

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