Evaluation of contamination by metals and radionuclides in periurban soils

This work evaluates contamination by metals and radionuclides with a chemometric approach, using peri-urban soils near the new International Airport, Mexico. The contamination was evaluated using conventional methods such as the Enrichment Factor (EF), Geoaccumulation Index (Igeo), Pollution Index (PI), and Pollution Load Index (PLI), which were compared with the probabilistic method of enhanced enrichment (EFImp). The EFImp involves stochastic mathematical methods based on the probability density function (PDF). The total radiation dose (DT) and the radiological risk due to the quantified radionuclides were estimated. The results obtained by conventional methods showed that in 226Ra there is an increase in the concentration of activity considered as "moderate". EFImp calculations showed that Cr, Mn, Fe, Ni, Cu, and Zn are in the “unenriched” category. Zn is likely to deteriorate to the "slightly enriched" category. The Pb, 137Cs, and 40K are in the “slightly enriched” category. Pb, 137Cs, and 40K present a slight tendency towards “moderate enrichment”. 226Ra is in the "moderate enriched" category, however, it presents a high probability of "severe enrichment". Comparing the results of the conventional and probabilistic methods, it is possible to establish that both types of methods are consistent. However, the EImp can quantify the potential risk of deterioration, among other advantages. Finally, considering that all calculated doses are below the limit for public exposure of 1 mSv/year, it can be concluded that the enrichment of 226Ra, 137Cs, and 40K does not constitute a radiological risk to the population or the environment.