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 (I_geo), Pollution Index (P_I), and Pollution Load Index (P_LI), which were compared with the probabilistic method of enhanced enrichment (EF_Imp). The EF_Imp involves stochastic mathematical methods based on the probability density function (PDF). The total radiation dose (D_T) 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". EF_Imp 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 E_Imp 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.