Numerical assessment of the radiological impact of dust inhalation from phosphogypsum piles. The case of Huelva city (SW Spain)

Fugitive dust particles from phosphogypsum (PG) stockpiles, located next to Huelva (SW Spain),were investigated in this study. 100 - 120 million tonnes of PG containing radioactive and toxictrace elements were accumulated in the proximity of the city throughout the 40 years operationof fertilizer plants. This study was focused on the development of a model of emission, dispersionand deposition of dust particles, originating from the PG piles, and validation of the modelresults against the collected field samples of deposition. Moreover, the results were used to assessthe radiological impact from inhalation of PG dust particles on the population of Huelva.Three different numerical formulations, concerning the PG dust emission rate by the means ofwind erosion, were tested in the AERMOD dispersion model. Validation studies have proven thatthe most accurate results of the PG particles deposition were associated with the formulationthat is commonly used to predict dust dispersion from mine tailings [1]. When the specificparameters concerning the PG particles and texture characterization are missing, it is advisedto use theMine Tailingformulation to describe the emission rate. In case of availability of thedata, the recommended formulation to use is the one developed by Nickovic et al. [2]. The latterrequires the introduction of many specific parameters in order to precisely represent the occurringphenomena but it strongly decreases the uncertainty of the model.The radiological impact from the inhalation of PG dust was evaluated based on the airconcentration and deposition results from the model. Assessed effective dose, assuming constantpresence at the particular location, has been estimated to be equal to 4.80μSv/yearat the PGstack and 0.34μSv/yearin the suburbs of Huelva, 0.5 km from the pile. The calculated dosesare well below the limit established for the general population (1 mSv/year). According to theseoutcomes, the risk associated to the fugitive PG particles in the city of Huelva is negligible.However, this study lacked the access to several specific parameters, regarding both the site andthe simulated particles. There are also concerns about the accuracy of the meteorological data,which has high significance in the air dispersion models. Hence, more work is recommended inthe case of the availability of more exact data.IncomingObjectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructur