{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T04:40:09Z","timestamp":1774240809694,"version":"3.50.1"},"reference-count":110,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2019,5,27]],"date-time":"2019-05-27T00:00:00Z","timestamp":1558915200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100008530","name":"European Regional Development Fund","doi-asserted-by":"publisher","award":["NORTE-01-0145-FEDER-000017"],"award-info":[{"award-number":["NORTE-01-0145-FEDER-000017"]}],"id":[{"id":"10.13039\/501100008530","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/AGR\/04033\/2019"],"award-info":[{"award-number":["UID\/AGR\/04033\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["UID\/QUI\/00616\/2019"],"award-info":[{"award-number":["UID\/QUI\/00616\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100011929","name":"Programa Operacional Tem\u00e1tico Factores de Competitividade","doi-asserted-by":"publisher","award":["POCI-01-0145-FEDER-006958"],"award-info":[{"award-number":["POCI-01-0145-FEDER-006958"]}],"id":[{"id":"10.13039\/501100011929","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Water"],"abstract":"<jats:p>There is currently some controversy in the scientific community regarding the efficiency of the water\u2013rock interaction process in the contamination of radon in groundwater. In this study, some difficulties were found in the sampling phase. Many of the water collection points are used for human consumption. As such, some municipalities did not want to collaborate. When this natural contaminant is undetectable to the human sense and may cause pulmonary neoplasms in the long term, it is difficult to obtain collaboration from the municipalities concerned. To overcome this controversy, it is important to understand that geogenic, climatic, hydrological, and topographic features may contribute to the effective transfer of radon from rocks to groundwater. In brief, this new approach combines the radon transfer from the geological substrate to the groundwater circulation through hierarchic agglomerative clustering (HAC) and partial least squares-path modeling (PLS-PM) methods. The results show that some lithologies with higher radon production may not always contribute to noticeable groundwater contamination. In this group, the high-fracturing density confirms the recharge efficiency, and the physical-chemical properties of the hydraulic environment (electric conductivity) plays the main role of radon unavailability in the water intended for human consumption. Besides, the hydraulic turnover time of the springs can be considered an excellent radiological indicator in groundwater. In the absence of an anomalous radioactive source near the surface, it means that the high-turnover time of the springs leads to a low-radon concentration in the water. Besides linking high-risk areas with a short period required to free local flow discharges, this study exposes the virtues of a new perspective of a groundwater contamination risk modeling.<\/jats:p>","DOI":"10.3390\/w11051107","type":"journal-article","created":{"date-parts":[[2019,5,27]],"date-time":"2019-05-27T11:19:27Z","timestamp":1558955967000},"page":"1107","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["An Assessment of Groundwater Contamination Risk with Radon Based on Clustering and Structural Models"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7140-9036","authenticated-orcid":false,"given":"Lisa","family":"Martins","sequence":"first","affiliation":[{"name":"Department of Geology, Centre for Research and Technology of Agro-Environment and Biological Science, University of Tr\u00e1s-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7392-2255","authenticated-orcid":false,"given":"Alcides","family":"Pereira","sequence":"additional","affiliation":[{"name":"Department of Earth Sciences, Centre for Earth and Space Research of the University of Coimbra, Rua S\u00edlvio Lima, Polo II University of Coimbra, 3004-531 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2465-2698","authenticated-orcid":false,"given":"Alcino","family":"Oliveira","sequence":"additional","affiliation":[{"name":"Department of Geology, Geosciences Centre of the University of Coimbra, University of Tr\u00e1s-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6124-1578","authenticated-orcid":false,"given":"Ant\u00f3nio","family":"Fernandes","sequence":"additional","affiliation":[{"name":"Centre for the Research and Technology of Agro-Environment and Biological Science, University of Tr\u00e1s-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9486-7160","authenticated-orcid":false,"given":"Lu\u00eds Filipe","family":"Sanches Fernandes","sequence":"additional","affiliation":[{"name":"Department of Civil Engineering, Centre for the Research and Technology of Agro-Environment and Biological Science, University of Tr\u00e1s-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2399-5261","authenticated-orcid":false,"given":"Fernando Ant\u00f3nio Leal","family":"Pacheco","sequence":"additional","affiliation":[{"name":"Department of Geology, Chemistry Research Centre, University of Tr\u00e1s-os-Montes e Alto Douro, 5001-801 Vila Real, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2019,5,27]]},"reference":[{"key":"ref_1","unstructured":"Council Directive 2013\/51\/Euratom (2013). 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