## 4 Conclusions  
Investigating uranium transport in desert environments--specifically through fragmentation and dissolution--provides valuable insights into how uranium behaves in arid ecosystems. The torrential rains characteristic of the sierras in deserts transport uranium from uraniferous minerals in the Pena Blanca area towards the Laguna del Cuervo. This process results in the coexistence of both anomalously high and low uranium concentrations at locations not far from the floodplain.  
Uranium adsorption and transport simulation experiments clarified these phenomena by using liquid scintillation, microwave plasma atomic emission spectrometry, scanning electron microscopy, and synchrotron radiation techniques to analyze uranium speciation in matrices. Different scenarios were implemented to simulate: (1) dissolution near the sources (UN experiments) followed by adsorption; (2a) dissolution of the mineral by the feed solution and subsequent adsorption; and (2b) transport of mineral fragments along the column, with minimal or no adsorption of the eventually dissolved fraction (URP experiments).  
The uranium concentration in the sediments from the various experiments exhibited the following sequence: C_URP \(<\) C_UN \(<<\) Batch. Simulations involving solution flow through a uranium mineral horizon in the sediments suggest the transport of mineral fragments by the feed solution. The findings also emphasize the role of sediment characteristics--fine sediments may enhance uranium adsorption, while coarser materials can facilitate its physical transport.  
The results of the various simulations suggest that fragmented mineral transport is the predominant type of transport in the SPB profile, accompanied by eventual dissolution and subsequent uranium adsorption in the sediments. These findings account for the low uranium concentration values observed in the lower zones of the SPB profile and the floodplain. This observation does not preclude the possibility that, in the future, the mineral fragments may dissolve and subsequently contribute to localized areas with uranium concentrations comparable to those found in the mud. This poses potential risks to nearby water sources and ecosystems.  
Finally, this study underscores the need for a holistic approach to understanding uranium mobility in desert landscapes, considering both fragmentation and dissolution to improve monitoring and management strategies for uranium contamination.  
Conceptualization, V.P.-R., I.A.R.-C. and M.E.M.-C.; Formal analysis, V.P.-R., J.G.C.-T., R.M.C.-L., C.H.-H. and M.R.-V.; Funding acquisition, M.E.M.-C.; Investigation, V.P.-R., B.P.C.-L., J.G.C.-T., C.H.-H., F.F.-G., [PERSON]-G., [PERSON]-S., [PERSON]-C., [PERSON]-P., [PERSON]-F. and [PERSON]-O.; Methodology, V.P.-R., G.G.-S., B.P.C.-L., J.G.C.-T., M.R.-V., G.V.-O. and R.M.C.-L.; Project administration, M.E.M.-C.; Supervision, M.E.M.-C.; Validation, M.R.-V. and G.G.-S.; Writing--original draft, V.P.-R., [PERSON]-L., [PERSON] and [PERSON]-[PERSON]; Writing--review and editing, V.P.-R., [PERSON], [PERSON]-[PERSON] and M.E.M.-C. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the CONAHCYT research project, funding number CF/2019 10853.  
Not applicable.  
Data Availability Statement: Data are contained within the article and associated materials in Appendices A and B.  
**Acknowledgments:** The authors would like to express their gratitude to CONACYT for funding the CF/2019 10853 project. We extend our thanks to [PERSON] and [PERSON] from CIMAV, as well as to [PERSON] from Diamond Light Source for their technical and scientific support. Finally, the XAS measurements were conducted as part of proposal SP31873 at Diamond Light Source in the UK. We sincerely appreciate their assistance.  
**Conflicts of Interest:** The authors declare no conflicts of interest.