Nikou Hamzehpour , Gholam Reza Mahdavinia , Mehdi Rahmati
{"title":"Sand sheets—the major dust source in the western Lake Urmia playa—A comprehensive study of the soil-dust properties and stabilization","authors":"Nikou Hamzehpour , Gholam Reza Mahdavinia , Mehdi Rahmati","doi":"10.1016/j.ijsrc.2024.04.003","DOIUrl":null,"url":null,"abstract":"<div><p>Climate change accelerated by anthropogenic activities has led to the shrinkage and eventually disappearance of salt lakes all over the world. Gradual desiccation of Lake Urmia (LU) in northwestern Iran, as one example of desiccating lakes, has led to the exposure of the lakebed sediment with enormous dust emission potential in some parts. Sand sheets of western LU are identified as one of the major contributors to aerosols in this region. Yet, dust blown from this area is not well characterized. The aims of the current study were, therefore, to comprehensively investigate the origin of dust from sand sheets; the characteristics of dust and temporal variability of the aerosol and to test the effectiveness of the application of sodium alginate (SA) on soil crusting and stabilization. Soil samples were collected from the two prevailing soil types from sand sheets in August 2020. Dust samples were also collected during four time periods: July and August (the beginning of the dry season); October and November (the beginning of the wet season). Using SA with varying concentrations and different methods of application, the effectiveness of the induced crusts was investigated. Authigenic aragonite minerals with elongated needle shapes were found to be the major constituent of the soil and dust samples. Temporal variability of the dust characteristics and their elemental correlation to dust sources revealed that while dust source 1 (DS<sub>1</sub>) with higher clay, salt, and silt contents contribute more to the dust composition from July to August (<em>R</em><sup>2</sup> > 0.75 for DS<sub>1</sub> versus <em>R</em><sup>2</sup> > 0.58 for DS<sub>2</sub>), dust source 2 (DS<sub>2</sub>) with less salinity and higher sand content becomes the major contributor to dust composition from October to November (<em>R</em><sup>2</sup> > 0.91 for DS<sub>2</sub> versus <em>R</em><sup>2</sup> > 0.75 for DS<sub>1</sub>). Results of stabilizing both DS<sub>1</sub> and DS<sub>2</sub> showed that SA-induced crusts on DS<sub>1</sub> are more stable than DS<sub>2</sub> due to the presence of higher clay, silt, salt, organic matter, and lower aragonite minerals. SA-induced crusts by a compaction method significantly performed better than a spray of SA on either dry (DSp) or soil at its optimum water content (WSp) at all concentrations. Nevertheless, spray methods are more feasible at the field scale and in both DSp and WSp methods, SA<sub>0.5</sub> improved the crust thickness. Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) along with thermogravimetric analysis (TGA) confirmed the remaining SA on the soil surface three months after its application indicating the effective performance of the SA solution in sand sheets stabilization. Hence, its application at the field scale could possibly reduce aerosol release and transport to surrounding areas.</p></div>","PeriodicalId":50290,"journal":{"name":"International Journal of Sediment Research","volume":"39 3","pages":"Pages 355-374"},"PeriodicalIF":3.5000,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1001627924000386/pdfft?md5=5e37c19304de4ff11ae48bf8dd7bfa5d&pid=1-s2.0-S1001627924000386-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Sediment Research","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1001627924000386","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
Climate change accelerated by anthropogenic activities has led to the shrinkage and eventually disappearance of salt lakes all over the world. Gradual desiccation of Lake Urmia (LU) in northwestern Iran, as one example of desiccating lakes, has led to the exposure of the lakebed sediment with enormous dust emission potential in some parts. Sand sheets of western LU are identified as one of the major contributors to aerosols in this region. Yet, dust blown from this area is not well characterized. The aims of the current study were, therefore, to comprehensively investigate the origin of dust from sand sheets; the characteristics of dust and temporal variability of the aerosol and to test the effectiveness of the application of sodium alginate (SA) on soil crusting and stabilization. Soil samples were collected from the two prevailing soil types from sand sheets in August 2020. Dust samples were also collected during four time periods: July and August (the beginning of the dry season); October and November (the beginning of the wet season). Using SA with varying concentrations and different methods of application, the effectiveness of the induced crusts was investigated. Authigenic aragonite minerals with elongated needle shapes were found to be the major constituent of the soil and dust samples. Temporal variability of the dust characteristics and their elemental correlation to dust sources revealed that while dust source 1 (DS1) with higher clay, salt, and silt contents contribute more to the dust composition from July to August (R2 > 0.75 for DS1 versus R2 > 0.58 for DS2), dust source 2 (DS2) with less salinity and higher sand content becomes the major contributor to dust composition from October to November (R2 > 0.91 for DS2 versus R2 > 0.75 for DS1). Results of stabilizing both DS1 and DS2 showed that SA-induced crusts on DS1 are more stable than DS2 due to the presence of higher clay, silt, salt, organic matter, and lower aragonite minerals. SA-induced crusts by a compaction method significantly performed better than a spray of SA on either dry (DSp) or soil at its optimum water content (WSp) at all concentrations. Nevertheless, spray methods are more feasible at the field scale and in both DSp and WSp methods, SA0.5 improved the crust thickness. Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) along with thermogravimetric analysis (TGA) confirmed the remaining SA on the soil surface three months after its application indicating the effective performance of the SA solution in sand sheets stabilization. Hence, its application at the field scale could possibly reduce aerosol release and transport to surrounding areas.
期刊介绍:
International Journal of Sediment Research, the Official Journal of The International Research and Training Center on Erosion and Sedimentation and The World Association for Sedimentation and Erosion Research, publishes scientific and technical papers on all aspects of erosion and sedimentation interpreted in its widest sense.
The subject matter is to include not only the mechanics of sediment transport and fluvial processes, but also what is related to geography, geomorphology, soil erosion, watershed management, sedimentology, environmental and ecological impacts of sedimentation, social and economical effects of sedimentation and its assessment, etc. Special attention is paid to engineering problems related to sedimentation and erosion.