Nanomaterials, i.e., those materials which have at least one dimension in the 1–100 nm size range, have produced a new generation of technologies for water purification. This includes nanosized adsorbents, nanomembranes, photocatalysts, etc. On the other hand, their uncontrolled release can potentially endanger biota in various environmental domains such as soil and water systems. In this review, we point out the opportunities created by the use of nanomaterials for water remediation and also the adverse effects of such small potential pollutants on the environment. While there is still a large need to further identify the potential hazards of nanomaterials through extensive lab or even field studies, an overview on the current knowledge about the pros and cons of such systems should be helpful for their better implementation.

Riprap resistance is a widely used solution for protecting earth dams from erosion but riprap can be displaced on the dam surface. This study examines the stability of riprap in the Taleqan Dam, Iran using rock mechanical tests and InSAR technology. Uplift of dam stairs and erosion of the riprap material have been observed during field work at the study site, and samples have been gathered from three rock categories. The purpose of this study is to explore the factors influencing the deformation of the Taleqan Dam. The InSAR method has been employed for monitoring surface deformation and the Los Angeles ASTM C test was used to establish the cause of dam deformation. InSAR analysis was carried out using Sentinel-1A images from 2014 to 2019. The results revealed subsidence at an average rate of 4 mm/yr over that period. The results of Los Angeles ASTM C indicated that the Andesite riprap was more easily eroded, has a relatively low durability and specific weight, and low resistance erosion. Therefore it is unsuitable for use as a protection layer for the crest and lower sectors of the riprap. It can also be concluded that the inadequate durability of certain rock materials may potentially cause weathering, depression, reduced thickness and displacement of the riprap.

Dam stability is one of the most essential geotechnical engineering challenges. Studying the structural behavior of dams during their useful life is an essential component of their safety. Terrestrial surveying network approaches are typically expensive and time-consuming. Over the last decade, the interferometric synthetic aperture radar (InSAR) method has been widely used to monitor millimeter displacements in dam crests. This research investigates the structural monitoring of the Lar Dam in Iran, using InSAR and the terrestrial surveying network technique to identify the possible failure risk of the dam. Sentinel-1A images taken from 5 February 2015 to 30 September 2019 and TerraSAR-X (09.05.2018 to 16.08.2018) images were analyzed to investigate the dam’s behavior. The InSAR results were compared with those of the terrestrial surveying network for the period of 1992 to 2019. The Sentinel-1 results implied that the dam on the left side moved over 8 mm/yr. However, the pillars to the left abutment indicated an uplift, which is consistent with the TerraSAR-X results. Also, the TerraSAR-X data indicated an 8 mm displacement over a three-month period. The terrestrial surveying showed that the largest uplift was 19.68 mm at the TB4 point on the left side and upstream of the body, while this amount was 10 mm in the interferometry analysis for the period of 2015–2020. The subsidence rate increased from the middle part toward the left abutment. The geological observations made during the ninth stage of the terrestrial surveying network indicate that there was horizontal and vertical movement over time, from 1992 to 2019. However, the results of the InSAR processing in the crown were similar to those of the terrestrial surveying network. Although different comparisons were used for the measurements, the difference in the displacement rates was reasonable, but all three methods showed the same trend in terms of uplift and displacement.