Loss Of Sand Research Articles

Evaluation of wind erosion resistance of EICP solidified desert sand based on response surface methodology

Wind erosion is the primary cause of land desertification in arid and semi-arid regions. Enzyme-induced carbonate precipitation (EICP) will produce a solid coating on the surface of desert sand that inhibits wind erosion. Three critical variables for EICP treatment, including enzyme-cementation ratio A, cementation solution concentration B, and spraying volume of reaction solution C, were evaluated with three wind erosion-resistance indexes (surface strength, calcium carbonate content, and solidified layer thickness) of desert sand, and further optimized with the response surface methodology (RSM). The mass loss of the EICP-treated desert sand was studied by wind tunnel tests with wind speeds of 8–14 m/s and erosion times of 0–30 min. Material composition and microstructure of the EICP precipitates were investigated with X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Results indicate that the three wind erosion-resistance indexes tend to rise with greater A and B values followed by a decline while monotonically increasing with C but the increments decrease when C>5 L/m2. The optimal solidification effect was reached when A=1.082:1, B=1.282 mol/L and C=8.70 L/m2, which corresponds to a maximum wind speed of 14 m/s for solidified desert sand. Large amounts of calcite crystals were produced in the EICP-treated sand and filled soil pores. The particle contacts transform from point contact to surface contact and the enhanced particle bonding induces a more compact soil skeleton. The above experiment evidence corresponds to increased surface strength and wind erosion resistance. The results of this study will provide an experimental foundation for the application of EICP technology to enhance wind erosion resistance of desert sands.

Sandy beach erosion: impacts and adaptation strategies in Thailand

AbstractThis paper focuses on sandy beach erosion as a result of rising sea levels, including adaptation option analysis in Thailand. Twenty-seven beaches in the provinces of Rayong, Nakhon Si Thammarat, and Trang were selected as study areas with high rates of erosion. The major scientific challenge entailed determining the relevance and contribution of rising sea levels (including storms) to beach erosion. The SimCLIM/CoastCLIM model was utilized to forecast changes in sea level and shoreline during the period of 1940–2100. A cost–benefit analysis (CBA) was conducted to evaluate adaptation options in terms of economics. The main outcome was a relevant contribution to knowledge on sea-level rise (including storm alteration) and its effects on sandy beach erosion, in terms of loss of sandy beach area and population migration. The results indicate that Mae Phim, Ban Ko Fai, and Pak Meng beaches are all threatened by erosion, and 8.02 and 23.26% of the erosion are attributed to storms and sea-level rise. Future scenarios (in 2100) showed 124.38 cm rise in 2100 sea level (compared to the 1995 baseline) leading to 507.90 m of eroded beaches, 2.15 km2 of sand loss and 873 people migrating. The results of CBA show that scenario 2 (beach nourishment) is not proper for application as an adaptation option on sandy beaches with high amounts of erosion (Ban Ko Fai and Pak Meng beach), while the option of beach nourishment alone is likely to be applied on Mae Phim beach due to its lower rate of erosion.

Influences of the Decomposition Atmosphere and Heating Rate on the Pyrolysis Behaviors of Resin Sand

The pouring of sand casting is accompanied by severe heat conduction, and there is an urgent need to investigate the pyrolysis properties of foundry sand. The main purpose of this study was to investigate the pyrolysis behaviors of resin sand, including precoated sand (PCS), hot box sand (HBS), and warm box sand (WBS), at heating rates of 20 °C/min, 30 °C/min, and 40 °C/min in nitrogen and air atmospheres. The mass loss of the resin sand was monitored continuously with a simultaneous thermal analyzer, and the kinetic parameters of the resin sand were calculated based on the Coats–Redfern method and thermal data. The average mass loss of the resin sand during pyrolysis was 3.03%, which was much smaller than that of the other sands. The volatile release characteristic index of resin sand could not be calculated based on this concept. To solve this issue, the term Tstv/mloss was established, and its value was determined. With increasing heating rates from 20 °C/min to 30 °C/min and from 30 °C/min to 40 °C/min, the mass losses of the resin sand increased by 0.79% and 0.64%, respectively, and the volatile release characteristic indices of the resin sand increased by 3.8 × 10−10 and 1.06 × 10−9, respectively. In addition, the mass losses and volatile release characteristic indices of resin sand in an air atmosphere were greater than those in a nitrogen atmosphere. With increasing heating rate, the activation energy of the resin sand decreased in a nitrogen atmosphere. The findings concerning the thermal decomposition behaviors of resin sand provided a theoretical basis for the pouring step of the sand casting process.

Particle Flow Simulation of Sand Loss through Cracks in Segmental Linings

Particle Flow Simulation of Sand Loss through Cracks in Segmental Linings

Storm and tidal interactions control sediment exchange in mixed-energy coastal systems.

Storms can have devasting effects on shorelines, causing flooding and the destruction of property and infrastructure. As global warming and the frequency and magnitude of tropical storms increase, barrier islands comprising 10% of the world's coast may undergo significant change caused by beach erosion, loss of dunes, and formation of washovers and tidal inlets. Understanding how storms affect sediment transport at tidal inlets is an understudied subject that directly influences barrier island erosional-depositional processes and long-term sediment budgets. This study models hydrodynamics and sediment transport at a conceptualized mixed-energy, mesotidal inlet system using 10 synthetic storm tracks. We investigate the provenance and the role of various storm characteristics and timing between the peak storm surge and high tide on sediment fluxes for different grain sizes. We find that most storms (38 of 40) cause a net import of sediment into the basin that is sourced primarily from the updrift and downdrift nearshore and secondly from the ebb-delta. Very little sediment comes from inlet channel scour. Cumulative (net) transport correlates well with peak significant wave height because wave height influences bottom shear stresses and sediment suspension on the ebb-tidal delta and in the nearshore. The duration of the storm surge also correlates with net transport because it controls the period of flood-directed currents. Our findings help explain the formation of flood deltas inside tidal inlets and the formation of sand shoals in backbarrier regions. Storm-induced enlargement of these deposits represents a permanent long-term loss of sand from barrier islands that will lead to erosion.

Analytical method for lateral capacity of pile foundations under vertical loads considering asymmetric scour hole in sand

Offshore pile foundations are generally subjected to lateral and vertical loadings. The loss of sand around piles because of scouring reduces the soil resistance and effective depth of pile foundations. Moreover, scour holes are asymmetric both physically and in finite element simulations, which may change the effect of vertical loads on the lateral capacity of pile foundations. In this study, we propose a nonlinear analytical method to estimate the lateral capacity of pile foundations in sand considering vertical loads and asymmetric scour holes. The p–y curve, frictional resistance, shaft resistance moment, and pile-end resistance were revised considering an asymmetric scour hole. The accuracy of the analytical method was validated through comparison with experimental results. The results show that the P–Δ effect caused by vertical loads increases with increasing active scour depth, positive scour depth, active scour width, and positive scour width; and decreasing active and passive scour slopes. The most adverse lateral loading direction was 90° to the water direction with the asymmetric scour hole.

Tourism impact on coastal erosion: a case of Alanya

Sandy coasts are constantly exposed to rapid coastal change. Projected climate change caused by Changes in sea level rise, wave circumstances, and storm occurrences will increase erosion rates, exposing these areas to increasingly hazardous conditions. For coastal management purposes, it is important to monitor and measure these changes. Erosion of sandy and pebbly beaches and their ecosystems. The loss of sand and gravel is not only due to the rise in sea level and the force of waves resulting from storms, which will intensify due to climate change. There is a new important factor of human intervention and impact on the beaches that must be mentioned and verified as to how the effect is in the long term with the increase in tourism in the coastal areas, especially in areas of a tourist nature. The amount of sediment that each individual transports from the coastal beaches in the Alanya region.
 In the experiment, we Collected samples of sand and gravel from different locations on the coast to be surveyed. Classifying the collected samples by means of sieve analysis. Executing the project by going to the sites of sand samples that were analyzed in different periods by collecting samples (collecting sand attached to the bodies of people of different sizes in basins Testing). The thesis also answers Identify the eroded beach by relating the average number of locals and foreigners who come to the project area for a year and use the coast with the data collected during the project.

Large scale study on influence of biopolymer to mitigate wind induced sand erosion with durability analysis

The desertification is a serious threat that affects the sustainable agriculture, ecosystem, and economic progress of society. There is an urgent need for an environment friendly, cost-effective, durable, and practical approach to mitigate wind induced erosion. The present study introduces a novel approach through large scale testing using biopolymer, including durability analysis. The research investigates the influence of biopolymer namely Acacia gum (AG) to mitigate wind induced sand erosion. For the experimental setup, rectangular trays (180 cm × 60 cm × 15 cm) containing 11 erosion pins (three rows along the length, in a staggered way at equal spacing) have been filled with desert sand. Solutions have been prepared using biopolymer concentrations (1%, 2%, and 3%) mixed with water. The prepared solution was sprayed onto specimens and the treated samples were then left for air drying (7 and 28 days curing period). The study has been performed on summer days with an average temperature of 40 °C. After biotreatment, the specimens were examined in a wind tunnel at variable wind speeds of 6, 10, and 15 m/s to measure sand loss rate (SLR) for different wind intervals (i.e., 1, 2, 3, 4, and 5 min). Surface strengths were assessed using a pocket penetrometer. To check the durability of biotreated sand samples, 28 days curing period samples, with all biopolymer percentages have gone through 5 wetting and drying cycles (WDC). After the last WDC, samples were left again for 28 days and then experienced all tests. The minimum and maximum SLR for desert sand ranged from 17 kg/m² at 6 m/s and 1 min duration to 123 kg/m² at 15 m/s and 5 min duration respectively. Instead biotreated sand samples presented negligible SLR. Surface strength increased with increasing biopolymer concentration and a curing period. The maximum surface strength was 334.47 kPa recorded at 3% concentration during the curing period of 28 days. Further analysis involving SEM, EDX, and PXRD, confirmed sand particle bonding. For surface strength, 3% biopolymer concentration consistently produced positive outcomes, even after undergoing 5 WDC.

Comparative Experimental Study of Geotube Groins and Mixed Clay–Geotube Groins under Various Flow Conditions

During the cofferdam construction of the toe reinforcement project at the Qiantang River Estuary, the scouring of the riverbed at the groin head often led to the collapse of geotube groins due to strong tidal currents. Based on field experience, employing a combination of clay and geotubes proved to be a more effective solution to this problem. This study adopted a flume model experiment to investigate the scouring and deposition around geotube groins and mixed clay–geotube groins. The results indicated that the influence of tidal surges on geomorphic changes surrounding the groins was more pronounced during spring tides than during neap tides. Under the same flow conditions, the scour depth at the head of the geotube groin was notably deeper than that of the mixed clay–geotube groin. Additionally, sediment silting behind the mixed clay–geotube groin was significantly greater than that behind the geotube groin. The clay component of the mixed clay–geotube groin served to mitigate the head scour, enhancing the overall structural stability to a certain extent. The geotube groin, with its surrounding scour pits expanding over time, experienced increasing tensile strain. This resulted in the rupture of the geotextile material, the loss of internal sand and, ultimately, groin collapse. It was found that mixed clay–geotube groins were better suited for cofferdam construction in strong tidal estuaries compared to geotube groin alternatives.

Experimental Research on Erosion Characteristics of Ecological Slopes under the Scouring of Non-Directional Inflow

Considering environmental sustainability, ecological embankments are often adopted in rivers, which benefit both the erosion resistance and the ecological balance of the bank. In this paper, the effectiveness of different types of dominant grass species in ecological slope protection and their impact mechanisms, as well as the impact of non-directional inflow on erosion characteristics, were investigated. Based on the principle of similarity theory in hydraulic modeling and the characteristics of flood erosion in riverbanks, a test model system for hydraulic ecological simulation was designed, including a vegetation bank slope and channels. Three types of dominant grass species were selected, and 12 series of erosion experiments were conducted in the grassed slope of the test model. Three types of root–soil composites and a reference plain soil were involved in the tests, and soil mechanical indicators such as shear strength were collected. Experimental results show that root–soil composite is a special elastic–plastic material, which provides additional cohesive force to the soil due to its root consolidation and reinforcement effects, Δc. The shear strength index reflecting soil cohesion was increased by 15% to 20%. The primary factor affecting slope erosion is the flushing velocity, and both the average erosion depth and the unit soil erosion loss present an exponential function with respect to this factor, while presenting a linear function with the angle of incoming flow. Compared with the plain soil slope, the ecological slope could decrease erosion significantly. The sand loss of the ecological slope is only 50~60% that of the plain soil slope as the flushing velocity is 3–4 m s−1. In vertical flushing, the sand loss in the plain soil slope is 1.73–2.43 times that of the ecological slope. This research might provide technical support for the anti-scourability design of the ecological embankment.

APPLICATION OF CROSS-SHORE MORPHOLOGICAL MODELS FOR PERCHED BEACHES

Perched beaches are beaches that are supported at the offshore side by a submerged structure. The advantages of such design schemes are that less dredged material is required, and more protected waters are created in front of the beach. Apart from the hydraulic stability of the submerged structure itself, the stability of the beach needs to be studied in order to make sure it fulfils the requirements during its design lifetime. Aspects that play a role here are the expected sand losses over the submerged structure, the (dynamic) equilibrium profile of the beach and the performance during storm conditions. In order to study the morphological responses of such beaches, morphological models should be applied that can take into account the influence of the submerged structure. This paper discusses two cross-shore models that have been used to study a large perched beach project that is under construction in unusually deep waters, severe wave climate (mostly unidirectional) and small tidal range. The models applied are SBEACH (Larson et al., 1989) and CROSMOR (Van Rijn et al., 2003). First the models are validated and calibrated hydrodynamically by comparing the wave transmission and wave setup with measurements from 2D flume tests. Next, the models have been used to predict the future cross-shore development of the beach.

Towards a solid-fluid territory: Sand dredging, volumetric practices, and earthly elements

Since 2020, although Taiwan has expelled dredgers and sand-transporting vessels from areas under its control, it has failed to stop sand loss. Marine researchers have noted that such issues problematise the ontology that underlies work on territory and ocean governance, wherein the ocean is regarded as a flat space that can be zoned and territorialised. Attention has thus shifted from considering the ocean as a flat terrestrial legal boundary to regarding it as a dynamic, volumetric entity, constantly shaped by the distinct qualities of the ocean and human endeavours. While such thought-provoking work offers crucial insight into our understanding of territory, its emphasis on the distinct qualities of water unconsciously reinforces the distinction between the land and the sea. Informed by recent materials-related social studies, this paper proposes the notion of the marine environment as a solid-fluid territory that foregrounds the importance of planetary dynamic geological processes. I argue that in this sense, territory is always involved in the governance of solid-fluid transitions in different voluminous contexts. The solid-fluid territory, I suggest, is characterised by three elements: solid-fluid transitions, resources, and volumetric practices. With reference to the controversy over sand mining in the Taiwan Strait, this paper reveals that while various geotechnologies are deployed to manage solid-fluid materials, state security practices often complicate our understanding of these shifting, dynamic geological processes and challenge human boundary-making. Therefore, geopolitics must acknowledge the nuances resulting from such solid-fluid movements and transitions, as well as their impacts on territorial issues.

Experimental Study on Pore Pressure Variation and Erosion Stability of Sandy Slope Model under Microbially Induced Carbonate Precipitation

With the development of a free trade port on Hainan Island, the construction of tourist roads around the island is currently underway. However, the weather conditions on Hainan Island, which include strong typhoons and rainstorms, pose challenges for the construction of highway-cutting slopes on the coastal weak sandy terraces. These slopes are susceptible to sand loss and erosion from rainfall. To address this issue, MICP green spray irrigation solidification technology is used to strengthen the sandy cutting, and pore water pressure monitoring is carried out on the slope model during MICP solidification and rainfall scour. Combined with the model pore water pressure and flow slip failure pattern, a dynamic analysis was conducted. The results show that MICP sprinkler irrigation technology can solidify the surface of the slope model in a short time, and after three sets of rotation reinforcement, the model achieved a cementation depth of 4 cm, with a well-reinforced surface and closely connected sand samples. Under the erosion effect of simulated rainfall intensity, the sand loss of the slope was weakened, without damage to the sand binding, and the integrity was enhanced. The cementation between the sand grains facilitated the conversion of most of the rainfall into runoff. However, despite these efforts, the slope eventually slid after 150 s. During the sliding process, the leading edge of the slope model lost sand and became unloaded, and the failure mode was graded a creep slip failure. Finally, the slope was divided into several blocks due to the continuous expansion of cracks following the slope failure. The erosion stability of the sandy slope under heavy rains was optimized and the sand loss was prevented effectively. This study proposes a new method of MICP remediation techniques that serve as a new test basis for the practical application of MICP technology in engineering projects.

Desert sand stabilization using biopolymers: review

Wind-driven sand erosion is the leading primary reason of earth deterioration in dry lands and a major global issue. Desert dust emissions and topsoil degradation caused by wind pose a global danger to the ecosystem, economy, and individual health. The aim of the current study is to critically analyze the different types of biopolymers and their interaction mechanism with sands for desert sand stabilization. Extensive experimental data with different percentages of biopolymers has been presented on various wind erosion studies using wind tunnel testing and their control rate on desert sand stabilization. Also, studies related to evaluating the engineering properties of sand using biopolymers were analyzed. Other biological approaches, namely Microbial-induced calcite precipitation (MICP) and Enzyme-induced carbonate precipitation (EICP), have been discussed to regulate wind-driven sand erosion in terms of percentage calcite formation at different compositions of urea and calcium chloride. Comparative analysis of MICP and EICP with biopolymer treatment and their limitations have been discussed. Biopolymers are not only demonstrated adeptness in engineering applications but are also helpful for environment safety. Biopolymers are suggested to be novel and nature-friendly soil-strengthening material. This review focuses on the fundamental mechanisms of biopolymer treatment to reduce wind-driven sand loss and its future scope as a binder for sand stabilization. The mechanism of soil-biopolymer interaction under various soil conditions (water content, density, and grain size distribution) and climatic circumstances (drying-wetting cycles) needs to be explored. Furthermore, before applying on a large scale, one should evaluate sand-biopolymer interaction in terms of durability and viability.

Measured Fate of Beach Nourishment Sand

Houston, J.R., 2023. Measured fate of beach nourishment sand. Journal of Coastal Research, 39(3), 407–417. Charlotte (North Carolina), ISSN 0749-0208. The fate of sand placed over a 20-year period in one of the largest series of beach nourishment projects ever conducted in the United States is determined by using direct measurements of elevation vs. distance from dunes to closure depth. Four projects placed 11.25 million m3 of sand from 1998–2017 on a 28.8-km-long shoreline at Panama City on Florida's Gulf of Mexico coast. Profile measurements were available in 1996 following Hurricane Opal and in 2018 after Hurricane Michael, one of the largest hurricanes to strike the United States, which came ashore only 30 km from Panama City beaches. The profiles were about 300 m apart within the project template and extended down to closure depth. After about 20 years, 87 ± 3% of the nourishment sand remained on profiles. Some sand used for nourishment was dredged within closure depth along a 3.6-km section and resulted in sand loss of 4% ± 1% as sand partially refilled the dredged holes. About 9% ± 3% was lost to longshore transport out of the project area. Calculations based on the equilibrium profile concept used in U.S. beach nourishment design predicted beaches should have widened 30.9 m ± 0.9 m and profiles raised 0.69 m ± 0.10 m due to the measured volume of sand remaining on profiles from the start of beach nourishment in 1998 to November 2018 after Hurricane Michael. The measured change in beach width was 32.4 m ± 4.0 m, and the rise was 0.66 m ± 0.05 m. The rise of 0.66–0.69 m is comparable to the 0.81 m mean sea-level rise by the year 2100 projected by the Intergovernmental Panel on Climate Change for its worst-case temperature scenario.

Application of Geomatic Techniques for the Assessment of Anthropogenic Changes in the Urban Beaches of “La Magdalena” (Santander, Spain)

Since the 1970s, dredging sands have been poured onto the embayed beaches of La Magdalena in the western mouth of the estuarine Bay of Santander (N Spain) in order to increase beach width. Up until the year 2000, the sands were systematically fed by a trailing suction dredge, which was later replaced by truck sand transfers from the surplus sands of the western beach to the eastern ones and by mechanical redistribution to create artificial berms. A recent project aimed to solve sand losses after each storm by building two perpendicular breakwaters about 620 m apart. The eastern breakwater was built in the early summer of 2018, and wave storms in November 2018, February 2019, October 2020 and the last days of 2021 progressively dismantled the reconstructed upper beach areas and eroded other segments. The western breakwater, however, designed to retain the E–W sandy beach drift, was never built. Four photogrammetric restitutions from 2005, 2010, 2014 and 2017 and an aerial LiDAR in 2012 were obtained to better understand the previous topographic distribution of the back and foreshore. Numerous field observations were made, and six field surveys have been performed since 2018 using laser TLS and GNSS, which occurred in November 2018, March 2019, October 2019, March 2020, October 2020 and April 2021. The definitive results of the evolution of the sand loss are presented, a hypothesis is proposed to explain the dynamo-sedimentary trend, in which longitudinal transport dominates promoting the formation in the progress of a new sand beach, and some sustainable solutions are proposed. The results show that the constructive solution has failed to stabilize the beach and that the predictive models that justified it have not coincided with the real dynamic and sedimentary evolution.

Beach reprofiling to improve reproductive output at the world’s largest remaining green turtle rookery: Raine Island, northern Great Barrier Reef

Raine Island is a low-lying reef island located on the outer edge of the northern Great Barrier Reef (nGBR). It is part of the Raine Island National Park (Scientific) and is managed to protect and conserve its exceptional natural, cultural, ecological and scientific values. High amongst these values is Raine Island's importance as the world's largest green turtle (Chelonia mydas) rookery. However, since at least the late 1990s the number of turtle hatchlings produced from nests on the island has significantly declined. The ramifications of reduced hatchling production at Raine Island for the nGBR green turtle population resulted in the establishment of the Raine Island Recovery Project (RIRP), a 5-year $AUS 7.95 million collaborative project involving government, industry and Traditional Owners. A primary aim of the RIRP is to restore viable turtle nesting habitat on Raine Island. Although reduced hatchling production and the potential demise of the nGBR green turtle population are very much an ecological concern, the key to understanding and addressing this management issue is largely geomorphological. Here we detail how the geomorphological attributes of Raine Island contributed to the drop in hatchling output, and outline how understanding and working with the geomorphology and coastal processes at Raine Island have contributed to the mitigation of that decline. In particular, geomorphological investigations established that the sand losses that have reduced the elevation of turtle nesting beaches were unlikely to be replenished by natural processes, and they informed strategic movements of beach sand to increase nesting habitat above tidal inundation which has boosted hatchling production by as much as 640,000 over the past five years. Although this outcome is undoubtedly a success, the future remains challenging as anthropogenic climate change impacts progress.

Effect of warp and weft uniaxial tension on the permeability of sand covered with geotextile

The permeability of sand covered with geotextile is affected by the permeability of geotextile, which is related to the tensile state of the geotextile. Considering the weaving mode of geotextile, the effects of warp tension and weft tension on the permeability of sand covered with geotextile were studied by experiment. Four different specifications of geotextiles were selected for warp and weft tension respectively. The changes of permeability parameters of sand covered with geotextile under non tension, warp and weft tension were measured by vertical permeability instrument, and the effects of warp and weft tension on permeability parameters such as seepage velocity, sand loss and gradient ratio were analyzed. The test results show that the water permeability and anti silting performance of the geotextile increase with the increase of tensile strain, and the soil conservation performance decreases with the tensile strain increasing. Meanwhile, the relationship between permeability and warp tensile strain is not monotonic. When the warp tensile strain 3%, the water permeability and anti silting performance of geotextile are the weakest, and the soil conservation performance is the strongest.

Arbuscular Mycorrhizal Fungi Reduce Cadmium Leaching from Sand Columns by Reducing Availability and Enhancing Uptake by Maize Roots.

To explore the effect of arbuscular mycorrhizal fungi (AMF) on the environmental migration of cadmium (Cd), a sand column-maize system containing 20 mg·L−1 Cd solution was used to investigate the AMF effect on maize growth, Cd uptake by maize, Cd adsorption by sand and Cd leaching loss. The results showed that AMF significantly increased the content of EE-GRSP and T-GRSP by 34.9% and 37.2%, respectively; the secretion of malonic acid, oxalic acid and succinic acid increased by 154.2%, 54.0% and 11.0%, respectively; the secretion of acetic acid and citric acid increased by 95.5% and 59.9%, respectively; and the length, surface area, volume, tip number and cross number of maize roots decreased by 10%, 15%, 17%, 20% and 36.4%, respectively. AMF significantly increased Cd adsorption by sand by 6.2%, Cd uptake by maize by 68.1%, and Cd leaching loss by 84.6%. In the sand column-maize system, 92.3% of the total Cd was adsorbed by sand, 5.9% was taken up by maize and 1.8% was lost due to leaching. Moreover, Cd adsorption by sand was significantly positively correlated with the GRSP content and oxalic acid secretion, and Cd uptake by roots was significantly negatively correlated with Cd leaching loss. Overall, AMF reduced the loss of Cd in the leaching solution by promoting the release of oxalic acid and GRSP, increasing the adsorption of Cd in the sand and fixing the Cd in the plant to the roots.

User Perceptions of the Pleasure Point Seawall in Santa Cruz County, California, U.S.A.

Anderson, R.B.; Carter, O.T.; Pearce, K.G., and Capdevila, L.A., 2022. User perceptions of the Pleasure Point seawall in Santa Cruz county, California, U.S.A. Journal of Coastal Research, 38(4), 828–843. Coconut Creek (Florida), ISSN 0749-0208. Communities up and down the California coast face the looming threat of rising seas, coastal erosion, and shoreline retreat. In this paper, the researchers use anthropological methods and a user survey to explore the social dimensions of the Pleasure Point seawall to assess some of the longer-term implications of coastal armoring in California and the U.S. more broadly. The users surveyed had an overall positive to neutral opinion of a coastal retention structure (in this case a seawall). About 35% had positive opinions of the seawall, 30% had neutral opinions, and 18% had negative opinions. While these results trend positive to neutral, they also reveal divided community opinions about and experiences with the seawall. The open-ended portions of the survey, combined with participant observation and follow-up interviews, add another qualitative dimension to this data. The participants in the survey and research expressed concerns about engineering and ecological issues, whether questions about how long the structure will last or observations/opinions about its impacts on local surf conditions, backwash, and loss of beach sand. Participants also expressed concerns about the social impacts of the seawall, including access issues, crowds, growing risks, problems with increasing numbers of inexperienced users, tourism growth, and fears about gentrification and local displacement. Combined, these insights illustrate how seawalls and other coastal armoring structures can and should be understood as engineered structures with critical social impacts that intersect with their physical, material, and environmental impacts.