Priestas, A.M.; Styles, R., and Bain, R., 2023. Vessel wake impact forces on marsh scarps. Journal of Coastal Research, 39(2), 207–220. Charlotte (North Carolina), ISSN 0749-0208.

A common morphological feature of high-energy coastal plain salt marshes is an erosive scarp separating the marsh platform from the abutting tidal flat. A noted deficiency in the understanding of scarp erosion is a lack of direct wave impact measurements to better constrain the physical processes driving material loss. To measure wave impact forces, load cells were embedded into a scarp face along the Intracoastal Waterway in northern Florida, which is frequented by shallow-draft vessels. The largest impact forces occurred when the mean water surface elevation was just below the midpoint of the scarp and decayed as the mean depth either increased or decreased. Early wave breaking around low tide reduced the direct impact on the scarp, whereas wave reflection around high tide reduced wave breaking and the associated maximum impact force. The sensitivity of impact force to tidal stage suggests that wave energetics (breaking vs. reflection) and scarp morphology (ramp vs. near-vertical surface) combine to produce a force pattern that favors maximum impact around midtide. Regression analysis indicated that the impact pressures were positively correlated with wave power and dynamic pressure, which are primary metrics used to model shoreline erosion. This study argues that the critical threshold for erosion may be refined by evaluating the relationship between impact pressures and marsh resistance, since wave exposure alone does not necessarily initiate erosion.

Helm, C.W.; Bamford, M.K.; Carr, A.S.; Cawthra, H.C.; De Vynck, J.C.; Dixon, M.G.; Quick, L.J., and Stear, W., 2023. Coprolites in cemented Pleistocene deposits on the Cape south coast of South Africa. Journal of Coastal Research, 39(2), 221–233. Charlotte (North Carolina), ISSN 0749-0208.

Ichnology, the study of trace fossils, has the potential to complement information from traditional body fossil studies. Six ichnosites, containing an array of features interpreted with varying degrees of confidence as vertebrate coprolites, have recently been identified on the Cape south coast of South Africa. They are embedded in Pleistocene deposits from Marine Isotope Stage 6 or 5e through Marine Isotope Stage 5a. Bovid, carnivoran, elephant, and reptile origins are inferred. In the majority of cases, vertebrate tracks occur in association with the coprolites. Petrography studies confirm an organic component in all samples, confirming the potential of coprolites to contribute to palaeoenvironmental reconstruction. Although initial palynology and phytolith studies were negative, a diligent search for further sites and further testing may help in realizing this potential. More broadly, the six ichnosites demonstrate the capacity of cemented dune and beach surfaces on the Cape south coast to preserve coprolites in open-air settings, compared with previously known coprolite records from carnivore dens and archaeological sites.

Finkl, C.W. and Makowski, C., 2023. Sigillographic representation of archimorphs and ideograms as related to the BCCS (Biophysical Cross-Shore Classification System) using distributive vexillology in coastal belt cartographic displays. Journal of Coastal Research, 39(2), 234–245. Charlotte (North Carolina), ISSN 0749-0208.

The sigillation (sigilization) process (i.e. creation of flags, signs, symbols, emblems) provides an opportunity to characterize coastal belts via semiotics through rapid visual inspection of satellite imagery. Emblematic depictions of eco-geomorphological units using the Biophysical Cross-Shore Classification System (BCCS) is offered as a semiotic proposal using graphic symbolization based on the development of a unique color scheme for cross-shore archetypes coupled with ideograms that are derived from predefined archimorphs. The resulting sigil formats are amenable to flagging coastal belts in a symbolization that combines color with ideographic displays. Although compliant to larger scale (smaller areas) coastal surveying and mapping efforts, the sigils are most useful in the characterization of smaller scale (larger areas) satellite image views. Derivation of classificatory units at smaller scales requires zoom capabilities to ascertain the dominant archetypes presented in the coastal sigil flags. In addition to the small-scale presentation of coastal belt characteristics as vexillographic overlays on satellite images, the sigillation process allows the amalgamation of colors and ideographs to represent dimorphic and polymorphic sigil combinations, as in the case, for example, of beach-dune (Be-Du) dimorphs or barrier island (beach-dune-wetland-lagoon-wetland; Be-Du-W-L-W) polymorphs. These color-symbol schema allow for a new kind of kinematic coastal classification mapping, where distributive dynamism results in cartographic displays at presentation scales (depending on paper page size) for using the BCCS. These cognitive mapping procedures compliment algorithmic autoclassification via machine interpretation by providing a rapid and simplified means of coastal characterization based on visual ques and cerebral perceptions.

He, Y.; Hu, Y.; Xie, S.; Li, C.; Xu, M., and Chen, X., 2023. Risk and impacts associated with marine carbon sink projects: An example from Guangdong, China. Journal of Coastal Research, 39(2), 246–256. Charlotte (North Carolina), ISSN 0749-0208.

This paper aims to measure the risk and impact of the marine carbon sink project in Guangdong, China. This measurement increases the investors' willingness to participate in development and operation of such projects, and promotes the transformation of a low-carbon economy and society. This research employs triangular fuzzy number and Structural Equation Model to develop the risk measurement model of the marine carbon sink project. The net present value and risk equivalent methods measure the impact of risk factors on the project value and investment decision of the representative project in China. The results showed that: (1) there are certain risks in developing marine carbon sequestration projects, including policy, natural, market, and human behavior risks. The comprehensive risk value is 0.444. (2) Among the different types of marine carbon sink risks, the large ones are those caused by storm surges, invasion of alien species, and unknown ownership of marine carbon sink. (3) The risk of marine carbon sequestration reduces the profitability of its projects. (4) Compared with the traditional net present value method, the risk equivalent method is more in line with the development and operation of marine carbon sink projects. Based on this, combined with the risk characteristics and potential factors of marine carbon sequestration projects, and to promote their sustainable development, this paper has the following suggestions: (1) Strengthen policy evaluation and regulation, and formulate policies and measures in line with the development stage of marine carbon sequestration trading. (2) Strengthen the early warning of natural disasters and formulate targeted disaster prevention, mitigation, and relief plans. (3) Strengthen the dynamic supervision of marine carbon sequestration transactions and formulate emergency plans for market transaction risks. (4) Improve public participation and establish a reward and punishment mechanism for human behavior risk prevention and control.

Youm, C.I.; Morales, J.A.; Doumbouya, M.F.; Garcia-Villalba, E.; Sow, I.S., and Sow, E., 2023. Dynamics, evolution, and facies preservation of a microtidal chenier plain, Joal-Fadiouth (Senegal, West Africa). Journal of Coastal Research, 39(2), 257–265. Charlotte (North Carolina), ISSN 0749-0208.

Cheniers are coarse sediment ridges formed above finer sediments deposited on a tidal flat, the origin and development of which have traditionally been attributed to storm waves. Joal-Fadiouth is a microtidal system located on the southern coast of Senegal (West Africa). This system presents a succession of sandy and shelly ridges displaying a facies architecture consistent with a chenier plain facies model. This study combines aerial orthophotographs and sediment cores to interpret the sedimentary dynamics and facies of the chenier plain under analysis. The genesis of the last active chenier is related to the arrival of sand from the frontal ebb-tidal delta. Breaching processes occurred in the ebb delta, inducing the abandonment of the frontal lobe by the ebb-tidal currents. Fair-weather waves rework the sand from the frontal lobe, causing a migration of the sand in a manner similar to the formation of a typical nearshore swash bar. In Joal-Fadiouth, these bars soar and migrate over a tidal flat through the action of normal waves during spring high tides. Relict cheniers present shelly gravel sediments coarser than those observed in active cheniers. Thus, the final stage of stabilization of cheniers was attributed to the action of more energetic storm waves. The cheniers that accumulate during the action of ordinary and continuous processes tend not to persist, and only the coarsest cheniers formed during high-energy events finally remain in the sedimentary record. In addition to discussing the preservation of active coastal forms, this work is of regional interest, given that so far there has been only one work on cheniers in West Africa since 1989.

Lu, C.; Fu, L.; Wang, J.; Xiong, L.; You, A., and Xu, K., 2023. Bird diversity and conservation threats in the CaoE River basin (southeast coastal China). Journal of Coastal Research, 39(2), 266–274. Charlotte (North Carolina), ISSN 0749-0208.

Rivers and their adjacent riparian areas provide satisfactory feeding and breeding habitats for birds. As a strong indicator for the environmental health of an ecosystem, bird diversity is introduced in this study to evaluate the environmental status of CaoE River basin located in SE coastal China. Various techniques, such as remote sensing images, photography, and high-resolution video recording, are used to monitor and record the bird communities in CaoE River basin and its three main tributaries during the on-site survey period at nine different sections with 102 transects. The bird-abundance coefficient and Margalef's diversity index are both utilized in this study to show the spatial discrepancies of bird diversity from upstream to downstream of CaoE River. The variation of bird diversity at different sections are analyzed, a higher bird diversity is shown in both the upstream and downstream regions of CaoE River, whereas it is relatively lower in the central regions. Additionally, the road types, vehicle density, and field vegetation components are also accounted for in this study. It is confirmed that the development of human society and the construction of the city of Shaoxing have significant impacts on bird communities and the nearby ecosystem.

Numbere, A.O. and Aigberua, A.O., 2023. Characterization of tidally accumulated plastic waste and the effect on mangrove ecosystems at Eagle Island, Niger Delta, Nigeria. Journal of Coastal Research, 39(2), 275–283. Charlotte (North Carolina), ISSN 0749-0208.

Plastic pollution has become a global problem with the proliferation of numerous plastic goods. This study hypothesized that accumulated plastic waste will have a negative effect on the mangrove ecosystem and associated organisms. The study was performed in a sand-filled and deforested mangrove forest at Eagle Island, Niger Delta. Ten soil samples (n = 10) were collected under and around accumulated plastic waste at five different georeferenced sites. Samples of fish, crab, plastic, and foil from each site were collected and sent to the laboratory for physicochemical analysis of total hydrocarbon content (THC) and heavy metals, i.e. zinc (Zn), lead (Pb), and cadmium (Cd), using the HACH DR 890 colorimeter (wavelength 420 nm) and microwave accelerated reaction system (MARS Xpress, North Carolina, U.S.A.), respectively. Furthermore, microbial analysis was completed for the soil samples. A germination experiment was conducted in the laboratory using seedlings of Rhizophora racemose and Rhizophora mangle grown in plastic and nonplastic waste soils. The results show that no significant difference occurs in THC and heavy metal concentration in surface soils, subsurface soils (F_1,30 = 1.83, P = 0.186), and soils collected around plastic waste (F_3,28 = 0.60, P = 0.619). In contrast, a significant difference occurs in seedling growth between the control and plastic soils (F_4,200 = 65.24, P < 0.001). Microbial population showed significant difference horizontally, i.e. some distance away from plastic waste (near, middle, and far; F_3,11 = 3.86, P = 0.04) but not vertically (surface vs. subsurface; F_1,11 = 4.60, P = 0.055). These results indicate that chemicals in plastic waste can migrate outwardly to contaminate neighboring organisms. Thus, plastic waste should be quickly removed from the forest to prevent its decomposition and deposition of chemicals that will move up the food chain, affecting humans who consume seafood.

Yuan, H.; Li, F.; Yan, Q.; Zhang, W., and Hu, J., 2023. Investigating pressure fluctuations on marine vessel rudders: Numerical results from propeller–rudder–hull interactions. Journal of Coastal Research, 39(2), 284–295. Charlotte (North Carolina), ISSN 0749-0208.

Severe pressure fluctuations induced by propeller wake enhance rudder vibrations. In the present study, the pressure fluctuations on the rudder are numerically investigated by using k-ω Menter's shear stress transport turbulence model. The pressure fluctuations on the port and starboard sides of the rudder are compared in time and frequency domains. Furthermore, the impact of the advance coefficient on the displacement of propeller wake and pressure fluctuations is also discussed. The numerical results indicate that the propeller wake displacement is oriented upward and downward at the port and starboard sides, respectively. The most intense pressure fluctuation occurs at the propeller blade passage frequency. As a result of vortex displacement, the suction-side fluctuations are weaker than those on the pressure side at frequencies of 100–300 Hz over an advance coefficient range of J = 0.75–0.925. The displacement of the propeller wake weakens when the advance coefficient decreases.

Tekoğul, H., 2023. Wastewater treatment of solid waste leachate and production of proteinaceous biomass using duckweed vegetation (Lemna minor). Journal of Coastal Research, 39(2), 296–302. Charlotte (North Carolina), ISSN 0749-0208.

Phytoremediation provides cost–effective wastewater treatment and recovery of wastewater as rich biomass by aquatic plants and produces bioenergy and various important by-products. This study was carried out to treat solid waste leachate with Lemna minor L. and convert wastewater nutrients into protein-rich biomass by this aquatic plant. To create the experimental setups, L. minor was produced in wastewater at six dilution ratios: 100% (T₁), 75% (T₂), 50% (T₃), 25% (T₄), Hoagland medium with Lemna (T_5c), and 100% wastewater without Lemna (T₆). At the end of the 45-day study,the pH 7.00 (T_5c) and 8.81, the protein yield rate (crude protein) in the trial groups was found to be T₁ = 40.10%, T₂ = 67.53%, T₃ = 75.24%, T₄ = 42.72%, and T_5c = 85.00%. In the study, the T₃ group showed the best performance in terms of initial weight, final weight, total biomass, specific growth rate, relative growth rate, and protein ratio in wastewater groups. The highest and lowest removal rates in leachate ranged between 85.40% (T₄) and 56.50% (T₁) for the NH₄ ⁺-N value, 14.20% (T₄) and 4.73% (T₂) for NO₂-N, 16.96% (T₄) and 6.53% (T₃) for NO₃-N, and 23.10% (T₃) and 16.08% (T₁) for PO₄^–3-P. The total biomass of the trial groups showed an average 50.55% increase from the baseline level. Although 46% biomass was obtained in the Hoagland medium with vegetative growth, a very high biomass of 61% was obtained in the T₃ group of solid waste leachate containing dilute wastewater. As a result, phytoremediation is recommended as a solid option for the management of wastewater resources. This efficiency has shown that aquatic plants can be used in the treatment of wastewater and the obtained high protein biomass can be used in various ways, such as animal feed and bioenergy.

Zhang, H.-s.; He, L.; Zhang, Z.-h., and Zhang, Y., 2023. Comparison of the characteristics of internal wave propagation under two surface boundary-conditions in continuously density-stratified oceans. Journal of Coastal Research, 39(2), 303–316. Charlotte (North Carolina), ISSN 0749-0208.

Complete theoretical solutions were developed for the propagation of internal waves (IWs) with small amplitudes in a continuously density-stratified ocean under the free surface-boundary condition and rigid lid assumption. Additionally, a numerical model was established for the propagation of IWs under the free surface-boundary condition. In the proposed model, the Euler equations are employed as the governing equations and are discretized with an improved SIMPLE algorithm. In waters with a constant depth, a comparison between the numerical and theoretical results proved the reasonability and accuracy of the proposed method. Additionally, the numerical results under the free surface-boundary condition were compared with those under the rigid lid assumption to analyse the differences between the calculated velocities and density fields. Herein, the influences of characteristic parameters, including the period and amplitude of the incident waves and the coefficient of density and the mode number on the velocity fields under the two surface-boundary conditions, are discussed thoroughly. In the waters with nonuniform varied depths, numerical simulations on the IWs propagation were performed under the two surface-boundary conditions. Differences between the calculated physical fields of IWs in front of and behind the submerged dike are discussed. The detailed analyses showed that differences exist between the calculation results under the two surface-boundary conditions. In particular, they were obvious for the cases with high mode number and variable topography. The results are significant considering the propagation mechanism of IWs under different surface-boundary conditions in a continuously density-stratified ocean.

Kosyan, R.D.; Krylenko, M.V., and Krylenko, V.V., 2023. Current state of the northeast Black Sea coast along the Russian Caucasus. Journal of Coastal Research, 39(2), 317–327. Coconut Creek (Florida), ISSN 0749-0208.

This paper describes the state of the NE Black Sea coasts in the 21^st century. The modern development and economic use of these coasts in the conditions of climate change and anthropogenic load are analyzed. A geomorphological feature of the Black Sea coast of the Caucasus is the predominance of denudation processes over accumulative ones. There is only one large accumulative sandy section—the Anapa Bay-Bar. Abrasion shores with narrow beaches are widespread in the NE part of the Russian Black Sea coast. There is no united longshore sediment flux. Local lithodynamic cells on concave sections of the shore are characteristic. The conditions of these shores are favorable for the use of local coast protection. In the SE section, the dynamics of the shores in natural conditions were determined by the sediment balance. The active abrasive processes were combined with a large volume of beach-forming sediments carried out by rivers. Up to the middle of the 20^th century, there was a single longshore sediment flux toward the SE and broad beaches near river mouths. The Imereti Lowland was formed between the mouths of the Mzymta and the Psou rivers. Irrational and excessive technogenic transformation of the shoreline and river basins in 20^th century resulted in a progressive lack of sediment supply. Since the beginning of the 21^st century, the width of the beaches has been decreasing throughout the entire area, and the stability of the coast has been maintained artificially by shore protection structures. The Russian sector of the Caucasus Black Sea coast is now densely populated and is an important recreational and economic zone. The main problems that had to be solved in the past and will have to be solved in the future are the shortage of beaches and the protection of the coast and objects located on it from wave impacts.

Feng, H.; Zhu, L.; Wu, J., and Squires, V.R., 2023. A review of disaster risk assessment and mitigation in vulnerable coastal communities: An example from the South China Sea coast. Journal of Coastal Research, 39(2), 328–333. Charlotte (North Carolina), ISSN 0749-0208.

This review examines and analyses key issues that underpin the development and successful implementation of risk assessment. The focus is on coastal areas (including the nearshore hinterlands) on the coast of the South China Sea, especially the coastal zone around the Gulf of Tonkin (also known as Beibu Gulf) that borders Vietnam. Consideration is given to aspects of the process of engaging with local communities in areas at risk of disasters and in those sites that are affected with severe consequences on peoples' income, wealth, health, and social state. Vulnerability is an important factor and its nature and implications are examined. This paper first sets out the context for this review, including some key information about the study region. Second, risk assessments and recent developments in mitigation are discussed. Third, the focus shifts to mechanisms (and benefits) of engagement with local peoples from areas that are at risk or have undergone severe damage. Finally, concluding thoughts and a synthesis of the whole paper is presented.

Robertson, Q.; Wozencraft, J.; Dong, Z.; Pierro, T., and Zhang, K., 2023. Demonstrated coastal engineering applications using lidar data. Journal of Coastal Research, 39(2), 334–346. Charlotte (North Carolina), ISSN 0749-0208.

This paper documents the many uses of light detection and ranging (lidar) data within the profession of coastal engineering. Lidar provides the capability to conduct large-scale mapping of coastal engineering projects at high spatial resolutions over short time periods. The National Oceanographic and Atmospheric Administration's Digital Coast is a major access point for lidar data in the United States that provides data sets in analysis-ready formats from a number of data providers, such as the U.S. Army Corps of Engineers National Coastal Mapping Program. Examples of engineering projects that utilize lidar data are grouped as feasibility studies, design of beach nourishment and borrow areas, monitoring of project performance, and emergency poststorm analysis. The Joint Airborne Lidar Bathymetry Technical Center of Expertise (JALBTCX) toolbox combines metric extraction from lidar data sets with shoreline and volume change within an ESRI GIS environment to provide rapid and long-term assessment of changes along sandy coastlines.

Lee, J.S. and Chang, J.-I., 2023. Benefits of beach erosion control on the east coast of Korea. Journal of Coastal Research, 39(2), 347–353. Charlotte (North Carolina), ISSN 0749-0208.

Coastal erosion control projects bring various benefits to people, such as reducing damage from coastal disasters, reducing erosion and flooding damage, and providing water-friendly spaces. Nevertheless, it is difficult to evaluate a project because there are few analyses of the economic impact of the project. Thus, this study aims to estimate the benefits of coastal erosion control and maintenance projects using people's willingness to pay (WTP). In particular, information on the effectiveness of a project for relatively unknown coastal regions is lacking. Therefore, this study targeted the Yeongrang coast in Gangwon-do, located on the east coast of Korea. The annual WTP per household was estimated to be approximately KRW 1999 (USD 1.81). The benefit–cost ratio based on this was estimated to be approximately 2.98, which is considered to be a sufficiently large benefit compared with the cost of the project. The findings of this study can be used as the basis for decision making regarding coastal erosion control policies for similar case areas.

Lee, J.-C. and Lee, D-H., 2023. Accuracy assessment of recent global ocean tide models using tide gauge measurements from the East Sea of Korea. Journal of Coastal Research, 39(2), 354–359. Charlotte (North Carolina), ISSN 0749-0208.

The continued rise in average sea level owing to climate change has intensified coastal damage worldwide. Therefore, various studies in the field of oceanography and hydrography including the development of ocean tidal prediction models are in progress. In this study, the accuracy of the recent ocean tide models using the long and short-term tide gauge measurements from seven tidal gauging stations and 10 tidal benchmarks at the coastal area in the East Sea of Korea was assessed. For this purpose, a total of five ocean tide models, DTU10, FES2014, OSU12, NAO99, and TPXO9 were used. The accuracy of the four major tidal components (M₂, S₂, K₁, and O₁) were assessed based on the same components determined from direct tide gauge measurements in east coastal area of Korea. The tide gauge measurements used in this study consisted of long-term observation data of over 1.7 years on average from seven permanent tide gauge stations and short-term observation data of about 6.6 months on average from 10 tidal benchmarks. Observation and determination of tidal components were performed by the Korea Hydrographic and Oceanographic Agency. The accuracy of each ocean tide model was assessed by comparing the amplitude of four major components with those from tide gauge measurements for each location of tide gauge. The lowest accuracy of modelled component values was detected in the M_2, S₂, K₁, and O₁ tidal components of NAO99 model. On the contrary, FES2014 was the most accurate in M₂, S₂ tidal components and TPXO9 was most accurate in the K₁, O₁ tidal components in the East Sea of Korea.

Kim, G.; Jeong, M.-H.; Jeon, S.-B., and Khan, M.S., 2023. Time-series analysis of ship movements using community detection and functional data analysis across the east coast of the Republic of Korea. Journal of Coastal Research, 39(2), 360–365. Charlotte (North Carolina), ISSN 0749-0208.

Because of the recent climate change caused by air pollution in ports, global interest in marine spatial planning (MSP) has increased to achieve cost-effective navigation, economic development goals, logistics, and energy transportation. Accordingly, research on ship traffic, the main cause of air pollution in ports, is attracting attention. This study aims to investigate the temporal characteristics of the port network on the east coast of the Republic of Korea using the automatic identification system data set. This study used the Louvain model, a community detection technique for complex networks, and functional data analysis (FDA). The results of the Louvain model showed that the port network of the Republic of Korea has a hub-and-spoke structure in which ports that are close to each other are regionally clustered around the main ports in the community. The FDA results showed seasonal changes in port arrival volume and detection of abnormal ports in Korea's east-coast ports. The results of this study are expected to provide a baseline for policy makers to establish an effective MSP for port management, cost-effective route development, and prediction of the number of operations.

Lee, J.; Kim, J.; Hur, H., and Wie, G., 2023. Coastal erosion monitoring using SEAHAWK Airborne Bathymetric LIDAR data on the east coast of Korea. Journal of Coastal Research, 39(2), 366–376. Charlotte (North Carolina), ISSN 0749-0208.

Coastal erosion is accelerating along the east coast of Korea because of natural and anthropogenic forces. A current constraint in understanding and modeling these changes within large coastal areas is the multitemporal bathymetric data or recursive observations. This is because the main survey techniques for coastal erosion monitoring depend on field and echo-sounding surveys. However, the recent availability of Airborne Bathymetric LIDAR (ABL) systems enables topography mapping over large coastal areas. In particular, the development of the SEAHAWK system, a Korean ABL system, provides more data on the east coast of Korea. The ABL system enables assessing temporal changes along the large coasts without other conventional survey data. However, there are issues with the accuracy of the technique relative to quantitative uncertainties and ability to resolve nearshore spatial patterns of erosion and deposition indicative of geomorphologic change. This study validates the ABL data for coastal erosion monitoring by using the multi-temporal data acquired in 2013 and 2020 on the east coast of Korea and analyzes the results to reveal the quantitative and qualitative effectiveness of this technique.

Choi, Y.; Ji, Y.-Y., and Joung, S., 2023. Experimental counting efficiency calibration of in situ marine radioactivity monitoring systems in Busan (Korea) based on seawater salinity. Journal of Coastal Research, 39(2), 377–383. Charlotte (North Carolina), ISSN 0749-0208.

In situ underwater gamma-ray spectrometry is an effective method for monitoring marine radioactivity. With in situ measurement, however, it is difficult to calibrate counting efficiency experimentally, and a simulation is thus generally used to calculate the theoretical efficiency without experimental verification. This paper proposes a method to establish experimental counting efficiency by estimating the radioactivity concentration of ⁴⁰K, which is a natural radionuclide emitting a 1,461 keV gamma ray, based on the salinity of seawater. The measurement was performed in a marine monitoring system in Busan equipped with a 3″φ × 3″ NaI(Tl) detector in a tank filled with sampled seawater. The results were compared with the theoretical counting efficiency calculated by simulation to verify the validity of the simulation. The results confirmed the experimental efficiency and theoretical efficiency were in very good agreement. In addition, using the validated simulation, a theoretical efficiency curve according to the gamma-ray energy was obtained. For simpler application, the concept of radioactivity conversion factor in units of s^–1 · Bq^–1 · kg for each peak was proposed. If the ratio of the conversion factor of each peak to the factor of ⁴⁰K is obtained, the conversion factors for artificial radionuclides, which are difficult to measure practically, can be estimated by multiplying these ratios by the ⁴⁰K conversion factor.

Joung, S.; Ji, Y.-y., and Choi, Y., 2023. Development of a floating radiation measurement system for underwater readings in the East Sea of Korea. Journal of Coastal Research, 39(2), 384–393. Charlotte (North Carolina), ISSN 0749-0208.

Following the Fukushima nuclear power plant accident and subsequent discharge of contaminated water, the need for marine radioactivity monitoring has emerged. Currently, various underwater radiation monitoring systems are being developed and utilized for monitoring radioactive contamination of seawater. In this study, a floating on-site radiation monitoring system that can measure the radiation energy spectrum of a water environment in the field in real time was designed and fabricated with the aim to reduce the effect of background radiation on the system, which is a problem for land-based measurement technology. This study performed computational simulations to derive the ambient dose rate conversion factor and efficiency of the developed floating on-site radioactivity analysis system, named MARK-U3. The system was tested in the laboratory and in the field in both freshwater and saltwater environments. From the experimental results, the MARK-U3 can perform precise radioactivity analysis without the need for a thick shield, and by strengthening mobility, it can operate continuously.

Min, B.I.; Suh, K.-S.; Park, K.; Kim, J.Y.; Choi, Y., and Kim, S., 2023. Modeling the diffusion of radioactive materials into the East Sea of Korea: Analysis of hypothetical nuclear power plant accident scenarios and long-term marine ecosystem impacts. Journal of Coastal Research, 39(2), 394–400. Charlotte (North Carolina), ISSN 0749-0208.

The East Sea is surrounded by South Korea, North Korea, Japan, China, and Russia and is connected to the Northwest Pacific Ocean through three narrow straits. In the East Sea, there are 18 nuclear power plants installed along the coasts of South Korea alone. This study evaluated the long-term diffusion of radioactive materials in the East Sea using a compartment model and described the effect on a marine food chain model. A hypothetical scenario in which soil near the power plant is contaminated and flows into rivers and seas due to rainfall was numerically tested. It took about 2 minutes to calculate the intake dose for 10 years, and there was no significant difference compared to the detailed model.