Southern Laizhou Bay Research Articles

Groundwater salinization under the influence of paleo sea-level fluctuation: a case study in southern Laizhou Bay, China

The groundwater environment in low-lying coastal regions is significantly impacted by global sea-level fluctuation. In Laizhou Bay, three large-scale transgressions have occurred since the late Pleistocene, resulting in the transformation of ancient seawater into brine. This brine has become a major contributor to groundwater salinity in the area. This study establishes a correlation between groundwater occurrence and paleoclimate changes in Laizhou Bay using borehole sediment data. The source and mechanism of groundwater salinity are analyzed based on sediment pore water characteristics and hydrogen and oxygen isotopes. The study reveals that the stratigraphic structures in the area consist of four layers: a Holocene transgressive layer, a continental confining bed from the late Pleistocene, a Cangzhou transgressive layer from the late Pleistocene, and a fluvial aquifer from the middle Pleistocene. All aquifers in the study area have been infiltrated by modern seawater, with the uppermost Holocene aquifer influenced by evaporation and leaching processes, the central late Pleistocene aquifer remaining relatively stable, and the lower middle Pleistocene aquifer affected by subsurface low salinity runoff and exhibiting an increasing trend with depth. Given the presence of numerous hydrogeological environments globally that are similar to the study area, the obtained mechanisms of groundwater salinization in this study will provide theoretical support for groundwater management in similar regions worldwide.

Sequence Stratigraphic Analysis of the Volcanic Rock–Evaporite–Clastic Rock Symbiotic Zone in the Fourth Member of the Shahejie Formation in the South of Laizhou Bay

Laizhou Bay Sag is a typical continental rift lake basin, which is affected by strike–slip activity, salt rock activity, volcanic activity, and paleoclimate change in the Tanlu fault zone, where three major lithologies—volcanic rock, clastic rock, and evaporite—mainly develop. In order to determine the sequence correspondence between the different lithologies in the study area based on drilling, logging data, and seismic data, it is determined that the fourth member of the Shahejie Formation in the southern Laizhou Bay mainly develops three types of sequences: clastic rock type sequences, salt lake type sequences, and volcanic rock/clastic rock type sequences. Two second-order sequence boundaries (SBs3L, SBs4L) and one third-order sequence boundary (SBs4U) were identified, and the principle of three divisions of system tracts (LST, TST, HST) and sedimentary processes in different types of sequences were determined by analyzing the stacking patterns of different sequences. Compared with the previous research results, this study provides a more detailed analysis of the sequence boundary definition of different blocks and different lithologic strata, and it improves the previous general sequence stratigraphic division method. Based on the study of distinct types of sequences, a unified stratigraphic framework is established in the whole zone, and the stratum thickness distribution of the fourth member of Shahejie Formation is smaller in the southwest and larger in the northeast. The study area is generally filled with pyroclastic rocks–evaporite–clastic rocks, changing from fan delta–saline lake filling to braided river delta–freshwater lake–fan delta filling from bottom to top. A sequence stratigraphic model for the comparison of steep slope–gentle slope differences is established to provide guidance for future oil and gas field exploration and development.

Using Principal Component Analysis (PCA) Combined with Multivariate Change-Point Analysis to Identify Brine Layers Based on the Geochemistry of the Core Sediment

The underground brine in Southern Laizhou Bay is characterized by its large scale and high concentration, which can affect the distribution and migration of geochemical elements in sediments. Most studies on the brine are based on hydrochemical analysis, with little consideration being given from a geochemical perspective. Principal component analysis (PCA) is a powerful tool for discovering relationships among many elements and grouping samples in large geochemical datasets. However, even after reducing the dimensions through PCA, researchers still need to make judgments about the meaning represented by each principal component. Change-point analysis can effectively identify the points at which the statistical properties change in a dataset. PCA and change-point analysis have their respective advantages in the study of large sets of geochemical data. Based on the geochemical data of the LZ908 core, by combining these two methods, this study identified four elements (U, MgO, Br, and Na2O) related to the action of seawater through PCA; then, multivariate change point analysis was conducted on these elements to detect the depths of different brine layers. The results of the analysis are basically consistent with those of other studies based on the water content, salinity, and other data, thus proving the effectiveness of this method. The combination of these two methods may also lead to novel approaches for related research.

Hydrochemical characteristics, quality and health risk assessment of nitrate enriched coastal groundwater in northern China

Groundwater quality is an essential factor restricting regional sustainable development owing to water resource scarcity, especially in coastal regions. Coastal groundwater is affected by natural conditions and strong human activities, and the evolution of water quality is extremely complex. Information on the hydrochemistry evolution and nitrate contamination status of coastal groundwater under the conjunctive effects of natural processes and human activities is a vital requirement for groundwater resource management in coastal regions. Thus, this study integrated traditional hydrochemical analysis approaches, the entropy-weight water quality index (EWQI), and the health risk assessment model to analyze hydrochemical characteristics, quality, and nitrate health risks in a typical coastal region (i.e., southern Laizhou Bay) simultaneously affected by seawater intrusion and anthropogenic activities, as well as to explore the dominant mechanisms controlling groundwater quality. The results indicated that the concentrations of major hydrochemical constituents in groundwater exhibited wide variability. The NO3− concentration varied from 0.59 to 824.80 mg/L; it surpassed the WHO drinking water standard (50 mg/L) at 89.47% of sampling sites. The predominant hydrochemical types of groundwater were SO4•Cl–Ca•Mg and HCO3–Ca•Mg. Governing factors influencing groundwater chemistry were recognized as rock weathering, inverse cation exchange and anthropogenic activities, and nitrate contents were largely controlled by agricultural practices. The computed EWQI showed that 55.26% of groundwater samples possessed EWQI values greater than 57, which is relatively poor-quality groundwater. The poor-quality groundwater was concentrated in the southwestern part of the study area. Non-cancer risks of nitrate in 96.71%, 94.74%, 89.47%, and 89.47% of the groundwater samples were unacceptable for infants, children, teens, and adults, and the spatial distribution of the hazard quotient (HQ) was in accordance with the spatial pattern of nitrate concentration. These findings can guide the exploitation and utilization of groundwater resources and water quality conservation in coastal regions.

Study on the Sources of Salinity of Groundwater in Holocene and Late Pleistocene Sediments Based on Hydrochemical and Isotopic Methods in Southern Laizhou Bay

A survey of the hydrochemistry and isotopes of the Quaternary aquifer on the southern coast of Laizhou Bay provides new insights into the hydrodynamic and geochemical relationships between freshwater, seawater, and brine at different depths in coastal sediments. This study used a combination of groundwater level analysis, hydrochemistry, and isotopic methods to study the chemical characteristics of groundwater and the origin of groundwater recharge and salinity. Because the sedimentary structure of the area and the formation background of saltwater were important factors controlling the distribution of groundwater, we analyzed the distribution of groundwater in Holocene and Late Pleistocene sediments. The variation of groundwater levels in the Holocene and Late Pleistocene sediments in the saline–freshwater transition zone over time showed that the Holocene and Late Pleistocene groundwater flow directions differed in the saltwater–freshwater transition zone. From south to north in the study area, the hydrochemical types of groundwater in the Holocene and Late Pleistocene sediments were as follows: HCO3-Ca (freshwater), SO4-Mg and HCO3-Ca (brackish water), Cl-Na·Mg (saltwater), and Cl-Na (brine). The results of the hydrochemical and isotopic studies indicated that the saltwater in the Holocene and Late Pleistocene sediments and the brine in the Late Pleistocene sediments were the result of evaporation. The salinity of freshwater in the Holocene sediments was produced by rock weathering, while the salinity of freshwater in the Late Pleistocene sediments was not only derived from rock weathering, but was also affected by evaporation and precipitation. The salinity of brackish water in the Holocene and Late Pleistocene sediments was derived from evaporation and precipitation. Ultimately, the origin of groundwater recharge in the Holocene and Late Pleistocene sediments was atmospheric precipitation.

Integrating hydrochemical and microbial methods to identify hydraulic connections between three saltworks in southern Laizhou Bay, China

Integrating hydrochemical and microbial methods to identify hydraulic connections between three saltworks in southern Laizhou Bay, China

The Distribution Characteristics and Human Health Risks of High- Fluorine Groundwater in Coastal Plain: A Case Study in Southern Laizhou Bay, China

High-F groundwater has caused serious human health problems worldwide. In this paper, a typical saline-fresh water mixing zone (SFMZ) in a coastal plain (south of Laizhou Bay, China) was chosen as an example to analyze and summarize the distribution characteristics and enrichment mechanism human health risks of high-fluorine groundwater. Thirty-two groundwater samples have F- concentrations that exceed the drinking water guideline value of the World Health Organization (WHO; 1.5 mg/L), Thirty-two groundwater samples exceeded the drinking water guideline value of the WHO (1.5 mg/L) and 43 groundwater samples exceeded the National Sanitary Standard for drinking water of China (1.0 mg/L), accounting for 68.1 and 91.5% of the total groundwater samples. The groundwater quality is relatively poor in this study area, and the water is unsuitable for human consumption. High-F groundwater is mainly found in the central and northern parts of the study area, and the concentrations increase in the direction of water flow. High-F groundwater is mainly found in the central and northern parts of the study area, and the concentrations increase in the direction of water flow. According to the analysis, the groundwater environment, saline water intrusion (SWI), evaporation and cation exchange are the main factors influencing the enrichment of F in the SFMZ. The neutral and weakly alkaline environment is conducive to the enrichment of F-. Cation exchange and evaporation are the most important factors in the enrichment of F. Human activity is not the main source of groundwater F. Na+ and HCO3− are adequately abundant in the groundwater environment in the study area, creating conditions that are conducive to the dissolution of fluorite and the release of F into the groundwater. An increase in the Na+ concentration and a decrease in the Ca2+ concentration can promote further dissolution of fluorite and other F-containing minerals, thereby releasing F- into the groundwater. Fluorite dissolution is prevalent in the groundwater environment, which can lead to an increase in the F concentration. This study is helpful to the development of strategies for the integrated management of high-F groundwater in coastal plains. The health risk assessment shows that long-term exposure to high-F groundwater can pose a great threat to four age clusters, especially for children and infants. The HQ values for shallow groundwater range from 0.32 to 2.89, 0.39 to 3.61, 0.56 to 5.11, and 0.42 to 3.85 for adults, teenagers, children and infants, respectively. The groundwater in this study area is not for irrigation and animal husbandry, which may indirectly affect human health.

Paleoclimatic interpretation in southern Laizhou Bay since the late Pleistocene: Evidence from groundwater and sedimentary strata

Understanding past climatic change and the associated responses of sea level may contribute to the ability to evaluate the relationship between these factors in the future under the background of sea-level changed. Here, we aimed to reveal the climate change and sea-level characteristics of southern Laizhou Bay (SLB) since the late Pleistocene by combining groundwater stable isotopes (2H, 18O and deuterium excess (dexcess)), age dating (14C) and the structural characteristics of sediments from several boreholes. The isotopic proxies for climates demonstrated the depletion of 2H, 18O and dexcess of groundwater recharged in the last glacial period of the late Pleistocene, indicating that the weather was cooler and wetter in the last glacial maximum, while the stable isotopes and dexcess of groundwater were enriched in the Holocene. Several transgressions were revealed through the structural characteristics of boreholes, which also indirectly reflected the large-scale changes of in global temperature. Finally, a conceptual model that describes the evolution of coastal saline groundwater based on the transgression process was proposed based on the sedimentary chronology of strata and groundwater age. These results not only contribute to the study of climate-related sea-level change since the late Pleistocene but also provides a theoretical explanation for the mechanism by which coastal saline groundwater forms.

Identification of groundwater microbial communities and their connection to the hydrochemical environment in southern Laizhou Bay, China.

The microbial community plays an important role in the biogeochemical cycle in coastal groundwater ecosystems. However, the composition and controlling factors of the microbial community in coastal closed groundwater systems (CCGSs) with high salinity have rarely been studied. Here, we investigated and analyzed the hydrochemical characteristics and microbial community composition of seven brine samples with high total dissolved solid (TDS) values ranging from 74.5 to 132.3g/L within and across three coastal saltworks (Yangkou, Hanting, and Changyi) in southern Laizhou Bay (SLB). The bacterial diversity was independent of salinity. Compared with those of low-salinity groundwater, the diversity of the microbial community in brine was lower, but the richness was slightly higher. There was a significant correlation between the microbial community diversity and groundwater sources, which indicated that the microbial communities were affected by groundwater sources. A comparison of the microbial community compositions of the three saltworks showed that the Hanting and Changyi saltworks had similar microbial communities due to their similar sampling depths. In addition, the main force shaping the differences in the microbial communities in both coastal open groundwater systems (COGSs) and CCGSs was identified as the hydraulic connection with the seawater controlled by hydrogeological conditions formed throughout geological history. This study can help to elucidate the biogeochemical processes in coastal aquifers.

The characteristics of saline submarine groundwater environment on a continental shelf: An example from the south of Laizhou Bay, China

• The main factors influencing the formation process of saline submarine groundwater are summarized. • The submarine aquifer in this study area is the extension of the terrestrial brine (or saline water) aquifer to marine environments. • Paleoclimatic characteristics is the main factors for the formation of submarine saline water (or brine) in southern Laizhou Bay.

Vegetation successions of coastal wetlands in southern Laizhou Bay, Bohai Sea, northern China, influenced by the changes in relative surface elevation and soil salinity

Vegetation successions of coastal wetlands were influenced by the changes in relative surface elevation and soil salinity. In this study, the vegetation successions of coastal wetlands in southern Laizhou Bay and the factors influencing the successions were investigated by quadrat survey. The changes of relative surface elevation and soil salinity in coastal wetlands of the study region were caused by climate change, sea-level rise, coastal erosion, sedimentation, neotectonism, storm surge, seawater intrusion, invasion of Spatina alterniflora, and utilization of underground brine. The changes led to the regressive vegetation succession of coastal wetlands without the protection of sea embankment and the progressive vegetation succession of coastal wetlands with the protection of sea embankment. The invasion of S. alterniflora resulted in the regressive vegetation succession of wetlands in the riparian zone. The successions weakened the coastal wetlands’ ecological capacities of carbon sequestration, pollutant purification, and resisting marine disasters, decreasing their species diversity. Some measures were proposed to resist the adverse impact of successions, such as introducing passenger water, storing water in flood season, digging 200 hm2 of ponds, and planting Salix matsudana and Tamarix chinensis around the ponds.

Hydrochemical characteristics and functions of groundwater in southern Laizhou Bay based on the multivariate statistical analysis approach

Influenced by paleoclimate, paleogeography and hydrogeology, groundwater with different total dissolved solids (TDS) levels, such as freshwater, brackish water, saline water and brine, widely occurs across southern Laizhou Bay (SLB) . Due to groundwater overexploitation, several groundwater depression cones have gradually formed since the 1970s, resulting in saline water intrusion. In this study, the multivariate statistical analysis (MSA) approach was adopted to identify the hydrochemical characteristics of shallow groundwater (SG) and deep groundwater (DG) in the SLB. Moreover, we applied Gibbs diagrams, hydrochemical facies evolution diagrams (HFE-Diagram) and ion proportion relations to analyze the factors influencing the hydrochemical characteristics. The results showed that hydrochemical zonation of the various water types (ranging from Ca-HCO3 to Na-Cl) from south to north was mainly controlled by migration and mixing of saline water with regional groundwater. Based on the MSA results and hydrochemical characteristics, SG functional areas were divided into the groundwater flow zone, intense groundwater mixing zone and groundwater-seawater interaction zone, and DG functional areas were divided into the groundwater flow zone, groundwater mixing zone and underground brine storage zone. Finally, SG and DG groundwater flow evolution models were developed . The comprehensive method proposed in this study combines the MSA approach with regional geological characteristics and provides a reference for the evaluation of complex multiaquifer systems and analysis of the groundwater evolution characteristics in other regions.

The morphodynamic difference in the western and southern coasts of Laizhou Bay: Responses to the Yellow River Estuary evolution in the recent 60 years

Abstract The Yellow River Estuary (YRE), which is famous for its abundant sediment, rapid accretion, and frequent migration, has experienced a remarkable decrease of sediment transported by the Yellow River (YR) during the past 60 years. By taking the west coast (Yellow River Delta, YRD) and the south coast of Laizhou Bay (LZB) as a unified coastal unit, this paper has analyzed the evolution of shorelines, isobaths, and geomorphic erosion/accretion during the last 60 years based on the remote sensing images and nautical charts; these data were also used to reveal the depositional dynamic mechanisms controlling the coastal geomorphic responses to YRE evolution in a hydrodynamic numerical simulation. Then, the coastal dynamics, subaqueous slope accretion, and geomorphic evolution were integrated spatially. Finally, the impacts of YRE evolution, including changes of the position and amount of sediment loading into the sea, on the coastal geomorphic evolution of western–southern LZB during the recent 60 year period were elucidated. Results showed that outside of the YRE delta lobes, there has always been an arc high-velocity zone, outside of which there has existed a northeast arc tidal shear frontal zone during the last 60 years. As the estuary delta lobes extended into the sea, the high-velocity zone moved toward the southeast, where its range and velocity also increased. As an overall trend, the duration of the tidal shear frontal zone (TSFZ) has grown longer and longer over a whole tidal cycle, while the interval time has grown shorter and shorter; moreover, the span between the southern and northern endpoints has grown larger and larger, while the southern end always remained confined to a fixed position in the northeast sea area of Qingtuozi. Under the control of TSFZ, the suspended sediment of the Yellow River deposits nearly entirely in the arc area in the vicinity of the estuary delta lobes on the west coast, and thus, the sediment cannot cross TSFZ and move into southern LZB. As a result, the western and southern coasts of LZB have shown significant differences in the evolution of shorelines, isobaths, and geomorphic erosion/accretion during the last 60 years. That is, these features have changed dramatically in the west coast but have remained relatively stable in the southern coast, and sediment deposition is now greatly reduced in the southern LZB. Therefore, the YRE evolution had a significant geomorphic impact on the coast of western LZB where the YRD is located, while it had only a slight impact on southern LZB.

Evolutionary process of saline-water intrusion in Holocene and Late Pleistocene groundwater in southern Laizhou Bay

Saline water intrusion is one of the most serious groundwater problems in southern Laizhou Bay. In this study, formation of groundwater with different qualities and saline water intrusion were analyzed using hydrochemical and stable isotopic methods, and the Hydrochemical Facies Evolution Diagram (HFE-Diagram). The results demonstrate that the structure of the sedimentary layer in this area is the dominant controlling factor of groundwater distribution. From the south (land) to the north (sea), the hydrochemical distribution presents a regular changing pattern following the order: HCO3-Na·Mg and HCO3·Cl-Mg·Ca (fresh water), HCO3·Cl-Na·Mg (brackish water), Cl-Na·Mg (saline water), Cl-Na (saline water) and Cl·HCO3-Na (brackish water). Hydrochemical data show that saline water and brine are not the result of evaporation or the concentration of seawater. Brackish water and saline water with low mineralization in Holocene groundwater are formed by the mixing of fresh water and highly mineralized saline water, dissolution of evaporates by meteoric water, and water/salt interaction. And the saline water formed through dissolution of evaporates in Holocene and Late Pleistocene groundwater. Isotopic results reveal that the main recharge of saline water in Holocene groundwater and Late Pleistocene groundwater is a combination of the meteoric water and lateral recharge from rivers. Saline water intrusion was found to follow a wedge-shaped intrusion pattern. Significant variations in Cl- and Na+indicate saline intrusion in the southern area. The degree of saline water intrusion in Holocene groundwater was found to be more serious than that in Late Pleistocene groundwater. Hydrochemical data and HFE-Diagram show that there is an intrusion process in Holocene groundwater. In this process, it is accepted the fresh water recharge, such as meteoric water and lateral recharge from rivers. In Late Pleistocene groundwater, it presents a simple intrusion process from saline water to fresh water.

Features and evaluation of sea/saltwater intrusion in southern Laizhou Bay

Features and evaluation of sea/saltwater intrusion in southern Laizhou Bay

Study on the marine sedimentary environment evolution of the southern Laizhou Bay under the impact of port projects

The southern Laizhou Bay is mainly composed of silt-sandy coasts with diverse landforms, and its marine hydrodynamic environment is sensitive to human activities. Marine hydrodynamic and sedimentary environments of the study area have changed under the influence of large-scale port projects in recent years. In this paper, the evolution of hydrodynamic environment, deposition rate, and geochemical characteristics were studied based on sediment grain size, element analysis and 210Pb dating of two cores, in order to analyze the influence of Weifang Port on marine environmental evolution, and provide theoretical and practical basis for protecting marine environment in developing marine resources reasonably. Results showed that sediments of the two cores were relatively coarser and mainly composed of silty sand. Sediments above 230 cm in core WF1 and 218 cm in core WF2 were deposited since 1855 when the Yellow River appeared to deposit its sediments within the modern active delta, and the average deposition rate was between 0.3 and 0.5 cm a−1. Implement of Weifang Port projects in 1997 and 2007 created great influence on the sedimentary environment evolution in the surrounding waters, and the deposition rate was significantly increased. The average annual deposition rates were 5.1 cm and 3.5 cm in WF1 and WF2 respectively between 1997 and 2007. Content of heavy metals in sediments showed no obvious change in the vertical, indicating that the heavy metals were less affected by human activity and there was no significant accumulation of such metals in the study area.

Distribution and environmental significance of live and dead benthic foraminiferal assemblages in surface sediments of Laizhou Bay, Bohai Sea

Abstract Surface sediment samples at 80 stations were collected from Laizhou Bay in the Bohai Sea, and the live and dead foraminifera were analyzed in order to understand the relationship between foraminiferal assemblages and environmental factors. Four representative zones (A, B, C and D) of natural stations were classified by the Hierarchical Cluster Analysis (HCA), based on the total (live plus dead) relative abundances of 25 species commonly observed in the study area. The distribution patterns of benthic foraminifera, especially the characteristic species, responded well to the slightly varying environment. In Zone A, the nearly consistent structural components of live and dead foraminifera indicate that there was no massive transportation process. Their distribution was mainly controlled by the deeper water depth, a higher bottom salinity and coarse sandy silt (ST) content. In Zone B, the high proportion of living miliolid tests might be related to the high-salinity tongues along the southern Laizhou Bay towards its center. The dilution effect of high sedimentation rate along the southern Yellow River (Huanghe) mouth led to the sparse amount of foraminiferal tests in Zone C. However, complex environmental factors limited the distribution and postmortem taphonomic process of the benthic foraminifera in Zone D. Under the coactions of large amounts of freshwater and nutrient from the Yellow River and some small rivers located in the western study area, and silt (T) substrates mainly from the suspended sediments of the Yellow River, the living group Cribrononion subincertum (Asano) and agglutinated species dominated in Zone D. Besides, part of the allochthonous miliolid tests from Zone B might have been transported and reburied along with the autochthonous species in Zone D due to the bottom circulation. Moreover, the small- and thin-shelled species C. subincertum that dominated in the living assemblages was poorly preserved or totally absent in the dead groups. It may have been transported as suspended load and redeposited by the circulation flowing towards the outer bay.

Tracking lead origin in the Yellow River Estuary and nearby Bohai Sea based on its isotopic composition

The Pb concentration and Pb isotopes (204Pb, 206Pb, 207Pb, and 208Pb) in surface sediments from the Yellow River Estuary and nearby Bohai Sea have been determined to investigate the Pb sources in this area. Results showed that Pb in the Yellow River Estuary and northern Laizhou Bay (YRE-NL) sediments was mainly from the Yellow River catchment as a consequence of lithogenic sediments (from rock weathering) accumulation. However, Pb in the coastal area of southern Laizhou Bay (CSLB) sediments was from both natural and anthropogenic sources. Sewage discharged near the Mihe mouth of the CSLB did not extend further to the middle and outer shelves because of the current in Laizhou Bay. The total Pb concentration varied from 14.5 to 30.4 μg/g with an average concentration of 20.1 ± 4.2 μg/g. Thus, significant Pb pollution was not observed in the Yellow River Estuary and nearby Bohai Sea. However, Pb contamination in some sites was indicated by Pb isotope ratios.

Environmental radionuclides in a coastal wetland of the Southern Laizhou Bay, China

The radioactivity concentration of 238U, 232Th, 226Ra, 40K, and 137Cs in soil samples collected in a coastal wetland of the Southern Laizhou Bay, China were measured. Mean activity concentrations were 54.4±11.7, 57.9±9.7, 28.6±4.3, 542±21, and 10.2±2.9Bqkg−1 dry weight for 238U, 232Th, 226Ra, 40K and 137Cs, respectively. Statistical analyses suggested significant correlations between clay content and 40K as well as 137Cs. The radium equivalent activity, the absorbed dose rate in the air at 1m above the ground surface, and the external hazard index were calculated. The result showed that the radioactivity level in the wetland was in normal range. But sites along the river tended to have higher radiological hazard indexes. The vertical distributions of radionuclides in profiles illustrated some phenomena, such as vertical transport of 238U, disequilibrium between 238U and 226Ra, and change in material sources.

Scenario Planning of Substitution of Wind Power for Coal-Fired Power: A Case Study from the Coastal Zone of Laizhou Bay, China

Emissions of air pollutants from coal-fired power plants pose a threat to healthy living environment. Developing renewable energy and changing electricity generation structure dominated by coal-fired power has become a vital national strategy. In this paper, taking a rapidly urbanizing coastal area in southern Laizhou Bay of China as the study area, a scenario planning concerning substitution of wind power for coal-fired power in enterprise-owned power plants was conducted. Coupled with the electricity generation prediction by a grey prediction model GM (1, 1) and the calculation of pollutant emission intensity, we obtained three scenario schemes: no substitution (Scenario 1), low substitution (Scenario 2) and high substitution (Scenario 3). The results showed that Scenario 1 is not acceptable; Scenario2 is acceptable, but not ideal; Scenario 3 is optimal. The electricity generation structure under Scenario 3 has been radically converted from the type dominated by fossil fuel to one dominated by renewable energy, becoming an environment-friendly power generation framework with fairly low pollutant emission densities. This study can contribute to local managers to seek more concrete measures in mitigating the conflict between electricity demand and environmental health.