Search Results (73)

As an important port in the Beibu Gulf of the South China Sea, Tieshangang Bay is potentially at risk of PTE pollution, yet systematic research integrating multi-hydrological period data remains limited. By applying pollution indices (C_f, WQI, I_geo, RI) combined with PCA, and PMF, we investigated PTE distribution characteristics, risk assessment, and source apportionment across different hydrological seasons. The results indicate that average PTE concentrations in surface seawater meet Class II standards of the Sea Water Quality Standard, with Zn and As showing relatively high concentrations compared to other PTEs. High-concentration areas were mainly located in the inner and middle bay. In sediments, concentrations of Zn and Cr were relatively high, with values generally higher inside the bay than outside. Both C_f and WQI values for seawater PTEs were below 1, indicating an overall low pollution risk. However, Cd and Hg in sediments presented a moderate potential ecological risk. Source apportionment revealed that seawater PTEs primarily originated from an industrial–aquaculture composite source (44.60%), while sediment PTEs were mainly attributed to composite terrestrial inputs (53.16%). These findings provide a scientific basis for PTE pollution management and sustainable development in Tieshangang Bay. Full article

Introduction: Establishing baseline descriptions of inorganic elements in the early life stages of sharks and in their respective nursery areas is essential for assessing anthropogenic impacts and supporting conservation strategies. Objectives: This study presents the first baseline of plasma trace element concentrations (Al, Zn, As, Cu, Cr, Cd, Co, Mn, Ti, Ni, Hg, Pb) for four juvenile shark species (Carcharhinus limbatus, Paragaleus pectoralis, Rhizoprionodon acutus, and Sphyrna lewini) from Sal Rei Bay, Boa Vista Island, Cabo Verde—the first multi-species shark nursery area described in Atlantic Africa. Methodology: Seawater and sediment samples were collected from eight sites and analyzed along with plasma samples using total reflection X-ray fluorescence spectroscopy (TXRF). Sediment granulometry and pollution indices, including the enrichment factor (EF), ecological risk index (RI), and metal pollution index (MPI), were used to characterize habitat contamination. Data were analyzed using statistical models to explore spatial and element-specific patterns. Results: Overall, environmental contamination was low, with slight increases in Cd, Co, and Hg at sites 1 and 2, near the fishing port, and at site 5, likely reflecting natural transport, sediment redistribution, and enhanced nearshore deposition. Juvenile sharks exhibited generally low plasma trace element concentrations, although species-specific elemental signatures were evident: elevated levels of Al and Cu in C. limbatus, Zn in S. lewini, and As in R. acutus and P. pectoralis. Conclusions: These findings establish critical baseline reference values for trace elements in juvenile sharks from a key Atlantic nursery area. The results provide an essential framework for future biomonitoring efforts and contribute to the management and conservation of Cabo Verdean shark nursery habitats. Full article

Maritime transport is energy-efficient but remains heavily dependent on fossil fuels. Renewable electricity-based ammonia (e-NH₃) has emerged as a promising alternative, particularly through small-scale, modular production. Assessing its economic viability is essential for future adoption, and techno-economic analysis offers a structured way to evaluate its feasibility. This study investigates the cost performance of a small-scale offshore e-NH₃ plant of 2.4 tons per day (tpd) at the Port of Santander, Spain, based on nitrogen obtained via membrane separation and hydrogen from electrolysis of pretreated seawater. The results are based on process simulation outcomes obtained using ASPEN v14, and the detailed cost breakdown is derived from modular costing methodologies applied to preliminary process designs and sensitivity analyses of the levelized cost of ammonia (LCOA) with respect to the main variables. A comparative review of LCOA values reported in the literature for offshore and onshore e-NH₃ plants is provided. An estimated CAPEX of 5.99 M EUR (equivalent to 0.53 M EUR/y), OPEX of 1.58 M EUR/y, and an LCOA of 2408 EUR/tNH₃ are obtained, with equipment investment and operating costs identified as the most influential parameters. The results highlight the need for supraregional techno-economic studies considering optimal offshore wind availability within a collaborative interregional framework. Full article

In order to reduce the energy consumption of a reverse osmosis seawater desalination system, a study was conducted on the port plate pair that affects the efficiency of the integrated seawater desalination power recovery motor pump. Based on its structural characteristics, a reverse thrust model of the port plate pair was established. A fluid–solid heat multi-field coupling simulation platform was built to study the temperature characteristics of the port plate pair under different conditions. A design method was proposed to use the local temperature characteristics of the port plate pair as the range of residual compression force coefficient values. When the residual compression force coefficient is determined to be 1.05, the compression force of the port plate pair is 33,019 N, the power loss is 307 W, and the temperature reaches 45.1 °C. The simulation accuracy is verified to be 97.31% through experiments. This solved the power loss and local high-temperature problems of the port plate pair and improved the efficiency of the integrated seawater desalination power recovery motor pump. Full article

The growing occurrence of emerging contaminants, particularly pharmaceutical residues, in aquatic environments represents a major environmental concern worldwide. While pharmaceutical contamination has been increasingly studied in marine systems, port environments remain largely understudied despite their complex anthropogenic pressures. This study investigates the occurrence, spatial distribution, and potential environmental risk of pharmaceutical residues in surface waters of the port of Cartagena, a multifunctional port on the Spanish Mediterranean coast. Fifteen pharmaceuticals were analysed across nine sampling sites, of which six were not detected. Diclofenac and several antibiotics (erythromycin, azithromycin, clindamycin, and trimethoprim) were the most frequently detected compounds, reaching maximum concentrations of up to 12,294.1 ng/L. Elevated concentrations were observed at sites associated with intense human activity, while the detection of multiple pharmaceuticals at a designated Special Area of Conservation suggests additional diffuse pollution sources, likely linked to insufficient wastewater management in nearby informal settlements. Most detected concentrations exceeded established environmental-quality or risk-threshold values, indicating a potential threat to marine ecosystems. These findings highlight the vulnerability of port environments to pharmaceutical pollution and underscore the need for continuous monitoring programs to support effective environmental management and biodiversity protection in coastal port areas. Full article

Multiple factors, including global climate change and rising sea levels, increase the frequency and intensity of seawater intrusion. However, most previous studies have not regarded seawater intrusion as a typical accident for systematic safety risk assessment. In view of this, this paper comprehensively employed the fault tree model, the “Man-Machine-Material-Method-Environment” system theory, the Bayesian network model, and the Attack-Defense game theory to conduct qualitative and quantitative analyses concerning seawater intrusion. The main research results were as follows: the fault tree model was applied to sort the hazard-inducing factors from the perspectives of nature and humans, which were further categorized based on the theoretical framework of the “Man-Machine-Material-Method-Environment” (4M1E) theory. Based on the Bayesian network model, and incorporating assessments of the existing defense conditions of the target port, the occurrence probability of seawater intrusion at the port was calculated as 3.05%. Simultaneously, the influence weights of the 4M1E factors on seawater intrusion were quantified; environmental and mechanical factors ranked as the top two contributors, accounting for 57.79% and 29.70% of the total impact, respectively. Utilizing the Attack-Defense game theory, two key risk evolution paths of seawater intrusion were identified, with occurrence probabilities of 7.627‰ and 4.164‰. Typical disaster cases clarified the underlying mechanisms by which these key risk paths triggered seawater intrusion, and targeted prevention and control measures were proposed accordingly. The research findings can not only deepen the systematic understanding of seawater intrusion as a typical marine disaster but also provide technical references for governments and enterprises to optimize their risk management systems. Full article

To investigate the distribution, sources, and partitioning of heavy metals at the sediment–water interface in the northern Jiangsu coastal waters, seawater and sediment samples were collected from 24 stations east of Yanwei Port in April 2021. The concentrations of seven heavy metals (Cu, Pb, Zn, Cd, Cr, Hg, and As) and environmental parameters were determined. Methods including principal component analysis (PCA), random forest (RF), positive matrix factorization (PMF), the partition coefficient (Kp), and the source-specific partition coefficient (S-Kp) were applied. The results showed the following: (1) The overall concentration order was Zn > Cu > As > Pb > Cd > Hg in seawater and Zn > Cr > Cu > Pb > As > Hg > Cd in sediments, with Cd and Pb characterized by high spatial variability. (2) PCA and RF indicated that dissolved heavy metals were mainly influenced by dissolved oxygen, petroleum, phosphate, and dissolved inorganic nitrogen, with DIN playing a common dominant role. PMF revealed three main sources for sediment metals: agricultural (contributing notably to Cu and Zn), traffic and industrial exhaust (dominating Pb, Cr, and Hg inputs), and industrial (primarily affecting Cd, Cr, and Pb). (3) Kp analysis suggested that Pb, As, and Cu were readily adsorbed by sediments, while Cd, Hg, and Zn tended to remain dissolved. Critically, S-Kp demonstrated source dependent partitioning: Pb derived from industrial sources was almost entirely associated with sediments, while Cu and Zn originating from traffic and industrial exhaust emissions were predominantly present in the aqueous phase, and Cu and Pb derived from agricultural sources were largely deposited in sediments. These findings provide a scientific basis for heavy metal pollution control in the region. Full article

The phenomenon of seawater flow-freezing exists during ballast water injection and drainage in polar vessels, but the heat transfer and ice evolution behaviors under low-temperature flow conditions remain unclear. This study developed a computational model for ballast tank freezing using the volume of fluid (VOF) and enthalpy–porosity method, and constructed a scaled experimental platform for the simulation model validation. Based on this model, the flow-heat transfer and ice evolution process in the ballast tank are analyzed in detail, with a focus on the influence of injection velocity, pipe diameter, and position on seawater freezing characteristics. The results show that during low-temperature water injection, phase change occurs preferentially in the tank bottom region, with ice presenting as a slurry morphology; when injection velocity increases from 0.25 m/s to 3.5 m/s, the maximum ice-phase volume fraction increases by 48.9%, indicating faster flow accelerates phase-change freezing; compared to other diameters, DN150 piping exhibits the highest turbulent kinetic energy (0.054 m²/s²) and the maximum shear stress (12.49 Pa), demonstrating optimal freezing resistance; compared to bottom injection, sidewall injection intensifies heat transfer/icing near tank walls and increases ice-clogging risk around ports. This study reveals intrinsic mechanisms of dynamic ice-blockage evolution, providing theoretical basis for anti-clogging design in polar ship systems. Full article

Background/Objectives: Environmental DNA (eDNA) is increasingly recognised as a powerful molecular tool for biodiversity monitoring, enabling the detection of species through trace genetic material found in environmental samples. This study investigates the utility of eDNA analysis for identifying vertebrate marine species in the central Mediterranean, with a focus on taxa that serve as ecological indicators to local ecosystems. Methods: Seawater samples were collected from nine sites around the Maltese Islands between May and August 2021, at depths ranging from 2 to 5 m. Samples were filtered and DNA was extracted, amplified and sequenced. The resulting sequences were processed through a bioinformatics pipeline, clustered into molecular operational taxonomic units (MOTUs) and assigned taxonomic identities using reference databases. Results: This study led to the detection of 70 MOTUs, including ecologically important species such as the loggerhead turtle (Caretta caretta), the striped dolphin (Stenella coeruleoalba) and the bottlenose dolphin (Tursiops truncatus), underscoring the method’s effectiveness in the detection of taxa of conservation value. Additionally, we detected a number of overlooked Blenniidae and Gobiidae taxa and deep-water or rarely encountered species such as the ocean sunfish (Mola mola), Cornish blackfish (Schedophilus medusophagus), Haifa grouper (Hyporthodus haifensis) and Madeira lantern fish (Ceratoscopelus maderensis). eDNA of the invasive dusky spinefoot (Siganus luridus) and that of the lumpfish (Cyclopterus lumpus), a species not previously recorded in Maltese waters, was also detected during this study. The latter’s detection highlights the potential of this methodology as an early detection tool for biological invasions. Conclusions: These findings support the integration of eDNA surveillance into marine biodiversity monitoring frameworks, particularly within marine protected areas to monitor native indicator taxa and assess the effectiveness of conservation measures, but also in ports and bunkering zones, where the risk of alien species introduction is elevated, with potential subsequent invasive species expansion that impacts native species and habitats. Full article

Port maintenance causes large quantities of dredged sediment throughout the world. The disposal of this material in authorised landfills is economically disadvantageous, as well as being at odds with a circular economy model with a reduced impact on the environment. The application of stabilization/solidification treatment to dredged marine sediments allows an improvement of their physical and mechanical properties, together with the production of cement-based materials that can be used for road construction, as well as for making blocks and bricks. In this study, an experimental laboratory investigation is carried out on two samples of sandy sediments collected from the Mola di Bari harbour (Southern Italy), to identify sustainable management options for recovering materials that will be dredged. To assess the influence on mortars made from sediments with variable organic matter content and seawater, these were characterised from a chemical–physical point of view before and after washing treatment and oxidative processes. The products of the Stabilization/Solidification (S/S) treatment were evaluated in terms of workability, flexural and compressive strengths, and, furthermore, a microstructural study was conducted using SEM-EDX and optical microscopy to analyse the internal structure of the materials. The mechanical performance evaluation clearly demonstrated organic matter’s negative impact on strength development, resulting in a 16% reduction. Pre-treatments, such as sediment washing, effectively improved the performance of treated sediments (e.g., 24% increase in compressive strength). This study aims to demonstrate the benefits of recycling marine sediments in cement-based materials, highlighting how this process can enhance circularity and sustainability while reducing the environmental impact of dredging activities. Full article

Coastal marine ecosystems are facing serious ecological risks from metals pollution, threatening biodiversity and human health. The main objective of this study is to evaluate the spatial distributions and ecological risks of dissolved cadmium (Cd), lead (Pb), and copper (Cu) in the Shandong Peninsula coastal areas, China. Two sampling campaigns were conducted at 21 sites in early spring 2025 to measure the concentrations of the three trace metals in the study area using an electrochemical detection system. The results revealed higher metals concentrations in nearshore areas (e.g., port entrances, aquaculture zones, and estuaries). Specifically, the Cd, Pb, and Cu concentrations in the study area ranged from 0 to 0.079 µg L⁻¹, 0.30 to 0.84 µg L⁻¹, and 2.19 to 4.79 µg L⁻¹, with average concentrations of 0.033, 0.55, and 3.18 µg L⁻¹, respectively. The contamination factors (C_f) of the three metals were below 1, indicating low pollution levels and thus meeting China’s Class I seawater quality standard. However, the ecological risk assessment, employing complementary methods, revealed varying interpretations: the risk quotient (RQ), based on species sensitivity distribution and predicted no-effect concentrations (PNECs), indicated low risks associated with Cd and Pb (RQ < 0.1) but a high risk for Cu (RQ > 1) at all sites, attributable to the exceedance of Cu’s protective threshold (0.46 µg L⁻¹), despite its low C_f. These findings highlight the need for continuous monitoring of Cu due to its high ecological impacts. In contrast, the Hakanson potential ecological risk index (ERI), which incorporates toxicity coefficients, suggested overall low risks (ERI < 150) for the combined metals; however, Cd contributed approximately 70% to the ERI due to its high toxicity coefficient, warranting attention despite the low individual Erⁱ values for Cd across the study area. This study provides valuable recent data on metals pollution dynamics in the Shandong Peninsula coastal areas, offering a scientific basis for developing marine pollution control policies and sustainable marine resource management. Full article

This study provides a comprehensive six-year assessment (2018–2023) of heavy metal contamination in the Romanian Black Sea sector, integrating data from seawater, surface sediments, and benthic mollusks. Sampling was conducted across a broad spatial gradient, including transitional, coastal, shelf, and offshore waters beyond 200 m depth. Concentrations of six potentially toxic metals, including cadmium (Cd), lead (Pb), nickel (Ni), chromium (Cr), copper (Cu), and cobalt (Co), were measured to evaluate regional variability, potential sources, and ecological implications. Results indicate some exceedances of regulatory thresholds for Cd and Pb in transitional and coastal waters, associated with Danube River input and coastal pressures. Seabed substrate analysis revealed widespread enrichment in Ni, moderate levels of Cr, and sporadic Cd elevation in Danube-influenced areas, along with localized hotspots of Cu and Pb near port and industrial zones. Biological uptake patterns in mollusks (bivalves Mytilus galloprovincialis and Anadara inequivalvis and gastropod Rapana venosa) highlighted Cd among key metals of concern, with elevated Bioconcentration Factor (BCF) and Biota–Sediment Accumulation Factor (BAF). Offshore waters generally exhibited lower pollution levels. However, isolated exceedances, such as Cr outliers recorded in 2022, suggest that deep-sea inputs from atmospheric or maritime sources may be both episodic in nature and underrecognized due to limited monitoring coverage. The combined use of water, sediment, and biota data emphasize the strength of multi-matrix approaches in marine pollution evaluation, revealing persistent nearshore pressures and less predictable offshore anomalies. These findings contribute to a more complete understanding of heavy metal distribution in the northwestern Black Sea and provide a scientific basis for improving long-term environmental monitoring and risk management strategies in the region. Full article

This dataset presents environmental observations collected in August 2021 from 18 port and harbor sites located around Jeju Island, Korea. It includes physical, biogeochemical, and greenhouse gas (GHG) variables measured in surface seawater, such as temperature, salinity, dissolved oxygen, nutrients, chlorophyll-a, pH, total alkalinity, and dissolved inorganic carbon. Concentrations and air–sea fluxes of nitrous oxide (N₂O), methane (CH₄), and carbon dioxide (CO₂) were also quantified. All measurements were conducted following standardized analytical protocols, and certified reference materials and duplicate analyses were used to ensure data accuracy. Consequently, the dataset revealed that elevated nutrient accumulation in port and harbor waters and GHG concentrations tended to be higher at sites with stronger land-based influence. During August 2021, most sites functioned as sources of N₂O, CH₄, and CO₂ to the atmosphere. This integrated dataset offers valuable insights into the influence of anthropogenic and hydrological factors on coastal GHG dynamics and provides a foundation for future studies across diverse semi-enclosed marine systems. Full article

Preventing fouling is crucial for maintaining ship performance, as it reduces speed, increases fuel consumption, raises greenhouse gas emissions, and spreads invasive species. Irgarol 1051, an antifouling agent (2, methythiol-4, tert-butylamino, 6-cyclopropylamino, s-triazine), is a toxic compound that impacts various marine species. It inhibits algal growth and disrupts key metabolites, posing a threat to the marine ecosystem. This study aimed to assess the toxic effects of Irgarol 1051 on Chlorella salina and Dunaliella bardawil, two nutrient-rich marine algae commonly used in fish feed. In addition, the suitability of the Mediterranean Sea coast for algal proliferation was assessed using geospatial techniques. The data were statistically examined using a two-way ANOVA test. Lethal and sublethal effects of Irgarol 1051 were measured in the laboratory to identify the consequences of this biocide on certain metabolite compositions. EC50 for C. salina and D. bardawil was estimated to be 0.50 µg·L⁻¹ and 0.025 µg·L⁻¹ respectively. IR spectroscopy of total cell constituents, protein profile, and the damaging effects of antioxidants have been evaluated for the two algal species. The findings of this study revealed that Irgarol 1051 negatively affected all the examined metabolites in both algal species, with more pronounced impacts on the wall-less alga Dunaliella bardawil compared to the walled alga Chlorella salina. A notable increase in total antioxidants was observed in both algae as the Irgarol concentration increased. The study reveals high algal growth areas near the Nile Delta along the Egyptian coast, potentially vulnerable to the effects of Irgarol 1051 due to nutrient runoff and eutrophication. The spatial analyses showed that the growth of C. saline and D. bardawil in Egyptian seawater is high in front of the Nile delta governorates: Port Said, Damietta, and Dakhalia shores reporting 6, 4.5, and 4 mg·m⁻³, respectively. The level of mass chlorophyll “a” in front of the Egyptian northern governorates can be ordered as follows: Port Said > Damietta > Dakahlia > North Sinia > Kafr El-Sheikh > Alexandria > Matrouh. This study highlights the use of spatial analyses to assess algal distribution, pollution impact, and ecosystem vulnerability along the Egyptian Mediterranean coast for effective environmental management. Full article

This study assesses the spatial distribution and contamination levels of some heavy metals (HMs), i.e., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and lead (Pb), in seawater and surface sediments along the Romanian Black Sea coast (RBSC). Sampling was conducted at 40 stations across 12 transects during May–June 2021, and the measured levels of HM concentrations were compared with Environmental Quality Standards (EQS), i.e., maximum allowable concentration (MAC) values, for seawater and effects range-low (ERL) thresholds for sediments. HM concentrations were measured using high-resolution continuum source atomic absorption spectrometry (HR-CS AAS). In seawater, the levels of Cd, Cu, and Pb concentrations exceeded the MAC values at three stations located in areas influenced by the Danube River or anthropogenic activities. In sediments, exceedances of ERL thresholds were found for Ni at 11 stations, for Cu at three stations, and for Pb at one station. HM contamination of sediment samples collected from these stations can be caused by both natural and anthropogenic sources, e.g., the Danube River, rock/soil weathering and erosion, agricultural runoff, port and construction activities, maritime and road transport, coastal tourism, petrochemical industry, wastewater discharges, offshore oil and gas extraction. Principal Component Analysis (PCA) provided valuable information about the relationships between relevant variables, including water depth and HM concentrations in seawater and sediments, and potential sources of contamination. The results highlight the influence of fluvial inputs and localized human activities on HM contamination. While the overall chemical status of Romanian Black Sea waters and sediments remains favorable, targeted management strategies are needed to address localized pollution hotspots and mitigate potential ecological risks. These findings provide valuable insights for environmental monitoring and sustainable coastal management. Full article