Regional Studies in Marine Science最新文献

{"title":"Environmental correlates of parasitic isopod Portunion conformis abundance in mud crabs (Scylla spp.) from tropical coastal aquaculture ponds","authors":"Xoan Bich Vo,&nbsp;Truc Van Le,&nbsp;Tung Gia Nguyen,&nbsp;An Thuy La,&nbsp;De Ngoc Doan,&nbsp;Thai Thanh Tran","doi":"10.1016/j.rsma.2026.105304","DOIUrl":"10.1016/j.rsma.2026.105304","url":null,"abstract":"<div><div>Parasitic isopods are an emerging concern in mud crab aquaculture in tropical coastal ponds, yet the pond conditions associated with infection remain poorly characterised. This study examined the environmental correlates of <em>Portunion conformis</em> abundance in mud crabs (<em>Scylla</em> spp.). Thirteen aquaculture ponds in the Ca Mau Peninsula, Vietnam, were sampled twice monthly during 2025. Parasite abundance was averaged across the 3–5 crabs collected from each pond at each sampling time, yielding 308 pond-level records paired with seven water quality variables: pH, temperature, salinity, dissolved oxygen, transparency, chemical oxygen demand, and H₂S. <em>P. conformis</em> was detected in 85.39% of these records (263 of 308). Three machine learning models, XGBoost, Random Forest, and Support Vector Machine, were used to examine the associations between pond-level abundance and these variables, and were benchmarked against a generalized linear model and a generalized additive model; a generalized additive mixed model was fitted as a sensitivity analysis to account for pond-level random effects. Because ponds were sampled repeatedly, model performance was assessed by pond-blocked cross-validation with entire ponds held out. XGBoost performed best (leave-one-pond-out R² = 0.515), with model ranking unchanged across validation schemes. SHAP analysis identified temperature and H₂S as the most important correlates of abundance, while pH, chemical oxygen demand, salinity, and transparency showed weaker, nonlinear associations. These results indicate that <em>P. conformis</em> abundance is associated with multiple pond conditions, including thermal stress, reduced benthic conditions, organic enrichment, and salinity, and provide ecological evidence to support parasite surveillance and water quality monitoring in tropical mud crab aquaculture.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105304"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Persistent PAH contamination in a tropical megacity bay: Sediment sources and chemical hazards","authors":"Thiago A.S.N. Moraes,&nbsp;Carlos G. Massone,&nbsp;Kamila C. Gramlich,&nbsp;Renato S. Carreira","doi":"10.1016/j.rsma.2026.105279","DOIUrl":"10.1016/j.rsma.2026.105279","url":null,"abstract":"<div><div>Guanabara Bay, located in the state of Rio de Janeiro, southeastern Brazil, is a highly urbanized tropical estuary historically affected by sewage discharge and petroleum-related activities. Despite extensive contamination documentation, integrated assessments combining concentration data, source apportionment, and quantitative chemical risk evaluation remain lacking, limiting a diagnosis of the bay’s health. Herein, parental and alkylated polycyclic aromatic hydrocarbons (PAHs) were quantified in surface sediments sampled from 19 stations in 2022 and the results were compared with datasets spanning the past two decades. Total PAH concentrations (Σ37PAHs) ranged from 310 to 71,070 ng g⁻¹ (median of 7317 ng g⁻¹), confirming persistent, spatially heterogeneous contamination, with hotspots associated with port–industrial areas and offshore oil logistics. A source apportionment assessment combining relative composition, hierarchical clustering, and fuzzy-logic inference revealed the accumulation of degraded pyrogenic sources throughout the bay, with a relatively higher contribution of petrogenic signatures in shipping- and fuel-handling influenced areas. A chemical risk assessment was conducted employing the Hazard Quotient for Chemicals (HQC) within a weight-of-evidence framework, with most stations classified as presenting severe risk. Comparisons with previous datasets suggest limited evidence of attenuation over the past two decades. These findings highlight the role of sediments as long-term contaminant reservoirs and provide evidence that coastal systems under multiple anthropogenic pressures require integrated management actions to ensure the sustainable use of ecosystem services.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105279"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution of Cassiopea sp. in Xel-Há Inlet, Mexico, and their relationship with benthic cover and physicochemical variability (2022–2024)","authors":"Villegas-Hernández Harold,&nbsp;Herrera-Martín Ivanna,&nbsp;Pech-Puch Dawrin,&nbsp;Monroy-López Juan Carlos,&nbsp;López-Aguiar Korynthia,&nbsp;Aguilera-Rivera Diana,&nbsp;Guillén-Hernández Sergio,&nbsp;Manzanero-Vázquez Eddie Alejandro,&nbsp;Raigoza-Figueras Rodolfo","doi":"10.1016/j.rsma.2026.105283","DOIUrl":"10.1016/j.rsma.2026.105283","url":null,"abstract":"<div><div>In recent years, a proliferation of the upside-down mangrove medusa, <em>Cassiopea</em> sp., has been observed in the Xel-Há inlet (Quintana Roo, Mexico), likely linked to changes in water physicochemical variables and excessive nutrient loading. Therefore, in the present study, the distribution and abundance of <em>Cassiopea</em> sp. were analyzed from 2022 to 2024, conducting four samplings per year (February, May, August, November), using 40 transects across four zones: Brazo Sur (BS), Brazo Norte (BN), Centro (CN), and Bocana (BO), to estimate the density and sizes of medusa, the benthic cover of sand, seagrass, algae, and turf. Additionally, water quality studies were conducted to determine physicochemical variables (pH, dissolved oxygen, temperature, and salinity) and nutrient concentrations [ammoniacal nitrogen (N-NH₄⁺), nitrate nitrogen (N-NO₃^-), nitrite nitrogen (N-NO₂^-), dissolved inorganic nitrogen (the sum of N-NH₄⁺ + N-NO₃^- + N-NO₂^-), soluble reactive phosphorous (SRP), and organic matter (OM)], and to identify relationships between these variables and medusae density. During the study, a total of 6956 <em>Cassiopea</em> sp. specimens were recorded. The highest number of specimens was observed in the 2023 sampling (n = 3749), compared to 2022 (n = 2069) and 2024 (n = 1138). The multivariate analysis of variance (years, months, and zones) showed significant differences (p-value &lt; 0.05) in medusae density, with higher average values in 2023 and in the BS area compared to the other years and zones. Furthermore, significant differences were noted in the average specimen size, with those recorded in 2024 (the month of May and the zone CN) being significantly smaller in diameter. The multivariate analysis indicated that 85.42% of the variance in medusae density was explained by the predictor variables, with the BS and BN samples exhibiting higher medusae density associated with higher benthic cover of TURF and macroalgae and higher concentrations of organic matter.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105283"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate warming and microplastic pollution in the arctic: Exploring synergies and joint governance approaches","authors":"Luhe Feng","doi":"10.1016/j.rsma.2026.105290","DOIUrl":"10.1016/j.rsma.2026.105290","url":null,"abstract":"<div><div>The Arctic, as an “amplifier” of global climate change, is under dual environmental pressure from climate warming and microplastic pollution. Climate warming accelerates sea ice melting, releasing previously trapped microplastics, while microplastics, in turn, may further contribute to warming by reducing surface albedo and altering ecosystem functions. Through literature analysis and current environmental data, this study identifies a bidirectional relationship between these two factors, forming a negative feedback loop that threatens Arctic ecological stability. However, the absence of an integrated governance framework, the mismatch between policy cycles and environmental change, and geopolitical conflicts hinder effective joint responses. To address this, the study proposes innovative strategies including the establishment of cross-sectoral governance mechanisms, the integration of AI-based environmental prediction tools, and the creation of carbon–plastic credit swap systems. These approaches aim to reduce institutional fragmentation, promote international cooperation, and build a feasible joint governance model to enhance Arctic ecological resilience and support the region’s sustainable development.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105290"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of the contribution rates of multiple 137Cs source pathways to the ocean after the Fukushima Daiichi Nuclear Power Station accident","authors":"Yuki Takahashi,&nbsp;Munehiro Asao,&nbsp;Yuko Hatano,&nbsp;Yugo Kinoshita,&nbsp;Daisuke Tsumune","doi":"10.1016/j.rsma.2026.105272","DOIUrl":"10.1016/j.rsma.2026.105272","url":null,"abstract":"<div><div>More than a decade after the Fukushima Daiichi Nuclear Power Station (F1NPS) accident, ¹³⁷Cs concentrations in the ocean have not yet returned to pre-accident levels. This is attributable to continued releases from the F1NPS site and its vicinity, and from surrounding rivers. Quantifying the contributions of these pathways is essential for understanding the long-term dynamics of ¹³⁷Cs. In this study, we estimated the contribution rates of source pathways to oceanic ¹³⁷Cs concentrations using an analytical approach based on time-series data. The analysis covered 2013-2016 and focused on direct release, fluvial discharge, and pre-accident background contributions. The results showed that in the Fukushima coastal region, where multiple source pathways are closely distributed, contribution patterns differed markedly even between adjacent sites due to subtle differences in their spatial relationships with the sources. This indicates that high spatial resolution is required to resolve source contributions in this region. In contrast, in the Miyagi coastal region, observation sites that were spatially close or shared similar geographical settings exhibited similar contribution patterns, allowing classification into several coastal subregions. This suggests that source contributions over a wide area can be estimated using observations from a few representative sites. These results demonstrate that site-specific source contributions can be extracted solely through analysis of concentration time-series data, without modeling complex advection–diffusion processes. Comparison with previous numerical simulation studies showed relatively good agreement up to 2015, whereas after 2016, simulations that did not account for background ¹³⁷Cs concentrations tended to overestimate the contribution of fluvial discharge.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105272"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding lithium bioaccumulation in bivalve mollusks from the French and Korean Mussel Watch programs: A cross-national monitoring perspective","authors":"Daniel F. Araújo,&nbsp;Hyeryeong Jeong,&nbsp;Kongtae Ra,&nbsp;Anne Pellouen-Grouhell,&nbsp;Nathalie Vigier","doi":"10.1016/j.rsma.2026.105281","DOIUrl":"10.1016/j.rsma.2026.105281","url":null,"abstract":"<div><div>Lithium (Li) is a strategic metal in the context of the global energy transition, but its baseline levels in marine biota remain poorly constrained. In this study, we measured Li concentrations in bivalve mollusks (<em>Mytilus spp.</em> and <em>Crassostrea gigas</em>) from 149 sampling stations through French and South Korean Mussel Watch programs to create the first standardized cross-national coastal baseline. Lithium levels ranged from 0.23 to 2.88 µg g⁻¹ dw, with a median of 0.96 µg g⁻¹ dw, and showed no significant differences between species or countries, indicating a consistent large-scale background signal. Strong positive correlations between Li and Al (p &lt; 0.001) suggest that Li bioaccumulation in bivalves mainly results from ingesting suspended particulate matter. Most sampling locations adhered to conservative Li–Al scaling, supporting a primarily geogenic origin. However, deviations in Li/Al ratios at specific sites highlight non-geogenic enrichments. A precautionary screening benchmark based on the 90th percentile (1.50 µg g⁻¹ dw) and an enrichment factor index based on Li/Al normalization are proposed to aid future monitoring and to pinpoint sites requiring further study to confirm potential anthropogenic contamination using complementary approaches, including dissolved-phase measurements, sediment analyses, and isotopic fingerprinting. The reference values presented here, therefore, provide a necessary starting point for biomonitoring future trends and potential emerging pressures associated with increasing Li production and environmental releases.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105281"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plan B on the reef: Rising temperatures induce a prey shift in Drupella cornus from Acropora to Pavona in Mauritius, Western Indian Ocean","authors":"Tanya Toofany,&nbsp;Shakeel Yavan Jogee,&nbsp;Marwyn Anasamy,&nbsp;Sundy Ramah,&nbsp;Jens Floeter,&nbsp;Ranjeet Bhagooli,&nbsp;Deepeeka Kaullysing","doi":"10.1016/j.rsma.2026.105303","DOIUrl":"10.1016/j.rsma.2026.105303","url":null,"abstract":"<div><div>Excessive corallivory by gastropods of the genus <em>Drupella</em> is an emerging threat causing considerable coral loss in the Indo-Pacific. However, the prey preferences around Mauritius in the Western Indian Ocean remain poorly understood, particularly under warming ocean conditions. This study assessed the distribution of <em>Drupella cornus</em> and the effect of temperature on its coral prey preference. Field surveys were conducted in December 2022 at two sites, namely, Le Bouchon and Grand Gaube, while <em>ex-situ</em> feeding experiments with the gastropods and corals were performed at 26°C, 29°C, and 32°C to simulate thermal stress. Field observations revealed a density of 122.80 ± 31.30 individuals m⁻² at Le Bouchon and 2.13 ± 0.46 individuals m⁻² at Grand Gaube. <em>In situ</em>, <em>Drupella</em> spp. were mainly found on <em>Pavona</em> spp., branching <em>Acropora</em> sp., massive <em>Porites lutea</em> and branching <em>Porites</em> sp. Experimental prey preference trials for <em>Drupella</em> feeding on corals corroborated field observations: across all three temperature categories combined, 11.11 ± 15.16% and 5.55 ± 6.82% individuals were attracted to branching <em>A. muricata</em> and massive <em>Porites lutea</em>, respectively. At 32°C, <em>Pavona cactus</em> hosted the highest percentage of <em>D. cornus</em> (11.67 ± 12.58%). This study highlights the adaptive response of <em>D. cornus</em> in terms of prey switching and a hierarchical feeding strategy, putting resilient coral species at risk of predation in the aftermath of bleaching events. Unlike many Indo-Pacific nations, Mauritius currently lacks a formal monitoring programme for <em>Drupella</em>, making these findings critical for informing future coral reef management strategies.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105303"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148658765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Life-history traits and secondary production of Donax striatus in a tropical macrotidal sandy beach of the Amazon coast","authors":"Ewertton Souza Gadelha,&nbsp;Daiane Aviz,&nbsp;Thuareag Monteiro Trindade dos Santos,&nbsp;Fábio Campos Pamplona Ribeiro,&nbsp;Marcelo Petracco","doi":"10.1016/j.rsma.2026.105257","DOIUrl":"10.1016/j.rsma.2026.105257","url":null,"abstract":"<div><div>Clams of the genus <em>Donax</em> are frequently a dominant group of the invertebrate community on sandy beaches, supporting artisanal and recreational fisheries around the world and are important components in the conversion of phytoplankton primary productivity to macrobenthos. This study aimed to assess for the first time the data on population structure (spatial-temporal distribution) and life history traits (growth, mortality, and secondary production) of <em>Donax striatus</em> on a tropical macrotidal Brazilian Amazon sandy beach. Monthly samplings were carried out from March 2015 through March 2016 along three transects established perpendicularly to the shoreline. The results showed that <em>D. striatus</em> has an aggregated distribution, and its density increases seaward and during the rainy season. The species exhibited fast growth (K= 1.60 year ⁻¹), short life span (∼1 years), high mortality rate (Z &gt; 3 year⁻¹) typical of tropical donacid populations. Despite the low mean annual biomass (0.19 g AFDM m⁻²) and annual production (0.41 g AFDM m⁻² year⁻¹), the high production-to-biomass ratio (2.19 year⁻¹) showed the importance of <em>D. striatus</em> in the energy flux of the Amazonian beach. Consequently, this data provides a baseline for the management and conservation of this species, which inhabits coastal environments increasingly threatened by anthropogenic impacts.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105257"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148658820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diurnal variability of the deep chlorophyll maximum in the Bay of Bengal","authors":"Pavithra Balamurugan,&nbsp;Alexkirubakaran Augustin Raj,&nbsp;Saravanakumar Ayyappan","doi":"10.1016/j.rsma.2026.105264","DOIUrl":"10.1016/j.rsma.2026.105264","url":null,"abstract":"<div><div>Using high-resolution, diurnally resolved observations, this study examines the physical and biogeochemical controls on the deep chlorophyll maximum (DCM) in the southwestern Bay of Bengal during the post–northeast monsoon transition (February 2024). Co-located hydrographic, optical, dissolved oxygen, and nutrient measurements were collected along an offshore latitudinal transect spanning Chennai, Puducherry, and Karaikal. A persistent DCM was observed between 55 and 80 m, aligned with the upper thermocline where light levels were reduced to ∼0.5–1% of surface photosynthetically available radiation. Chlorophyll-a concentrations within the DCM ranged from 0.6 to 1.2 mg m⁻³ and deepened northward in response to reduced haline stratification, deeper thermoclines, and improved optical clarity. Despite pronounced diurnal heating-cooling cycles at the surface, the DCM depth exhibited only minor fluctuations, indicating strong density-controlled confinement. Nutrient concentrations within the DCM ranged from 1.5 to 3 µmol L⁻¹ nitrate, 0.10–0.30 µmol L⁻¹ ammonium, and 2.5–5 µmol L⁻¹ silicate, while dissolved oxygen remained relatively uniform (3.4–4.0 mg L⁻¹). These results indicate that the Bay of Bengal DCM is closely associated with a stable density structure and exhibits variability consistent with photoacclimation and potential in situ nutrient recycling, rather than vertical displacement.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105264"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148658821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pollution characteristics and ecological risk assessment of heavy metals and total petroleum hydrocarbons in sediments from panjin port and its adjacent dumping areas, China","authors":"Jize Liu,&nbsp;Xinyu Ren,&nbsp;Wenchao Yang,&nbsp;Shuang Song,&nbsp;Xinlong Zhou,&nbsp;Zhaowei Wang,&nbsp;Jianbo Han","doi":"10.1016/j.rsma.2026.105284","DOIUrl":"10.1016/j.rsma.2026.105284","url":null,"abstract":"<div><div>In this study, Panjin Port and two dredged sediment disposal areas (Panjin Dumping Area and Yingkou Dumping Area) are investigated to assess the spatial distribution of pollutant concentrations and changes in the chemical fractions of heavy metals and total petroleum hydrocarbons (TPHs) in sediments at different locations. The ecological risks associated with these contaminants are also assessed. Based on 39 surface sediment samples collected in June 2024, the highest concentrations of heavy metals and TPHs are found in the port area, particularly near the industrial zone and river estuary. BCR sequential extraction results indicate that heavy metals exhibit similar dominant fractions and proportional distributions across sediments from the port and two dumping areas in this single sampling campaign. The metals under investigation are predominantly found in the residual fraction, whereas Cd is primarily present in the non-residual fractions. Pb exhibits the highest proportion in the reducible fraction among the metals, which is associated with Fe-Mn oxides. The Geoaccumulation Index (I_geo) shows that Cd contamination is the most severe. The Global Contamination Factor (GCF) suggests that both Cd and Pb pose the highest environmental risks. The Toxic Risk Index (TRI) demonstrates that Cr poses the highest toxic risk. The Pollution Load Index (PLI) assessing the combined contamination from heavy metals and TPHs indicates that some sampling points in the port area and Yingkou dumping area are suffering from progressive contamination, while the Panjin dumping area is unaffected. All four indicators suggest that the overall contamination levels among the three areas are ranked as Panjin Port Area &gt; Yingkou Dumping Area &gt; Panjin Dumping Area. Pearson correlation analysis reveals that the distribution of contaminant concentrations is closely related to the sediment grain size.</div></div>","PeriodicalId":21070,"journal":{"name":"Regional Studies in Marine Science","volume":"101 ","pages":"Article 105284"},"PeriodicalIF":2.7,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148638144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}