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Streamflow records are biased toward large streams and rivers, yet small headwater streams are often the focus of ecological research in response to climate change. Conventional flow measurement instruments such as acoustic Doppler velocimeters (ADVs) do not perform well during low-flow conditions in small streams, truncating the development of rating curves during critical baseflow conditions dominated by groundwater inflow. We revisited an instantaneous solute tracer injection method as an alternative to ADVs based on paired measurements to compare their precision, efficiency, and feasibility within headwater streams across a range of flow conditions. We show that the precision of discharge measurements using salt dilution by slug injection and ADV methods were comparable overall, but salt dilution was more precise during the lowest flows and required less time to implement. Often, headwater streams were at or below the depth threshold where ADV measurements could even be attempted and transects were complicated by coarse bed material and cobbles. We discuss the methodological benefits and limitations of salt dilution by slug injection and conclude that the method could facilitate a proliferation of streamflow observation across headwater stream networks that are highly undersampled compared to larger streams., (Published 2024. This article is a U.S. Government work and is in the public domain in the USA.)

[Display omitted] • MTZ-AgNPs based rapid, accurate Pb2+ detection. • Characterization of MTZ-AgNPs and mechanism for selective Pb2+ sensing. • Portable microfluidic paper-based devices for on-site Pb2+ detection. • High performance with low detection limits in different analyses. • Successful Pb2+ detection in environmental samples for real-time monitoring. This work presents the development of metronidazole-functionalized silver nanoparticles (MTZ-AgNPs) based LSPR sensing for rapidly detecting Pb2+ ions. Advanced characterization techniques provided insights into the morphological, structural, and surface properties of the MTZ-AgNPs. The sensing mechanism and selective interaction of MTZ-AgNPs with Pb2+ ions were explored, elucidating the binding process. The MTZ-AgNPs-based LSPR sensor showed a very low detection limit of 0.018 μM (3.73 ppb). MTZ-AgNPs-based sensing material was also integrated with smartphone-assisted dual read-out microfluidic paper-based analytical devices (µPADs) for rapid detection of Pb2+ ions. The fabricated devices were associated with color and height changes. The detection limits of developed sensors were 0.05 μM (10.36 ppb) for color change and 0.1 μM (20.72 ppb) height changes associated with dual read-out microfluidic paper-based analytical devices. The practicality of the MTZ-AgNPs-based sensing strategy was demonstrated by detecting Pb2+ in various samples, including soil, rock, air particulates, and water. [ABSTRACT FROM AUTHOR]

Mining operations contribute to higher environmental contaminant levels, such as particulate matter (PM) hosting potentially toxic elements (PTE). This study aimed to comprehensively characterise atmospheric PM in an environment impacted by former tungsten-tin mining exploration at Regoufe mine (Arouca, Portugal). Although this is a deactivated mine, its location near population clusters and integration into a Geopark belonging to the "World Geoparks Network" with frequent presence of hikers highlight the importance of air quality monitoring to keep its Geopark classification. A seasonal and cumulative sampling approach was used, with samples collected over a seasonal period, between April 2022 and April 2023, through passive sampling, wet and dry sedimentation, and air mass filtration. All samples were analysed using SEM-EDS for detailed imaging. Samples from wet deposition and filtration were also analysed with ICP-MS to determine the concentration of the inorganic elements. The PTE determined in the atmospheric particulate matter of the studied area occurs in variable concentrations as a function of the sampling period. The mineralogy of the PM sampled includes Sn- and W-minerals, pyrite, quartz, phosphates, sulfates, and As-oxides. These materials are typical in the site's soils, suggesting their resuspension by the wind and transported to nearby areas. Angular to sub-angular dense particles indicate limited transportation, depositing closer to their emission source. The smaller particles (<25 μm) tended to be angular with sharp edges. Our results emphasise the importance of monitoring potentially toxic elements in atmospheric particulate matter of abandoned mining areas for developing mitigation strategies to reduce impacts on human health and surrounding environments., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Reducing urban fine particulate matter (PM 2.5 ) concentrations is essential for China to achieve the Sustainable Development Goals (SDGs). Identifying the key drivers of PM 2.5 will enable the development of targeted strategies to reduce PM 2.5 levels. This study introduces a machine-learning model that combines CatBoost and the Tree-Structured Parzen Estimator (TPE) to analyze PM 2.5 concentration across 297 cities between 2000 and 2021. SHapley Additive exPlanations (SHAP) were employed to identify the primary factors influencing urban PM 2.5 concentrations. The study revealed that the proposed model has high accuracy in predicting urban PM 2.5 concentrations, achieving a coefficient of determination (R 2 ) score of 96.44%. Socioeconomic and industrial activity are key drivers of PM 2.5 concentrations. This study not only quantifies the primary factors exacerbating or alleviating pollution for each city or province during the 2000-2021 period but also evaluates the influence of operational factors such as technological and public financial expenditures. In 2000, the main contributors to pollution in four heavily polluted cities included substantial nitrogen oxide emissions, inadequate technology investments, and excessive population density and liquefied gas consumption. Due to the rapid reduction in nitrogen oxide emissions, pollution levels in these cities have improved substantially. In the future, the most effective strategies for pollution reduction in these cities will focus on controlling population density and slowing down mining development. The proposed framework serves as a robust evaluation tool and can propose tailored strategies to control PM 2.5 concentrations effectively in each city., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ultrafine particles (UFP), commonly expressed as particle number concentrations (PNC), have been associated with harm to human health yet are currently not regulated or routinely monitored in many places. This has limited the potential for studies of health effects of long-term exposure to UFP. The present study aims to understand the spatial and temporal variation in façade-level UFP exposures in Copenhagen, Denmark. We measured PNC at the façades of 27 residences across the city for approximately 72 h each in two campaigns and continuously at an urban background reference site for twelve consecutive months, using portable monitors (miniature diffusion size classifiers [DiSCminis]). We estimated annual means at the residential sites based on temporal adjustment using reference site data. Furthermore, we co-located the DiSCminis at a regulatory monitoring station on three occasions and compared daily means from our reference site to those from seven fixed-site monitoring stations throughout the city. Annual mean PNC at the reference site was 4715 (SD of hourly mean: 3001) pt/cm 3 , while annual means at 27 residences were slightly higher with a mean of 5201 pt/cm 3 (SD: 807), ranging between 3735 and 6588 pt/cm 3 . The two individual adjusted campaign-specific means at 27 residential sites were weakly correlated (Spearman's correlation 0.11) and had an intra-class correlation coefficient of 0.06 (95%-confidence interval: -0.18, 0.28). Daily PNC at the reference site was highly correlated (R = 0.64-0.84) with PNC monitored at seven fixed-site stations throughout the city. We observed a seasonal trend at the reference site with the highest PNC in spring. Our measurement campaign revealed that façade-level PNC at residences in Copenhagen in 2021-2022 was relatively low with small spatial variability. The large variability in time suggests possibly longer and more frequent measurement campaigns to obtain more stable annual averages. Our study illustrates the challenges of UFP long-term exposure assessment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Monitoring airborne nanoparticles has a vital role in indoor air quality control due to their hazardous effects on human health. Detecting particles becomes more challenging as their sizes decrease. While research-grade instruments like the scanning mobility particle sizer (SMPS) can provide detailed and useful information, they are not practical for personal use due to their size and cost. This study aims to provide a comparable prediction of the temporal size distribution of ultrafine particles (UFPs, <100nm) using mid-cost measurements from a handheld particle sizer, which is more economical but has a narrower detectable size range. To achieve this, the study builds upon a computational modeling approach based on a mass-balance equation to estimate the time-varying particle size distribution, while accounting for particle evolution processes such as coagulation, deposition, and ventilation. The analytical model for indoor UFPs requires prior information regarding particle dynamic behavior, such as the size-resolved deposition rate and source emission rate. This study estimates, rather than pre-determines, the model parameters required for the temporal prediction of indoor UFP size distribution by applying Bayesian parameter inference with the analytical model of indoor aerosol. The results indicate that the present model reasonably predicts the temporal evolution of particle distributions, comparable to that of the SMPS. Furthermore, this study demonstrates the identifiability of model parameters, considering both the entire and detectable size ranges, through variance-based global sensitivity analysis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) are toxic and persistent pollutants that raise concerns due to their accumulative characteristics in the environments and biota. Atmospheric PCDD/Fs can enter various recipient environments and impact the entire ecosystem, thereby arousing more attention. Dry deposition is deemed the dominant migration pathway of atmospheric PCDD/Fs owing to their predominant distributions in the particulate phase. So far, however, there is no universally accepted method and device for dry deposition sampling. Here, we selected two widely used dry deposition samplers that work in different modes, water surface sampler (WSS) and wet-dry deposition sampler (WDDS), and investigated their differences in dry deposition sampling of PCDD/Fs. The average monthly total (∑ 17 PCDD/Fs) dry deposition fluxes (F P ) in the particulate phase measured with the WSS and WDDS were 314 ± 158 pg/m 2 -day (36.6 ± 24.6 pg I-TEQ/m 2 -day) and 108 ± 39.4 pg/m 2 -day (11.4 ± 5.21 pg I-TEQ/m 2 -day), respectively. The difference between flux values indicated their collection efficiencies and artifacts during the sample collection. Higher dry deposition fluxes were measured in winter. This was mainly due to higher atmospheric levels of PCDD/Fs in colder months. The highest and lowest values of PCDD/Fs in both samplers were observed for OCDD and 2,3,4,6,7,8-HxCDF, respectively. This could indicate parallel collection characteristics of both samplers. A high-volume air sampler was used simultaneously with the WSS to determine the ambient air concentrations. Then, dry deposition velocities (V d ) were calculated by dividing the dry deposition fluxes (F p ) by the particulate phase concentrations (C p ) for each PCDD/F congener. The mean dry deposition velocity for PCDD/F congeners was determined with the WSS and WDDS 1.71 ± 0.88 cm/s and 0.64 ± 0.39 cm/s, respectively. Furthermore, the study underscored that water surfaces and shorter sampling periods provided more reliable values for particulate PCDD/F deposition than steel surfaces with prolonged exposure due to the degradation and volatilization effects observed on the latter., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The Western Himalayan mountains, with several riverine systems, are considered one of the most fragile environments in the world. Among them is Beas, a primary river that provides essential ecosystem benefits to thousands of indigenous people in North India. One of the major pollutants, microplastics (MPs), are ubiquitous contaminants, yet their occurrence in the Beas and ecological risk factors remain largely unexplored. Due to extensive tourism and urban-related burdens, the usage and release of enormous amounts of plastics and MPs into the Beas are apparent. Here, we investigated the extent of MPs pollution and subsequent environmental risks in water and sediments from Beas along a stretch of 300 km. Our results showed that MPs were abundant and widely distributed, with the abundance range (mean ± SE) being 46-222 (112.27 ± 12.43) items/L in water and 36-896 (319.47 ± 49.25) items/kg in sediment samples. We found significant differences in MPs' abundance in water but not sediments among the five sampling sites. There was a significant positive correlation between population size and the abundance of MPs, with the highest abundance in populated Kullu and the lowest loads at the remote Dhundi Glacier. Fibers and film were common morphotypes; most items measured <1 mm. Of the eleven polymers identified, the majority were polyethylene. The pollution load index ranged up to 4.99 (low-risk category); however, the polymer hazard index exceeded 1000 (highest-risk category), and the potential ecological risk index was 13,761 (extreme-risk category) at selected sites. This study fills a crucial knowledge gap and raises concerns about the possible impact on human health, as many riparian residents depend on Beas as their primary source of potable water. Our findings may assist governmental agencies in formulating comprehensive eco-friendly policies and advancing environmentally sustainable strategies in vulnerable locales adjoining the Beas waterway., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Contaminants of emerging concern (CECs) are ubiquitous in aquatic environments and pose a range of biological effects including endocrine disruption. Yet, knowledge of their occurrence in wildlife including seabirds remains scarce. We investigated the occurrence of selected bisphenols, benzophenones, phthalate metabolites, benzotriazoles, benzothiazoles, parabens, triclosan, and triclocarban in plasma of 18 breeding female common eiders (Somateria mollissima) from an endangered population in the Baltic Sea as most of these CECs have never before been examined in eiders. We sampled blood at the start (T1) and end (T2) of incubation to investigate concentration changes during incubation. As early- and late-breeding eiders tend to differ in how they finance reproduction (local vs stored nutrient reserves), we compared early and late breeders to assess whether CEC concentrations differed by breeding phenology. Of the 58 targeted CECs, 21 were detected in at least one female, with bisphenol A (BPA) and benzophenone-3 (BzP-3) occurring most frequently (T1: 78% and 61%; T2: 61% and 67%, respectively), while mono(2-ethyl-1-hexyl) phthalate (mEHP), BPA, and monoethyl phthalate (mEP) were detected in the highest concentrations (median concentrations 27.1, 12.7, and 11.2 ng/g wet weight, respectively, at T1). No CEC concentrations differed between early and late incubation. Late breeders had significantly higher concentrations of BzP-3, monomethyl phthalate (mMP), and mEP during early incubation (4.55 vs 1.24 ng/g ww, 7.05 vs 3.52, and 11.2 vs < limit of detection (LOD), respectively) and significantly higher concentrations of mMP and mEP during late incubation (6.16 vs 

Wind farms (WFs) have grown significantly in recent years, especially in the offshore. However, their construction can adversely affect marine life and expose species to microplastics (MPs) pollution, posing a threat to human health through seafood consumption. In order to further understand the impact of WF construction activities on swimming animal resources and the accumulation of MPs ingested by dominant economic species occupying significant ecological niches, this study investigated changes in swimming animal resources over six periods during three years of WF construction in the South Yellow Sea and evaluated MPs ingestion in three economically valuable dominant species (Portunus trituberculatus, Collichthys lucidus, and Coilia nasus) before and after construction. The study found that the most significant negative impacts on swimming animal resources occurred during the early construction stages, with recovery observed as construction finished. By the operational phase in autumn 2021, all indicators had exceeded pre-construction levels from spring 2019, except for biomass, which had not fully recovered. MPs were identified in every biological sample, and the MPs contamination in the gills was higher than that in the gut and skin tissues. The average abundance of MPs and the overall MPs hazard index of the three organisms were higher than those in other areas and pre-construction levels. WF construction in the South Yellow Sea caused short-term negative impacts on swimming animal resources with long-term recovery, but the increased MPs pollution during the construction process requires continuous monitoring and management to achieve sustainable development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Vehicle emissions are recognized as a primary source of particle-phase polycyclic aromatic hydrocarbons (PAHs), significant contributors to the hazardous properties of PM 2.5 . This study investigates the profiles of PAHs through measurements conducted in a tunnel and an urban roadside environment in 2020. We quantified real-world vehicle emission factors for mixed fleets in the Zhongshu tunnel in Guizhou, southwest China, and found that the total PAHs had an emission factor of 8.15 μg veh -1 km -1 , with higher factors observed for high-ring PAHs. Additionally, we analyzed concentrations of 15 PAHs at a roadside environment in Hefei, southern China, with an average concentration of 23.81 ng/m 3 . PAHs with 4, 5, and 6 rings comprised 80% of total PAHs at the roadside and 87% in the tunnel. Gasoline emissions were the predominant source in both the tunnel and roadside environments, supplemented by non-tailpipe emissions, catering, domestic cooking, and asphalt from road surfaces. Notably, while the total toxicity equivalent concentration of Benzo[a]pyrene (BaP) significantly exceeded the World Health Organization (WHO) guidelines of 1 ng/m 3 , the presence of additional compounds such as Dibenzo[a,h]anthracene (DahA) markedly increased the toxicological impact of PM 2.5 from vehicle emissions. Therefore, it is essential to implement targeted pollution control strategies in central urban areas that address not only the overall concentration of PAHs but also their specific toxic contributions Continuous monitoring and assessment of PAHs in the urban environment are indispensable for effectively reducing their health impacts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Marine anthropogenic litter (MAL) pollution is a growing concern in coastal environments. These ecosystems are home to rich biodiversity but face significant challenges due to the accumulation of plastics and other solid waste, compromising the region's natural aesthetics and environmental health. This study investigates how marine pollution and the accumulation of MAL impact these ecosystems. We use the burrowing owl (Athene cunicularia) as an example to illustrate the potential risks associated with this pollution, especially for those species that nest near coastal regions along the Brazilian Amazon coast. At Atalaia Beach, the data collected revealed a significant diversity of MAL, totaling approximately 532 items. Among them, styrofoam and foam were the most representative, with 33.08% and 21.05%, respectively, totaling 54.14% of the recorded MAL. The distribution of these materials indicates a correlation with human activities, especially the use of plastics for fishing and recreation. Notably, styrofoam and foam were frequently found in burrowing owl burrows, highlighting the use of MAL around nests and the potential risks this plastic material poses to the species' nesting and rearing of their chicks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) contamination was investigated along a freshwater-seawater continuum from Chumphon River to the Gulf of Thailand. The vertical distribution in the water column and contamination in green mussels were also studied. MPs were detected in all water samples and sediment samples. Furthermore, MPs were detected in 75% of the green mussels. A higher abundance of MPs was observed in the river system than in the coastal region, indicating that river runoff associated with inland human activities is the major sources of MPs in the coastal regions and cultured green mussels. In the water column, a polymer gradient varying with depth existed where low-density particles decreased from surface to subsurface and sediment while high-density particles exhibited the opposite pattern. Polymers in surface and subsurface water were predominantly composed of low-density polyethylene, polypropylene, and polystyrene particles. However, sediment samples were equally dominated by those mentioned low-density polymers and high-density polyethylene terephthalate, polyamide, rayon, and cotton particles. Furthermore, fibers were the most common shape found in water, sediment, and mussel samples representing 95% of all particles in river water samples and were evenly distributed throughout the water column regardless of density. However, only shorter fiber (mostly <1 mm) was detected in green mussel samples similar to their living environment. Blue, black and white particles dominated all samples. During the tidal cycle, half of the MPs entering the Gulf of Thailand returned to the river during high tide. This backflow predominantly comprised small fibers and low-density polymer MPs. The average daily load of MPs from Chumphon River to the Gulf of Thailand was 3.33 × 10 2 million items/day., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Narainrit Chinfak reports financial support was provided by East China Normal University. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The Arctic region, including Svalbard, faces unique environmental challenges from the presence and persistence of organochlorine pesticides (OCPs), pollutants known for their long-range atmospheric transport and potential local sources. In Svalbard, the melting of sea ice and glaciers due to climate change may release OCPs trapped over decades, while human activities in the area could contribute additional local contamination. This study aimed to identify and quantify different sources of OCPs in soil and marine sediments at Svalbard. Samples were collected from Kongsfjorden, Rijpfjorden, and in Ny-Ålesund. The concentrations of 23 OCPs in sediments sampled were in the range of 0.36-0.90 ng/g, which were lower than those in the soils from Ny-Ålesund (0.28 ng/g to 3.6 ng/g). The highest OCP levels were detected at locations near the research station in Ny-Ålesund, where local contamination from research activities, mining, and dumpsites could occur. Hexachlorobenzene (HCB) were the most prominent compound, followed by various DDTs and HCHs. Dignostic ratios and the Positive Matrix Factorization (PMF) model were employed to determine the primary sources of OCPs. The results from modeling showed that historically used pollutants were the primary contributor, accounting for 90% of OCPs present, while recently input OCPs were a minor contributor. However, newly input pollutants significantly contributed to HCHs (43%). It is suggested that the contribution of legacy OCPs mainly comes from the melting of sea ice and glaciers. This was especially true for Rijpfjorden (95%), while it was also significant for Kongsfjorden (55%). The local contamination and fresh inputs played a substantial role in the area near the research station in Ny-Ålesund. The study emphasizes the importance of secondly source, especially the role of melting sea ice and glaciers as well as local contaminations as sources of OCPs in Svalbard's marine sediment, which highlight the urgent need to address the impact of climate change on the Arctic environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Imidacloprid (IMI), a leading neonicotinoid insecticide, is widely used in China. Nevertheless, owing to its high toxicity to pollinators, regulatory scrutiny of its usage has increased in recent years. Despite this, no relevant issues have been announced in China, and its usage continues to rise. In this study, we systematically reviewed the development history, pollution characteristics, and environmental problems associated with IMI in China, which is imperative to promote its green development. The results show that most IMI products (97.1%) in China are registered for agricultural use. Owing to its extensive use and strong migration ability in different environmental matrices, IMI has been broadly detected in multiple environmental media. The average detection rate (DR) of IMI in soils, ambient water, and sediments were 90.7%, 81.3% and 84.5%, respectively, and the corresponding concentrations were 54.6 ± 83.8 ng/g dry weight (dw), 32.8 ± 103 ng/L, and 1.7 ± 2.9 ng/g dw, respectively, indicating high IMI abundance in multiple environmental media in China. The spatiotemporal distribution of IMI was generally determined by its application modes, transport, and degradation rates. IMI is commonly overused in China, leading to the development of high IMI resistance in many pests, and a high DR of IMI in food, drinking water, and human bodies. To alleviate IMI pollution in China, the joint efforts of the government, farmers, and scientists are necessary, including but not limited to formulating laws and regulations, strengthening governmental supervision, improving farmers' knowledge of IMI use, and promoting technological innovation in IMI and application methods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Marine sediments are recognized as major sinks for microplastics, including remote areas which were previously considered "plastic-free". The understanding of microplastic dynamics in marine sediments is however limited due to the numerous pelagic and benthic pathways involved, and how these are influenced by physico-chemical interactions with the particles. European continental shelves border densely populated areas and face a high risk of microplastic contamination. In this study we quantified microplastics in soft-sediments of European coastal seas and characterized their polymer composition separating surface sediments from deeper layers. We then analyzed the influence of water column and sediment properties on spatial variability of seabed microplastics and investigated the relationship with macrofauna communities. A higher proportion of negatively buoyant polymers in surface sediments (0-1 cm) across stations was explained by seawater salinity and sediment microalgal detritus, highlighting the role of riverine input and possibly the formation of hetero-aggregates in defining polymer deposition. Additionally, we found that seawater temperature influenced polymer composition in deeper sediment layers (0-3 cm), likely together with biological activities performed by macrobenthos such as ingestion and burial. Finally, we demonstrate that seabed microplastics contribute to the spatial variability in macrobenthos, highlighting that marine ecosystem functioning effects of microplastic pollution are likely mediated via the benthos., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ozone pollution was widely reported along with PM 2.5 reduction since 2013 in China. However, the meteorological drivers for ozone varying with different regions of China remains unknown using explainable machine learning, especially during the COVID-19 pandemic. Here we first analyzed spatiotemporal variations of PM 2.5 and ozone from 2015 to 2022 in eleven urban agglomerations of China. PM 2.5 decreased in all regions, with the largest drop in Beijing-Tianjin-Hebei (BTH). In contrast, ozone declined initially but rose during the pandemic in most regions, especially in Cheng-Yu. Probability density curves showed pronounced increase (24.7%) and slight change in the proportion of PM 2.5 and ozone meeting the pollution criterions during the pandemic, respectively. Leveraging Random Forest with SHAP analysis, we further established ozone models in typical urban agglomerations with good performance (CV-R 2  = 0.80-0.90; CV-RMSE = 8.52-19.20 μg/m 3 ) during the pandemic, and compared their relative importance of meteorological variables. Particularly, temperature and incoming shortwave flux at top of atmosphere were identified with high importance in high-ozone regions such as Middle Plain and BTH. Increasing importance of PM (e.g., PM 10 ) was found in southern China, e.g., Yangtze River Delta and Pearl River Delta regions. The western China was characterized with more importance of meteorology, especially in Tibet. Surface albedo and sensible heat flux from turbulence were noted distinctively with high importance in Tibet, partly due to their impacts on ozone formation by generating heat source and sink. In addition, sea level pressure (SLP) was revealed with the highest importance (25.2%) in Cheng-Yu, consistent with the fact that synoptic patterns characterized by SLP field could affect ozone pollution in Sichuan Basin. Our results not only provide an understanding of meteorological factors in regional ozone formation in China, but also highlight the feasibility of explainable machine learning in ozone studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Contamination of water resources with mixtures of organic micropollutants (OMP) including pesticides, pharmaceuticals, and industrial chemicals is a serious threat to aquatic organisms and human health. Long-term exposure to such pollutants may cause detrimental effects even at very low concentrations. Water resources in urban agglomerations in low- and medium-income countries may be under particular pressure due to high population densities, significant industrial activities, and limited water treatment and management resources. In these areas, many inhabitants directly rely on healthy urban water resources. Using the agglomeration of Lahore, Pakistan, as a case, we studied the occurrence, spatial distribution, and toxic risks of OMP mixtures in different urban water resources using target screening with liquid chromatography high-resolution mass spectrometry. In total, 266 of 576 target analytes were detected in at least one of the 200 samples taken from groundwater, canals, River Ravi and drains within the urban agglomeration. Notably, very high concentrations ranging from 10 to over 100 μg L -1 were found for highly toxic pesticides including several fungicides such as picoxystrobin, the transformation product phthalamic acid, and imazalil, the insecticide etofenprox but also industrial chemicals stemming for example from traffic such as 2-naphthalene sulfonic acid. Our study revealed high toxic risks particularly for invertebrates, fish and algae, with etofenprox as a dominant risk driver. This compound is extensively used in Lahore to control insect vectors of malaria and dengue fever in the urban agglomeration. Mixture risks were assessed using a toxic unit (TU) approach based on organism group specific effect concentrations, complemented with a risk quotient (RQ) approach using the lowest predicted no effect concentrations (PNECs). Acute and chronic risk thresholds were frequently exceeded, often by many orders of magnitude. These very high mixture risks strongly exceed those with previous studies in Europe, Africa and South America., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The nationwide prevalence of brownfields, with often unknown types and quantities of subsurface chemical contaminants, highlights the need for rapid, cost-effective, and noninvasive methods to reduce routes of exposure. In post-industrial cities such as Detroit, Michigan, anthropogenic volatile organic compounds (VOCs), known to negatively impact human health, are typically detected at brownfields through conventional methods, e.g. screening soil, and groundwater. Recently, the method of phytoscreening-the chemical analysis of plant tissues to provide evidence for belowground contamination-has become a viable alternative to conventional methods. However, few studies have been designed to directly compare conventional and plant-based methods of detecting VOCs. To fill this knowledge gap, we sampled and compared the concentration of six VOCs including BTEX, PCE, and TCE detected in conventional media (soil, soil vapor, groundwater, sewer vapor) and different plant tissue (tree core, leaf, root, shoot) at two brownfields sites in Detroit: an abandoned gas station with a leaking underground storage tank, and a former dry cleaning facility. Our results suggest that the concentrations of VOCs detected in plants are similar to or in some cases greater than conventional methods and can differ across the growing season. For example, leaves and roots detected, on average, a higher concentration of VOCs compared to shoots and tree cores, however, TCE and PCE were generally in higher concentrations in soil and soil vapor. Moreover, the frequency at which conventional versus phytoscreening methods failed to detect VOCs was similar at one site and higher at another, suggesting that phytoscreening may yield fewer non-detects at known sites of contamination. While additional work is needed to understand the relationship between concentrations of VOCs detected in soil versus co-located plant samples, our results suggest that phytoscreening may be a viable and reliable method to detect belowground chemical contaminants while reducing screening times and cost, and increasing access to private property., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Elucidating the chemical composition, sources, and health risks of fine particulate matter (PM 2.5 ) is crucial for effectively preventing and controlling air pollution. This study collected PM 2.5 samples in Linyi from November 10, 2021, to October 15, 2022, spanning the period of the 2022 Winter Olympics and Paralympics. The analysis focused on seasonal variations in the chemical composition of PM 2.5 , including water-soluble ions, inorganic elements, and carbonaceous aerosols. Results from the random forest model indicated that control measures during the Olympics and Paralympics reduced PM 2.5 concentrations by 21.5% in Linyi. Organic matter was the dominant component of PM 2.5 , followed by NO 3 - , SO 4 2- , and NH 4 + . Among secondary inorganic ions, SO 4 2- exhibited the highest concentration in summer, while NO 3 - and NH 4 + showed the lowest concentrations. The inorganic elements S, K, Fe, and Si had high mean annual concentrations, underscoring the need for targeted control measures for plate production, bulk coal burning, and biomass combustion in Linyi. The organic carbon (OC) to elemental carbon ratio (17.7-20.5) in Linyi was high, highlighting the importance of addressing secondary OC pollution. According to the positive matrix factorization model, coal burning, and the secondary formation processes of sulfate and nitrate were the dominant sources of PM 2.5 . Backward air mass trajectories revealed substantial contributions from the southeastern, local, and southwestern regions of Linyi. This suggests the need for enhanced regional joint prevention and control efforts between Linyi and neighboring cities, such as Rizhao and Jining in Shandong Province, as well as northern cities in Jiangsu Province. The highest non-carcinogenic and carcinogenic risks (CRs) were associated with As. coal burning posed significant noncarcinogenic risks and a moderate CR, contributing 41.7% and 44.0% of the total health risk, respectively. These findings are crucial for developing effective air pollution prevention and control strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

One of the leading challenges in Water Resource Recovery Facility monitoring and control is the poor data quality and sensor consistency due to the tough and complex circumstances of the process operation. This paper presents a new principal component analysis fault detection approach for the nitrate and nitrite concentration sensor based on Water Resource Recovery Facility measurements, together with the Fisher Discriminant Analysis identification of fault types. Five malfunction cases were considered: constant additive error, ramp changing error in time, incorrect amplification error, random additive error, and unchanging sensor value error. The faults' implementation, fault detection, and identification methods are presented and evaluated in terms of accuracy and promptitude. The models are originating from a municipal plant. The amount of required electrical energy and greenhouse gas released during the Water Resource Recovery Facility operation were assessed for the cases of nitrates and nitrites NO sensor normal and malfunctioning regimes. The environmental and economic evaluations show the benefits of detecting and identifying nitrates and nitrites NO sensor defects aimed at providing efficient and environmentally friendly operation of the Water Resource Recovery Facility. The fault-affected operation cases showed increased values, up to 10% for the total energy demand and 4% for the total greenhouse gas emissions, when they are compared to the normal operation case., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

This study applied integrated statistical approaches, including GIS mapping and the water quality index (WQI), to assess the quality of water, soil, and plant samples which collected from Darawat Dam, Sindh, Pakistan. The samples were analyzed for physicochemical parameters and metal analyses. Results of cations in water samples were in the range Na + 26.74 to 39.67 mg/L, K + 0.92 to 2.89 mg/L, Ca 2+ 28.67 to 39.45, and Mg 2+ 19.67 to 34.43 mg/L. The values of Cl - in water samples were 44.54 to 61.26 mg/L, sulfate 27.11 to 46.45 mg/L, and bicarbonate (HCO 3 - ) 100 to 135 mg/L. The results of major and trace elements in soil samples were varied for Na + 1259-1781 mg/kg, K + 306-498 mg/kg, Ca 2+ 689-1093 mg/kg, Mg 2+ 357-795 mg/kg, Zn 194-235 mg/kg, Fe 124-242 mg/kg, Cu 25.34-33.56 mg/kg, Co 19.45-27.32 mg/kg, Mn 97.83-131 mg/kg, Ni 39.65-52.44 mg/kg, Cr 69.64-83.65 mg/kg, Cd 3.98-8.66 mg/kg, and Pb 5.34-9.62 mg/kg respectively. The major and trace elements in plant samples were varied from Na + 3456 to 5016 mg/kg, K + 1197 to 1654 mg/kg, Ca 2+ 2367 to 2892 mg/kg, Mg 2+ 1429 to 1686 mg/kg, Zn 132 to 155 mg/kg, Fe 255 to 354 mg/kg, Cu 19.54 to 28.56 mg/kg, Co 11.64 to 14.65 mg/kg, Mn 23.54 to 34.78 mg/kg, Ni 8.44 to 11.03 mg/kg, Cr 6.34 to 9.55 mg/kg, Cd 0.43 to 0.93 mg/kg, and Pb 4.33 to 6.59 mg/kg. The GIS maps were drawn for TDS, Cl - , Na + , heavy metals Cr, Cd, and WQI and these graphs showed that most of the water samples of Darawat Dam is good for human consumption. The results of electrical conductivity (EC) and total dissolved salts (TDS) of water samples were found to be from 648 to 753 µS/cm and 414 to 482 mg/L. The Darawat Dam water samples were good for drinking as well as irrigation based on the results of water quality parameters. The WQI specified that 100% of samples were excellent to good for water quality for drinking. The 100% samples were also excellent for crops. The scatter diagram disclosed that weathering and ion exchange were chief processes. The Gibbs diagram revealed that all samples showed rock dominance which confirmed the dissolution of rock as the main source for the water quality of the Dam. The hydrogeochemical facies (Piper diagram) showed that sample points were gathered in the center of the diagram which indicated mixed type water with no particular parameter effluents the water quality., Competing Interests: Declarations. All authors have read, understood, and have complied as applicable with the statement on “Ethical responsibilities of Authors” as found in the Instructions for Authors. Ethical approval: This paper is submitted in this journal and not considering in any other journal. The manuscript did not contain any third-party data in this research work. Competing interests: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The pervasive presence of microplastics (MPs) in the environment is well established, yet many critical questions remain about their distribution and potential impacts on both ecological and human health. To assess the risks that MPs pose, especially through marine ecosystems and human consumption, monitoring their ingestion by fish in natural environments is essential. This study investigated the contamination of 12 fish species, the most commonly consumed in Morocco, collected from the Atlantic Ocean off the Moroccan coast. Analysis of 240 fish (20 individuals per species) revealed that 100 % of the samples contained microplastics. MPs were detected in the gills, gonads, and gastrointestinal tracts of all 12 species. The average abundance of microplastics per fish ranged from 20.6 to 133.2 MPs, with the forms identified as fragments (60 %), fibers (30 %), films (8 %), and pellets and foams (1 %). Additionally, omnivorous and demersal species presented the highest levels of MP contamination. Infrared spectroscopy (ATR-FTIR) analysis identified seven polymers, with high-density polyethylene (34 %), polyethylene terephthalate (30 %), and polypropylene (17.5 %) being the most prevalent. The microplastics were predominantly dark or light in color, with a notable presence of red and blue particles. Fish ingest various sizes of microplastics, primarily particles smaller than 1 mm. Scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX) revealed that most MPs exhibited visible signs of weathering and contained inorganic components on their surfaces. The potential risk of MPs to fish, as assessed by the polymer hazard index (PHI), was categorized as level V, indicating that MPs may pose significant risks to human health. The highest estimated daily intake (EDI) of microplastics was found in children (1620 MPs/year), whereas the lowest intake was estimated in women (350 MPs/year) and men (337 MPs/year). Given the widespread presence of microplastics in commonly consumed fish species in Morocco, there is an urgent need for regulatory measures to ensure the safety of fisheries, both for domestic consumption and export. Policymakers should consider the development of guidelines for acceptable levels of microplastic contamination in fish to safeguard public health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study examines the aging of industrial crude oil to simulate the chemical transformations that occur when it is exposed to environmental conditions over time. It was triggered by the finding of plastitar - a mixture of tar and plastic waste - on the coast of Milazzo, Sicily. Research began with a chemical characterization of the tar component of plastitar, followed by aging experiments designed to simulate environmental conditions such as seawater, UV light and sunlight. Fourier transform infrared spectroscopy (FTIR) was used to analyze the chemical changes during the aging process and compare the results with local tar samples. The results showed significant chemical changes in the aged crude oil, including oxidation, degradation of hydrocarbons and the formation of oxygenated compounds. In particular, the FTIR spectra of the aged crude oil closely matched those of the local tar and provided valuable insights that could help address similar coastal pollution issues in other regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The objective of this study is to assess the potential impact of nickel mining activity on zooplankton communities in a coral reef channel lagoon (Voh Koné, New Caledonia). During a multidisciplinary campaign in February 2018, we analyzed the variation in zooplankton abundance, biomass and taxonomic diversity, as a function of the distance from the metallurgical plant site and of hydrodynamic conditions and environmental variables. We also compared these results with those obtained in an earlier study conducted in 2009 prior the mining. The results show the high variability of planktonic variables between stations and periods, mainly related to natural factors (hydrodynamics, climatic events). However, lagoon zooplankton also appears to be affected by mining development, and in particular by the increase in sediment inputs and consequent turbidity. Zooplankton taxonomic richness and diversity were negatively correlated with non-algal particle concentrations (C NAP considered as an indicator of turbidity) with 10 more sensitive taxa completely absent at the highest concentrations. We interpret these negative relationships as the result of the degradation of food quality by mixing with inedible and less assimilable non-algal particles. The effect of metal toxicity cannot be excluded, even though the metal concentrations recorded in the lagoon are far from known toxic concentrations, but this hypothesis should be further developed. Overall, our results highlight the good resilience of lagoon zooplankton probably partly related to the high renewal rate of the lagoon water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Macrobenthic communities play a crucial role in the functioning of estuarine ecosystems and serve as bioindicators of environmental quality. This study assessed the ecological quality of an estuarine system using the AMBI and M-AMBI indices. The following parameters were considered: (i) environmental factors (total organic matter, organic carbon, grain size, calcium carbonate), (ii) sediment trace metals (Pb, Zn, Cu, Cr, Co, Ni, Hg, Li, As), (iii) species composition (morphological and molecular identification), and (iv) anthropogenic activities. The results demonstrated notable differences between study areas, reflecting hydrodynamic processes and human activities. The AMBI index indicated that all areas exhibited conditions classified as "slightly disturbed." However, the composition of the ecological groups and M-AMBI results differed according to the identification method. This approach allowed for a more complete understanding of communities, by integrating the influence of anthropogenic activities on the sediment and macrobenthic communities, highlighting the importance of using both identification methodologies., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Joana Marujo Neves reports financial support was provided by Foundation for Science and Technology. Joana Marujo Neves reports equipment, drugs, or supplies, statistical analysis, and writing assistance were provided by Portuguese Institute for the Sea and Atmosphere. Joana Marujo Neves reports equipment, drugs, or supplies was provided by Marine and Environmental Sciences Centre. Joana Marujo Neves reports a relationship with Foundation for Science and Technology that includes: funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Plastics are incredibly useful materials that have many benefits for both society and individual daily lives. However, the extensive utilization of plastic and plastic-derived products has led to plastic pollution in various environmental compartments across the world at alarming levels. Due to different biogeochemical processes, this plastic waste is broken down into tiny, omnipresent, and long-lasting fragments known as microplastics (<5 mm), which are causing great concern among scientists. Microplastics tend to bioaccumulate, contain toxic chemicals, and have other pollutants and pathogens adsorbed on their surface, thus having adverse effects on organisms. Globally dispersed, microplastics can now be found in almost every environmental niche. Therefore, the purpose of this paper is to give an overview of the research that has been done on this topic, summarize the evidence of microplastic pollution in surface waters, and discuss the analytical summary of recent findings on the microbial degradation of microplastics and effects of various parameters on its degradation as well as the potential degradation mechanism of microplastics. A summary of the most recent and relevant literature is provided on microplastic pollution and microorganisms that can break down various microplastics are classified according to their types including bacteria, fungi, and algae. The environmental factors influencing microplastic degradation and the associated degradation effects are therefore generalized. Additionally, a brief discussion of the mechanism underlying the microbial-mediated degradation of microplastics is provided. This review serves as a reference for upcoming research looking into efficient ways to reduce microplastic pollution., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study investigates Hg, Cd, Cu, Zn, and Pb concentrations in 324 fish samples from 43 species, including two cephalopod species, in the Andaman Sea. The fish were categorized into pelagic and demersal groups. The findings revealed average heavy metal concentrations in the order: Zn > Cu > Hg > Pb > Cd, with pelagic fish showing higher levels than demersal fish. Certain larger pelagic fish had mercury concentrations above prescribed limits, posing possible health hazards, even though they are less commonly consumed by humans. Cd and Pb levels in certain species exceeded regulatory thresholds of 0.05-1 μg/g and 0.3 μg/g, respectively, while Cu and Zn remained within safe limits. Although the overall cancer risk was low, the Target Hazard Quotient (THQ) and Hazard Index (HI) values surpassed 1, indicating significant health risks from consuming species such as Alopias superciliosus, Isurus oxyrinchus, Lepturacanthus savala, Makaira mazara, and Sphyraena barracuda. These findings underscore the need for ongoing monitoring and public advisories to mitigate health risks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In recent years, jellyfish outbreaks have been frequent in near-shore waters and have become a worldwide problem. At present, the main species that form jellyfish disasters along the coast of China is aurelia. In order to control jellyfish outbreaks from the source of growth, this paper proposed a hydroid detector HD-YOLO improved from YOLOv7, and established a hydroid of aurelia dataset. Firstly, the original dataset was established by acquiring images of hydroids via the web, in the laboratory and undersea photography. Secondly, MSRCR, a multi-scale enhancement algorithm with color recovery, was used to improve the underwater image quality. Then the dataset is augmented by the combination of Mosaic and Mixup. Finally, the effectiveness of HD-YOLO, underwater image enhancement and dataset augmentation methods were verified through a series of comparative experiments. This study provides a more accurate and faster method for the hydroid of aurelia detection and a more generalised dataset., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Petroleum industry in the southern Gulf of Mexico possesses relevant importance for the Mexican economy but it has also impacted the marine and coastal environments of this region. The objective of the current review is to provide a substantial panorama of the polycyclic aromatic hydrocarbons (PAHs) during the XXI century. The highest PAHs concentration in water was found in the Dos Bocas Maritime Terminal and the Mecoacán Lagoon; sediments and cores were found in Sontecomapan, Mandinga, and La Mancha Lagoons; maximum PAHs levels in biota were found in fish in Términos Lagoon. PAHs in water and oysters were comparable to others around the world; sediments concentrations were higher than in other regions. Mecoacán Lagoon, coastal shelf Tamaulipas, and Cayo Arcas Reef Complex showed a higher risk estimation based on sediment concentrations. It is necessary to establish monitoring programs in the study region due to the trends found in PAHs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This study investigated 17 organophosphate esters (OPEs) in the surface sediments of Hangzhou Bay and the East China Sea. The mean concentration of ∑OPEs in Hangzhou Bay (235.3 ng/g) was slightly lower than that in the East China Sea (273.5 ng/g), with detected analytes dominated by Diethyl phosphate, Tris(2-chloropropyl) phosphate, and Tris(1-chloro-2-propyl) phosphate. Based on principal component analysis and cluster analysis for the source apportionment of OPEs, the results indicated that the high levels of OPEs in the East China Sea close to Yangtze River estuary can be attributed to a significant large-scale OPEs production site located along the southern Yellow Sea and the western coast of the East China Sea. Furthermore, the risk assessment conducted on aquatic organisms indicated the non-ecological risk of OPEs. However, future research should focus on the potential composite impacts of OPEs on the water systems and human health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Harmful algal blooms (HABs) pose serious threats to coastal economies and ecosystems, yet effective monitoring remains challenging due to diverse bloom types and complex environmental conditions. This paper proposes a Mixed Algal Blooms Index (MABI) that uses a new color space to improve HABs detection. By employing Sentinel-2's near-infrared, short-wave infrared, and green bands to calculate tristimulus values-replacing traditional RGB bands-MABI significantly enhances the distinction between algal blooms and water. And an improved grid-based Otsu automatic threshold segmentation algorithm is utilized to extract algal blooms. The inter-class distance is employed as an indicator to compare 14 commonly used algal blooms indices. Validation across nine global sites, covering coastal and inland areas, shows MABI's robustness, with an overall accuracy of 0.98 and a Kappa coefficient of 0.95. Compared to traditional algal bloom indices, the proposed MABI shows notable advantages in detecting blooms, effectively identifying both mixed blooms from multiple algae species and single-species blooms. We also verified the effectiveness of MABI with Landsat-8, and the combination of Landsat and Sentinel-2 imagery is expected to enhance its capability to monitor the full lifecycle of algal blooms. While MABI shows some resistance to thin clouds and shadows, its detection accuracy can still be affected in optically complex waters. Therefore, careful threshold selection or combining with other indices is recommended for comprehensive assessment. This study utilized Google Earth Engine (GEE) for data acquisition, processing, algorithm development, and validation, offering an efficient and reliable tool for accurately monitoring HABs with wide-ranging applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The vertical distribution, sources and influencing factors of polycyclic aromatic hydrocarbons (PAHs) in soil across ecosystem habitats were investigated around the Liaohe River Estuary (LRE) Wetland. The concentration of Ʃ 16 PAHs ranged from 41.0 to 435.4 ng g -1 dw, with a predominance of low molecular weight PAHs. Overall, PAHs and physicochemical properties of soil decreased with depth. Vegetation was found to increase soil PAHs. Additionally, soil physicochemical properties also regulated PAHs concentration, particularly for PAHs with high molecular weight. Among the habitats, total organic carbon was the key influencing factor for Suaeda heteroptera, while specific surface area was crucial for Phragmites australis. Results of characteristic ratio method and principal component analysis revealed that PAHs in LRE primarily originate petroleum, coal and biomass combustion. In summary, vegetation colonization significantly affected the distribution, sources, and controlling factors of PAHs. These findings are meaningful for management of soil PAHs across various ecosystem habitats., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Target, suspect, and non-target analyses were conducted to investigate the accumulation status of halogenated organic pollutants (HOPs) in spotted seals (Phoca largha Pallas, 1811) from Peter the Great Bay, East Sea/Sea of Japan. Despite long-standing regulations, polychlorinated biphenyls (PCBs) and organochlorine pesticides were highly accumulated, likely due to placental and lactational transfer. Hexabromocyclododecanes were the predominant brominated flame retardants, with their levels increasing with age. Suspect and non-target analyses identified 35 non-target PCBs not routinely monitored, suggesting conventional methods may underestimate PCB concentrations. Regression analysis showed significant correlations between the concentrations of major PCBs (CBs 138 and 153) and the sum of target and non-target PCBs. The study found that 95 % of the seals exceeded threshold levels for PCBs, posing potential health risks. These findings highlight the need for integrated monitoring, combining target and non-target analyses, to better assess and manage the risks of HOPs to marine mammals., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Total organic carbon (C org ), total nitrogen (N tot ), C org /N tot , δ 13 C org , δ 15 N, calcium carbonate (CaCO 3 ), and grain size were analyzed in 70 surface samples and 19 short cores from the southwestern Portuguese shelf. Perylene and USEPA-16 PAHs were quantified in a subset of these samples. The findings suggest that organic matter derives from a mix of terrestrial and marine sources, outlined by C org , N tot , and isotopic signatures. Perylene combined with δ 13 C org was used to identify the main PAH sources in these environments. Diagnostic perylene ratios revealed contributions from natural sources in the Tagus region and contaminated materials from the Sado Dredged Disposal Site, with additional perylene in Sines linked to atmospheric deposition of pyrogenic sources. A significant correlation between perylene and USEPA-16 PAHs indicates natural and anthropogenic inputs from the Tagus. This multiproxy approach-combining USEPA-16ΣPAHs, perylene, and δ 13 C org -offers insights for assessing environmental risks and guiding marine environmental management according to the MSFD., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Mario Mil Homens reports financial support was provided by Portuguese Institute for the Sea and Atmosphere. Mario Mil Homens reports a relationship with Portuguese Institute for the Sea and Atmosphere that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

This study evaluated and minimized bias in estuarine total dissolved solids (TDS) patterns predicted using geostatistical approaches. The acquired TDS data was divided into three parts: 29 points (60 %) for predicting TDS patterns with spatial interpolation techniques, 12 points (25 %) for validation and bias correction, and 7 points (37 %) for testing the corrected bias. Inverse Distance Weighting (IDW), Ordinary Kriging (OK), Universal Kriging (UK) and Regression Kriging (RK) were applied to map TDS patterns. R-square and Relative Error of Mean showed significant discrepancies between observed and predicted TDS levels. The Mean field bias (MFB) correction technique was applied to minimize bias in TDS patterns. After correcting bias, the TDS values predicted by IDW, OK, UK and RK at random locations deviated from measured values by -2.85 %, 0.71 %, 4.66 %, and - 6.03 % respectively. At the test locations, these values deviated by -1.45 %, 1.41 %, 2.11 %, and - 2.65 % respectively., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Global marine litter monitoring initiatives present information and integration gaps that can be addressed through multi-sectoral collaboration. Social Network Analysis (SNA) helps identify stakeholder roles in accessing, sharing, bridging, and coordinating data for effective monitoring. This study established a theoretical basis and an analytical-operational approach for structuring effective networks for marine litter monitoring. Our research examined a network of 105 stakeholders engaged in a subnational governance arrangement for marine litter monitoring in São Paulo, Brazil. We found that the network allows access to and information-sharing among every actor (i.e., it is non-fragmented), even from different sectors (i.e., it is heterophilic). Although connections are still scarce (i.e., low-density) and decentralized (i.e., low-centralization), bridging and coordinating information relied on central and intermediary actors. SNA findings at the actor level (i.e., degree and betweenness centrality) highlighted the most suitable institutions for these roles, linking otherwise disconnected data producers and addressing critical gaps in data reporting. Our findings suggest that coordinated, centralized network structures may be more effective than denser, highly collaborative structures in the context of litter monitoring governance. These findings contribute to the development of effective, networked actions for marine litter monitoring across diverse scales and contexts, advancing the implementation of Sustainable Development Goal 14, the forthcoming treaty on plastic pollution, and other relevant monitoring initiatives., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Research on microplastics must be harmonized. Therefore, we thoroughly evaluated in the Association of Southeast Asian Nations (ASEAN) region, addressing challenges and priorities in protocol harmonization and microplastics research promotion. Of the 615 papers searched by the Web of Science, 164 were used for this systematic review. The number of ASEAN research articles has increased over time. Examination of research protocols in various sampling environments revealed several challenges: 1) Disparities in access to sampling locations affect the research extent; 2) Outdated protocols and limited access to technologies such as FTIR (Fourier-transform infrared) spectroscopy result in less harmonized and potentially lower-quality data; and 3) Insufficiently detailed methods and QA/QC information hampers comparability. We offer procedure updates to overcome these limitations and cover environmental microplastic study gaps. Other countries in the Global South may encounter similar challenges, making this review a valuable contribution to advancing global microplastics research and fostering international collaboration., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The Jiaozhou Bay (JZB) intertidal zone is a significant carbon reservoir that plays a crucial role in transporting and accumulating organic matter; however, quantitative studies of organic matter sources are scarce. In this study, we present bulk parameters of total organic carbon (TOC), TOC/TN, δ 13 C, and biomarker contents in 36 surface sediment samples from the JZB intertidal zones to quantify the contribution of organic carbon (OC) derived from terrestrial/marine sources, such as C 3 plants, C 4 plants, estuarine productivity, sewage outlets, and marine productivity. The results demonstrated that a two-end-member model based on the traditional indicators of TOC/TN or δ 13 C is not appropriate for quantifying the OC source. The presence of C 3 plants, C 4 plants, and sewage outlets in the JZB intertidal zone could lead to errors in determining OC contribution when solely using TOC/TN or δ 13 C. A classical mixing diagram (three-end-member model) utilizing TOC/TN and δ 13 C values revealed that OC contribution was dominated by marine productivity throughout the intertidal zone. In the west, the average OC contribution from marine productivity, estuarine productivity, and C 4 plants was 73.8 %, 14.2 %, and 12.0 %, respectively. In the east, the average OC contribution from marine productivity, estuarine productivity, and sewage outlets was 57.6 %, 24.9 %, and 17.4 %, respectively. The higher OC contribution from marine productivity in the west was attributed to the occurrence of Spartina alterniflora, while the OC contribution from estuarine productivity in the east was primarily due to the presence of more rivers flowing into the JZB compared to the west. By combining biomarkers and OC contents, a significant positive relationship verified the suitability of the end-member values selected for the three-end-member mixing model in the west and east intertidal zones of JZB. This finding was further supported by principal component analysis (PCA) analyses of these proxies. This study demonstrated that OC sources in intertidal zones varied among contrasting coastal environmental conditions and addressed the knowledge gap regarding biogeochemical cycles and ecological protection in the JZB intertidal zones., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study examines the concentrations of arsenic (As), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), mercury (Hg) and zinc (Zn) in three fish species (Sardina pilchardus, Engraulis encrasicolus, Trachurus trachurus) from Betoya Bay, collected in winter and summer. Significant variations were observed between tissues (p < 0.05), with the liver being the most contaminated. A seasonal increase in Potentially Toxic Elements (PTEs) was observed during the wet season, particularly for As, Cd, Hg and Zn in S. pilchardus. The Metal Pollution Index (MPI) showed no overall toxicity except in the liver (3.07-6.69). The Estimated daily intake (EDI) values remain below the provisional tolerable daily intake limits, indicating no health risk. However, Cd and Fe values exceed these limits in children. The Hazard Quotient (HQ) and Total Hazard Quotient (THQ) indices associated with muscle consumption suggest a non-carcinogenic risk for adults. For children, a hazard was identified for iAs in S. pilchardus in winter and in T. trachurus in both seasons. Furthermore, the carcinogenic risk indices (CR iAs and CR Cr ) indicate a potential risk for certain species, both for adults and children, highlighting the need for measures to reduce PTE contamination. In the short term, PTE concentrations in fish do not appear to pose an immediate risk to human health or ecosystems. However, there is evidence of long-term accumulation due to human activities, which could be of concern. It is recommended that bioaccumulation analyses and exposure monitoring of local populations be included in future studies to better anticipate and manage potential risks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Following the Hebei Spirit oil spill (HSOS) in December 2007, benthic organisms of the Taean coast on the west coast of Korea were heavily affected. A month after HSOS, the alkyl PAHs in the oyster body elevated to 13,500 ng/g dry wt, although it dropped to 5335 ng/g dry wt in December 2008, and returned to the levels before the accident (547-858 ng/g dry wt) by 2010. In 2008 spring, the damaged oysters exhibited deteriorated growth and reproduction, exhibiting signs of physiological stress. However, a year after the accident, oysters exhibited signs of recovery from the stresses. Gonad maturation, reproductive effort, and carbohydrate content recorded in 2010 were comparable to the levels in 2009 and the levels in undamaged oysters. Our study suggested that the Pacific oysters recovered from the HSOS stresses within a year, although long-term monitoring of oyster health must be carried out to ascertain the recovery., Competing Interests: Declaration of competing interest The co-authors of this study “Sublethal Impacts of Hebei Spirit Oil Spill on the Growth and Reproductive Physiology of the Pacific Oyster Crassostrea gigas at Taean on the West Coast of Korea (2008-2010)” declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Harmful algal blooms (HABs) present severe risks to marine ecosystems, wildlife, human health and economies globally. This study investigates the diversity and abundance of the primary HAB group-dinoflagellates-in Hervey Bay, Queensland, Australia, a region notable for its ecological uniqueness and high susceptibility to HABs. By employing DNA metabarcoding targeting the 18S rRNA V8-V9 regions, we aimed to provide a comprehensive overview of dinoflagellate communities across various substrates and locations, identifying both toxic and non-toxic species. Our findings revealed 66 distinct genera, including known toxin producers such as Alexandrium, Gambierdiscus, Karenia and Prorocentrum, with some toxic species detected in Australian waters for the first time. Additionally, we assessed the abundance of these toxic species and examined the influence of environmental factors on their occurrence. This study emphasises the importance of ongoing monitoring and ecological assessments to manage HAB impacts in vulnerable coastal areas such as Hervey Bay., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

In this study, we investigated for the first time anthropogenic microparticles in the franciscana dolphin Pontoporia blainvillei, the most endangered cetacean of the Southwest Atlantic Ocean. The intestinal content of the proximal and distal sections, and wall tissues of the proximal section of ten female dolphins collected during 2013-2023 were analyzed. All samples contained anthropogenic particles (%FO = 100). Fibers were the most abundant shape (99 %). Micro-Raman and micro-FTIR spectroscopies revealed the presence of polyester, polypropylene, acrylic, polyethylene, and semi-synthetic cotton polymers. Manufactured pigments such as reactive blue 238, Indigo 3600, and diarylide azo pigment (yellow 152) were also detected. We observed variations in the color and types of polymers present in the different sections of the intestine and within the wall tissue, suggesting a differential microplastic absorption. These findings confirm both the presence and absorption of microplastics in the intestines from franciscana dolphins., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Organophosphate esters (OPEs) are emerging pollutants and used extensively in industrial production as alternative to the traditional flame retardants. This study investigated the contamination characteristics and health risks of OPEs in 104 mollusks from 15 cities along the coastal region of South China. Σ8OPEs ranged from 48.2 to 1937 ng/g dw, with a mean value of 295 ng/g dw. TDCIPP, TCPP, and TCEP were the dominant OPEs. Different spatial distributions were observed, with higher concentrations in Guangdong Province. A statistically positive but non-significant linear correlation was found between the trophic level of mollusk and OPEs concentration. The trophic magnification factors were >1, suggesting that OPEs have the potential to biomagnify in mollusks. OPEs in mollusks pose low non-carcinogenic and carcinogenic risks to consumers. This study provides an important basis for managing the safety risks associated with OPEs in mollusks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study revealed the greenhouse gas (GHG) emission patterns during shrimp mariculture in both semi-indoor and indoor ponds. In the semi-indoor ponds, the average carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) concentrations of pond water varied from 1373.0 ± 721.7 μatm, 4.4 ± 1.3 nM, and 14.2 ± 3.5 nM, respectively, at the initiation of stocking to 5296.0 ± 1474.7 μatm, 3.8 ± 0.3 nM, and 28.1 ± 17.9 nM, respectively, in the harvest stage. In the indoor pond, these varied from 562 μatm, 3.5 ± 0.2 nM, and 10.7 ± 0.1 nM, respectively, at the initiation of stocking to 4728.0 μatm, 18.2 ± 0.7 nM, and 94.1 ± 0.6 nM, respectively, in the harvest stage. An upward trend in CO₂ and N₂O concentrations was observed in the water of both semi-indoor and indoor ponds as the culture period progressed. The discharged waters exhibited the highest GHG concentrations, potentially acting as emission hotspots if left untreated. The total average CO₂-equivalent (CO₂-eq) fluxes from pond water during the shrimp mariculture period were 49.8 ± 40.7 mg CO₂-eq m -2  h -1 in the semi-indoor ponds, with 44 % of these GHG emissions attributable to shrimp mariculture practices. In the indoor pond, the fluxes were 101.5 ± 52.6 mg CO₂-eq m -2  h -1 , with 86 % of the GHG emissions attributable to shrimp mariculture practices. According to these results, shading effects may increase the GHG emissions from aquaculture pond waters., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

To overcome the difficulty of estimating the oil slick thickness using remote sensing techniques, the feasibility of applying the proposed ultrasonic method for measuring the thickness of the oil slick in open water was experimentally investigated by conducting tests in various sea wave states. The second cross-correlation method was implemented to calculate the time of flight (TOF). The influences of sea waves on measurement accuracy were deeply evaluated by calculating the difference of the average thickness in the sea wave state compared with the average thickness in the calm sea state (no waves). The results showed a high measurement accuracy with a maximum difference ∼17.3%, and most of the tests (10 in 15) had a difference within ±10%. The measurement accuracy was further improved by correcting singular thicknesses caused by the ROV's pitch and roll, and surface waves. The study will advance the development and transition of this method to be implemented in open water., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Microplastics (MPs) have emerged as a significant class of contaminants due to their widespread presence in various environmental compartments. The ingestion of these particles poses a risk to both human health and the local biota. The investigation of the Santos estuary reveals the abundance of microplastics in the mangrove sediment. The highest concentration was 62,850-93,050 MPs·kg -1 dw, never seen before in Latin America coast. The region investigated is characterized for silting sites and low energy events, notably Rio dos Bugres, influenced by anthropic aspects, while the São Vicente e Santos channels prevail the high energy hydrodynamic regime. In consequence, the MPs are entrapped in the interior of the estuary, affecting drastically the biota of mangrove. Spectroscopic investigation identified: polymers, pigments, herbicide and additives. The hypothesis is that densely populated siltation areas combined with low-energy events serve along the estuary for MPs accumulation and hotspots formation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Coastal regions, including beaches, constitute major tourism assets. Concurrently, beaches are hotspots for microplastic generation, and accumulated beached litter substantially influences future microplastic abundance in the marine environment. Although the stock of plastic litter on beaches has been estimated in previous studies, knowledge gaps exist with regard to the amount of annually generated litter by beach users and the absence of litter generation rate (LGR) in g/person/h or items/person/h. This study aimed to estimate beach-based litter using a novel method. We collected beach-based plastic litter and measured the person-hours of the users using regular photography or videography in summer and autumn/winter at four popular beaches in Japan to obtain LGR and estimate the total litter abundance generated annually from 770 Japanese beaches as a baseline. In summer (autumn/winter), LGR ranged from 0.178 (0.128) to 1.10 (0.453) g/person/h. The LGR in weight was on a 10 -1 order regardless of the season and site, except for one survey (1.1 g/person/h). In number, it ranged from 0.064 (0.042) to 0.196 (0.122) items/person/h. Using mobile phone big data to assess the person-hours of users on 770 beaches, we estimated the total abundance of litter generated by beach users nationwide for the first time owing to these smaller variances in LGRs. The mean weight (number) was estimated as 12.50 t/y (2.80 million items/y) with a 95 % confidence interval of 6.54-18.40 t/y (1.70-3.89 million items/y). These findings would assist in the development of effective strategies for beach debris management., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Hirofumi Hinata reports financial support was provided by Japan Society for the Promotion of Science: Hirofumi Hinata reports financial support was provided by Government of Japan Ministry of the Environment. Hirofumi Hinata reports financial support was provided by New Energy and Industrial Technology Development Organization. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)