Sentinel-2 (S2) images have been used in several projects to detect large accumulations of marine litter and plastic targets. Their limited spatial resolution though hinders the detection of relatively small floating accumulations of marine debris. Thus, this study aims at overcoming this limit through the exploration of fusion with very high-resolution WorldView-2/3 (WV-2/3) images. Various state-of-the-art approaches (component substitution, spectral unmixing, deep learning) were applied on data collected in synchronized acquisitions of plastic targets of various sizes and materials in seawater. The fused images were evaluated for spectral and spatial distortions, as well as their ability to spectrally discriminate plastics from water. Several WV-2/3 band combinations were investigated and five litter indexes were applied. Results showed that: a) the VNIR combination is the optimal one, b) the smallest observable plastic target is 0.6 × 0.6 m² and c) SWIR bands are important for marine litter detection.

An analytical framework was proposed for analyzing long-term chemical pollution in a coastal region with limited environmental data. The framework consists of compiling and synthesizing the available knowledge including the chemical's properties and the environmentally relevant data, as well as the data obtained by past monitoring studies. The gathered data is analyzed to assess multimedia fate of the pollutant by using fugacity-based intermedia transport calculations. Uncertainty analysis by applying Monte Carlo simulations is an integrated part of the framework. Dispersion factor (k) values were adopted, enabling a unified and intuitive way to define lognormal uncertainty distributions. The proposed framework was applied to polycyclic aromatic hydrocarbon (PAH) pollution in Izmit Bay, a coastal region in Turkey, impacted by industrialization and population growth. The analysis showed the importance of atmospheric pollution as a PAH source and indicated that Izmit Bay sediments may be at steady state for most PAHs.

It's a new perspective to explore the influences of chromophoric dissolved organic matter (CDOM) components and environmental factors on the removal of sulfisoxazole (SIX) from the water matrix. Reactive intermediates (RIs) trapping experiments demonstrated that excited triplet-state CDOM (³CDOM⁎) played a dominant promoting role (54.11%) in the CDOM-mediated SIX indirect photodegradation. Additionally, terrestrial humic-like (C1, C3 and C4) and marine humic-like (C2) fluorescent components were identified by parallel factor (PARAFAC) analysis of CDOM excitation-emission matrix spectroscopy (EEMs). C1 and C4 were significantly correlated (R² > 0.91) with the SIX degradation rate owing to their higher productivity of RIs and a greater contribution to the production of ³CDOM⁎ compared to others. Salinity, pH and HCO₃⁻ were conducive to the SIX indirect photodegradation, while metal ions (Fe³⁺ and Cu²⁺), halogen ions (Cl⁻ and Br⁻) and NO₃⁻ were opposite. These findings are essential for understanding the environmental fate of SIX in coastal waters.

A copepod bioassay with Tigriopus japonicus was applied to evaluate the relative ecotoxicity of sediments in the Yellow and Bohai seas, and contributions of individual PAHs to copepod toxicity were evaluated. Mean toxicity was greatest in the Yellow Sea of China, followed by the Bohai Sea and Yellow Sea of Korea. Elevated concentrations of sedimentary PAHs, alkylphenols, and styrene oligomers back-supported the significant toxicities observed in bioassay. Copepod toxicity in relation to PAHs indicated the greatest contribution by indeno[1,2,3-c,d]pyrene. However, lacked contribution by PAHs, viz., 2.4 and 3.0 % for the total immobilization and mortality, respectively, indicated a large proportion of unknown toxicants being widely distributed along the Yellow Sea Large Marine Ecosystem (YSLME) coastline. Overall, the present study provides useful baseline information for evaluating the potential sedimentary toxicants, with emphasizing further investigation to identify the unknown toxicants at an LME scale, and elsewhere.

The effects of marine litter pose ecological, economic and optional value threats to the countries and territories on the margins of the Atlantic Basin. As the abundance of transboundary marine litter increases, this in turn has triggered the development of marine litter policy action plans and inter-regional collaboration. The OSPAR Commission and Cartagena Convention of North-East Atlantic (NEA) and the Wider Caribbean Region (WCR) respectively, have established a memorandum of understanding to facilitate collaboration for enhanced marine litter management. In light of this development, this paper conducts a scoping review of management measures of marine litter within these regions as well as a coherence analysis between their regional action plans (RAPs). The analysis uses a proactive framework based on a modified categorization by Chen (2015) and Williams and Rangel-Buitrago (2019) for comparatively analyse management measures. The analytical categorizations include legislation and enforcement measures, prevention, removal, monitoring, research, information management and exchange and education and outreach. Although specific approaches differed among the regions depending upon geographical and individual situations, each categorization included detailed management activities except for prevention in NEA and removal in the WCR. The comparative analysis demonstrates that there are opportunities for inter-regional cooperation, knowledge sharing and overall enhanced and informed marine litter management.

Rhizoprionodon longurio is an important commercial species captured in an area with heavy metal presence due to the mining waste from Santa Rosalia, Gulf of California, and levels of heavy metals in its muscle remain unknown. This study aimed to investigate whether contamination levels are below the limits allowed for human consumption and to prevent health damage. Concentrations of essential (Cu, Fe, Mn, and Zn) and non-essential (Ag, Cd, and Pb) trace elements were determined in fifty-seven muscle samples of R. longurio. The average concentrations of Fe > Zn > Cu > Mn > Cd > Ag did not exceed the permissible limits for human consumption established by the Mexican norm, WHO, and FAO. The mineral daily ingestion was 0.10 to 0.53 % × 100 g of muscle, and the percentage of weekly consumption was 2.5 % to <12 % concerning corporal weight. The meat from this shark can be consumed due to its low toxic potential for human health.

Mercury (Hg) is a toxic globally spread pollutant that has been found at increasing concentrations in the South Atlantic Ocean. The present work provides the first insight into the total mercury (HgT, unfiltered waters) content in the water of the Brazilian Exclusive Economic Zone (BEEZ), within a 24°S to 20°S. Water samples were collected from surface to 3400 m depth along transects, and analyzed with atomic fluorescence. The mean HgT concentration for the Tropical Water mass (TW) was 6.3 ± 1.4 pM (n = 16), for the South Atlantic Central Water (SACW), 5.9 ± 0.7 pM (n = 8), for the Antarctic Intermediate Water (AAIW), 5.0 ± 0.6 pM (n = 2), for the Upper Circumpolar Deep Water (UCDW), 6.5 pM (n = 1), and for the North Atlantic Deep Water (NADW), 5.7 ± 0.9 pM (n = 12). HgT concentrations were highest throughout the BEEZ in comparison with other parts of the Atlantic Ocean, farther from the coast.

Water transparency, commonly measured as Secchi disk depth (SDD), is essential for describing the optical properties of coastal waters. We proposed a regional linear corrected SDD estimation model based on the North Sea Mathematical Models for GOCI and the mechanical model developed by Lee et al. (2015) in the Jiaozhou Bay. Combined with the multiple variable linear regression analysis, the diurnal SDD variations of the bay inside and the bay mouth are controlled by the solar zenith angle (SZA) and tides. The bay outside mainly varies with SZA. From GOCI observations between 2011 and 2021, wind force influenced the entire area on the inner-annual SDD variations. It exhibits an increasing trend in the inter-annual dynamics, which was more stable inside the bay with an annual increase of 0.035 m, and air temperature was the most significant contribution. However, human activities cannot be ignored in causing water environment changes.

In this study, we have reported an efficient and stable degradation of pollutants at salinity condition using newly developed solar-light-driven silicone-TiO₂ based photocatalytic immobilized system. The interfacial layer of Silicone-PEG-P/Ag/Ag₂O/Ag₃PO₄/TiO₂ (S-PEG/PAgT) photocatalyst exhibited higher surface roughness, hydrophobicity, better light absorption, and narrow band gap than S-TiO₂. The Rh B degradation by S-PEG/PAgT (91.2%) was 1.71 folds higher than S-TiO₂ (53.5%) under simulated solar light irradiation. The reduction rate was significantly higher in S-PEG/PAgT (0.0792 min⁻¹) than S-TiO₂ (0.0229 min⁻¹). The S-PEG/PAgT demonstrated high TOC removal (>80%), high repeatability (10 cycles) and excellent activity after 30 days of incubation in aqueous NaCl. The mechanism analysis revealed the synergistic effect of surface morphology with irregular chamfered edges and photoinduced reactive species (O₂⁻) with successive formation of free chlorine radicals (Cl) contributed to the removal of pollutants in saline wastewater. Therefore, considering the above advantages of high efficiency and effective elimination of organics illustrates the potential of newly developed S-PEG/PAgT immobilized system in long-term practical treatment real seawater and ballast water.

Proliferation of microplastics in rivers, lakes, estuaries, coastal waters and oceans is a major global challenge and threat to the environment, livelihoods and human health. Reliable predictive tools can play an essential role in developing an improved understanding of microplastics behaviour, exposure and risk in water bodies, and facilitate identification of sources and accumulation hot spots, thereby enabling informed decision-making for targeted prevention and clean-up activities. This study presents a new numerical framework (CaMPSim-3D) for predicting microplastics fate and transport in different aquatic settings, which consists of a Lagrangian, three-dimensional (3D) particle-tracking model (PTM) coupled with an Eulerian-based hydrodynamic modeling system (TELEMAC). The 3D PTM has several innovative features that enable accurate simulation and efficient coupling with TELEMAC, which utilizes an unstructured computational mesh. The PTM is capable of considering spatio-temporally varying diffusivity, and uses an innovative algorithm to locate particles within the Eulerian mesh. Model accuracy associated with different advection schemes was verified by comparing numerical predictions to known analytical solutions for several test cases. The implications of choosing different advection schemes for modeling microplastics transport was then investigated by applying the PTM to simulate particle transport in the lower Saint John River Estuary in eastern Canada. The sensitivity of the PTM predictions to the advection scheme was investigated using six numerical schemes with different levels of complexity. Predicted particle distributions and residence times based on the fourth-order Runge–Kutta (RK4) scheme differed significantly (residence times by up to 100 %) from those computed using the traditional first-order (Euler) method. The Third Order Total Variation Diminishing (TVD3) Runge-Kutta method was found to be optimal, providing the closest results to RK4 with approximately 27 % lower computational cost.