We investigated spatiotemporal distributions of dissolved inorganic nutrients and organic carbon (DOC) and nitrogen (DON) in coastal waters and land-based fish farm wastewater to determine effects of wastewater on seawater of Jeju Island, Korea. The nutrient concentrations in seawater were lower than in wastewater with negative correlations against salinity, indicating a terrestrial source. Wastewater-derived DOC and DON were transported offshore while wastewater-derived inorganic nutrients were effectively removed, likely via biological production, and this was closely linked to decline in N:P ratios. The correlations between DOC, DON, and colored dissolved organic matter suggest that organic matters likely originate from the fish farm wastewater. Quantitatively, the estimated wastewater-derived DOC flux was equivalent to that through submarine groundwater, which is a significant water source on the island. Our results will be able to trace contaminant sources and support assessments of seawater quality for appropriate regulation of fish farm wastewater discharge into coastal zones.

Marine debris, particularly plastic debris is a ubiquitous global pervasive problem. The international community recognizes that a reduction in plastic debris density is central to sustainable ocean use based on reduction performance metrics. Although many national databases already exist or are being developed, an internationally accepted index of plastic debris density does not currently exist. Standardized methods for monitoring marine debris can help inform policy decisions to reduce sources marine debris and support mitigation effectiveness.Vietnam recently committed to addressing marine debris nationally and internationally and developed ambitious targets to manage and reduce ocean plastic debris, yet Vietnam does not currently have a national marine debris monitoring database. This study identified international best practices and standards; developed a marine plastic database for accurate, efficient information gathering, management, and reporting; and developed a centralized database platform for future marine plastic debris management in Vietnam that can be adapted for other jurisdictions.

The potentially toxic elements (PTEs) concentrations in water and sediments were measured in the Hoor Al-Azim wetland to evaluate the spatial distribution, pollution rate, fate, partitioning, and ecological risk and also to recognize the PTEs sources in sediments using MLR-APCs (multiple linear regression-absolute principal component scores) receptor model. The human health risk was investigated based on the seven fish species consumed in the study area. Based on the results, water and sediment contamination was observed at some stations in the southern part of the wetland where agricultural water drains. Also, the sediments of oil well drilling disposal site was polluted by PTEs. Based on the MLR-APCs model, 80.8% of Mo and 81.5% of Se originated from agricultural source. Total target hazard quotients (TTHQ) values suggested that the children could experience adverse health effects due to consumption of Coptodon zillii, Aspius vorax, Carassius auratus and Carasobarbus luteus.

Richards Bay Harbour (RBH) is situated in the industrialized area on the northeast coast of South Africa. To decipher recent human activities and accompanying environmental degradation, surface sediment was collected across RBH and analysed for granulometric and elemental composition, microfaunal assemblages, and microplastics. Microplastics occur most abundantly near recreational areas, whereas metal contamination relates to activities at bulk goods terminals from which they are imported or exported. In particular, Cr and Cu concentrations in surface sediment near bulk goods terminals exceed South African sediment quality guidelines. In metal contaminated sediment, bioindicators reflected stress and were noticeably impacted. A transect of short sediment cores reflects spatial and historical metal contamination and allows quantification of the load of metals within the sediment column. The volume of metal (Cr) contaminated sediment was estimated at almost 2 million m³.

Interactions between corals and macroalgae are important in influencing benthic community structures on coral reefs and have become increasingly common occurrences. However, little is known about their temporal variation as most studies have only documented them from single surveys. To investigate the dynamics of coral–macroalgal interactions, we surveyed three urbanised reefs in Singapore bi-monthly for three years. We found that the frequency of coral–macroalgal interactions varied greatly across sites and seasons. The extent of coral–macroalgal contact was positively correlated with macroalgal abundance, but the correlation differed significantly among macroalgal genera. The growth rates of Goniopora, Montipora and Pavona corals, but not Platygra, were also negatively correlated with the extent of macroalgal interactions. Overall, our results highlight that coral–macroalgal interactions are spatially and temporally dynamic, with varying effects among coral species. It is critical to consider seasonal fluctuations of macroalgae if the overall long-term impacts of macroalgae are to be understood.

The presence of microplastics (MPs) was determined in Mediterranean mussel (Mytilus galloprovincialis Lamarck, 1819) and grooved carpet shell (Ruditapes decussatus Linnaeus, 1758) together with water samples from in İzmir Bay (Aegean Sea, Western Turkey). A total of 895 MPs from Karşıyaka (Station 1), and 787 MPs from Gülbahçe (Station 2) were detected in 60 mussel samples, giving a total content of 1682 MPs. In water samples, a total of 545 MPs were detected in samples from Station 1 and 1287 MPs in samples from Station 2 (1832 MPs total). The amount of MPs in water samples was less in Station 1 than in Station 2. This difference is probably caused by Çiğli Wastewater Treatment Plant (WWTP) located near Station 1. Public health risk assessment on the consumption of the species M. galloprovincialis revealed that 70.82 items person⁻¹ year⁻¹ MPs through this species could enter consumers' digestive systems.

Plastic debris in the coastal environment is subject to complex and poorly characterized weathering processes. To better understand how key environmental factors affect plastic degradation in a coastal zone, we conducted an in situ experiment. We deployed strips of high density polyethylene (HDPE) and polystyrene (PS) in paired coastal areas of contrasting conditions (hydrodynamic activity: erosional or depositional; water depths: subtidal or intertidal). Strips were collected after environmental exposures at 4, 8, and 43 weeks and analyzed for change in mass, algal biofilm growth, and imaged by petrographic and electron microscopy (SEM-EDS). Significant surface erosion was evident on both polymers, and was more rapid and more extensive with PS. Degradation of PS was responsive to intensity of hydrodynamic activity, and was greater at intertidal depths, highlighting the critical role played by photo-oxidation in the coastal zone, and suggesting that algal biofilms may slow degradation by playing a photo-protective role.

Long-term assessments are needed to identify water quality trends and their socio-environmental drivers for coastal management and watershed restoration. This study provides the first long-term assessment of fecal bacterial pollution in the northwestern Gulf of Mexico using enterococci data spanning the Texas coast from 2009 to 2020. The data were representative of 66 beaches, 169 stations, and over 75,000 samples. Findings demonstrate that 22 beaches are ‘hotspots’ of pollution and experienced enterococci levels that frequently exceeded the USEPA beach action value. Further, enterococci were correlated with time, population size, and sea level. Weak correlations detected in some counties highlight the multifactorial nature of water quality; additional factors are likely influencing enterococci levels. The correlation with sea level is concerning, as counties vulnerable to sea level rise frequently reported enterococci concentrations exceeding the beach action value. In consideration of sea level rise predictions, targeted studies are needed to pinpoint drivers of fecal pollution.

The present study was conducted to assess the distribution of plastic debris in pre- and post-cyclonic beach sediments in Silver beach, Cuddalore, southeast coast of India. The total amount of macroplastic in pre-cyclonic beach sediments was higher than that in the post-cyclonic coastal sediments (pre-cyclonic 16.1%; post-cyclonic 5.4%). The polymer varieties in pre- and post-cyclonic sediments were present in the following descending order: Pre-cyclonic sediments: polyvinyl chloride (79.06%) > polyethylene (13.9%) > nylon (6.9%); post cyclonic sediments: polypropylene (31.4%) > polyethylene (30.5%) > polystyrene (16.0) > nylon (15.5%) > polyvinyl chloride (5.1%). The different varieties of polymers with irregular shapes in the sediments are most probably introduced into the coastal environment by cyclonic floods. Wind and cyclone-induced rainfall were the driving forces for the transportation and deposition of plastic debris. The results of this study will be useful to formulate effective beach litter management policies in an attempt to develop long-term solutions.

Through the application of the Water Pollution Emergency Response System (WPERS) in the Changjiang Estuary, it was found that tidal flats significantly affect the trajectory of an oil film, and the deposition of the oil film on tidal flats is remarkable. In this study, the Estuarine Oil Spill Model (EOSM) was developed to simulate the process of the oil film landing on tidal flats. The Lagrangian particle algorithm and oil fate experience algorithms were adopted. An algorithm for generating dynamic shorelines was also involved. Compared to the oil spill algorithm without wet-dry functionality, the spatial distribution of the oil film deposition simulated in the EOSM better matched the reanalysis data of the satellite remote sensing image. This indicated that the dynamic wet-dry switch phenomenon of tidal flats could be involved in the simulation of offshore oil spills to improve the accuracy of accident prediction and ecological loss assessment.On December 30th, 2012, a vessel carrying 400 tons of heavy oil sank in the Changjiang Estuary, China. The heavy oil leaked at around 4 am the next day. In this study, a new oil spill model was developed to simulate the process of an oil film landing on land and tidal flats. An algorithm for generating the dynamic shorelines in an oil spill simulation was adapted for the wet-dry switch of tidal flats. The landing distribution of the oil film in this new model was well matched to the satellite image for this accident. This indicated that the dynamic wet-dry switch phenomenon of tidal flats could be involved in the simulation of oil spills offshore, to improve the accuracy of accident prediction and ecological loss assessment. The research results could provide some new ideas for the development of offshore oil spill simulation technology.