Assessing the coastal sensitivity to oil spills from the perspective of ecosystem services: A case study for Canada's pacific coast

Characterization of oil exposure parameters affecting impact, recovery, and reestablishment of mangrove forests: Lessons learned

The recovery and reestablishment times of mangrove forests exposed to oil are highly dependent on the oil type and oil-related contaminant levels in water and sediments, spill magnitude, oil exposure duration and frequency, duration of the oil contamination remaining in water and sediments, and post-spill events and clean up actions. Estimating the adverse effects of oil exposure and recovery times of mangrove forests is often done by referencing other spills in different geographical regions or locations with different coastal and environmental characteristics. As a result, these projections may not provide reliable estimates for recovery times and the success of the recovery efforts. A systematic methodology is needed to categorize the prespill conditions and oil exposure vulnerability of mangrove forests. The objectives of this review are to: 1) emphasize the need for a systematic process to document the pre- and post-spill characteristics of mangrove forests, 2) identify key factors that influence the vulnerability of mangrove forests to oil exposure, 3) highlight the differences in mangrove forest characteristics and types of spilled oil to develop effective recovery strategies, 4) emphasize the importance of developing a recovery estimation tool to project the adverse effects of oil spills and recovery times, considering geographical features, mangrove characteristics, and the nature of the spilled oil, and 5) stress the necessity for using appropriate monitoring tools for systematically tracking the recovery of mangrove forests after exposure to oil.

Oil spill environmental sensitivity mapping of Rio de Janeiro, Brazil

The current case study focuses on the Environmental Sensitivity Index (ESI) mapping of Guanabara Bay, Rio de Janeiro, Brazil - a region at risk from petroleum sector pollution. By mapping 981.5 km of coastline and classifying it in 10 oil sensitivity indices, we integrated biotic resources, socioeconomic attributes, and geoenvironmental diversity into a georeferenced database. Results reveal a high oil sensitivity of the bay, with approximately 89 % of the mapped coast scoring ESI 8 and ESI 10. These scores comprise, respectively, estuarine and solid substrate habitats that are sheltered from wave action. Notably, numerous manufacturing and oil handling plants, along with intensive urbanization, also contribute to the bay's oil sensitivity. Additionally, the rich biotic diversity in the study area, particularly in protected areas housing 79 conservation units, further amplifies its environmental vulnerability. This study aims to serve as a reference for detailed ESI mapping of coastal areas in tropical rainy zones with significant environmental diversity, industrial development, and a dense population.

Enhanced oil-water emulsion separation through coalescence filtration utilizing milkweed fiber: a sustainable paradigm

Over the past few years, the environment and public safety have suffered due to the detrimental effects of oily industrial effluents. Natural fibers have gained popularity for their affordability, reusability, and effectiveness in separating oil from oily wastewater. Milkweed fibers were characterized using FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), and contact angle techniques. With four porosities (0.90, 0.92, 0.95, and 0.98), deep bed coalescence filters were built at three different filter bed heights (10 mm, 20 mm, and 30 mm). Using milkweed coalescence filtering technology, a novel oil separation method is described along with a method to calculate oil film thickness following emulsified oily water saturation. By combining a bed height of 30 mm and a porosity of 0.98, a maximum oil separation of 99.73% and an optimized D50 droplet ratio were achieved. Throughout a prolonged operational period lasting 250 min, the filter bed, possessing a depth of 30 mm and a porosity of 98%, exhibited no discernible fouling indications. Following five cycles, the milkweed filter bed measuring 30 mm in depth and featuring a porosity of 98% displayed an impressive oil separation efficiency of 91.5%. This study found that using a milkweed deep bed filter, coalescence filtering effectively removes oil from oily effluent. Furthermore, milkweed is a natural and biodegradable fiber that is easy to dispose of after use and does not harm the environment.

Identification of the driving factors of microplastic load and morphology in estuaries for improving monitoring and management strategies: A global meta-analysis

Estuaries are one of the primary pathways for transferring microplastics (MPs) from the land to the ocean. A comprehensive understanding of the load, morphological characteristics, driving factors, and potential risks of MPs in estuaries is imperative to inform reliable management in this critical transboundary area. Extracted from 135 publications, a global meta-analysis comprising 1477 observations and 124 estuaries was conducted. MP abundance in estuaries was tremendously variable, reaching a mean of 21,342.43 ± 122,557.53 items/m3 in water and 1312.79 ± 6295.73 items/kg in sediment. Fibers and fragments take up a majority proportion in estuaries. Polyester, polypropylene, and polyethylene are the most detected MP types. Around 68.73% and 85.51% of MPs detected in water and sediment are smaller than 1 μm. The redundancy analysis revealed that the explanatory factors influencing the morphological characteristics of MPs differed between water and sediment. Regression analysis shows that MP abundance in water is significantly inversely correlated with mesh/filter size, per capita plastic waste, and the Human Development Index, whereas it is significantly positively correlated with population density and share of global mismanaged plastic waste. MP abundance in sediment significantly positively correlated with aridity index and probability of plastic entering the ocean, while significantly negatively correlated with mesh/filter size. Analysis based on Geodector identified that the extraction method, density of flotation fluid, and sampling depth are the top three explanatory factors for MP abundance in water, while the share of global mismanaged plastic waste, the probability of plastic being emitted into the ocean, and population density are the top three explanatory factors for MP abundance in sediment. In the studied estuaries, 46.75% of the water and 2.74% of the sediment are categorized into extremely high levels of pollution, while 73.08% of the water and 43.48% of the sediment belong to class V of the potential ecological index.

Applications of bubble curtains in marine oil spill containment: Hydrodynamic characteristics, applications, and future perspectives

Although the marine oil spill pollution issue does not bring us to flock in droves as the new emerging oceanic techniques like wave energy converters, remote operated vehicle (ROV), blue ammonia and green hydrogen, the huge pollution risks of the marine oil spills caused by man-made intentional discharge, old equipment, accidental leakage, war and other aspects should arouse our sufficient attention and concern. As the primary countermeasure of emergency response to a marine oil spill, rapid & efficient oil containment is crucial to limit the pollution scope and the subsequent recovery and treatment. Here, we summarized the existing investigations on oil-spill containment with a marked emphasis on the applications of bubble curtains and their working mechanisms. The critical research progress and trends about the remediation techniques and the application of bubble curtains in marine environments were briefly introduced. The article thoroughly analyzed the basic working mechanism of the bubble curtains in oil spill containment, the technical difficulties of the existing methods, the potential application prospects of coupling with the traditional oil containment booms and the critical scientific problems to be studied in the future. Regarding the issues involving insufficient oil retention performance and inconvenient deployment of the existing traditional oil boom under complex and variable sea conditions, the performance and structural optimization of bubble curtain enhanced oil containment boom will get the top priority in developing the next-generation oil containment techniques.

Tide-induced infiltration and resuspension of microplastics in shorelines: Insights from tidal tank experiments

In the present study, the infiltration and resuspension of microplastics (MPs) in a slope substrate under the influence of repeated tidal forces were investigated using a tidal tank. In the scenario in which MPs were placed on the top of the slope, increasing numbers of particles were observed on the water surface with the increase in tidal cycles. More particles of smaller equivalent particle diameter (d_MP) and low density floated to the water surface. The horizontal positions (positive toward the lower tide zone) of MPs showed significant positive correlation with the shortest length c of MPs, MP density, MP weight, d_MP, and Corey shape factor, whereas they showed significant negative correlation with the rate of tidal level change and the longest length a of MPs. The vertical positions (positive in the downward direction) of MPs showed significant positive correlation with the shortest length c of MPs, MP density, MP weight, d_MP, and Corey shape factor, while they demonstrated significant negative correlation with the largest cross-section area and surface tension of MPs. In the scenario in which MPs were placed at the bottom of the tank, the smaller and low-density particles had a higher possibility of moving upward to the water surface under repeated tidal forces. High-density particles also migrated to the water surface due to the surface tension force. Further, a lower rate of tidal level change contributed to more floating of particles. The horizontal positions of MPs showed significant positive correlation with MP density, while they demonstrated significant negative correlation with the largest cross-section area and surface tension of MPs. The vertical positions of MPs showed significant positive correlation with the longest length a of MPs, MP density, MP weight, and d_MP. These results imply that large, high-density, and less flatty particles tend to be distributed in the lower tidal zone and deeper substrate layers. These findings can help understand the redistribution of MPs and assess their risk in the shoreline environment.

Detection of marine oil spills from radar satellite images for the coastal ecological risk assessment

Coastal ecosystems offer substantial support and space for the sustainable development of human society, and hence the ecological risk evaluation of coastal ecosystems is of great significance. In this article, we propose an innovative framework for evaluating coastal ecological risk by considering oil spill risk information and environmental vulnerability information. Specifically, a deep learning based marine oil spill monitoring method is presented to obtain the oil spill risk information from Sentinel-1 polarimetric synthetic aperture radar (PolSAR) images. The environmental vulnerability information is then obtained from biological sample data and habitat information. Finally, a weighted probability model is introduced to utilize the oil spill risk and environmental vulnerability information, to evaluate the coastal ecological risk. In the experimental part, the proposed oil spill monitoring method shows its reliability in global ocean areas, and the proposed model is adopted to evaluate the ecological risk in Jiaozhou Bay, China. The results show that the ecological situation of more than half of the areas in Jiaozhou Bay is unstable, and the areas with high risk are mainly concentrated in the ports, shipping channels, and those areas with high biodiversity. This study provides some new perspectives on ecological risk assessment for coastal ecosystems, facilitating the planning process and the actions to be taken in response to the accidents that occur in the ocean, especially oil spill accidents.

An ensemble machine learning model for water quality estimation in coastal area based on remote sensing imagery

The accurate estimation of coastal water quality parameters (WQPs) is crucial for decision-makers to manage water resources. Although various machine learning (ML) models have been developed for coastal water quality estimation using remote sensing data, the performance of these models has significant uncertainties when applied to regional scales. To address this issue, an ensemble ML-based model was developed in this study. The ensemble ML model was applied to estimate chlorophyll-a (Chla), turbidity, and dissolved oxygen (DO) based on Sentinel-2 satellite images in Shenzhen Bay, China. The optimal input features for each WQP were selected from eight spectral bands and seven spectral indices. A local explanation strategy termed Shapley Additive Explanations (SHAP) was employed to quantify contributions of each feature to model outputs. In addition, the impacts of three climate factors on the variation of each WQP were analyzed. The results suggested that the ensemble ML models have satisfied performance for Chla (errors = 1.7%), turbidity (errors = 1.5%) and DO estimation (errors = 0.02%). Band 3 (B3) has the highest positive contribution to Chla estimation, while Band Ration Index2 (BR2) has the highest negative contribution to turbidity estimation, and Band 7 (B7) has the highest positive contribution to DO estimation. The spatial patterns of the three WQPs revealed that the water quality deterioration in Shenzhen Bay was mainly influenced by input of terrestrial pollutants from the estuary. Correlation analysis demonstrated that air temperature (Temp) and average air pressure (AAP) exhibited the closest relationship with Chla. DO showed the strongest negative correlation with Temp, while turbidity was not sensitive to Temp, average wind speed (AWS), and AAP. Overall, the ensemble ML model proposed in this study provides an accurate and practical method for long-term Chla, turbidity, and DO estimation in coastal waters.

Exploring the effects of substrate mineral fines on oil translocation in the shoreline environment: Experimental analysis, numerical simulation, and implications for spill response

Mineral fines act a pivotal part in determining the fate and behavior of oil. In this study, the infiltrations of oil emulsion in simulated sediments and natural shoreline sediments were investigated using a fixed bed experiment. Oil infiltration process was simulated based on fixed-bed dispersion model. The role of mineral fines in oil release was explored using simulated and natural sediments. Although mineral fines exhibited a higher affinity for oil, it was found that increasing fines fractions decreased the flow rate of oil emulsion, thereby decreasing the oil retention in the sediment column. In terms of oil release from the sediment, the highest level of oil mass was observed in the oil-mineral flocculation phase compared to the water column and the water surface compartments. Compared to light crude oil, the release of engine oil from sediment was less. The effects of mineral fines on oil infiltration and release were also confirmed by using natural shoreline sediments. Results of our detailed field studies also showed that current shoreline classification datasets do not characterize the presence and fraction of mineral fines at a level of detail required to accurately predict the significance of oil translocation following spill incidents.

Sources, behaviors, transformations, and environmental risks of organophosphate esters in the coastal environment: A review

The rapid growth in the global production of organophosphate esters (OPEs) has resulted in their high environmental concentrations. The low removal rate of OPEs makes the effluents of wastewater treatment plants be one of the major sources of OPEs. Due to relatively high solubility and mobility, OPEs can be carried to the coastal environment through river discharge and atmospheric deposition. Therefore, the coastal environment can be an important OPE sink. Previous studies have shown that OPEs were widely detected in coastal atmospheres, water, sediments, and even aquatic organisms. OPEs can undergo various environmental processes in the coastal environment, including adsorption/desorption, air-water exchange, and degradation. In addition, bioaccumulation of OPEs was observed in coastal biota but current concentrations would not cause significant ecological risks. More efforts are required to understand the environmental behaviors of OPEs and address resultant environmental and health risks, especially in the complicated environment.