The dynamics of crude oil and different surface ocean drifters were compared to study the physical processes that govern the transport and landfall of marine oil spills. In a wave-tank experiment, drifters with drogue did not follow oil slicks. However, patches of undrogued drifters and thin bamboo plates did spread at the same rate and in the same direction as the crude oil slicks. Then, the trajectories of the Deepwater Horizon oil spill and 1300 drifters released near the spill source were investigated. Undrogued drifters were transported twice as fast as drogued drifters across the isobaths. 25% of the undrogued drifters landed, versus about 5% of the drogued ones, for the most part, on the same coastline locations where oil was found after Deepwater Horizon. Results highlight the importance of near surface gradients in controlling the cross-shelf transport and landing of surface material on the Gulf of Mexico's northern shores.

The increasing abundance of marine litter is impacting the environment, human health and economies in the South Pacific. Small Islands Developing States are particularly affected by marine litter, primarily due to insufficient waste management systems. For the first time, marine litter was quantified and characterised on 13 beaches in Solomon Islands and Vanuatu in the South Pacific region using the OSPAR beach litter monitoring guidelines. A total of 1053 (±1017) and 974 (±745) items of litter per 100 m beach were recorded in Solomon Islands and Vanuatu respectively. Litter composition and distribution show that the majority of the litter comes from local land-based sources and large quantities of fragments and single use plastics were found by cities and river mouths. Actions to reduce single use plastic, improve collection, reuse and recycling, together with outreach campaigns would reduce marine litter significantly in these countries. Furthermore, there is great potential to develop a more circular economy to manage the substantial quantities of recyclable items that were found stranded on the beaches.

Corrosion and disintegration of munition shells from the World Wars increase the risk that explosives are released into the marine environment, exposing a variety of organisms. Only few studies investigated contamination of fish with explosives in the field under environmental conditions. Here we present a comprehensive study on the contamination status of dab (Limanda limanda) from a munition dumpsite and from reference sites in the Baltic Sea. Bile of 236 dab from four different study sites, including a dumpsite for conventional munitions, was investigated and explosive compounds were detected by high performance liquid chromatography-mass spectrometry. Five explosive compounds were identified, including 2,4,6-trinitrotoluene, 4-amino-2,6-dinitrolouene, and hexahydro-1,3,5-trinitro-1,3,5-triazine. 48% of the samples from the dumpsite contained at least one explosive compound. The results prove that toxic explosive compounds from a dumpsite in the Baltic Sea are accumulated by flatfish and may therefore pose a risk to fish health and human food safety.

Wastewater treatment plants (WWTPs) play a pivotal role in removal of microplastics (MPs) particles before the waste streams are discharged into aquatic environments. Indiscriminate disposal of the effluent and untreated wastewater not only contribute to accumulation of MP in the marine environment, but they can also act as a carrier for various hydrophobic compounds and contributors of pollutants that leach from them via natural degradation. In this assessment, we have summarized the MP concentrations in influent and effluent streams, and provide quantification of the discharges from these WWTPs. Almost 50% of the global wastewater influent of 3,562,082 × 10⁵ m³ remains untreated. Some conservative estimates indicate that treated effluent disposal can add around 1.47 × 10¹⁵ MPs annually, whereas the discharge of untreated effluent is likely to add a staggering 3.85 × 10¹⁶ MPs annually to the aquatic environments. The efficiency of MP removal in wastewater treatment plants varies between 88 and 99.9%, indicating the potential of capturing the majority of the MP from escaping into the freshwater and marine environment. Based on WWTP removal efficiencies for MPs, calculations suggest that if all the globally produced wastewater was treated prior to release, a reduction of over 90% of the current amount of MP inputs into the aquatic environment could be achieved. From the number of studies conducted and assessments made on MPs in waste streams, it is obvious the methodologies followed were quite different, and the use of acids and heating are likely to deteriorate the MPs, emphasizing the need to develop harmonized protocols for microplastic assessment in wastewater treatment plants.

Microplastics (MPs) pollution has been increasingly investigated in marine and freshwater environments, even in atmosphere in China. Current literatures show that MPs contamination is highly related to human activities and geomorphology. Higher MPs occurrences were detected in freshwaters than those in seawaters in China. Furthermore, the abundance of MPs was influenced by many factors, including sampling method, unit of measurement, characteristics of sampling area, and others. Currently, investigating the condition of MPs occurrences and distribution on a broader scale and developing standardized protocol, along with basic toxicological research, will help to address crucial knowledge gaps regarding MPs pollution, their interaction with other pollutants and ecological consequences on individual, population or ecosystem levels in the environment. Meanwhile, this review calls for more efforts to be made for better and scientifically sound risk management for mitigation of MPs pollution in China.

The heavy metal pollution status of oyster reefs has been assessed with respect to ten metals pollutants in seawater, sediments, and tissues of above two oysters (soft tissues and shells) for assessing the pollution status in a short food chain in Hab River Delta. The results showed that heavy metals accumulated in M. bilineata were higher than those in M. cuttackensis. Simultaneously, the population of M. bilineata species has been ironically decreasing as a results of high pollution. The determined concentrations revealed a significant differences in their profiles among sediments, seawater and bioaccumulation in tissues and shells of two native oysters. The present study also compared these metal concentrations with national and international database by applying different pollution indices. Heavy metals in all samples were above the national environmental quality standards (NEQS-Pakistan). High level of pollution with an alarming condition of Hab River Delta need more attention for coastal management.

Plastics pollution is ubiquitous. Microplastics (<5 mm in diameter) and mesoplastics (5–20 mm in diameter) are emerging as the most common plastic particulates found in the marine environment. In this study, the occurrence of microplastics and mesoplastics in the gastrointestinal tract (GI) of some commercially important fish collected from Chennai and Nagapattinam of Tamil Nadu, Southeast coast of Bay of Bengal was assessed. A new and improved alkaline digestion method, using alcoholic potassium hydroxide (KOH) was carried out to destroy the organic matter. Following this method, twenty plastic particulates were isolated from the GI tract of 17 individual fish. Fourier Transform Infrared Radiation analysis (FTIR) showed that polymers found in GI tracts were of Polyethylene, Polyamide and Polyester types. Given the dry fish is India's biggest market and popular delicacy, the presence of microplastics in the fish gut is a potential serious human health concern, as they are directly consumed.

Marine noise pollution (MNP) can cause a multitude of impacts on many organisms, but information is often scattered and general outcomes difficult to assess. We have reviewed the literature on MNP impacts on Mediterranean fish and invertebrates. Both chronic and acute MNP produced by various human activities - e.g. maritime traffic, pile driving, air guns - were found to cause detectable effects on intra-specific communication, vital processes, physiology, behavioral patterns, health status and survival. These effects on individuals can extend to inducing population- and ecosystem-wide alterations, especially when MNP impacts functionally important species, such as keystone predators and habitat forming species. Curbing the threats of MNP in the Mediterranean Sea is a challenging task, but a variety of measures could be adopted to mitigate MNP impacts. Successful measures will require more accurate information on impacts and that effective management of MNP really becomes a priority in the policy makers' agenda.

In the province of Newfoundland and Labrador, fishing is a core occupation and also a source of marine plastic pollution. To look at this relationship, we examined 216 gastrointestinal tracts of Atlantic cod (Gadus morhua) caught by commercial fishers at Fogo Island, Newfoundland and Labrador, Canada. We found three tracts contained plastic for a frequency of occurrence of 1.4%. While this result is consistent with other cod sampled in the province, this study found two gastrointestinal tracts contained intact bait bags, used in commercial pots, and the third tract contained a polypropylene thread, likely originating from fishing rope. Our findings demonstrate the frequency of plastic ingestion in this region is low, but fishing-gear related plastics represent a key source of marine plastics in the region that should be addressed.

A model is proposed for the beach process of buoyant marine plastics, specifically its beaching and backwashing, by introducing beaching and backwashing diffusion coefficients and the onshore-offshore advection-diffusion equations of plastics for the upper layers in the beach and adjacent coastal sea. The backwashing diffusion coefficient was estimated from the average residence time of the beached plastics and the beach width, and then the beaching diffusion coefficient was estimated from the flux-balance assumption between the beaching and backwashing fluxes. Finite difference calculations in the staggered-grid system demonstrated that the amount of beached plastics responds as predicted by the linear system analysis when the beach had an exponential decay type of unit impulse response regardless of the ratio between the residence time and the period of beaching flux fluctuation from the nearshore. The condition in which the flux balance assumption holds was also discussed.