Beach accumulation surveys can be used as a proxy to estimate litter flows into the marine environment. However, litter loads can be influenced by various factors including catchment area characteristics, weather conditions and ocean water movements. This complexity is evidenced by the results of five beach surveys conducted in Cape Town in 2017. Observed average litter accumulation rates across the beaches ranged from 36 to 2961 items·day⁻¹·100 m⁻¹. Item mass ranged from 0.01–367 g, with items weighing <1 g contributing 61–85% of count. Plastic items accounted for 94.5–98.9% of total count and this prevalence appears to have increased relative to older data (1989–1994). The top ten identifiable items accounted for 40–57% of plastic debris. Nine of these were associated with foods commonly consumed on-the-go, including polystyrene packaging, snack packets and straws. A mitigation approach focused on these items may address one third to one half of marine litter sources in Cape Town.

This work attempted to prolong the validity of the molybdate mixed solution and ascorbic acid solution used in the phosphomolybdenum blue spectrophotometric method by improving their preservation according to the influence factors. The results showed that the molybdate mixed solution can be directly preserved in darkness with validity over half a year. The ascorbic acid solution is influenced by light, temperature, pH, metal ions, oxygen, and bacteria. The validity of ascorbic acid is shortened as the temperature rises. Through keeping in darkness, adding complexing agents, adjusting pH, removing oxygen and sterilization, the validity of ascorbic acid solution was prolonged to over 2.7 times under 4 °C and over 5 times under 25 °C. At the same time, the hybrid solution of ascorbic acid solution and molybdate mixed solution should be preserved separately, otherwise the using effect is poor.

The distribution, composition, potential sources and ecological risk of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) were investigated in surface water from coastal Bohai Bay. The PAH concentrations ranged from 48.0 to 607 ng L⁻¹ with the mean value of 267 ng L⁻¹ in dissolved phase and 198 to 935 ng L⁻¹ with the mean value of 424 ng L⁻¹ in particle-associated phase, and decreased following the order: Qinhuangdao (QHD) > Caofeidian (CFD) > Huanghuagang (HHG). The 2–3 ring PAHs accounted for 79.9% to 86.2% in particle-associated phase and 65.6% to 73.2% in dissolved phase of total 16 PAHs, in which naphthalene (Nap) was the most dominant compound. The PAHs in surface seawater mainly originated from petrogenic sources according to the molecular ratios of benzo[a]anthracene/228 and fluoranthene/202. Risk quotients indicated that there was potential ecological risk for PAHs in surface seawater, especially for pyrene and fluorene.

Plastic pollution is a major ecological catastrophe that endangers vulnerable species. Small plastic fragments and filaments enter the food web in the ocean threatening marine species health. Here microplastics between 0.5 and 5 mm were quantified from eight beaches of southwest Bay of Biscay (Spain) within Natura-2000 Special Protection Areas for birds. Sand samples were taken using a randomized quadrat-based protocol. Between 145 and 382 particles per kg of dry sand were found, which is relatively high in comparison with other European beaches. Microfibers were more abundant than microplastics. PERMANOVA revealed a significant effect of the beach location (inside versus outside the estuary). Open beaches contained a higher microplastic density than sheltered ones suggesting that many beached microplastics come from the ocean. Birds are at risk in the studied protected spaces as revealed from high concentrations of fibres in depositions of European shag and gulls.

Recent technology developments have turned present-day unmanned systems into realistic alternatives to traditional marine animal survey methods. Benefits include longer survey durations, improved mission safety, mission repeatability, and reduced operational costs. We review the present status of unmanned vehicles suitable for marine animal monitoring conducted in relation to industrial offshore activities, highlighting which systems are suitable for three main monitoring types: population, mitigation, and focal animal monitoring. We describe the technical requirements for each of these monitoring types and discuss the operational aspects. The selection of a specific sensor/platform combination depends critically on the target species and its behaviour. The technical specifications of unmanned platforms and sensors also need to be selected based on the surrounding conditions of a particular offshore project, such as the area of interest, the survey requirements and operational constraints.

In this paper results of laboratory studies of damping of gravity-capillary waves due to emulsified oil films (EOF) are presented and compared to crude oil films (COF). A laboratory method based on measuring the damping coefficient and the length of parametrically generated gravity-capillary waves is applied to a 50% EOF and to crude oil films. Measurements of wave damping were carried out in a range of surface wave lengths, corresponding to Bragg waves of X- to Ka-band radars. The obtained dependences of wave damping coefficient on EOF thickness have demonstrated the existence of a damping maximum at thicknesses of about 1–2 mm, and the maximum is approximately twice the one for COF, the damping maximum for EOF is located at larger film thicknesses than for COF. Theoretical calculations of wave damping have been performed and viscoelastic parameters of EOF have been estimated from comparison between theory and experiment.

The MYTIAD project focused on the assessment of chemical contamination (metals, PAHs, PCBs and organochlorine pesticides) in the Adriatic coastal waters by active mussel watching. Its purpose was harmonising and standardising strategies and methodologies used to assess the contamination status of the Adriatic Sea, in the framework of the WFD, the MSFD and UNEP/MAP Integrated Monitoring and Assessment Programme. Data on metals pointed out some hotspots along the eastern and western Adriatic Sea coasts, with the highest values of total PAH concentration detected in Split, Trieste, and Taranto (Ionian Sea). PCB and endrin contamination was higher in the Adriatic Sea than in the western Mediterranean Sea. This is the first comprehensive overview of contamination in the Adriatic Sea with critical comparisons of related studies over the Mediterranean Sea. It provides a useful harmonised dataset to support a coordinated definition of baselines, targets and thresholds, and further management of chemical contamination.

We study the evolution of large systems of sticky patches of pollution that float on the sea surface and are moved around by realistic wind and simulated surface currents. The study area is the Gulf of Finland in the eastern Baltic Sea that hosts extremely heavy cargo and tanker traffic. It is assumed that patches merge at collision. Collisions are enhanced by wind impact that depends on the patch size. We implement a space partitioning algorithm for fast simulations of large systems of >8000 patches and perform a series of simulations with different initial size and location of the patches. The resulting empirical distribution of the number of patches of different size is governed universally by a stretched-exponential power law f(x) = A exp (−xb). This indicates that the evolution of large systems of pollution patches on the sea surface exhibits classic self-organization and scale invariance properties. This may be the key effect explaining how the patchiness of waste in marine environment is formed under the impact of different drivers.

Heavy metals may adversely affect health in marine organisms. As top predators, sharks may be especially vulnerable to exposure over long lifespans. Here we evaluate plasma levels of 14 heavy metals and 12 trace elements in white sharks, Carcharodon carcharias, in South Africa to determine whether they are related to sex, body size, and/or body condition and other health parameters. High levels of mercury and arsenic were found in shark blood at levels considered toxic in other vertebrates. Heavy metal concentrations were not related to body size or sex. Metal concentrations were not related to body condition with exception of copper, which was positively correlated. Protective effects of elements such as selenium, zinc, and iron were not detected. No negative effects on health parameters, such as total leukocytes or granulocyte to lymphocyte ratios were observed. Results suggest that sharks may have protective mechanisms that mitigate harmful effects of heavy metal exposure, providing new opportunities for future studies.

To examine whether historical fish bones can record the magnitude of heavy metal pollution, we analyzed up to 700 years old fish bone remains extracted from an ornithogenic sediment profile on Nandao Island, South China Sea. Bulk sediments and subfossil fish bones were analyzed for elemental and mineralogical composition, as well as stable carbon and nitrogen isotopes. The results showed that pre-1850 CE fish bones experienced significant diagenesis, and could not be used to reconstruct historical record of heavy metal pollution. Fish bone diagenesis was mainly attributed to the erosion from guano in sediment profile. In contrast, the fish bones from in post-1850 CE time were well preserved and could provide useful information on historical pollution loads over the past 160 years. Since 1850 CE, relatively high concentrations of heavy metals from anthropogenic sources, especially Zn, were recorded in fish bone subfossils on Nandao Island, South China Sea.