The emergence of the COVID-19 pandemic has caused worldwide health constraints. This study was conducted to establish a baseline monitoring survey to describe the distribution of PPE litters during the COVID-19 pandemic in the province of Palawan, Philippines. A total of 386 COVID-19-related PPE items were present in 83 % of coastal sampling sites with over a cumulative area of 48,200 m², with a density of 8 × 10⁻³ items m⁻². The facemask (98 %; n = 377) was the primary type of PPE, followed by face shield (2 %; n = 9). Meanwhile, the daily density of PPE litters in San Manuel, Puerto Princesa ranged from 0 to 9.9 × 10⁻² items m⁻², with a mean density of 8 × 10⁻³ items m⁻². The accumulation rates of PPE items ranged from 3.27 × 10⁻¹ items to 1.143 items d⁻¹, with an average rate of 7.29 × 10⁻¹ items d⁻¹.

Estuaries have long been preferred areas of human settlement, where multiple anthropogenic activities take place, which have contributed to a significant decrease in environmental quality of these ecosystems. Accordingly, environmental monitoring and management have long relied on the development of tools that summarize and simplify complex information and provide direct interpretation of quality status. Here, the fatty acid profiles of three abundant estuarine species, namely Hediste diversicolor, Carcinus maenas and Pomatoschistus microps, were used to develop and validate a multimetric index, based on the Euclidean dissimilarities of profiles between sites, in response to contamination gradient in a large urban estuary. Spatial differences were generally related to unsaturated fatty acids (mono- and polyunsaturated, of the n−3 and n−6 series) in all species, albeit more pronounced in P. microps. Multivariate models returned high classification accuracies for the three sampled sites, varying from 73.3% in the invertebrate species to 100.0% in the fish species. Results show the applicability of the developed FA-based index, particularly due to the easy of communication, for managers and the public alike, but also highlight the need for prior validation on species suitability or sensitivity to depict environmental contamination.

Single-use plastic, few global engagement and lack of policies contribute to the global challenge about plastic marine litter. This form of contamination can cause injury and death of marine wildlife. Microplastics (>5 mm) represent an important fraction of plastic litter. They include the plastic pellets that are used as raw material within plastic industry that can be unintentionally spilled into the environment during the industrial processes. In an initiative in order to facilitate the understanding and communication of plastic pellets as a social and environmental problem, we applied the Drivers-Activities-Pressures-State changes-Impacts (on Welfare)-Responses (as Measures) (DAPSI[W]R[M]) framework to plastic pellets chain. We also analyzed possible mitigating measures and their actions along the plastic pellets chain. This DAPSI(W)R(M) framework aim to show an overview of the plastic pellets chain and solutions for politicians and decision makers to help solve this socio-environmental problem that needs the engagement of all stakeholders involved.

To prevent the spread of the COVID-19 contagion, some regions of Brazil implemented a prohibition of beach use, which contributed to a reduction of artisanal fishing activity. This study aimed to evaluate the influence of these beach closures on the incidence of abandoned, lost, or discarded fishing gear (ALDFG) along four beaches located on the northern coast of Pernambuco, Brazil. The absolute and relative frequency of occurrence and the number of observations per unit of effort (OPUE) between the periods before and after the prohibition period were analyzed. A total of 1935 fishing gear residues were found (63% before and 37% after prohibition). There was also a significant reduction in OPUE and in absolute frequency (p < 0.05) between these two periods. Although beach closures appear to have contributed to a reduction in the amount of ALDFG in the region, it does not indicate a complete pause in fishing activities.

To assess the role of near-hypoxic and hypoxic conditions on the mesozooplankton community, we studied twenty stations in the Persian Gulf and the Gulf of Oman. The physicochemical parameters were measured using a CTD probe and mesozooplankton were sampled vertically using a closing net. Results showed the hypoxic conditions of 0.52 ± 0.11, 1.40 ± 0.48, and 0.84 ± 0.08 in the lower layers in stations T11S3, T0S8B, and T9S5 in the Gulf of Oman and near-hypoxic conditions in station T6S3 (2.99 ± 0.05) in the Persian Gulf. The marginal test revealed that stratification during summer and dissolved oxygen and salinity during spring in the Persian Gulf and temperature, stratification, and dissolved oxygen during spring in the Gulf of Oman significantly explained the variation of mesozooplankton composition in the study areas (p < 0.05). The present study reveals some general patterns of mesozooplankton assemblage in near-hypoxic and hypoxic conditions, but a future detailed investigation will be essential.

Haze is a well-known air pollution phenomenon linked to the severe and persistent particulate matter (PM) episodes in Southeast Asia (SEA), which significantly impacts the environment, health, and economy. This work reviewed for the first time the characteristics of haze episodes in terms of PM concentrations, chemical compositions, and the causes of haze in both Lower (Maritime) and Upper (Mainland) SEA. In addition, we carried out a systematic comparison of the frequency and intensity of haze events through SEA regions in recent years. Our finding indicated that the different trend of haze frequency and intensity between SEA cities are not only due to local air pollution sources such as biomass burning (BB) but also meteorology and long-range transport. Other sources such as secondary aerosols also play an important role in haze formation, but they have not been comprehensively investigated in previous studies. Due to the complicated formation mechanisms and the transportations of haze and its impacts on SEA’s human health and economy, more sophisticated and specific policies are needed to deal with haze issues not only for individual countries but also on a regional scale.

Total mercury (THg) concentrations were measured in muscle and liver of two placental viviparous sharks, the Pacific sharpnose shark (Rhizoprionodon longurio) and the brown smooth-hound (Mustelus henlei); as well as in the muscle, liver, and yolk of the yolk-sac viviparous speckled guitarfish (Pseudobatos glaucostigmus) in Baja California Sur. The aim was to determine which factors could be involved in maternal transfer and resultant maternal and embryonic THg concentration. Higher THg concentrations were found in pregnant females compared to embryos paired tissues. THg concentrations of embryo tissues decreased with total length (TL), except for the muscle of the Pacific sharpnose shark. THg concentrations of embryo muscle was positively related to THg concentration in the muscle of pregnant females. Embryos TL, muscle THg concentration of pregnant females, percentage of THg concentration in embryos, along with the reproductive strategy are relevant factors required to improve our understanding of THg concentration in embryo tissues.

If biodegradable plastics tackle the marine plastic pollution problem sufficiently remains questionable. To gain more insight in degradability, performance, and the impact of degradation on the toxicity, commercial bags made from two biodegradable plastics and one conventional plastic (PE) were exposed for 120 days in a mesocosm featuring benthic, pelagic, and littoral habitat simulations. Degradability was assessed as weight loss, and specimens were tested for toxicity using Paracentrotus lividus sea-urchin larvae after different exposure times. Both biodegradable bags showed degradation within 120 days, with the littoral simulation showing the highest and the pelagic simulation the lowest decay. Disregarding habitat, the home-compostable plastic showed higher marine degradation than the industrial-compostable material. The relevant initial toxicity of both biopolymers was lost within 7 days of exposure, pointing towards easily leachable chemical additives as its cause. Interestingly, littoral exposed specimens gained toxicity after 120 days, suggesting UV- induced modifications that increase biopolymer toxicity.

Dredging is an excavation activity used worldwide in marine and freshwater environments to create, deepen, and maintain waterways, harbours, channels, locks, docks, berths, river entrances, and approaches to ports and boat ramps. However, dredging impacts on marine life, including marine mammals (cetaceans, pinnipeds, and sirenians), remain largely unknown. Here we quantified the effect of dredging operations in 2005 and 2019 on the occurrence of Indo-Pacific bottlenose dolphins (Tursiops aduncus) and long-nosed fur seals (Arctocephalus forsteri) in the Port River estuary, a highly urbanized estuary in Adelaide, South Australia. We applied generalised linear models to two long-term sighting datasets (dolphins: 1992–2020, fur seals: 2010–2020), to analyse changes in sighting rates as a function of dredging operations, season, rainfall, and sea surface temperature. We showed that the fluctuations in both dolphin and fur seal occurrences were not correlated with dredging operations whereas sea surface temperature and season were stronger predictors of both species sighting rates (with seals more prevalent the colder months, and dolphins in summer). Given the highly industrial environment of the Port River estuary, it is possible that animals in this area are habituated to high noise levels and therefore were not disturbed by dredging operations. Future research would benefit from analysing short-term effects of dredging operations on behaviour, movement patterns and habitat use to determine effects of possible habitat alteration caused by dredging.

At present, there are no standardised tests to assess metal leaching during submarine tailings discharge. In this study the influence of variables known to affect metal mobility and availability (dissolved organic carbon (DOC), pH, salinity, temperature, aerated/anoxic conditions) along with variables affected by the discharge conditions (flocculant concentration, suspension) were studied in bench-scale experiments. The leaching tests were developed based on the case of a copper mine by Repparfjorden, northern Norway, which is planned to re-open in 2022. The experiments, which had three week duration, revealed low (<6 %) leaching of metals. Multivariate analysis showed that all variables, apart from DOC, highly influenced leaching and partitioning of at least one metal (Ba, Cr, Cu, and/or Mn). The high quantity of the planned annual discharge of mine tailings to the fjord (1–2 million tonnes) warranted estimation of the leached quantity of metals. Multivariate models, using present-day conditions in the fjord, estimated leaching of up to 124 kg Ba, 154 kg Cu and 2400 kg Mn per year during discharge of tailings. Future changes in the fjord conditions caused by climate change (decreased pH, increased temperature) was predicted by the multivariate models to increase the leaching up to 55 %, by the year 2065. The bench-scale experiments demonstrated the importance of including relevant variables (such as pH, salinity, and temperature) for metal leaching and -partitioning in leaching tests. The results showed that metal leaching during discharge is expected and will increase in the future due to the changed conditions caused by the foreseen climate change, and thereby underline the importance of monitoring metal concentrations in water during operations to determine the fate of metals in the fjord.