We determined levels of mercury, cadmium, lead and selenium in muscle and liver of 29 specimens of a large pelagic fish rarely investigated, the Mediterranean spearfish Tetrapturus belone (Raf., 1810). The following element concentration ranking (mean ± S.D.; espressed in mg/kg dry weight) was recorded in muscle: Hg (3.401 ± 1.908) > Se (1.727 ± 0.232) > Pb (0.532 ± 0.322) > Cd (0.019 ± 0.015), and Se (6.577 ± 1.789) > Cd (5.815 ± 3.038) > Hg (2.698 ± 2.214) > Pb (0.661 ± 1.334) in liver. Levels of Hg, Se and Cd were compared to those reported for other Istiophoridae from oceanic areas and for other large predators of Mediterranean Sea, like swordfish and tuna. Organotropism of trace elements and their relation to size was discussed. Ecophysiological considerations regarding the Se-Hg relationship as well as Se-Cd indicate a possible detoxification mechanism. The implications for human consumption are briefly discussed.

Phthalate esters (PAEs) are a class of the emerging pollutants that pose a potential environmental threat to marine ecosystems. In this study, a simple analytical method using ultrasound-assisted extraction combined with gas purges microsyringe extraction (GP–MSE) coupled with GC–MS was utilized for the reliable and rapid determination of PAEs in different types of marine sediment. The analytical results showed that the method exhibited excellent reproducibility, linear responses, and detection limits, which verified the suitability of the method for the determination of PAEs in marine sediment. This approach requires minimal reagents, solvents, and sample pretreatment procedures as well as a short analysis time; thus, procedural blanks can be kept to a minimum. This method was demonstrated to be a highly efficient and sensitive quantitative analytical method for the simple detection of PAEs in marine sediment.

The common lionfish Pterois miles has rapidly spread across the eastern Mediterranean Sea. We compiled occurrence data from both native and invaded range under the framework of Species Distribution Modelling (SDM). Through a construction of an environmental suitability model and estimation of spread rates we investigated the lionfish climate niche in both its native and invaded domains, this latter represented by the Mediterranean region. Model projections allowed to identify suitable areas for lionfish establishment in the Mediterranean. Spread analysis suggested that a further geographical expansion in this basin could be completed within the next years. Our results did not provide evidence for niche expansion but highlighted a high degree of niche unfilling thus prospecting a likely spread of Mediterranean lionfish invasion beyond the predictions of current SDMs. These findings provide novel inputs to forecast the future geographical evolution of the lionfish in the Mediterranean Sea and asses the related risk of invasion.

Litters are the most pollutants in progress of the interests in marine environments. Macro litter samples were collected from 66 stations to estimate litter contribution from pleasure crafts along bays of the most Turkish touristic coasts (Antalya-Muğla) by the divers in June/July 2019. Average abundance and weight were 19 items/km² and 18 kg/km², respectively. The most abundant litter was plastics and the most contributors in weight were metals, followed by glass/ceramics. Abundance of the litters increased with number of pleasure crafts in active in summer. Pleasure crafts contributed most abundantly with the personal wares to the total litter, particularly in the coasts of Muğla. Litters were differentiated with interaction of region × bottom depths. The litter composition and abundance were different between region of Antalya in active mostly by tour boats and region of Muğla by private yachts. The litter types were however correlated with sea surface temperature.

In this study, Acid-Volatile Sulfur (AVS), trace metals Cu, Cd and Zn and their chemical speciation based on BCR-sequential and simultaneous extraction (SEMs) in Antarctic lake sediments (Y2-1 and YO) were analyzed to investigate the restriction of sulfate reduction on the bioavailability and toxicity of trace metals. Much higher trace metals in Y2-1 indicating a primary source from penguin guano. The main chemical speciation of Cu and Cd in Y2-1 was their oxidizable fraction in contrast to those of weak-acid extraction in YO. Lower ratio of ΣSEM/AVS in Y2-1 indicating less toxicity of the trace metals. The main chemical speciation of Cd in Y2-1 was their oxidizable fraction in contrast to that exchangeable fraction in penguin guano, indicating that although amounts of Cd was transported from marine to lake by penguins, strong sulfate reduction in ornithogenic sediments restricts the bioavailability and toxicity of Cd through the formation of insoluble sulfide.

Globally, coral reefs have drastically degraded due to local and global environmental stressors. Concurrently, coral reef tourism is rapidly growing in developing economies, which is one of many anthropogenic stressors impacting reefs. At the Malvan Marine Sanctuary, a Marine Protected Area (MPA) on the West coast of India, we investigated the impact of recreational diving on the reef from 2016 to 2019. To evaluate the diver's underwater behavior, a novel approach was used, wherein the video-log broadcasting website www.youtube.com was perused. Evidential proof substantiates heavy physical damage to corals because of recreational diving activity, which may lead to the collapse of coral habitat if it continues unabated. This resource depletion ironically elevates the economy of dependents averting consequences due to lost corals, thus making this a ‘tragedy’ for corals which are not meant to be ‘commons’. The study asserts need for proactive conservation efforts with stringent implementation and restoration initiatives in this MPA.

Through collaboration with Inuit hunters, we examined the stomach contents of 142 seals (ringed seals [Phoca hispida; n = 135], bearded seals [Erignathus barbatus; n = 6], and one harbour seal [Phoca vitualina; n = 1]) hunted between 2007 and 2019 from communities around Nunavut to assess whether seals in the eastern Canadian Arctic ingest and retain plastics in their stomachs. The seals in this study ranged from juveniles to adults of up to 30 years of age, and 55% of the seals were males. We found no evidence of plastic ingestion in any of the seals suggesting that seals in Nunavut are not accumulating plastics (>425 μm) in their stomachs. These data provide important baseline information for future plastic pollution monitoring programs in the Arctic.

This study evaluated in the dry and rainy periods, the anthropogenic influence and the hydrodynamics in the distribution of plastic items in surface waters and bottom and beach sediments of the Jurujuba (Guanabara Bay, low and medium hydrodynamic) and Itaipu (oceanic region, high hydrodynamics) embayments; places of cultivation and extraction of mussels. Microplastics were 83% of the wastes collected, with a higher average concentration (138.41 items.kg⁻¹) in beach sediments. High density polyethylene (HDPE) (38%), polypropylene (21%), and styrene (10%) were the most frequent polymers. There was no difference between the water and bottom sediment samples in the different embayments, in the studied periods, different from that observed in the beach sediment samples, with higher concentrations in the rainy season in Jurujuba. The results suggest that beach sediments are the best compartment to understand the dynamics of the distribution of plastic waste over time.

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.