In a context where the problem of plastic pollution is globally increasing, more studies are needed to assess the real impact in oceanic megafauna. Here, we reported on the incidence of plastic and also retained hooks in two species of commercially exploited pelagic sharks in two ocean basins, the North Atlantic and South Pacific. In the South Pacific, 1.18% of caught blue sharks were observed with plastic debris on their body and 4.82% and with retained hooks, while 0.00% of shortfin makos had plastic debris and 1.76% were recorded with retained hooks. In the North Atlantic, 0.21% of blue sharks had plastic debris and 0.37% of blue, and 0.78% of shortfin makos were observed with retained hooks.

Despite the beneficial aspect of aquatic food's consumption, bioaccumulation of toxic metals in fish can enhance the health risk for the consumers. Heavy metals were measured from editable tissues of some commercial fish species like Latis calcarifer, Silonia silondia, Clupisoma garua, Planiliza subviridis, Otolithoides pama, Tenulosa ilisa, Rhinomugil corsula, and Aila coila in the Meghna river estuary in Noakhali district. Heavy metals such as As, Pb, Cd, Cu, and Cr were detected by ICP-MS, which were significantly different (p ≤ 0.01), and the hierarchy of all mean concentrations were: Cu (5.14 mg/kg) > Pb (3.79 mg/kg) > As (1.08 mg/kg) > Cr (0.78 mg/kg) > Cd (0.12 mg/kg). The mean concentration of Cu (6.62 mg/kg) imparted to the maximum level in L. calcarifer, which slightly exceeded the Bangladesh food safety guideline. The mean BAFs of the contaminants were found as: Pb (1042.29) > Cr (1036.47) > As (934.84) > Cd (832.77) > Cu (772). Further, L. calcarifer, S. silondia, C. garua, and P. subviridis showed the bioaccumulative status. To assess the health risk effects, estimated daily intake (EDI), target hazard quotient (THQ) and carcinogenic risk (CR) were conducted. THQs for both adult and children consumers were <1, indicating that, consumers would not experience the non-carcinogenic health effects. Although children were more susceptible than adults, CR for all the consumers was found in the acceptable range (10⁻⁶ to 10⁻⁴).

Macrozoobenthos living around several pipelines placed at different depths and sediment types in the Western Adriatic Sea was investigated for three years after structures' deployment to detect possible effects due to their installation and presence. Three environmental habitats were considered based on the grain size (silty clay, clayey silt and sand). Samplings were taken within a radius of 100 m from the pipelines and at control sites. Multivariate and univariate analysis showed peculiarities of the three habitats due to the different sediment type, without differences between pipelines and controls inside each group. Silty clay and clayey silt communities appeared quite similar, being mainly represented by opportunistic species typical of the Adriatic coastal area. Benthic populations found at the offshore relict sand were characterized by a higher percentage of sensitive species. Independently of sediment typology, pipelines' installation seems to not affect the benthic populations that appear more influenced by environmental features.

Pot fisheries occur worldwide with a significant proportion of the gear becoming derelict. Derelict pots induce detrimental ecological and economic impacts, and more recently were found to reduce blue crab harvests in the Chesapeake Bay commercial fishery. We simulated the presence of derelict pots near actively fished pots in seasonal field experiments to quantify the effect derelict pots have on blue crab harvest. Derelict pots reduced harvests by 30% during the summer, but not during the fall. Female blue crab capture rates were consistently lower when derelict pots were present; while capture rates of the less abundant males were not negatively affected by derelict pots. Variable responses to derelict pots may be due to seasonal differences in female and male blue crab behavior and movements. The costly effect that derelict pots have on harvest should be investigated in other pot fisheries to recognize the magnitude and mechanisms behind these impacts.

A cliff-face disposal system discharging approximately 940 ML/day, or 80% of sewage generated by the City of Sydney (Australia) (population 3.3 million) was replaced by three deepwater ocean outfalls in the early 1990s. Enrichment of anthropogenic chemicals from cliff-face discharges raised concerns regarding long-term accumulation of sewage particulates and associated contaminants in offshore sediments and for reduced beach water quality. The current post-commissioning investigation detected a southward gradient of sediment fining and increased total organic carbon in the study region. Deepwater ocean discharges have not contributed to an accumulation of fines, or to increased metallic/nonmetallic chemicals of concern with no elevated risk of adverse biological effects beyond pre-commissioning conditions. Instead, the best modelled relationship was recorded between benthic infauna and sedimentary fines and not to contaminants. Historic sea dumping prior to 1932 in the north of the study area has resulted in enrichment of some non-bioavailable sedimentary metals.

Stable isotopes and geochemical proxies (TOC/TN and Chla/TOC) in sediments can be used to distinguish organic matter sources (anthropogenic, terrestrial, or marine). This study aims to characterize organic matter (OM) in superficial sediments from three sectors of central Chile (33°S) that are highly influenced by urban and industrial development. Our results show that a substantial fraction of these OM in Quintero Bay is anthropogenic, from industrial and domestic wastewater sources. In contrast, a mixture of terrestrial and anthropogenic OM dominates the isotopic signal of surface sediments from Concón, derived from non-point industrial and agriculture sources associated with the Aconcagua River basin, while Ritoque exhibited a mixture of different OM sources. However, deposition of allochthonous OM in our study area depends on coastal topography, which influences the local currents and well-ventilated waters, promoting the dispersion and assimilation of OM and thus providing an environment with a high capacity for natural remediation.

Polychlorinated biphenyls (PCBs) found in marine molluscs could be a serious threat to the health of consumers; however, studies on this subject are limited. To understand this threat, the indicator PCBs (PCB-28, PCB-52, PCB-101, PCB-118, PCB-138, PCB-153 and PCB-180) found in six different kinds of molluscs were determined, and the associated cancer risk for consumers that intake these indicator PCBs via molluscs was assessed. The total concentrations of PCBs in molluscs ranged from 17.51 to 47.43 ng/g (d.w.). The order of contamination levels for indicator PCBs in molluscs was Perna viridis > Ruditapes philippinarum > Crassostrea gigas > Mimachlamys nobilis > Glossaulax didyma > Anadara antiquata. Tri-, tetra- and penta-PCBs were the dominant congeners in molluscs from Haikou City. Tetra-PCBs are the most common PCB, accounting for 38.49% of total PCBs. Compared with previous global studies on PCBs in molluscs, the pollution level of indicator PCBs in the molluscs from Haikou City was lower than most of reports in Europe and China, but higher than those from France and Korea, suggesting a moderate pollution level. The 50% and 95% cancer risks of indicator PCBs in molluscs for adult consumers were 2.75 × 10−7 and 4.32 × 10−7, indicating that the cancer risk was at an acceptable level. Since the dioxin like-PCBs were not analyzed in this study, the cancer risk of PCBs to human health might be underestimated; therefore, more studies on PCB pollution in molluscs are required.

The beaches of Goa state in India are frequently polluted with tarballs, specifically during pre-monsoon and monsoon seasons. Tarballs contain hydrocarbons, including polycyclic aromatic hydrocarbons, which pose significant environmental risks. Microbes associated with tarballs reportedly possess capabilities to degrade toxic hydrocarbons present in tarballs. In this study, bacterial diversity associated with tarballs from Vagator and Morjim beaches of north Goa was analysed based on V3–V4 regions of 16S rRNA gene sequenced using Illumina Miseq Platform. The Proteobacterial members were dominant in both Vagator (≥85.5%) and Morjim (≥94.0%) samples. Many of the identified taxa have been previously reported as hydrocarbon degraders (e.g. Halomonas, Marinobacter) or possible human pathogens (e.g. Acinetobacter, Klebsiella, Rhodococcus, Staphylococcus, Vibrio). This is the first study reported on a metagenomic analysis of bacteria associated with tarballs from Goa.

This is the first study on polychlorinated biphenyls (PCBs) in fish from the Cau Hai lagoon, a part of the largest coastal lagoon in Southeast Asia. Seven selected PCB congeners and organochlorine pesticides in sediments and edible fish tissues were quantified by GC–MS. The sum of ICES-7 PCB and DDTs concentrations in fish species consumed regularly and of economic value were in ranges 26–43 ng g−1 lw and 182–277 ng g−1 lw, respectively. The ratio between the parent DDT compound and the sum of metabolites, DDE and DDD, was most of the time smaller than 1, suggesting primarily an historical contamination of the lagoon. An agglomerative hierarchical clustering indicates sites located in the north-western part of the Cau Hai lagoon were characterized by above-average concentrations of DDE and DDT. Comparing to previous data, a large decrease in ∑DDT residues can be seen over the past 20 years.

Concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were determined in surface sediment from five estuaries of central coasts of Vietnam to understand the spatial distributions and seasonal variations. The contamination pattern was in the order: PCBs (9.72–3730 ng g⁻¹ dry wt.) > PBDEs (11.8–311 ng g⁻¹ dry wt.) > DDTs (0.462–26.7 ng g⁻¹ dry wt.) > HCHs (0.491–22.6 ng g⁻¹ dry wt.) > endosulfan compounds (0.196–19.4 ng g⁻¹ dry wt.). DDTs and HCHs showed a little geographical variation, whereas PCBs and PBDEs exhibited clearer spatial distribution trend. Elevated concentrations of PCBs and PBDEs were detected in some sites in Nghe An and Quang Binh Province, which could be related to the human activities such as tourism, transportation, and domestic consumption. Seasonal variations of DDTs and HCHs were observed, showing higher residues in rainy seasons.