A new method consisting of enrichment factor (EF) determination, nonmetric multidimensional scaling (NMS), and the geographic information system (GIS) technique was firstly developed to identify anthropogenic heavy metal sources in marine sediments of Hong Kong. Firstly, the EF was determined to differentiate between heavy metals originating from human and natural sources. Subsequently, NMS was applied to identify various source patterns of heavy metals, and the NMS score was calculated and spatially interpolated using GIS technology to evaluate the spatial influences of anthropogenic impacts in different areas. The concentrations of heavy metals in sediments of Hong Kong substantially exceeded their background values, demonstrating anthropogenic pollution. Two different types of human sources could be identified via NMS, one representing the industrial pollution discharges in the period from the 1960s to the 1980s before pollution control was introduced and one representing sewage discharge before the Tolo Harbour Action Plan in the mid-1980s.

European research efforts to address concerns in relation to increasing levels of marine litter and potential effects on ecosystems and human health have been launched. We assessed a total of 52 European projects which researched or contributed to the implementation of European marine litter legislation. These projects ranged from national initiatives, to large scale programmes involving multiple EU member states. The best represented topics within those European projects were ‘Policy, Governance and Management’ and ‘Monitoring’. Comparatively ‘Risk Assessment’, ‘Fragmentation’ and ‘Assessment Tools’ were underrepresented. The analyses showed that West-European countries have contributed more to marine litter research and therefore received more funding. As a result, thematic hotspots were present, and scientific capacity is concentrated by topic and countries. The results indicate the need to continue to support initiatives to cover clearly identified gaps, either geographic or thematic, to deliver risk assessments and recommendations to address the marine litter issue.

Surface sediments (n = 35) and a core sample around Pars Special Economic Energy Zone were analyzed to address spatiotemporal variations of heavy metals. Enrichment factors classified the elements as: (1) poorly enriched, geogenic elements (Co, Cr, Fe, Li, Mn, Mo, Ni, Ti, and V), (2) minimal enriched elements (Zn and Mg), (3) moderately enriched elements (Ag, Cd, Pb, Se, and Sr), and (4) significantly enriched element (As and Hg). The core profile showed that As, Hg, Ag, and Cd had considerable anthropogenic inventories. Arsenic levels were continuously increasing toward the top of the core and sedimentary cycling was not an effective factor on its enrichment. Pollution load index classified the area as a severely affected region and Risk Index values suggested that 57% of the sediments had a moderate potential risks. The mapping techniques proposed a polluted and hazardous patch at the entrance and center part of the Nayband Bay.

The interaction of anthropogenic litter (by incorporation litter in nests, ingestion, and entanglement) with birds was systematically reviewed using Google Scholar database. A ‘black-list’ of 258 species was compiled. Among them 206 (79.8%) were seabirds. Four seabird orders (Gaviiformes, Phaetontiformes, Procellariformes, Sphenisciformes) showed the highest percentage of interacting species. At family level, >70% of species of Gaviidae, Diomedeidae, Sulidae, Stercoraridae and Alcidae were involved in interactions with litter. We observed (i) a significant correlation between Scholar recurrences and species citations about anthropogenic litter only when considering seabirds; (ii) a low number of references before 1981 with a bimodal pattern showing a first peak in 1986–90 and a progressively increasing trend in the 2000s. Regarding the type of interaction, there was a significantly higher percentage of species involved in ingestion when compared to the percentage involved in entanglement. We suggest the use of consolidated standardized litter nomenclature and characterization and the adoption of a logical causal chain helping researchers in defining suitable frameworks.

The toxic equivalences (TEQs) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) from sediment of aquatic systems in Durban, South Africa were determined in two ways: 1) TEQs of PAHs and PCBs were determined by instrumental analyses and converted to 2,3,7,8‑tetrachlorodibenzo‑para‑dioxin equivalence (TCDDeq). 2) Bioassay equivalences (BEQs) of aryl hydrocarbon receptor (AhR) ligands were analysed using the H4IIE-luc bioassay. TEQs of PCBs ranged from below limit of detection (<LOD) to 57 pg TCDDeq·g⁻¹ while PAHs ranged from <LOD to 790 pg TCDDeq·g⁻¹. BEQs were 100- to 1000-fold greater than TEQs. Potency-balance revealed <10% of the BEQs were explained by instrumentally analysed compounds. Sediment quality guidelines indicated di minimis risk relating to TEQs, however had potential risk due to BEQs. The results reveal that far more AhR ligands were present in the sediments than what was instrumentally analysed and capable of causing AhR-mediated toxicity.

Polymer science is one of the most revolutionary research areas of the last century, instigated by the discovery of Bakelite, the first synthetic plastic. Plastic, once a revolutionary material, has gradually become a global environmental threat with ubiquitous distribution.The term ‘microplastics’ coined in 2004, is used to describe the smaller plastic particles recorded, however there is still no all-inclusive definition that accurately encompasses all criteria that could potentially describe what a microplastic is.Here, the authors focus on the currently reported methods for describing and identifying microplastics and propose a new definition that incorporates all the important descriptive properties of microplastics. This definition not only focuses on size and origin, but also considers physical and chemical defining properties. While this manuscript may promote debate, it aims to reach a consensus on a definition for microplastics which can be useful for research, reporting and legislative purposes.

Selenium and mercury were evaluated in tissues and stomachs of the dolphinfish Coryphaena hippurus from two sites in the Southeastern Gulf of California. Hg levels were consistently low and exhibited the following patterns: muscle (0.14 ± 0.01 μg/g wet weight) followed by kidney (0.12 ± 0.02 μg/g), liver (0.11 ± 0.01 μg/g), and gonads (0.04 ± 0.00 μg/g). The maximum of Se was found in the kidney (5.60 ± 0.40 μg/g) and the minimum in muscle (0.60 ± 0.01 μg/g). All the Se:Hg molar ratios were between 3.7 and 697.1, with the minimum in muscle and the highest in gonads. The results indicate a contrasting behavior biomagnification of Hg and Se; smaller fish (<80 cm FL) did not exhibit biomagnification, in contrast with larger fish (>90 cm FL: 100% for Hg; 65% for Se). These results appear to be related to different feeding habits and availability of prey.

The sorption of polybrominated diphenyl ethers (PBDEs) onto polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyamide (PA) microplastics was analyzed using different kinetic and isotherm models, and under various environmental conditions, including temperature, pH, salinity and dissolved organic matter (DOM). The sorption capacity was in the order of PS > PA > PP > PE, due to the different crystallinity, specific surface area, and surface structure. PS demonstrated the equilibrium sorption capacity, namely, 6.41 ng/g BDE-47, 12.83 ng/g BDE-99, and 14.42 ng/g BDE-153. The second-order kinetic model described the sorption kinetics of PBDEs, and surface sorption was the main mechanism. The sorption of PBDEs by microplastics was a multilayer and physical process. Low temperatures reduced BDE-47 sorption on microplastics, and sorption was a spontaneous and endothermic process. The sorption of BDE-47 was not significantly influenced by pH and salinity. However, DOM exerted a negative effect on the sorption of BDE-47.

Microplastics (MPs) in the Arctic Ocean have gained considerable attention due to its ubiquity and impacts within ecosystems. However, little information is available on MPs in the Pacific section of the Arctic Ocean. The present study determined the abundance, distribution, and composition of MPs in surface waters from the Northwestern Pacific, the Bering Sea, and the Chukchi Sea. The MPs abundances varied from 0.018 items/m3 to 0.31 items/m3, with a mean abundance of 0.13 ± 0.11 items/m3. The highest level of MPs was found in the Chukchi Sea. Of all of the detected MPs, polyethylene terephthalate (PET) accounted for the largest proportion of MPs, and fiber was predominant with regard to the total amount. Our results highlighted that the Arctic Ocean is becoming a hotspot for plastic pollution, and the risks posed by MPs need to be paid closer attention in future investigations.

In this study, positive matrix factorization, multilinear engine 2, and geographic information systems were used to characterize the spatial-temporal patterns of sources for nine heavy metals in the surface sediments of the Yangtze River Estuary in different seasons. Results showed that six sources were identified: agricultural pesticide, marine transportation, chemical factory wastewater, metal smelter waste, atmospheric deposition, and agricultural fertilizer. The proportions of sources were similar during the entire year but varied among the seasons. The differences in the proportions of agricultural pesticide between winter and other seasons were greater than 12%. Over 40% of the Cd concentration in most seasons was attributed to atmospheric deposition, while less than 5% in autumn. The impact strength of most sources, except marine transportation and metal smelter waste, decreased from the inner regions to the adjacent sea. The difference in the impact strength of agricultural pesticide was the largest throughout the study area.