Recent completion of oil fate modeling and a mass budget of the Deepwater Horizon (DWH) oil spill allows for a counter-historical study using quantitative Comparative Risk Assessment (CRA) methodology. Novel application of subsea dispersant injection (SSDI) during the response reduced surfacing oil, volatile organic carbon emissions, and oil on shorelines. The effectiveness of that application, and potential alternatives had dispersant not been used or been used more aggressively, were evaluated by modifying and comparing the validated oil fate model under different SSDI strategies. A comparison of mass balance results, exposure metrics, and CRA scoring for Valued Ecological Components (VECs) shows the value of SSDI in achieving risk reduction and tradeoffs that were made. Actual SSDI applied during the DWH oil spill reduced exposures to varying degrees for different VECs. Exposures and relative risks across the ecosystem would have been substantially reduced with more effective SSDI.

The gastrointestinal tract and its enteric nervous system are the first routes of food and xenobiotics uptake. Considering the importance of this organ, this study evaluated intestinal biomarkers of Sphoeroides testudineus integrating the data to generate tools for pollution assessment. The fish were collected in three sites of São Paulo Coast and their intestines were analyzed for biochemical, histology, and neuronal density and morphometry biomarkers. To evaluate the differences among the data, a PERMANOVA was applied, followed by a FA/PCA. The PERMANOVA indicated differences (P < 0.001) between the regions (RA, A1, and A2). Four factors were extracted from the FA/PCA (62% cumulative), showing that the animals from A2 presented severe alterations, mainly in intestinal morphometry and neuronal density. A1 alterations refer mainly to the increase of neuronal metabolism. Our results also evidence a gradient of environmental quality related to the protection level (AR > A1 > A2).

Sediment samples from 53 stations of the southwestern Chukchi sea were investigated to the spatial distributions and assess the state of trace metals contamination using ecological indices. The mean concentrations (mg kg⁻¹) in sediments were: Cr (70.5), Ni (41.0), Cu (16.5), Zn (82.7), As (15.90), Cd (0.27), Pb (15.96), Hg (32.0 μg kg⁻¹). The spatial distribution pattern of trace metals was similar with maximum values in the northern of the Chukchi Sea in the outer shelf sediments, while the high values of Cd were noted at stations located in the southern part of the sea where a strong influence of the Pacific waters penetrating through the Bering Strait. The ecological indices indicated no signs of anthropogenic pollution in the study sediments of the Chukchi Sea. Received data are of value for detecting and tracking future chemical changes in the sediments of the Chukchi sea, particularly in light of environmental changes.

We studied the macrobenthic invertebrate biomass (B), production (P), productivity (P/B̅-ratio), and transfer efficiency (TE) influenced by sewage effluents discharge in a diffusion zone. Our results indicated a clear distribution pattern of macrofauna communities along the sewage discharge gradient where biological factors (B, P, P/B̅, and TE) were driven by changes observed in community structure, composition, and the influence of environmental variables. The lowest B, P, and P/B̅ were observed at the stations sampled close to the pipelines. Abundance, biomass, production, and productivity increased with increasing distance from the pipelines toward stations placed at 100 m distance and then decreased toward the stations placed at >200 m, where there was a negative relationship between TE and B of macrofauna at sampling stations. Overall, there was a clear influence of the sewage discharge on macrofauna communities, but surrounding environment was influenced moderately by organic impact and discharges had no negative impacts.

Dissolved heavy metal pollution in the ocean is becoming an environmental concern. Their distribution patterns are complex and influenced by multiple factors in the coastal ocean. Therefore, more investigations are needed to understand their behavior in the seawater. This study systematically investigated the distribution of Cu, Pb, Cd, As, Zn and seawater properties in the surface and bottom water off the Yangtze River Estuary, East China Sea in spring, summer and autumn, 2019. The results showed significant spatiotemporal distribution that three-zone-pattern of estuary, nearshore, and offshore can be divided. While sources, hydrodynamics, biological uptake and sediment resuspension affected the overall distribution, dissolved oxygen and pH dominantly influenced the estuary and offshore respectively, with more complex factors in the nearshore. Low ecological risks were assessed during the study, but global warming, ocean acidification and hypoxia are essential concerns to understand the biogeochemistry of dissolved heavy metals in the ocean.

This study focused on marine sediments from the Black Sea, mainly due to bacterial diversity-induced public health / biotechnology application value. Sediment samples were gathered from 14 locations at differing depths across Turkish shores on a seasonal basis over 10 months, with bacterial identifications performed through using multimodal analytical platforms. Overall, 26 differing, predominantly Gram-positive (57.5 %) bacterial species were identified for this region, including Bacillaceae (50.0 %) and Pseudomonadaceae (15.0 %). The most dominant classes were identified as Bacilli (52.5 %) and Gammaproteobacteria (40.0 %). Ten isolates (25 %) to the species level and thirty-six isolates (90 %) to the genus level were identified using VITEK® MS and Bruker Microflex® LT/SH, in comparison to 16S rRNA sequencing results. Identified species – particularly, novel reported species – can contribute to the knowledge of microbial life dwelling upon sediments of the south-eastern regions of the Black Sea.

Microzooplankton (<200 μm) are essential intermediates between primary production and organisms at the higher trophic levels. Their ecological functions could be substantially affected by crude oil pollution. A natural plankton community was exposed to 10 μL L⁻¹ of chemically dispersed crude oil (DOil) in outdoor mesocosms for 7 days, with control (Ctrl) mesocosms set up for comparison. Dilution experiments were conducted to estimate the grazing rates of microzooplankton on the 2nd and 6th days of the pollutants exposure. Results showed 0.36–2.28 d⁻¹ microzooplankton grazing rates in the Ctrl mesocosms on both days but negative rates in the DOil mesocosms. A significant linear relationship between in situ phytoplankton growth and microzooplankton grazing rates was found in the Ctrl treatment but not in the DOil treatment. This suggests a de-coupling between phytoplankton growth and microzooplankton and the potential for the formation of phytoplankton blooms in seawater after an oil spill event.

Due to the distinct environment condition and geographic location, Svalbard has been recognized as a potential pollution reservoir in the Arctic. In this study, 8 surface sediment samples were collected from two fjords in Svalbard (Kongsfjorden and Rijpfjorden) in 2017, and they were searched for microplastics and polycyclic aromatic hydrocarbons (PAHs). PAHs were also investigated in 10 soil samples of Ny-Ålesund for local anthropogenic source analysis. The level of microplastics and other anthropogenic particles ranged from not detected (ND) to 4.936 particles/kg dry weight (DW). Fiber was the only shape of the microplastics found and three polymers (polyester, rayon and cellulose) were detected, which suggested that fisheries-related debris and textile materials were possible sources of microplastics and anthropogenic particles. For PAHs, the level of ∑₂₆PAH was 9.2 ng/g to 67.1 ng/g (DW), and were dominated by lnP and BghiP, indicating petroleum combustion source. Further analysis revealed that traffic emissions from cars and diesel combustion from a local power plant were major sources of PAHs in soils of Ny-Alesund, while traffic emissions from ships were the dominate source of PAHs in sediments of Kongsfjorden and Rijpfjorden. A higher level of PAHs was observed in Ny-Alesund, confirming an anthropogenic input, while transport via ocean currents might contribute to the higher abundance of microplastics in Rijpfjorden. Further research and even long-term observation of pollutants are needed to fully understand the pollution status in polar regions.

Selected potentially toxic elements (PTEs), including As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, and Zn, along with microplastic particles (MPs) were characterized in the muscle of seafood species in order to study potential health risk and also investigate biomagnification of the contaminants. The results revealed high levels of the analyzed PTEs and MPs in crustaceans. The cancer risk among the consumer population (adult and children) posed by As is higher than the acceptable lifetime risk of 10⁻⁴. Portunus plagicus and Platycephalus indicus had the highest and lowest amount of MP particles in their muscles, respectively, among investigated species. Finally, PTEs (except Hg) and MPs are not biomagnified in the collected species. The results of this research emphasize the importance of accounting for health risks posed by potential pollutants via consumption of contaminated seafood.

Granulated coal ash (GCA) is a strong in-situ capping material for removing PO₄-P and H₂S-S in contaminated coastal sediments. Although GCA performance is weakened by sediment deposition, related research is rare. To evaluate sediment deposition effects on PO₄-P and H₂S-S removal by GCA, GCA was placed on the top of sediment (C-GCA), was partially mixed with sediment (M-GCA), and was fully covered by sediment (N-GCA). Effective PO₄-P and H₂S-S removal from sediments occurred in the order of C-GCA > M-GCA > N-GCA. C-GCA and M-GCA significantly decreased PO₄-P and H₂S-S concentrations by 84– 90% and 100%, respectively, through calcium phosphate and iron sulfide precipitation. N-GCA was less effective in PO₄-P and H₂S-S removal than the control after 2.5 months, as fine sediment particles blocked the GCA pores, decreasing calcium and iron elution. The results provide a better understanding of how sediment deposition negatively impacted GCA performance.