On or about July 25, 2010, approximately 843,000 gal of condensate diluted bitumen (dilbit, a heavy oil) was released into the Kalamazoo River near Marshall, Michigan. As the discharged Line 6B oil migrated downstream the lighter diluent volatilized, formed visible oil droplets/flakes in the water column, became denser than water and/or became aggregated with sediment and migrated to the underlying bottom sediments. Accurate identification and determination of the amount of Line 6B oil present in the sediment was a primary requirement for remediation and allocation of liability. Based on a multi-tiered application of advanced hydrocarbon fingerprinting methodology, key chemical characteristics of the spilled oil were identified that allow for distinguishing heavy oil-related contamination from the complex river sediment background hydrocarbon contamination. It was determined that among the characteristics evaluated, concentration ratios of selected tri-aromatic steranes and triterpanes were most efficient parameters for identification and quantification of the spilled oil in the environment. This quantification approach was successfully applied and validated with field sample results and is consistent with the well-established environmental stability of these petroleum biomarkers and modern hydrocarbon fingerprinting methodology.

Microplastic contamination in beach sediments along coast of Dubai is un-documented. In this study, microplastic contamination in beach sediments collected from the wrack lines of 16 beaches in Dubai was evaluated. Five samples were collected from each beach along a 100 m stretch using a 0.5 m by 0.5 m, quadrant. The number, color, and shape of microplastics were documented. The polymer types of large fibers and strings were identified through FT-IR analysis. 480 microplastics from each of the 16 beaches were selected to detect heavy metals using XRF analysis. The results showed that the average weight of microplastic is 0.33 mg per gram of dry sediment (or 953 mg·m⁻²) and the number of microplastic is 59.71 items per kg of dry sediment (or 165 items·m⁻²). Blue and fibrous microplastics were dominant. Polyethylene strings and fibers were abundantly found. 13 heavy metals were identified of which five are priority pollutants.

Coastal ecosystems are increasingly threatened by a wide range of human activities. Fish otolith chemistry, by creating a unique specific signature, can be used as a natural tag for determining life stage dispersal, spatial connectivity and population structure. In this study, we tested whether differences in otolith composition among juveniles of gilthead sea bream, Sparus aurata, could enable their proper allocation to polluted areas based on higher concentrations of elements related to contaminants. Otoliths were embedded, sectioned and analysed by LA-ICP-MS in line scan mode. Multivariate analysis confirmed clear separation between sites and elements. Samples from the site under the strongest anthropogenic impact from industrial and agricultural river input were characterized by higher values of Pb/Ca and Zn/Ca. However, these relatively low values likely do not have a negative effect on S. aurata recruitment, though they could serve for identifying the contribution of polluted nurseries to stock dynamics.

Marine litter is a major global challenge, even in the remote reaches of the Arctic. Monitoring temporal trends in litter loadings and composition is key to designing effective preventative and mitigative measures, and to assess their impact. Few data are available, however, by which to do this in the Arctic region. Citizen science data organised by the local waste management company in the Lofoten archipelago in the Norwegian Sea is an exception to this. We analysed volunteer cleanup data (total weight and counts of select litter types, standardised to density per 100 m) from over 200 locations from 2011 to 2018. Results indicate a general decline in beach litter in the region, and particularly in litter types related to private use, such as beverage bottles. These declines are most likely the combined result of extensive cleanup activities and a considerable reduction in local litter inputs.

Concentrations of Fe, Mn, Zn, and Cu in the muscle, lung, liver, and kidney tissues of 49 cetaceans, including 11 Kogia sima (Ks), 10 Lagenodelphis hosei (Lh), 14 Grampus griseus (Gg), and 14 Stenella attenuata (Sa) from 1994 to 2012 in Taiwan were measured. Ks exhibited the highest Fe, and the lowest Zn, Cu and Mn tissue concentrations. The Kogiid and Delphinid groups were significantly categorized by nMDS analysis. Fe muscle concentrations were found to be positively correlated with Ks, Lh, and Gg but not Sa body length. The different levels of Zn-, Cu-, and Mn- tissue concentrations of the two families were due to their different SOD systems. Their calves contained higher Cu liver concentrations. The four essential elements in cetaceans regulate homeostasis to meet their eco-physiological demand. The baseline levels for these four elements in these four tissues in the Delphinid group are defined.

Microplastics are widespread pollutants in the marine environment, yet few studies have assessed the abundance and characteristics of microplastics in commercial species. This study evaluates the presence of ingested microplastics in the gastrointestinal tract of Nephrops norvegicus (n = 150), collected from five Irish prawn grounds. The efficiency of three digesting solutions was assessed. The most efficient digestion was the KOH (10%) solution incubated at 40 °C for a 48 h period. An average of 1.75 ± 2.01 items per individual was ingested by c. 69% of N. norvegicus examined. A total of 262 microplastic, predominantly fibres (98%), between 1 and 2 mm were recorded. Although, no spatial pattern was identified, samples from the North Irish Sea recorded highest occurrence of microplastics (~83%). A positive correlation was found between microplastic abundance and prawn carapace condition. Results indicate microplastic exposure in seafood for human consumption, in Ireland, is estimated to range from 15 to 4471 particles per year.

The effects of polystyrene (PS) of different sizes of diameter (65 nm, 100 nm and 1 μm) with different treat concentrations (control, 1 mg L⁻¹ and 10 mg L⁻¹) on growth and oxidative stress for K. mikimotoi were assessed across PS short-term exposures (3 d) and long-term exposures (13 d). The endpoints of physiological parameters such as cell density, antioxidant enzyme activity of SOD and CAT, the content of MDA and ROS level were monitored. The results showed that the CAT activity, SOD activity, MDA content and the relative ROS level reached to 377 U mgprot⁻¹, 164 U mgprot⁻¹, 157 nmol mgprot⁻¹ and 10.8% when treated with 10 mg L⁻¹ PS of 65 nm diameter; the CAT activity, SOD activity and MDA content in single K. mikimotoi reached to 0.46 U mgprot⁻¹, 0.36 U mgprot⁻¹ and 0.16 nmol mgprot⁻¹ under 10 mg L⁻¹ PS of 65 nm diameter on the third day. The relative ROS level in single K. mikimotoi was 71% under 10 mg L⁻¹ PS of 100 nm diameter on the 13th day. The works found that the size of nano/micro-PS was a key factor that cannot be ignored. Smaller size had more serious negative effects on the growth, oxidative stress and cell microstructure. The potential cytotoxicity mechanisms were that monodisperse nanoscaled PS crossed the biological barriers and the agglomerate nanoparticles caused physical blockage, while microscaled PS may not have such an equally strong negative effects. Visualized SEM images also proved that exposing to nano/micro-PS of varies diameters led to apparent size-dependent effects. The arms race of systematic oxidative defensive and offensive between K. mikimotoi and nano/micro-PS would have considerable value in deliberating the relationship between nano/microplastics and marine phytoplankton.

This paper discusses about the role of two different wastewater treatment technologies in the abatement of microplastics (MPs) from the final effluent of an urban wastewater treatment plant (WWTP); i.e., membrane bioreactor technology (MBR) and rapid sand filtration (RSF). For this purpose, a WWTP with these two technologies was monitored for 18 months. The average microplastic concentration was 4.40 ± 1.01 MP L⁻¹ for the influent, 0.92 ± 0.21 MP L⁻¹ for MBR, and 1.08 ± 0.28 MP L⁻¹ for RSF, without statistically significant differences for MPs removal between both technologies (F-test = 0.195, p = 0.661). The main MP forms isolated in our study were fibers (1.34 ± 0.23 items L⁻¹), followed by films (0.59 ± 0.24 items L⁻¹), fragments (0.20 ± 0.09 items L⁻¹), and beads (0.02 ± 0.01 items L⁻¹). All of them probed to be statistically significant reduced after both technologies, but without statistically significant differences between them. The MP removal efficiency was 79.01% and 75.49% for MBR and RSF, respectively, although higher for microplastic particulate forms (MPPs), 98.83% and 95.53%, than for fibers, 57.65% and 53.83% for MBR and RSF, respectively, displaying a selective removal of particulate forms against microfibers. Fourteen different plastic polymers were identified in the influent, only persisting low-density polyethylene (LDPE), nylon (NYL), and polyvinyl (PV) in RSF effluent, and melamine (MUF) after MBR treatment. The MP size ranged from 210 μm, corresponding to NYL fragment form in the influent, to 6.3 mm, corresponding to a red microfiber also from the influent. The maximum MP average size significantly decreased from MBR (1.39 ± 0.15 mm), to RSF (1.15 ± 0.08 mm) and influent (1.05 ± 0.05 mm) (F-test = 4.014, p = 0.019), exhibiting the fiber selection carried out by these advanced technologies for wastewater treatment.

Residue concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were measured in sediment core samples from two estuary areas of central Vietnam to elucidate recent status and temporal trends of pollution based on the depth profiles. Concentrations of PCBs, PBDEs, and endosulfan compounds were generally higher than those of the remaining OCPs. Peak concentrations of OCPs were found in the sediment layers corresponding to the late 1950s to the early 1980s, implying the intensive application of these insecticides in Vietnam during such periods. Although the highest PCB concentrations were measured in sediment layers dated in the 1970s, increasing PCB residues observed in the shallower layers may be related to the strong industrialization and urbanization in Vietnam. BDE-209 exhibited increasing concentrations and proportions to total PBDEs towards shallower depths, suggesting substantial use and on-going releases of deca-BDE products in recent years.

To understand the status of the radionuclides released during the Fukushima Dai-ichi Nuclear Power Plant accident, the ¹³⁴Cs, ¹³⁷Cs and ⁹⁰Sr in the seawater in the public area of the northwest Pacific Ocean were analyzed in November–December 2012. The radioactivity of ¹³⁴Cs, ¹³⁷Cs and ⁹⁰Sr decreased sharply from June 2011 to November–December 2012. The highest average values of ¹³⁴Cs and ¹³⁷Cs were found at a depth of 500 m, suggesting that ¹³⁴Cs and ¹³⁷Cs had been transported to a depth of 500 m or deeper by the end of 2012. Total inventories of 0.80 ± 0.20 pBq for ¹³⁷Cs from the surface to a depth of 500 m and 0.07 ± 0.02 pBq for ⁹⁰Sr from the surface to a depth of 100 m were obtained in the waters southeast of Fukushima. ¹³⁴Cs was detectable in the Chinese exclusive economic zone, and the seawater quality was much lower than the target level for China.