Metal/metalloid concentrations in water sediment and commercial fishes of Loreto Maritime National Park (MNP), Baja California Sur, Mexico were determined for a comprehensive geochemical study. In-situ physical characteristics (pH, conductivity, redox potential, dissolved oxygen, turbidity) of water clearly indicated the unique oceanographic properties of the Gulf of California. Likewise, the distribution pattern of metals/metalloid in water, sediments and fishes denoted the influences of local geology, longshore currents, upwelling process, natural hydrothermal vents and the 100-year old mining activities of Santa Rosalia region, situated to the north of Loreto. Calculated carcinogenic indices in commercial fish species showed safe human consumption. Thus, the present research validates a comprehensive geochemical study of protected areas upholding the need for continuous monitoring for a better conservation of coastal ecosystems.

The Arabian Gulf is a warm (summer SST > 30 °C) and hypersaline (salinity > 40 psu at any time) marginal sea of the Indian Ocean. This paper reports on a 3-year study of seasonal and spatial changes of primary production and associated physico-chemical and biological parameters in the coastal waters of Saudi Arabia in the western Arabian Gulf. The primary production rates were low and yet showed a seasonality, with a major spring peak and a minor autumn peak, and a possible significant role for heterotrophs. While the strong relationships between the net changes of carbon uptake and nutrients between seasons showed a control of primary production by the availability of nutrients, the decrease in primary production between spring and summer when nutrients continued to increase suggests that the primary production at this time could have been controlled by higher ambient temperatures and intensities of incident light.

The Sergipe River estuary has been subjected to a range of anthropogenic activities including food, plastic, textile, ceramic and metallurgical production plants along with domestic sewage inputs, all of which are of environmental concern. In this study, the levels of fecal coliforms (FC) in surface water samples and sterols in superficial sediment samples collected from the Sergipe River estuary were determined. Based on the FC concentrations, 58% of the water samples were considered Water Potentially Unusable (WPU) according to the United States Environmental Protection Agency (USEPA). Concentrations of coprostanol ranged from 13 to 1072 ng g−1, indicating a significant input of sewage at some points in the estuary. Principal Component Analysis (PCA) showed that there is no clear correlation between the coprostanol and coliform data, which may be due to the high resistance to degradation of coprostanol in sediments and to recent inputs of sewage at the water sample collection points.

The impact of ghost fishing in large coastal ecosystems has generated considerable interest. In smaller, understudied systems with fewer stakeholders, derelict fishing gear (DFGs) may have impacts similar to these larger systems at the same relative scale. Four years of side scan sonar surveys in the Mullica River-Great Bay Estuary (New Jersey, USA) supported the recovery of 1776 DFGs off-season by commercial partners. Locations with high densities of recovered DFGs (>200 DFGs/km²) occupied intersections of recreational vessel traffic and commercial crabbing activity. Condition and depth-in-sediment of recovered DFGs was used to evaluate true bycatch (terrapins, whelks, blue crabs) versus species utilizing degraded gear as habitat (juvenile tautog, oyster toadfish). Critically, gear recovered in-season with low cost sonars (an additional 225 DFGs) prevented the accumulation of new DFGs which likely generate the highest percentages of bycatch. Removal of DFGs in this system led to significant ecological (reduced bycatch), economic (>$61,000 in direct pay, reused gear), and anticipated future benefits (increased harvest).

This study investigated the network of polycyclic aromatic hydrocarbon (PAH) degraders in the Yangtze estuarine and coastal areas. Along the estuarine gradients, Proteobacteria and Bacteroidetes were the dominant bacterial phyla, and forty-six potential PAH degraders were identified. The abundance of genes encoding the alpha subunit of the PAH-ring hydroxylating dioxygenases (PAH-RHDα) of gram-negative bacteria ranged from 5.5 × 10⁵ to 5.8 × 10⁷ copies g⁻¹, while that of gram-positive bacteria ranged from 1.3 × 10⁵ to 2.0 × 10⁷ copies g⁻¹. The PAH-degraders could represent up to 0.2% of the total bacterial community and mainly respond to PAHs and Cu concentrations, which indicate anthropogenic activities. Salinity and pH showed negative regulating effects on the PAH-degrading potential and the tolerance of bacteria to pollutants. PAH degraders such as Novosphingobium and Mycobacterium exhibit heavy-metal tolerance and core roles in the network of PAH degraders. These outcomes have important implications for bioremediation.

As microplastic pollution evolved to a well-established research field, microplastic scientists started to explore new avenues in the field. Yet, while a multitude of different types of microplastics (microbeads, fibres, fragments) have been well-documented in microplastic literature, our analysis of this literature shows that glitter particles have been overlooked by the field. However, due to the presence of glitter-based research in forensic science, we explore the idea that glitter may have the potential to act as “flag items” - or markers – of a likely source, due to the often complex and individual composition of glitter particles compared to traditional microplastics, such as microbeads. As such, this article demonstrates glitter has insofar been overlooked as a microplastic particle, and demonstrates that glitter may have an important role in explaining microplastic pollution dynamics from source to sink.

In the early 1990s, 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. An 18-year benthic infauna monitoring study was undertaken to address earlier concerns of long-term accumulation from sewage discharges and potential adverse effects on the marine environment. Assessment of outfall community structure indicated organic input from discharges has not resulted in sediment anoxia. The current post-commissioning investigation detected a gradual change in community structure from north to south in the study area, which was also displayed in taxonomic turnover south of the Malabar outfall. Temporal fluctuation in community structure detected at the three outfall and three reference locations in the current study was also noted in the pre-commissioning study at these locations. Evidence provided by this study indicated the Sydney deepwater ocean outfalls do not cause significant ecological impact.

The main objectives of the present study were to measure the concentration of mercury in Alosa spp. muscle tissue and to assess the health risk to consumers. For this purpose, fish samples were collected from four regions of the southern coast of the Caspian Sea. Mean concentrations of mercury in the regions of Bandar Torkaman, Feridonkenar, Chalos and Bandar Anzali were 264.10, 73.74, 161.90, and 183.80 μg g−1 dw, respectively. The mercury averages obtained in all four regions were below the standards recommended by the World Health Organization (WHO), the Food and Agriculture Organization (FAO), the Standardization Administration of China (SAC) and the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The values of hazard quotient also showed no potential health risk for consumer. However, the assessment of other contaminants is recommended for more accurate conclusions about the health risks of consumers through the consumption of the fish.

Riverine input is an important source of contaminants in the marine environments. Based on a hydrodynamic model, the dilution characteristics of riverine contaminants in the Seto Inland Sea and their controlling factors were studied. Results showed that contaminant concentration was high in summer and low in winter. Contaminant concentration decreased with the reduction of its half-life period, and the relationship between them followed power functions. Sensitivity experiments suggested that the horizontal current and vertical stratification associated with air-sea heat flux controlled the seasonal cycle of contaminant concentration in the water column; however, surface wind velocity was the dominant factor affecting the surface contaminant concentration. In addition, contaminant concentration in a sub-region was likely controlled by the variations in river discharges close to the sub-region. These results are helpful for predicting contaminant concentrations in the sea and are expected to contribute to assessing the potential ecological risks to aquatic organisms.

Micropollutants or contaminants of emerging concern (CECs) are released into the environment from a wide variety of sources. Due to the adverse effect on human health, micropollutant-containing wastewater needs to be treated before its discharge. A number of conventional physicochemical methods have been extensively studied for micropollutant degradation. However, owing to their one or more disadvantages, biological treatment using suitable microorganisms is of recent interest. Numerous bacteria and fungi are capable of degrading these micropollutants even at high concentrations. However, in order for the biological treatment to be commercially viable and industrially scalable, bioprocess development with efficient bioreactor systems is highly essential. This paper reviews state-of-the-art techniques for the removal of micropollutants by conventional biological systems such as activated sludge process, biofilm-based reactor, and trickling bed bioreactor. However, compared with conventional systems, advanced biological systems, namely two-phase partitioning bioreactor, membrane-based reactor, and cell-immobilized bioreactor systems, have not been examined and, hence, need detailed exploration. Such advanced treatment systems are capable of tolerating high pollutant load and are also able to treat highly water insoluble pollutants. Furthermore, hybrid systems comprising of a combination of different physicochemical and biological processes are discussed in this paper, which are not only capable of improving the treatment efficiency but also eliminate any accumulation of the toxic by-product produced during the treatment. Among the different hybrid systems, a combination of different biological systems is found to be highly efficient in treating micropollutant-containing wastewater. Finally, scope for future research prospects in the field are derived and addressed in details.