Laizhou Bay is plagued by many environmental problems (e.g., acidification and eutrophication) that are likely to increase in the coming decades along with social and demographic trends. We thus conducted 12 cruises from July 2019 to December 2021 in the Laizhou Bay to evaluate the potential influences of human activities on its eutrophication status. The results showed that the parameters of dissolved inorganic nitrogen (DIN) and oxygen (DO) exceeded the water quality standard in some cases during the past 3 years, suggesting DIN and DO were the crucial factors controlling water quality in the bay. Meanwhile, DIN was identified as a major pollutant in the region, and played an important role in driving the phytoplankton dynamics. Furthermore, with the increases in human-related nutrient inputs (especially DIN), the bay environment reached the mild eutrophication level and was probably at risk from excessive nutrient loads at present, further evidencing the ecosystem degradation.

Large amounts of Gd-based contrast agents are used in magnetic resonance imaging (MRI) that are then excreted in urine. These agents are subsequently discharged into the environment because they are difficult to remove by usual sewage treatment techniques. In this study, changes of the Gd anomaly during wastewater treatment processes were determined by analyzing wastewater samples and the possibility for future prediction of the changes was evaluated based on the relationship between the Gd anomaly and the number of MRI devices in use. After the wastewater treatment processes, the values of final effluent were increased 1.8 times compared to those of influent, and the Gd anomaly of effluent had a positive correlation to the number of MRI devices. The finding suggested that the changes of environmental impact were predictable based on the number of MRI devices.

PM₂.₅ is one of the major air pollutants in port cities of the Yangtze River Delta (YRD) of China. Understanding the driving factors of PM₂.₅ is essential to guide air pollution prevention and control. We selected 17 major port cities in YRD to study the driving factors of PM₂.₅ in 2019 and 2020. Generalized Additive Models were built to model the non-linear effects of single, multiple and interactions of driving factors on the variations of PM₂.₅. NO₂, SO₂ and the day of year are most strongly associated with the variation of PM₂.₅ concentration when used alone. Anthropogenic emissions play complicated roles in regulating PM₂.₅ concentration. Although the effect of cargo throughput (CT) on PM₂.₅ concentration is non-monotonic, higher PM₂.₅ levels are found to be associated with higher levels of SO₂ and CT. This work can potentially provide a scientific basis for formulating PM₂.₅ prevention and control policies in the region.

PURPOSE OF REVIEW: The utilization of attached microalgae and bacteria to degrade wastewater has become a more promising treatment process to replace traditional methods. That is because the algae-bacteria biofilm can not only remove nutrients from the water but also achieve the effect of carbon fixation. Besides, the attached microalgae are easy to harvest and can be used for the processing of high value-added products. This paper reviews the knowledge of microalgae biofilm combined with bacteria to treat wastewater and provides insights into the bioremediation of the ecosystem by algae and bacteria. RECENT FINDINGS: Due to the photosynthesis of algae and the oxidative decomposition of bacteria, the symbiotic system of algae biofilm and bacteria from wastewater has significant advantages in harvesting and degradation. To further improve wastewater utilization efficiency and carbon fixation, it is necessary to understand the algae-bacteria symbiotic system of mechanism and influencing factors of nitrogen and phosphorus removal and carbon fixation. The photobioreactor for microalgae cultivation is gradually developed and optimized, laying a solid foundation for actual production and application. The algae-bacteria symbiotic system is more effective compared to individual microalgae treatment since the algae-bacteria biofilm has better removal efficiency and adsorption capacity as well as easy to harvest. This article introduces the mechanism and influencing factors of the algae-bacteria symbiotic system to remove nutrients and organic pollutants from water in detail. Furthermore, the research progress of photobioreactors is summarized as well. Finally, the application prospect of microalgae biofilm in wastewater treatment was prospected.

Bioelectrochemical system (BES) is an emerging technology for wastewater treatment. The urgent requirement for dealing with water shortage, wastewater treatment and reuse, energy generation, and resources recovery has promoted intensive research in BES during the last decade. This review summarizes the latest typical BES configurations based on specific functions, including microbial fuel cells (MFC), microbial electrolysis cells (MEC), microbial electrosynthesis systems (MSS), microbial desalination cells (MDC), microbial recycling cells (MRC), microbial solar cells (MSC), and microbial electrochemical snorkel (MES). The removal of contaminants, particularly emerging organic, non-metallic, metallic, and metalloid contaminants, and the recovery of resources in the form of bioenergy, biofuel, nutrients, metals, and metalloids in wastewater treatment using BES technology have been reviewed in this work. Limitations of BES technology in terms of reactor performance, scale-up, and construction costs for real-world wastewater treatment applications are discussed and future research directions needed for the successful deployment of BES technology are proposed.

This study helps understand the ballast water-mediated species spread risk dynamics in the Mediterranean and examine potential policy options for ballast water management to further reduce species spread risk in the region. Results show that Gibraltar, Suez, and Istanbul remained high-risk ports from 2012 to 2018, and they are hub ports connecting several clusters. We reveal ballast water management implications for both the Mediterranean region and individual hub ports respectively. To further reduce the risks of individual Mediterranean hub ports beyond the IMO standards, the most effective (cost-effective) regulatory method is to set more stringent regulation towards such hub ports besides the IMO regulation. To further reduce the risks of the Mediterranean as a whole, the most effective (cost-effective) regulatory scenario is to set more stringent regulation towards all Mediterranean ports besides the IMO regulation. The barge-based method is the most cost-effective technology to achieve stricter regulations.

Estuaries are ecologically valuable ecosystems that process nutrients through complex biogeochemical processes. Here we identify drivers and inhibitors of nitrogen removal in unvegetated intertidal sandflats at six sites in Manukau Harbour (37° 2.00′S 174° 42.00′E) to quantify the exchange of solutes across the sediment-water interface, with nitrogen removal rates (NRR) measured at two contrasting sites (PI and CB) near and far, respectively, from an historical wastewater treatment plant. Solute fluxes were paired with sediment and macrofauna community data to identify drivers of ecosystem function. Fluxes of oxygen, nitrogen and phosphorous were found to vary among sites, with differences attributed to variation in sediment characteristics (grain size, chlorophyll a, organic content) and macrofauna community structure. Mean NRR was found to vary between sites (PI = 32.2 vs CB = 217.9 μmol N₂/m²/h), with bioturbating macrofauna (bivalves Austrovenus stutchburyi and Macomona liliana), microphytobenthic biomass, and exposure to nutrients likely key contributing drivers.

This study compared the ability of Sargassum fusiforme to accumulate As, Cd, Cr, Cu, Ni, Pb and Zn in its five tissues (main branch, lateral branch, leaf, receptacles and pneumathode). The concentrations of these trace elements in seawater, surface sediments and different tissues of S. fusiforme were analyzed in different areas in Dongtong County (Wenzhou City, China). The presence of receptacle at all sites indicated that S. fusiforme had entered the mature stage. However, the proportion of each tissue in S. fusiforme in different sites was varied, indicating subtle differences in growth. S. fusiforme has a great capacity to accumulate trace elements, showing relatively high levels of As (28.2–64.2 mg kg⁻¹) and Zn (19.9–80.8 mg kg⁻¹). The elements are mainly stored in leaf, receptacles and pneumathode. Compared to element concentrations in the surrounding environment, the seaweed exhibited stronger bioconcentration capacity for As and Cd than for other elements. According to our health risk assessment results, the hazard index and carcinogenic risk were below the limit, suggesting that the S. fusiforme ingestion would not pose any health risk and the potential risk of intake branches was even lower than that of other tissues.

The number of studies on microplastic accumulation in marine organisms has increased precipitously recently, though information is geographically-skewed and limited in terms of local effects. We characterized microplastic accumulation in oysters (Saccostrea cucullata) along a Bornean coastline, focusing on spatial variation. Comparisons were made between locally-polluted (Brunei Estuarine System, BES) and relatively pristine, open-shore (South China Sea, SCS) coastlines. Sixteen coloured microplastic types were characterized into three shapes (fragments, fibres, pellets). Fragments (74.9%), especially smaller polypropylene black fragments predominated in the samples (<50 μm, 31.7%). Site-specific levels of microplastic accumulation varied from 0.43 to 7.20 particles/g oyster tissue. BES and SCS sites differed qualitatively, indicating limited interaction. In the BES, accumulation was greatest near the predicted source (Bandar) and declined strongly seawards, implying current flow, environmental sequestration (local sinks) and seawater dilution effects. Such local-scale variation in microplastic loading in estuaries cautions against extrapolating from limited sampling.

Heavy metal-contaminated wastes can threaten mangrove forests, one of the most biodiverse ecosystems in the world. The study evaluated the geospatial distribution of heavy metals concentrations in soils, the ecological and human health risks, and metal contents in soil fractions and mangrove organisms in the Botafogo estuary, Brazil, one of the most environmentally impacted estuaries in the country. The metal concentrations exceeded by up to 2.6-fold the geochemical background; 91%, 59%, 64%, 31%, and 82% of the soils were contaminated with Cr, Zn, Pb, Cu, and Ni, respectively. Adverse effects to the biota may occur due to Cr, Cu, Ni and Pb exposures. Contents of clay and organic matter were the main factors governing the distribution of metals in soil, contributing to up to 63% of the total variability. However, the geospatial modeling showed that the predictive ability of these variables varied spatially with the metal and location. The ecological and human health risks assessments indicated that the metal concentrations in soils are safe for the environment and human beings. There was a low transfer of metals from the soil to the biota, with values of sediment-biota accumulation factor (SBAF) and biological accumulation coefficients (BAC) lower than 1.0, except for Zn (SBAF = 13.1). The high Zn bioaccumulation by Crassostrea rhizophorae may be associated with the concentrations of Zn in the bioavailable fractions.