An Eulerian passive tracer model coupled with a quadruple-nested 3D circulation model was used to assess the coastal dispersal of treated wastewater effluent from a sewage treatment plant and the associated impacts on an adjacent seaweed farm using three different operational scenarios. When the discharged volume and source effluent fluxes were decreased by ~16.7%, the accumulated effluent in the farm was reduced by ~25.4%. A tracer flux budget analysis revealed the apparent predominance of the transient component that accounts for the nonlinear interactions primarily from tidal currents and eddies. The transient flux promoted the effluent influx to impede effluent accumulation in the farm, whereas the mean flux contributed to the outgoing flux. A source flux reduction caused a remarkable decrease in the transient flux and thus an even greater effluent accumulation reduction. In turn, a modified source density scenario without total effluent volume change did not work as expected.

In this study we examined the adsorption characteristics of heavy metals on microplastic through laboratory test and field test. We demonstrated that polyvinyl chloride, polypropylene, polyethylene, polyamides and polyformaldehyde could adsorb lead, copper and cadmium in the simulating solution, and the heavy metals showed higher adsorbance on PVC and PP particles compared with PA, PE and POM. In the field experiment, the adsorption rate and concentration of heavy metals varied significantly among different plastic types and locations. The adsorbability of PP and PVC toward Pb and Mn was strongly correlated with the metal concentration in seawater. We also compared the adsorption quantity of PP to heavy metals and polycyclic aromatic hydrocarbons which resulted in an order of magnitude within one month. During the adsorption, the surface morphology of the microplastics which were washed and corroded by seawater underwent a rough-smooth-rough changing process, and different materials had great differences.

Plastic pollution is an omnipresent problem that threatens marine animals through ingestion and entanglement. Marine mammals are no exception to this rule but their interaction with plastic remains understudied in the Mediterranean Sea. Here we highlight this problem by analyzing the stomach contents of 34 individuals from seven odontocete species stranded in Greece. Macroplastic (>5 mm) was found in the stomachs of nine individuals from four species (harbour porpoise Phocoena phocoena, Risso's dolphin Grampus griseus, Cuvier's beaked whale Ziphius cavirostris and sperm whale Physeter macrocephalus) with the highest frequency of occurrence in sperm whales (60%). Gastric blockage from plastic was presumably lethal in three cases, with plastic bags being the most common finding (46%). Plastic ingestion is of particular conservation concern for the endangered Mediterranean sperm whales. A regular examination of stranded cetaceans with a standardised protocol is critical for allowing spatiotemporal comparisons within and across species.

In situ studies of plastic deterioration can help us understand the longevity of macroplastic as well as the generation of microplastics in the environment. Photo-oxidation contributing to the generation of microplastics in the marine environment was explored using four types of plastic (polyethene, polystyrene, poly(ethylene terephthalate) and Biothene® exposed in light and in shade, in both air and sea water. Metrics for deterioration were tensile extensibility and oxidation rate. Measurements were conducted at intervals between 7 and 600 days' exposure. Deterioration was faster in air than in sea water and was further accelerated in direct light compared to shade. Extensibility and oxidation were significantly inversely correlated in samples exposed in air. Samples in sea water lost extensibility at a slower rate. Polystyrene, which enters the waste stream rapidly due to its wide application in packaging, deteriorated fastest and is, therefore, likely to form microplastics more rapidly than other materials, especially when exposed to high levels of irradiation, for example when stranded on the shore.

Anthropogenic contamination of beaches in the south of Brazil was assessed by detection of Escherichia coli, human mastadenovirus species C (HAdV-C) and F (HAdV-F) and hepatitis E virus (HEV). Sampling was carried out in October (2016), and in January, April and July (2017). Water, sediment, sea surface microlayer (SML), bivalves, and air sentinel samples were evaluated. Quantitative microbiological risk assessment (QMRA) was used to estimate the probability of swimmer infection. HAdV-C was present in 26% of the samples, for both qPCR and viral isolation. The highest rates of detection in genomic copies (GC) were in water (2.42E+10 GC/L), SML (2.08E+10 GC/L), sediment (3.82E+08 GC/g) and bivalves (3.91E+07 GC/g). QMRA estimated daily and annual risks with a maximum value (9.99E-01) in almost all of the samples. Viable HAdV-C was often detected in the SML, pointing that this is a source of infection for people bathing in these waters.

A suite of eight polyhalogenated carbazole (PHCZ) congeners were detected in sediments of the Jiaozhou Bay wetland. 3,6-dichlorocarbazole (36-CCZ), and 3,6-dibromocarbazole (36-BCZ) were detected in all samples. The concentrations of ΣPHCZs ranged from 6.9 to 33.4 ng/g dry weight (dw). The recovery of surrogate standard ranged from 85 to 109%. Significant relationships were found between the concentrations of 36-CCZ and those of the other three detected compounds (36-BCZ, 36-ICZ, and 1368-BCZ). However, with regard to the other chemicals, only 1368-BCZ was related to 36-ICZ. The toxic equivalent (TEQ) was used to assess the relative toxicity of PHCZs, which ranged within 0.1–3.9 pg TEQ/g dw in sediment. The inventory of ΣPHCZs was 58.9 kg. These results indicate that PHCZs are widely distributed in the Jiaozhou wetland and the dyeing and finishing industries may be important contamination sources of PHCZs.

The distribution and potential ecological risks of eight heavy metal elements including Cr, Cu, Zn, As, Cd, Pb, Hg, and W in the overlying water and sediments of the Taojiang River were investigated. The concentrations of eight heavy metals were measured by inductively coupled plasma mass spectrometer (ICP-MS), and the distribution coefficients were exploited to estimate the partition coefficient between overlying water and sediment phases, which were subsequently used to establish the potential ecological risk of heavy metals in sediments. The results revealed that the contents of Pb (33.47 μg·L⁻¹), Cd (153.03 μg·L⁻¹) and Hg (1.12 μg·L⁻¹) in the water samples exceeded threshold values as proposed by the limits of the class III environmental quality standard. On the other hand, Cr, Cu, Zn, As, and Pb within sediments were below threshold limits.

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.

We investigated the validity of Autonomous Reef Monitoring Structures (ARMS) as monitoring tools for hard bottoms across a wide geographic and environmental range. We deployed 36 ARMS in the northeast Atlantic, northwest Mediterranean, Adriatic and Red Sea at 7–17 m depth. After 12–16 months, community composition was inferred from photographs, in six plate-faces for each ARMS. Overall, we found a highly significant effect of sea region, site (within seas), and plate-face on community composition. Plate-faces thus represent distinct micro-habitats and provide pseudo-replicates, increasing statistical power. Within each sea region taken individually, there was also a highly significant effect of site and plate-face. Because strong effects were obtained despite the fusion of taxonomic categories at high taxonomic ranks (to ensure comparability among biogeographic provinces), ARMS photo-analysis appears a promising monitoring tool for each sea region. We recommend keeping three ARMS per site and analyzing more numerous sites within a sea region to investigate environmental effects.

To investigate the effects of mariculture on the sources, distribution and preservation of sedimentary organic carbon (SOC), sediments from an mariculture area in Ailian Bay, China, and a control area were analyzed for grain size composition, total organic carbon (TOC), total nitrogen (TN), carbon/nitrogen (C/N) ratio, and stable carbon and nitrogen isotopic composition (δ13C and δ15N). The sedimentary type of sediments in study area was clay silt. TOC, TN, C/N, δ13C, and δ15N ranged from 0.58 to 1.21%, 0.06–0.17%, 6.29–9.82, −23.20 to −18.50‰, and 6.17–7.38‰, respectively, and followed similar spatial patterns. TOC, TN and δ13C were higher in mariculture area than in control area. Biodeposit and kelp OC contributions greater of SOC in mariculture area than the control area (biodeposits: 20.10 ± 4.84 to 6.2 ± 1.3%; kelp: 15.3 ± 6.63 to 5.2 ± 0.84%). Overall, mariculture activities significantly influence the sources, distribution and preservation of SOC.