PURPOSE OF REVIEW: Phenolic wastewaters represent a serious health and environmental problem. The remediation of phenolic wastewaters using oxidoreductase enzymes has emerged as an attractive environmentally friendly treatment method. However, the loss of enzyme activity during the treatment remains a key limitation. Thus, the aim of this article is to review and assess the recent progress in utilizing surface active additives (i.e., polymers, biopolymers, surfactants, and biosurfactants) for the reduction of enzyme inhibition and, thus, the enhancement of enzymatic remediation of phenolic wastewaters. RECENT FINDINGS: The reported effect of polymeric and surfactant additives on the enzymatic remediation of phenolic pollutants is mixed. Some studies reported significant enhancements while others demonstrated minimal or no gains. More seriously, it has been reported that these fossil-based additives might lead to a higher toxicity of the treated wastewaters. Bio-based (biopolymers and biosurfactants) additives might address this toxicity issue; however, the bio-based additives are not always as effective as the fossil-based ones. Despite the beneficial effect, with some exceptions, of additives, the enhancement level varies widely, probably due to the variations in the reaction environment. Thus, to draw meaningful and reliable conclusions on which additive(s) is more promising, thorough studies under unified conditions are needed. Additionally, generation of secondary pollutions associated with the fossil-based additives urges the replacement of such additives with bio-based ones. However, the effectiveness of the bio-based additives is still not sufficiently documented, stressing the need for more in-depth studies.

We analyze Pb content and Pb isotope ratios in 29 surface sediments and one sediment core from the eastern Beibu Gulf, Southern China. The results indicate that obvious Pb enrichment was limited to the oil and gas exploration area in the central gulf and the mud deposit in the northern gulf. The enrichment of Pb in sediment core A97 started in the 1860s, but a notable drop of Pb content occurred in the 1970s, suggesting variations in human activity. The Pb isotope ratios in sediments were very similar to those in natural sources, except for the sediments near the oil platform, which may be polluted by anthropogenic input. Sediments with relatively high radiogenic Pb isotope compositions may be mainly sourced from northern coast of Beibu Gulf, sediment flux through Qiongzhou Strait, or the Red River, while the coastal zone of western Hainan Island and nearby bottom erosion area produce as minor provenances.

Contaminated sediments at a pulp mill and former chor-alkali effluent treatment facility in Nova Scotia, Canada will undergo remediation. However, baseline studies assessing contaminants in marine biota in the marine receiving environment are lacking. Historical qualitative and quantitative contaminant data in biota from Boat Harbour (a former tidal lagoon which was used to treat industrial effluent since 1967), and surrounding marine environment were reviewed to establish baseline pollution from industrial effluent and contaminated sediments. Elevated metal, dioxins and furan concentrations previously measured in marine biota needs updating to help inform pre-remediation monitoring. Selection of species, contaminants of concern and sampling locations were ad hoc and often inconsistent with environmental effects monitoring requirements under Canadian federal Pulp and Paper Effluent Regulations. These consolidated baseline data are required to determine historical impacts and to assist future monitoring during Boat Harbour sediment remediation to compare against.

Desalination has the potential to provide an important source of potable water to growing coastal populations but it also produces highly saline brines with chemical additives, posing a possible threat to benthic marine communities. The effects of brine (0%, 50%, 100%) were compared to seawater treatments with the same salinity (37, 46, 54 psu) for seagrass (Posidonia australis) in mesocosms over 2 weeks. There were significant differences between brine and salinity treatments for photosynthesis, water relations and growth. Germinating seedlings of P. australis were also tested in brine treatments (0%, 25%, 50%, 100%) over 7 weeks followed by 2.5 weeks recovery in seawater. Growth was severely inhibited only in 100% brine. These experiments demonstrated that brine increased the speed and symptoms of stress in adult plants compared to treatments with the same salinity, whereas seedlings tolerated far longer brine exposure, and so could potentially contribute to seagrass recovery through recruitment.

Anthropogenic marine debris (AMD) is a global problem and the identification of its sources is essential for adequate mitigation strategies. Herein we examined whether AMD density and composition differed between two countries with contrasting socio-economic backgrounds and marine litter sources (i.e. Chile and Germany). In nationwide beach litter surveys, we used a citizen science approach with schoolchildren and their teachers. Litter densities were substantially higher in Chile than in Germany. The different geographic zones surveyed in both countries showed strong grouping tendencies according to their main economic activities (tourism, shipping, fisheries/aquaculture), major litter sources, and AMD composition, in terms of dominance and diversity of AMD types. The results suggest that beach litter composition can be used as a simple proxy to identify AMD sources, and also that law enforcement and education can help mitigate the problem; however, for efficient solutions, production and consumption of plastics must be reduced.

To investigate the effects of the water-sediment regulation on the spatial variations of metals in the surface sediments of the Yellow River Estuary (YRE), sampling sites were set in 2015 (51 sites in June and 33 in October). The content of Cu, Pb, Cd, Cr, Zn, Ni and Mn was determined using inductively coupled plasma spectrometry and of Hg and As atomic fluorescence spectrometry. The results showed that the concentrations of metals in the sediments of YRE were lower after the regulation, while that of most metals increased in the tidal areas of the current estuary with fine particles. Environmental pollution and ecological risk of metals were mainly from Hg and Cd. Metals carried with the silt of the river should be focused. The findings were expected to update the current status of metal pollution of YRE and be helpful for the delicacy management of the regime and silt-laden rivers.

P-glycoprotein (P-gp) is a molecular pump, responsible for extruding xenobiotics. The aim of the study was to demonstrate the role of P-glycoprotein (P-gp) in cadmium (Cd) exhaustion. The activity of P-gp was regulated in Crassostrea gigas, which was previously exposed to Cd by using rifampicin (inducer) and verapamil (inhibitor), respectively. Comparing with Crassostrea gigas depurated in natural seawater, Cd content increased significantly from 14.28 mg/kg dw to 17.49 mg/kg dw accompanied by a changed metallothionein level from 9.84 μg/g fw to 10.67 μg/g fw after 25 μg/L verapamil treatment, while Cd content after 25 μg/L rifampicin treatment reduced to 12.21 mg/kg dw. Moreover, after treatment with rifampicin and verapamil, beneficial metal elements, fats, and proteins were maintained, and the tissue-dependent difference was found in the variation of antioxidant defenses and oxidative damage in Crassostrea gigas. In brief, the study provided new evidence on possibility of Cd removal by inducing P-glycoprotein.

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.

Seagrass meadows are recognized as critical and among the most vulnerable habitats on the planet. As a worldwide concern, there is an urgent need to develop techniques to restore and preserve these vital coastal ecosystems due to their alarming decline rate. To effectively preserve and restore seagrasses, more research is required on the germination ecology of seeds. The seagrass Zostera japonica Asch. & Graebn is an endangered species in its native range, the Northwestern Pacific Coast. The present study investigated the germination and seedling establishment in Z. japonica seeds (collected from northern China) under different temperature and salinity conditions to explore suitable seed germination and establishment conditions, as well as the seedling formation process. Results showed that salinity had a more significant influence on seed germination rate. Germination rate decreased with an increase in salinity, and seeds did not germinate when salinity was higher than 40 psu. Temperature was more likely to influence germination speed, which increased with an increase in temperature, with high germination rates and the most rapid germination speed observed at 30 °C. Therefore, the optimal culture conditions were 10 psu salinity at 30 °C for germination and 10–20 psu salinity at 20 °C for seedling establishment, with a seed germination rate of 45.6% after 6 days of germination culture and a seedling establishment rate of 14.3% after 6 days of seedling culture, respectively. A new seedling raising method with low salinity (5 psu) germination and high salinity (20 psu) seedling establishment was proposed and a flow chart of seedling formation of Z. japonica was created. The results provide insight into the seed germination and seedling establishment in Z. japonica, and will facilitate future large-scale seedling culture and field restoration activities for this seagrass species.

Oceanographic processes are examined and used to assess their effect on the movement and dilution of wastewater discharged from Sydney's three deepwater ocean outfalls. Such processes link wastewater discharges with observed changes in biological communities and the accumulation of contaminants in the sediments. The East Australian Current, coastal trapped waves and local winds contribute 40%, 20% and 10% respectively to the total spectral energy in the along-shore currents off Sydney. Median dilutions at the edge of the initial dilution zone range between 185:1 and 347:1. Plumes remain submerged 95% of the time, surfacing only in the middle of winter and during large storms. Negatively buoyant particles sink from the plumes and first reach the ocean floor within 10 km of the discharge location. Resuspension of the sediments due to currents occurs 2.5% of the time and due to waves 1%–4% of the time.