Nowadays, due to increase in worldwide population and rapid urbanization, water demand in the region is increasing fast while water quality is deteriorating. The physical, chemical, and biological characteristics are changing in a fast way due to the accumulation of contaminants such as heavy metals, synthetic dyes, and organic and inorganic materials. This makes the water harmful for the biotic and abiotic components of the ecosystem. Various noble approaches have been employed by the researchers in order to replace the traditional wastewater treatment methods. In this regard, nano-technology has occupied a central position in the areas of research. The term “nano-technology” is a branch of science which acknowledges the manipulation of materials at nano-scale. These materials may have large specific surface area, high reactivity, degree of functionalization, size-dependent properties, etc., which make them suitable for execution in water purification and wastewater treatment. This paper briefly reviews the current advances and application of nano-materials for wastewater treatment. Here, various types of nano-materials such as carbon nano-tubes, MnO₂ nano-sheets, graphene composites, metal oxides, antimicrobial nano-materials, and photocatalysts, which are employed in the field of wastewater treatment, have been dissertated.

Variable and occasionally high concentrations of cadmium in wild oysters at a remote location with the potential to develop aquaculture enterprises motivated research into the distribution and sources of metals in oysters, seawater, sediment, suspended solids and phytoplankton.Saccostrea mytiloides and Saccostrea mordax contained cadmium concentrations exceeding the food standard maximum level (ML) at three of four sites. At one site with high zinc levels in sediment, oyster cadmium levels were below the ML. Metal levels in seawater were not correlated with cadmium levels in oysters but high cadmium/zinc ratios were measured in Trichodesmium erythraeum blooms.We suggest that oysters accumulate cadmium mainly from annual phytoplankton blooms except at sites where zinc availability is sufficiently high to prevent uptake though a mechanism of antagonistic exclusion. Knowledge of the source and uptake mechanisms of cadmium in oysters should lead to new management strategies to reduce cadmium levels in farmed oysters.

Measurements of microplastics in biota and abiotic matrices are key elements of exposure and risk assessments for this emerging environmental pollutant. We investigated the abundance of microplastics in field-collected biota, sediment and water. An improved sediment extraction method, based on density separation was developed. For analysis of microplastics in biota we found that an adapted enzymatic digestion protocol using proteinase K performed best, with a 97% recovery of spiked plastic particles and no observed degradation effects on the plastics in subsequent Raman analysis. Field analysis revealed that 8 of 9 tested invertebrate species from the North Sea and 68% of analyzed individuals of brown trout (Salmo trutta) from the Swedish West Coast had microplastics in them. Based on the number of plastic particles per kg d.w. the microplastic concentrations found in mussels were approximately a thousand-fold higher compared to those in sediment and surface water samples from the same location.

Nitrogen isotope ratios (δ15N) in juvenile winter flounder, Pseudopleuronectes americanus, were used to examine changes in nitrogen inputs to several Rhode Island, USA estuarine systems. Fish were collected over two three-year periods with a ten-year interval between sampling periods (2002–2004 and 2012–2014). During that interval numerous changes to nutrient management practices were initiated in the watersheds of these estuarine systems including the upgrade of several major wastewater treatment facilities that discharge to Narragansett Bay, which significantly reduced nitrogen inputs. Following these reductions, the δ15N values of flounder in several of the systems decreased as expected; however, isotope ratios in fish from upper Narragansett Bay significantly increased. We believe that low δ15N values measured in 2002–2004 were related to concentration-dependent fractionation at this location. Increased δ15N values measured between 2012 and 2014 may indicate reduced fractionation or that changes in wastewater treatment processes altered the nitrogen isotopic ratios of the effluents.

Concentrations of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) were measured in 15 marine wild organism species from South China Sea. The concentration (dry weight) of 16 PAHs ranged from 94.88 to 557.87ng/g, with a mean of 289.86ng/g. The concentrations of BaP in marine species were no detectable. The composition of PAHs was characterized by the 2- and 3-ring PAHs in marine species, and NA, PHE and FA were the dominant constituents. PAHs isomeric ratios indicated PAHs mainly originated from grass, wood and coal combustion, and petroleum. The human health risk assessment based on the excess cancer risk (ECR) suggested the probability of PAHs posing carcinogenic risk to human beings with consumption of marine organisms were negligible (probability<1×10−6).

The main goal of this study was to determine the concentrations of trace elements in the mineralogically contrasting shells of two Arctic bivalves: Chlamys islandica and Ciliatocardium ciliatum. Aragonite shells seem to be more susceptible to the binding of metal ions, which is most likely a result of their crystal lattice structure. We suggest that less biologically controlled aragonite mineralization tends to incorporate more metal impurities into the crystal lattice in waters with a lower pH, where metal ions are more available. Higher concentrations of impurities may further increase the lattice distortion causing lower crystal lattice stability and higher susceptibility to dissolution. Calcitic shells seem to be less prone to bind metal ions than aragonite shells most likely because under strict biological control, the uptake of ions from ambient seawater is more selective; thus, the final crystal lattice is less contaminated by other metals and is more resistant to dissolution.

The influence of salinity, pH, temperature, and dissolved organic matter on the photolysis rate of 2,4,6-trinitrotoluene (TNT) in marine, estuary, and laboratory-prepared waters was studied using a Suntest CPS+® solar simulator equipped with optical filters. TNT degradation rates were determined using HPLC analysis, and products were identified using LC/MS. Minimal or no TNT photolysis occurred under a 395-nm long pass filter, but under a 295-nm filter, first-order TNT degradation rate constants and apparent quantum yields increased with increasing salinity in both natural and artificial seawater. TNT rate constants increased slightly with increasing temperature (10 to 32°C) but did not change significantly with pH (6.4 to 8.1). The addition of dissolved organic matter (up to 5mg/L) to ultrapure water, artificial seawater, and natural seawater increased the TNT photolysis rate constant. Products formed by TNT photolysis in natural seawater were determined to be 2,4,6-trinitrobenzaldehyde, 1,3,5-trinitrobenzene, 2,4,6-trinitrobenzoic acid, and 2-amino-4,6-dinitrobenzoic acid.

Stormwater runoff is the largest source of pollution in the Southern California Bight (SCB), resulting from untreated runoff and pollutants from urban watersheds entering the coastal waters after rainstorms. We make use of both satellite SAR and MODIS-Aqua ocean color imagery to examine two different components of runoff plumes, the surface slick and the sediment discharge. We expand on earlier satellite SAR studies by examining an extensive collection of multi-platform SAR imagery, spanning from 1992 to 2014, that provides a more comprehensive view of the plume surface slick characteristics, illustrated with distribution maps of the extent and flow direction of the plumes. The SAR-detected surface plumes are compared with coincident rain and runoff measurements, and with available measured shoreline fecal bacteria loads. We illustrate differences in the detection of SAR surface plumes with the sediment-related discharge plumes derived from MODIS imagery. A conceptual satellite stormwater runoff monitoring approach is presented.

Mussels (Mytilus spp.) are worldwide utilized in marine biomonitoring by a multi-biomarker approach. However, for a correct interpretation of different biomarker responses, information is needed on their natural seasonal variability due to environmental/physiological factors.In this work, the seasonal variations of different biomarkers were investigated in M. galloprovincialis from 4 different sites from the gulf of La Spezia (Ligurian sea, Italy), an intensive rearing area in the north-western Mediterranean near La Spezia harbor, an important commercial and touristic port. Lysosomal membrane stability-LMS, stress on stress-SoS, phagocytosis, tissue metallothionein-MT content, oxidative stress related enzyme activities (GST, catalase), and nitric oxide (NO) production were evaluated. The results underline the importance of LMS and SoS as core descriptors of the mussel health status in relation to seasonal variations in temperature and reproduction. These data represent the baseline information for ongoing biomonitoring studies related to dredging activities in this area.

Three one-off burial treatments were designed in intertidal zone of the Yellow River estuary to determine the effects of sediment burial on decomposition and heavy metal levels of Suaeda salsa. Sediment burial showed significant effect on decomposition rate of S. salsa. With increasing burial depth, Cu, Zn, Cd and Co levels generally increased, while Cr and Mn levels decreased. Except for Zn, Mn, Cd and Co, stocks of Pb, Cr, Cu, Ni and V in S. salsa among burials were greatly different. The S. salsa in three burials was particular efficient in binding V and Co and releasing Pb, Zn and Cd, and, with increasing burial depth, stocks of Cr, Cu, Ni and Mn shifted from accumulation to release. In future, the eco-toxic risk of Pb, Cr, Cu, Zn, Ni, Mn and Cd exposure might be serious as the strong burial episodes occurred in S. salsa marsh.