Microplastics pollution has become a matter of global concern because of its effects on aquatic life and the ecosystem. This study investigated the abundance and types of microplastics found in an urban canal of Thailand. Water quality and the relationship between microplastics pollutants and the physicochemical properties of water quality were also analyzed to provide evidence for this study. The mean abundance of microplastics was 370 ± 140 particle(p)/m3. The highest number and concentration of microplastics were found on surface water corelated with urbanization. Transparent brown and transparent colors in the form of film and fiber/lines were the predominant morphology. Polypropylene (PP) and polyethylene (PE) were the most abundant polymer type in all surface water samples. Furthermore, water quality was related with microplastic pollution. The physicochemical properties of turbidity (0.99), conductivity (0.97), total solid (0.95) and biological oxygen demand (0.84) were accounted for greatest influences on microplastics distribution. The estimated equation of microplastics was also closely corelated with water quality. These results demonstrate that microplastic pollution has progressed more in poor water quality than good water quality, indicating that the inflow process and sources of microplastics are similar to those of other pollutants. Therefore, this study is expected to encourage and enforce solid waste and wastewater management policies that prevent microplastics pollution in the environment.

Severodvinsk city is the largest industrial center for the construction and repair of naval vessels in the NW Russia. The purpose of the presented study was to identify the main sources of pollution of the Severodvinsk industrial region and assess the ecological situation based on analysis of toxic metals in water and snow. Heavy metals content in water, melt snow filtrate and solid residue was measured using ICP-MS. On the urban area, there were high concentrations of Fe (up to 2843 MPC) in soluble form of snow, Al (up to 4680 MPC), Fe (up to 2807 MPC), Ni (up to 66.5 MPC), Pb (up to 44.7 MPC), Cd (up to 43.3 MPC), Cr (up to 43.2 MPC), Mn (up to 13.3 MPC), Co (up to 7.3 MPC), and As (up to 3.4 MPC) in insoluble form of snow, Fe (up to 56213 MPC) in water from wells. There were high values of mineralization (598 mg/L) and low pH values (to 5.21) in sites most susceptible to anthropogenic pollution. Statistical analysis showed that most of the metals in snow cover were linked with each other by strong correlation (r>0.9). Calculation of toxicological indices HMEI, HMPI, HMTL, HI and CR showed extremely high and dangerous for public health level of heavy metal pollution in the Severodvinsk industrial district. Studied radiation parameters of water from wells were within acceptable limits. Results obtained indicate the need to change the type of fuel in thermal power plant and reduce toxic emissions from the shipbuilding enterprises.

Antimicrobial nanomaterials provide numerous opportunities for the synthesis of next-generation sustainable water disinfectants. Using the keywords graphene and water disinfection and graphene antibacterial activity, a detailed search of the Scopus database yielded 198 and 1433 studies on using graphene for water disinfection applications and graphene antibacterial activity in the last ten years, respectively. Graphene family nanomaterials (GFNs) have emerged as effective antibacterial agents. The current innovations in graphene-, graphene oxide (GO)-, reduced graphene oxide (rGO)-, and graphene quantum dot (GQD)-based nanocomposites for water disinfection, including their functionalization with semiconductor photocatalysts and metal and metal oxide nanoparticles, have been thoroughly discussed in this review. Furthermore, their novel application in the fabrication of 3D porous hydrogels, thin films, and membranes has been emphasized. The physicochemical and structural properties affecting their antibacterial efficiency, such as sheet size, layer number, shape, edges, smoothness/roughness, arrangement mode, aggregation, dispersibility, and surface functionalization have been highlighted. The various mechanisms involved in GFN antibacterial action have been reviewed, including the mechanisms of membrane stress, ROS-dependent and -independent oxidative stress, cell wrapping/trapping, charge transfer, and interaction with cellular components. For safe applications, the potential biosafety and biocompatibility of GFNs in aquatic environments are emphasized. Finally, the current limitations and future perspectives are discussed. This review may provide ideas for developing efficient and practical solutions using graphene-, GO-, rGO-, and GQD-based nanocomposites in water disinfection by rationally employing their unique properties.

The Kingdom of Saudi Arabia is facing an acute shortage of high-quality water, which is further aggravated due to inadequate and nonrenewable groundwater resources. Hence, it is crucial to explore other alternatives, such as natural wastewater treatment (phytoremediation), for water supplies that can both lower the dependence on groundwater resources and overcome the challenges and limitations associated with conventional wastewater treatment technologies. Therefore, the main objective of this research was to study the performance and efficiency of green plants such as Typha latifolia L. (T. latifolia) (broadleaf cattail) and Phragmites australis (Cav.) Train, ex Steud. (P. australis) (common reed) for wastewater treatment in eastern Saudi Arabia. The experiment was conducted in fiberglass tanks (each with a capacity of 4.0 × 7.0 × 0.5 m³) in the field. There were a total of 4 fiberglass tanks with 2 replications. A percent decrease of 72.86% and 49.74%, 39.30% and 18.07%, 39.84% and 52.87%, 38.73% and 40.86%, 74.49% and 57.82%, and 66.82% and 63.14% was observed for turbidity, TSS, nitrate, ammonia, BOD, and COD by growing P. australis and T. latifolia, respectively. Heavy metals such as aluminum, zinc, and arsenic showed a considerable reduction in pollutants in treated water compared to raw wastewater under both plants. Overall, it appears that the improvement in wastewater quality was better by growing P. australis than T. latifolia; however, there were no statistically significant differences (p > 0.05) between the two plant means in their performance of raw wastewater treatment. The study results indicate that green plants could be used in a phytoremediation system to treat wastewater in rural and small communities.

Beaches with monazitic sands show high natural radiation, and the knowledge of this radiation is fundamental to simulate the effects of natural terrestrial radiation on biological systems. Monazite-rich sand from a beach in the southeastern Brazil were collected and analyzed by X-ray fluorescence, X-ray diffraction, and magnetic susceptibility. The natural terrestrial radiation of the beach sand showed a positive correlation with the Th and Y elements, which are closely associated with Ce, Nd, Ca, and P, suggesting that this grouping is mainly associated with local natural radiation. Based on the sand characterization, a physical simulator of natural gamma radiation was built with parameters similar to those of the monazite beach sand, considering areas with high natural radiation levels. The simulation revealed that the natural radiation of the monazite sands has a significant effect on reducing the growth of the bacteria strains of E. coli and S. aureus present in the beach sand, with a reduction of 23.8% and 18.4%, respectively.