The problem of pollution of aquatic ecosystems with microplastics has been actively studied by the world scientific community. Most of this research has been devoted to marine ecosystems, whereas scant research has been conducted on fresh water bodies. Lake Baikal (Russia) is a unique natural reservoir. Previous studies devoted to the amount of microplastics in the waters of Lake Baikal were carried out singularly and were not of a systemic character; therefore, previously obtained data does not reflect a complete picture of the state of the lake. Within the framework of this study, our goal was to study the composition and morphological structure of microplastic particles in the ice of Lake Baikal at different distances from the coastline. To do this, a number of ice samples were taken from the upper and lower sides at five different points in South Baikal opposite the village of Bolshiye Koty. Later these samples were analyzed for the types of microplastics and their amount. In the samples taken, two types of microplastics were found—fragments and fibers—with fibers being predominant. The median values of the number of microplastics particles are higher in samples taken at the interface between water and ice, compared to samples taken from the ice surface. Presumably, main part of microplastic fibers found opposite the village of Bolshiye Koty were brought in by a constant circular current from the opposite east coast. In turn, the low number of fragments in the samples may be due to the freezing of the coastline.

Plastic pollution is a threat to the environment because of its slow degradation rate and high usage. The aim of this study is to isolate plastic degrading microorganisms from soils. The soil samples used for this study were collected from dumpsites filled with plastic and plastic materials and the effectiveness of the degradation of plastic materials was studied over a period of six (6) weeks in broth and agar culture under laboratory conditions by weight determination method. Physicochemical and microbiological analysis was carried out on the various soil samples using standard protocols. The biodegradation of polyvinylchloride (PVC) was done in-vitro using the microorganisms isolated from the soil. Microorganisms that were able to degrade a higher percentage of the plastic materials were; Staphylococcus aureus, Streptococcus sp, Bacillus sp, Escherichia coli Aspergillus niger, Aspergillus flavus and Trichoderma viridae. The total viable count for bacteria and fungi were within the range of 11.8x105 CFU/g to 2.0x1010 CFU/g and 3.3x105 CFU/g to 0.1x1011 CFU/g respectively. Staphylococcus aureus, Streptococcus sp, Bacillus sp, Micrococcus sp, Aspergillus niger, Aspergillus flavus, and Trichoderma viridae, degraded plastic up to 25%, 31.2%, 25% 31.2%, 12%, 10% and 10% respectively. These isolates may be used to actively degrade plastics, thereby reducing the rate of plastic pollution in our ecosystem.

In advanced oxidation processes, the application of ozonation has been immensely used in recent years for the treatment of effluent water from pharmaceutical, textile and chemical industries. In this study, procian blue, a major and vastly used reactive dye in the textile industry was chosen for ozonation. This work investigated the effect of ozonation for the treatment of synthetic textile effluent water. The change of pH values of dye solutions from 2-12 had moderate effect on dye removal. The degradation rate was faster during the initial period of ozonation and reached highest dye removal around 90 minutes. The highest 87% removal of dye was observed for the case of 60 mg/L dye solution at pH 12. At higher pH, the dye degradation increased as the rate of formation of hydroxyl radical increased with pH. Factors influencing on dye degradation like concentration of dye, time of ozonation, and addition of H2O2 with ozone (combined treatment) were also evaluated. The combined treatment (5 g/L of hydrogen peroxide) increased the degradation of dye to 92% as compared to 85% for pure ozonation process of 60 mg/L dye solution of initial pH 10. The procian blue dye degradation followed pseudo-first order kinetics with a value of rate constant 2.48×10-2 /min.

Batch adsorption process was employed to remove copper(II) and cadmium(II) ions from contaminated water using dried orange peel powder as a cellulosic adsorbent, which supports circular economy and sustainability. Metal ion concentrations were determined using a flame atomic absorption spectroscopy (FAAS). Effects of pH, sorbate-sorbent contact time, metal ion concentration and adsorbent dose on the removal efficiency of the metal ions was investigated. The adsorption equilibrium was reached at 120 and 150 minutes for Cu(II) ions and Cd(II) ions, respectively. At optimized pH and biosorbent load, 10 mg L-1 of Cu(II) and Cd(II)  ions could be removed to the extent 96.9% and 98.1%, respectively, within 2 hrs. However, the percentage removal of metal ions decreased with increasing their initial concentrations. The observed adsorption data was also interpreted in terms of Langmuir and Freundlich adsorption isotherm models. The calculated equilibrium data fitted more adequately with Freundlich model (higher correlation coefficient, R2) than Langmuir model, indicating heterogeneity of adsorption sites due to different functional groups in cellulose. Cd(II) ions showed less binding affinity and less desorption than Cu(II) ions. The maximum adsorption capacity (qmax) of dried orange peel were 2.78 mg/g and 2.57 mg/g for copper(II) and cadmium(II) ions, respectively.

The present work is aimed at decreasing pollutants emitted by diesel engine exhaust tailpipe and enhancing performance by incorporating cobalt oxide nanoparticles in water emulsified diesel. Water concentration of 5% and 10% is used to prepare various WD emulsion blends, with nano particle dosage levels of 50PPM and 100PPM. High speed homogenizer and ultrasonicator devices are used to disperse water droplets in diesel. Surfactant mixture of span80 and tween20 is used to achieve long term stability of emulsified fuel. The functional groups of emulsified fuel are analysed using FTIR spectroscopy. The characterization of cobalt oxide nanoparticles is carried using scanning electron microscope. Physiochemical properties such as calorific value, density, viscosity of emulsion blends and pure diesel are determined and compared. Experimental results reveal that addition of cobalt oxide nanoparticles in emulsified fuel with increased dosage of 100PPM shows 23%, 33.3%, 25%, and 44.6% reduction in NOX, HC, CO and smoke emission compared to pure diesel. The improvement in BTE and BSFC were observed for all emulsion blends.

Preparation of an efficient hybrid structure photocatalyst for photocatalytic decomposition has been considered a great option to develop renewable technologies for environmental remediation. Herein, ternary magnetic Fe3O4/GQD/g-C3N4 nanocomposite (FGC) was prepared using the ball mill method. Binary nanocomposites Fe3O4/g-C3N4 (F/CN) and GQD/g-C3N4 (G/CN) were prepared to compare photocatalytic activity with FGC. The performance of photocatalysts for degradation of rhodamine B (RhB) was studied. EDX results showed that Fe3O4, GQD and g-C3N4 nanoparticles (NPs) are uniformly distributed in the FGC. The FGC nanocomposite shows superparamagnetic behaviour with a saturation magnetization of 12 emu. g-1, which makes it favourable compound for magnetic separation procedure. Photocatalytic activity of FGC (100%) was much higher than those of the G/CN (88%) and F/CN (77%) photocatalysts. The superior activity of FGC compared to binary composites was attributed to broader absorption in the visible light band and greater suppression of electron-hole recombination. The photocatalytic degradation of RhB using FGC was consistent with pseudo-first-order kinetics. The reusability of FGC was examined for four runs and no noticeable decrease was observed with the same irradiation time for each run. Finally, it can be argued that FGC photocatalyst can be an efficient semiconductor for the degradation of organic dyes from wastewater.

In this study, the purpose was to investigate the histopathological, genotoxic effect, oxidative stress and cell death due to Metronidazole (MTZ), which is a 5-nitroimidazole compound used widely for the treatment of anaerobic organism infections in fish and humans on gill and liver tissues of Oncorhynchus mykiss.Trout fishes were exposed to 5, 10, and 20 mg/L of MTZ in the aquariums for 2, 4 and 8 days. Staining technics namely H&E, NOS immunohistochemistry, and TUNEL were performed to determine histopathological changes, oxidative damage and apoptosis. Additionally, smear preparations were also prepared from gill blood for genotoxic evaluations. The organ damage started in the 2nd day with 5 mg/L MTZ application and effects increased per duration and dose-dependent manner. It was observed that the gills had the primary and secondary lamellae lengths, with formation of clavate lamellae, fusion in secondary lamellae, separation of epithelium and aneurysm. Regional necrosis, vacuolization of hepatocytes, pycnotic nucleus, enlarged sinusoids were also determined in the liver. NOS immunoreactivity increased with the inducible immunoreactivity (iNOS) that was more prominent when compared to the endothelial immunoreactivity (eNOS). Apoptotic immunoreactivity was higher in the 10 mg 8th day experimental group at liver and gills, and was lower 20 mg 8th day experimental group. When the gills and liver compared with each other, in all doses, immunoreactivity was lower in gills, compared with liver. Genotoxic examinations showed that both number of micronucleated erythrocytes and nuclei abnormalities were higher in MTZ-treated groups.

Worldwide there is an immense demand for plastic material that results in “white pollution”. Petrochemical-based plastic is used all over the world which leads to adverse impacts on every sphere of the earth. However, many steps have been taken to control this plastic pollution globally, such as chemical treatments, plastic waste incineration, sanitary landfilling, and 7 R programs. Still, plastic pollution is one of the major international problems. Non-biodegradable plastic would not eradicate from our environment until we have an economically feasible and more biodegradable substitute. In recent years algae, especially microalgae, have got attention worldwide, owing to their various applications. Microalgae is one of the sustainable ways of bioplastic synthesis as during cultivation it also purifies wastewater. This review paper has summarized various species of microalgae used for the synthesis of bioplastic, their cultivation system, and methods for bioplastic production by using microalgae biomass, followed by multiple challenges, solutions, and future prospects.

Humans spend close to 90% of their time within the indoor environment. Deteriorating indoor air quality, especially high PM10, PM2.5 and PM1 is slowly becoming a major concern. A study was carried out, for two years, to characterize the spatiotemporal variation of PM in the indoor-outdoor environment across different residential setups (R1, R2, R3, and MC) in the Delhi region. The study established correlation between monthly variations of Indoor/Outdoor (I/O) ratios and meteorological factors. The results showed Spatio-temporal variation in the average mass concentrations of PM10 recorded peak values during the winter season (avg. 514± 72.15 µg/m3) and minimum concentration was observed during monsoon (avg. 91.41± 22.64 µg/m3) months. Among all the sites, the mixed cluster (MC), a residential cum commercial zone reported the highest particulate matter concentration (avg. 308.10 ±37.23 µg/m3) and while R2 reported the least concentration (avg. 244.9± 27.65 µg/m3) within the indoor environment. The I/O ratios of particulate matter were observed to be highest in January (I/O ratio1.6) and lowest in June month (I/O ratio 0.8). PM10, PM2.5, and PM1 dynamics were found to be critically influenced by meteorological factors, regular household activities, and diverse building designs. The short- or long-term exposure of particulate pollutants (beyond the permissible limits) can increase the probability of acute health effects, so there is an utmost requirement to collect better and systematic information about actual exposure levels experienced in different urban residential environments.

The biotoxins can enter the marine food chain, and, accordingly, seafood consumers are also at risk of ingesting toxins from contaminated aquatic animals. Hormozgan Province in the north of Persian Gulf is an area with high industrial and urbanization rising rate. In the present work, the aim was to identify the okadaic acid and domoic acid producers in the coastal waters and to investigate on their accumulated concentrations in edible bivalves in order to assess the consumer’s health risk. Water samples were collected during winter 2018 and summer 2019 from one blank and four stations facing industrial and municipal effluents. Four species of edible bivalves were collected from coastal lines of Hormozgan province, at the lowest tide time. The concentrations of toxins were determined by indirect competitive ELISA method. Pseudonitzschia delicatissima, Nitzschia punges and Nitzschia seriata in the production of domoic acid and Dinophysis caudate, Prorocentrum Lima and Ceratium tripos in the production of okadaic acid were identified. The okadaic acid concentrations ranged from 59.8 ± 2.38 to 121.96 ± 28.25 µg/kg, ranging from 0.85 to 83.59 ± 38.72 for Domoic acid. Among the studied bivalves, Pinctada radiate contained the maximum concentrations of measured toxins. For the first time at Hormozgan Province, the consumption guidelines for domoic and okadaic acid were calculated. The human health risk assessment showed that at present time, the algal consumers from Hormozgan province are not at risk of domoic and okadaic acid toxins.