Emerging trends in wastewater treatment: Addressing microorganic pollutants and environmental impacts.

This review focuses on the challenges and advances associated with the treatment and management of microorganic pollutants, encompassing pesticides, industrial chemicals, and persistent organic pollutants (POPs) in the environment. The translocation of these contaminants across multiple media, particularly through atmospheric transport, emphasizes their pervasive nature and the subsequent ecological risks. The urgency to develop cost-effective remediation strategies for emerging organic contaminants is paramount. As such, wastewater-based epidemiology and the increasing concern over estrogenicity are explored. By incorporating conventional and innovative wastewater treatment techniques, this article highlights the integration of environmental management strategies, analytical methodologies, and the importance of renewable energy in waste treatment. The primary objective is to provide a comprehensive perspective on the current scenario, imminent threats, and future directions in mitigating the effects of these pollutants on the environment. Furthermore, the review underscores the need for international collaboration in developing standardized guidelines and policies for monitoring and controlling these microorganic pollutants. It advocates for increased investment in research and development of advanced materials and technologies that can efficiently remove or neutralize these contaminants, thereby safeguarding environmental health and promoting sustainable practice.

Effect of iron nanoparticles and conventional sources of Fe on growth, physiology and nutrient accumulation in wheat plants grown on normal and salt-affected soils.

Salt stress is becoming a serious problem for the global environment and agricultural sector. Different sources of iron (Fe) can provide an eco-friendly solution to remediate salt-affected soils. The Fe nanoparticles (FeNPs) and conventional sources of Fe (iron-ethylene diamine tetra acetic acid; Fe-EDTA; and iron sulfate; FeSO4) were used to evaluate their effects on wheat crop grown in normal and salt-affected soils. Application of FeNPs (25 mg/kg) on normal soil increased the dry weights of wheat roots, shoots, and grains by 46%, 59%, and 77%, respectively. In salt-affected soil, FeNPs increased the dry weights of wheat roots, shoots, and grains by 65%, 78%, and 61%, respectively. The application of FeSO4 and Fe-EDTA increased the growth parameters of wheat in both normal and salt-affected soils compared to the respective controls. The photosynthetic parameters, including chlorophyll a (50%), chlorophyll b (67%), carotenoids (62%), and total chlorophyll contents (50%), were increased with the application of FeNPs under salt stress. The FeNPs increased plant-essential nutrients like iron, zinc, calcium, magnesium, and potassium in both normal and salt-affected soils. The experiment revealed that the application of Fe plays a significant role in enhancing the growth of wheat on alkaline normal and salt-affected soils. Maximum growth response was recorded with FeNPs than other Fe sources. The future must be focused on long term field experiments to economize the application of FeNPs on a large scale for commercialization.

Application of silicon and sodium hydrosulfide alleviates arsenic toxicity by regulating the physio-biochemical and molecular mechanisms of Zea mays.

Soil contamination with toxic heavy metals (such as arsenic (As)) is becoming a serious global problem due to rapid development of social economy, although the use of silicon (Si) and sodium hydrosulfide (NaHS) has been found effective in enhancing plant tolerance against biotic and abiotic stresses including the As toxicity. For this purpose, a pot experiment was conducted using the different levels of As toxicity in the soil, i.e., (0 mM (no As), 50, and 100 µM) which were also supplied with the different exogenous levels of Si, i.e., (0 (no Si), 1.5, and 3 mM) and also with the NaHS, i.e., (0 (no NaHS), 1, and 2 mM) on growth, photosynthetic pigments, gas exchange characteristics, oxidative stress biomarkers, antioxidant machinery (enzymatic and non-enzymatic antioxidants), and their gene expression, ion uptake, organic acid exudation, and As uptake of maize (Zea mays L.). Results from the present study showed that the increasing levels of As in the soil significantly (P < 0.05) decreased plant growth and biomass, photosynthetic pigments, gas exchange attributes, sugars, and nutritional contents from the roots and shoots of the plants. In contrast, increasing levels of As in the soil significantly (P < 0.05) increased oxidative stress indicators in terms of malondialdehyde, hydrogen peroxide, and electrolyte leakage and also increased organic acid exudation patter in the roots of Z. mays, although the activities of enzymatic antioxidants and the response of their gene expressions in the roots and shoots of the plants and non-enzymatic such as phenolic, flavonoid, ascorbic acid, and anthocyanin contents were initially increased with the exposure of 50 µM As, but decreased by the increasing the As concentration 100 µM in the soil. The negative impact of As toxicity can overcome the application of Si and NaHS, which ultimately increased plant growth and biomass by capturing the reactive oxygen species and decreased oxidative stress in Z. mays by decreasing the As contents in the roots and shoots of the plants. Our results also showed that the Si was more sever and showed better results when we compared with NaHS under the same treatment of As in the soil. Research findings, therefore, suggest that the combined application of Si and NaHS can ameliorate As toxicity in Z. mays, resulting in improved plant growth and composition under metal stress, as depicted by balanced exudation of organic acids.

New insights in to the ameliorative effects of zinc and iron oxide nanoparticles to arsenic stressed spinach (Spinacia oleracea L.).

Nanotechnology is capturing great interest worldwide due to their stirring applications in various fields and also individual application of iron oxide nanoparticle (FeO-NPs) and zinc oxide nanoparticle (ZnO-NPs) have been studied in many literatures. However, the combined application of FeO and ZnO-NPs is a novel approach and studied in only few studies. For this purpose, a pot experiment was conducted to examine the plant growth and biomass, photosynthetic pigments, gas exchange attributes, oxidative stress and response of antioxidant compounds (enzymatic and nonenzymatic), sugars, nutritional status of the plant, organic acid exudation pattern As accumulation from the different parts of the plants in spinach (Spinacia oleracea L.) under the different As concentrations i.e., 0 (no As), 60 and 120 µM] which were primed with combined application of two levels of FeO-NPs (10 and 20 mg L-1) and ZnO-NPs (20 and 40 mg L-1). Results from the present study showed that the increasing levels of As in the soil significantly (P < 0.05) decreased plant growth and biomass, photosynthetic pigments, gas exchange attributes, sugars, and nutritional contents from the roots and shoots of the plants. In contrast, increasing levels of As in the soil significantly (P < 0.05) increased oxidative stress indicators in term of malondialdehyde, hydrogen peroxide, and electrolyte leakage, and also increased organic acid exudation patter in the roots of S. oleracea. The negative impact of As toxicity can overcome the combined application of ZnO-NPs and FeO-NPs, which ultimately increased plant growth and biomass by capturing the reactive oxygen species, and decreased oxidative stress in S. oleracea by decreasing the As contents in the roots and shoots of the plants. Research findings, therefore, suggest that the combined application of ZnO-NPs and FeO-NPs can ameliorate As toxicity in S. oleracea, resulting in improved plant growth and composition under As stress, as depicted by balanced exudation of organic acids.

ZnO Nano-swirlings for Azo Dye AR183 photocatalytic degradation and antimycotic activity.

The sol-gel technique was used to fabricate ZnO Nano-swirlings (ZNsw) at a predetermined agitation rate (of >> 1900 rpm), with around 21.94 gm of zinc acetate dihydrate and 0.2 g cetyltrimethylammoniumbromide (CTAB) and a cationic surfactant (drop-wise). The impact of the predetermined agitation condition on the molecular size and morphology of ZNsw is examined, and the outcomes are dissected by useful characterization tools and techniques viz. XRD, SEM embedded with EDS, TEM, FT-IR and UV-visible. The SEM and TEM results suggest that the product formed into a big cluster of adequate ZNsw, containing a significant quantity of folded long thread-lengths. Each group indicated a fair amount of the volume of these lengths. The photocatalytic process of ZNsw was carried out as a result of the irradiation time due to the deterioration of Azo Dye AR183, resulting in approximately 79 percent dye discoloration following an 80-min UV light irradiation in the presence of ZNsw. Additionally, the synthesized ZNsw was tested for antagonistic activity, and the growth hindrance of two plant pathogenic fungal strains found. Per cent inhibition in growth of Rhizoctonia solani and Alternaria alternata were observed in response to ZNsw.

Chromium-resistant Staphylococcus aureus alleviates chromium toxicity by developing synergistic relationships with zinc oxide nanoparticles in wheat.

Chromium (Cr) is a toxic heavy metal that contaminates soil and water resources after its discharge from different industries. It can act as carcinogen and mutagen for biological systems. Microbe-assisted phytoremediation is one of the most emergent and environment friendly technique used for detoxification of Cr from Cr-contaminated soils. In this study, wheat as a test crop was grown under varying stress levels (0, 50, 100 and 200 mg/kg) of Cr in a pot experiment under a complete randomized design. Alleviative role of Staphylococcus aureus strain K1 was assessed by applying as a treatment in different combinations of zinc oxide nanoparticles (0, 50, 100 mg/L). Growth and yield attributes data presented nurturing impact of bacterial inoculation and ZnO NPs in improvement of wheat defense system by decreasing Cr toxicity. Increase in chlorophyll and carotenoids contents, antioxidant enzymes (SOD, POD, APX, CAT) activities and nutrient uptake also confirmed the mitigative potential of bacterial inoculation when applied solely or in combination with ZnO NPs. The Cr accumulation in different parts of plant was significantly reduced with the application of NPs and S. aureus strain K1. Taken together, the results showed that combined application of Staphylococcus aureus strain K1 and ZnO NPs detoxifies the effects of Cr on wheat plants and boosts its growth, physiology and defense system.

Effect of Individual, Simultaneous and Sequential Inoculation of Pseudomonas fluorescens and Meloidogyne incognita on Growth, Biochemical, Enzymatic and Nonenzymatic Antioxidants of Tomato (Solanum lycopersicum L.).

This study was conducted on tomato (Solanum lycopersicum cv. K-21) to investigate the bioprotective nature of Pseudomonas fluorescens and its interactive effects with Meloidogyne incognita in terms of growth biomarkers, changes in biochemical attributes and modulation in antioxidant enzymes of the tomato plant. In this study, we grew tomato plants with M. incognita and P. fluorescens in separate pots, simultaneously and sequentially (15 days prior or post) after 15 days of seed sowing. The sequential inoculation of Mi15→Pf maximally increased the root-knot index and decreased the nematode population. It was also noted that inoculation suppressed the plant growth biomarkers in comparison to control. However, maximum suppression in nematode reproduction and increment in growth and physiological attributes were observed when P. fluorescens was applied 15 days prior to the nematode (Pf15→Mi) as compared to control. All the treatments showed an increase in antioxidant enzymes. Expression of phenol content and defensive enzymes such as peroxidase (POX) and superoxide dismutase (SOD) increased, in contrast to a significant reduction in malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents when compared with the untreated inoculated plants. However, the highest levels of POX and SOD, and a lowest of phenol, MDA and H2O2 were displayed in the treatment Pf15→Mi, followed by Mi+Pf and Mi15→Pf.