The factors limiting micropollutant biodegradation in the environment and how to stimulate this process have often been investigated. However, little information is available on the capacity of microbial communities to retain micropollutant biodegradation capacity in the absence of micropollutants or to reactivate micropollutant biodegradation in systems with fluctuating micropollutant concentrations. This study investigated how a period of 2 months without the addition of micropollutants and other organic carbon affected micropollutant biodegradation by a micropollutant-degrading microbial community. Stimulation of micropollutant biodegradation was performed by adding different types of dissolved organic carbon (DOC)—extracted from natural sources and acetate—increasing 10 × the micropollutant concentration, and inoculating with activated sludge. The results show that the capacity to biodegrade 3 micropollutants was permanently lost. However, the biodegradation activity of 2,4-D, antipyrine, chloridazon, and its metabolites restarted when these micropollutants were re-added to the community. Threshold concentrations similar to those obtained before the period of no substrate addition were achieved, but biodegradation rates were lower for some compounds. Through the addition of high acetate concentrations (108 mg-C/L), gabapentin biodegradation activity was regained, but 2,4-D biodegradation capacity was lost. An increase of bentazon concentration from 50 to 500 µg/L was necessary for biodegradation to be reactivated. These results provide initial insights into the longevity of micropollutant biodegradation capacity in the absence of the substance and strategies for reactivating micropollutant biodegrading communities. Graphical abstract: (Figure presented.)

This study was conducted in Hezhang County, Bijie City, Guizhou Province. The soil in the zinc smelting area has been contaminated with cadmium, lead, and zinc. Therefore, these elements are the focus of this research. Rice husk biochar was used as the passivation material. The Fourier infrared spectrum was utilized to study the biochar’s morphology, element content, mineral composition, structure, and surface functional groups. Moreover, the physical and chemical properties of the biochar were analyzed to explore its passivation effect. Biochar is beneficial in the cleaning of cadmium, lead, and zinc minerals and can be used for the passivation of heavy metals in contaminated soil. This study aims to understand the detailed mechanism behind this process and provide experimental data and ideas for pollution control. The results indicate that the biochar contains many functional groups, including -OH, C-H, C-O, C=O, C=C, and C-O-C. It also consists of a significant quantity of potassium salt, calcite, and quartz. Biochar has a noticeable pore structure, and as the pyrolysis temperature increases, the pore structure becomes more developed and thinner, with a smooth surface. The main minerals in the soil are quartz, mica, zeolite, illite, and chlorite. The aromatic degree of biochar increased with pyrolysis temperature. In contrast, the aromatic degree and polarity first increased and then decreased. The 0.2-0.45 mm biochar exhibited the best passivation effect on cadmium, lead, and zinc.

Fly ash is generally obtained as a by-product from the combustion of coal and other waste materials. It is used for making bricks, but it has few limitations. The fly ash consists of Silica, Alumina, and other metal oxide components in minor quantities. Fly ash particles are observed in the range of nanometers to micrometers and can act as a catalyst in various reactions. The use of low-cost catalysts in the pyrolysis of thermoplastic waste would achieve a high percentage of low molecular weight fractions in liquid form which increases its applicability in commercial sectors. Hence, there is a need to enhance these fractions to achieve a sustainable approach in the catalytic pyrolysis process. fly ash, being a side product, is very cheap, so its effect on the plastic waste pyrolysis process has been studied. In the present research paper, Physical & chemical characterization of fly ash has been carried out. As fly ash consists of different metal oxides in proportion, its applicability in the process of pyrolysis of HDPE, LDPE, and PP waste has been studied. The different weight percent of fly ash (i.e., 5, 10, 15, 20) have been tried in all pyrolysis experiments. It has been observed that 5 wt % fly ash is effective for enhancing the yield of liquid fuel as compared to that without a catalyst. Liquid fuel obtained from catalytic pyrolysis of HDPE, LDPE, and PP waste with Fly ash consists of a high percent of low molecular weight fractions as compared to that of liquid fuel without catalyst, which has been concluded by calorific values & GC-MS result.

Bengawan Solo River water is a source of drinking water and raw materials for the government of Surakarta city, but the water has been mixed with domestic, industrial, and agricultural wastes. The waste contains estradiol-17 derived from urine and feces, both from livestock and humans as well as industries around the sub-watershed Bengawan Solo River. The content of estradiol-17 in the Bengawan Solo sub-watershed is quite high. This study is the first conducted in Bengawan Solo River to look at natural estrogens that are very rarely studied in the environment, which are likely could cause several health effects in humans and wildlife due to their relatively strong estrogenic potential and high levels in wastewater and river water. Therefore, research on the elimination of these compounds using effective, energy-efficient, and low-maintenance technologies for water treatment such as phytoremediation is highly expected. The purposes of this study were to identify estradiol, to measure the estradiol levels through HPLC tests as well as to test the effectiveness of phytoremediation with Portulaca plant as biological agents. The results show that the water of Bengawan Solo River contained estradiol substances ranging from 3.88 ppm to 5.76 ppm. The Portulaca plant species was effective at eliminating estrogenic waste up to 99.89%.

Nature reserves have played a crucial role in biodiversity conservation for decades. Rapid urban sprawl has increased the amount of solid waste created by littering and illegal dumping in metropolitan nature reserves. This paper examines how two nature reserves, Wolfgat Nature Reserve and Witzands Aquifer Nature Reserves, can combine community conservation with waste management. To determine aspects such as the socioeconomic impact of the nature reserves on the surrounding communities, questionnaires with a specific focus on the topic were distributed to the surrounding communities and subsequently administered. Data was collected using semi-structured interviews with key informants from the nature reserve staff and observational methods, and SPSS was used to analyze the data. Consistent with previous research, this study revealed that ignoring local populations frequently results in people disobeying the appropriate regulations in these protected areas and that education does not guarantee conservation support. Despite this, the survey revealed an absence of community participation; conservators were more reactive than proactive. In this study, the level of education, which in some studies is always associated with knowledge, was contradicted; those with post-secondary education knew little about these areas, and the vast majority of participants were unaware of the protected areas just a few kilometers away from their communities.

Marginal land has low nutrient content (nitrogen, phosphorus, potassium). Addressing nutrient deficiencies on marginal land requires a strategic approach. Biological fertilizers like Arbuscular Mycorrhizal Fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) enhance nutrient availability through symbiotic interactions. In addition, organic fertilizers such as compost could provide organic matter and improve soil structure to increase plant growth and productivity. Combining these three fertilizers with the addition of low doses of NPK fertilizer can increase the growth and productivity of maize crops on sub-marginal land. This study aims to determine the effect of AMF, consortium of PGPR, and a low dose of NPK on the growth and productivity of maize and soil nutrients on sub-marginal land by measuring plant growth up to 8 WAP (week after planting) (parameters: plant height, stem diameter, number of leaves, leaf area, chlorophyll content, stomatal density) and productivity (parameters: cob length, cob weight with husk, fresh weight, dry weight) and levels of N, P, and K elements at 8 WAP in the soil after planting. All treatments showed an increase in the level of N and K elements, while the P element showed a decrease compared to the control (soil without treatment). Moreover, each parameter did not show a significant difference, but the P2 (Compost + PGPR consortium + AMF + 50% of NPK) treatment showed the best growth and productivity. Overall, the data showed the utilization of PGPR and AMF combination was able to reduce the usage of chemical fertilizer by 50%.

Naturally derived cyanotoxins, cylindrospermopsin (CYN), and microcystin-LR (MC-LR) have shown hepatotoxic and nephrotoxic effects in several studies. The present study aimed to determine the possible nephrotoxicity of MC-LR and CYN on mammalian kidneys using male Wistar rats as an animal model. Potential nephrotoxicity was evaluated at different doses of CYN (0.175 μg.kg-1, 0.140 μg.kg-1, 0.105 μg.kg-1) and MC-LR (0.105 μg.kg-1, 0.070 μg.kg-1, 0.035 μg.kg-1) was observed. Water samples from dug wells contaminated with CYN (0.161 μg.kg-1) and MC-LR (0.091 μg.kg-1) from the Padaviya area in Anuradhapura, Sri Lanka were used as environmental samples. The control groups were treated with distilled water. The exposure time of rats to the toxin was 90 days. Evaluation of urinary creatinine, serum creatinine, and Kidney Injury Molecule-1 (KIM-1) were estimated using standard protocols. A significant increase in serum creatinine levels was observed in all CYN and MC-LR treated groups (p<0.05) after 7 and 42 days of exposure, respectively, compared to control. It was found a decrease of urine creatinine when rats were treated with different concentrations of CYN and MC-LR (p<0.05) after 7 days compared to the control. The highest KIM-1 concentrations were recorded at 0.175 μg.kg-1 of CYN and 0.105 μg.kg-1 of MC-LR. The concentrations of KIM-1 in the control groups for CYN-treated and MC-LR-treated were not detected. Luminal protein, nuclear pyknosis, mild tubular epithelial swelling, vascular congestion, and interstitial inflammation in CYN and MC-LR treated groups were common. No predominant changes were observed in the control groups treated with CYN and MC-LR. The results of the present study confirm that the consumption of CYN and MC-LR-contaminated water may lead to kidney injury in Wistar rats.

Composting is an integral component of sustainable Municipal Solid Waste (MSW) management within the circular bio-economy platform. However, it faces challenges due to malodorous emissions that impact environmental and societal equilibrium. The present study aims to minimize odorous emissions and expedite compost maturation using a novel, efficient microbial consortium. Bacteria sourced from open dump sites in Sri Lanka were carefully screened based on concurrent enzyme production. Five developed consortia were tested for their performance in reducing malodors during the composting process of MSW. Consortium No. 5 (C5), comprised of Bacillus haynesii, Bacillus amyloliquefaciens, and Bacillus safensis, demonstrated outstanding performance with a significant (p < 0.05) reduction in odorous emissions. Additionally, consortium C5 exhibited impressive control over gas emissions, maintaining VOC, CH4, NH3, and H2S concentrations within ranges of 0.5-6 ppm, 0.5-0.8 ppm, 0.3-0.5 ppm, and 0.5-0.6 ppm, respectively, compared to control concentrations of 4.5-10.2 ppm, 0.5-5.5 ppm, 0.3-5.5 ppm, and 0.5-6.4 ppm, respectively. Additionally, comprehensive Electronic nose (E-nose) analysis substantiated C5’s efficiency in attenuating Methane-Aliphatic compounds, Sulfur and Aromatic compounds, along with low-polarity aromatic and alkane compounds, all with statistical significance (p < 0.05). Further, the developed consortium could reduce the composting time from 110 ± 10 days to 17 ± 3 days, offering a sustainable solution for global MSW management.

There is a pressing demand for the introduction of environmentally safe technologies for the industries that supply the basic needs of industrialized societies. Advanced Oxidation Processes may become one of the answers to these uprising pollution management problems in the near future. The present investigation aimed to reduce the refractory organics present in the biologically treated (Activated Sludge Process) tannery effluent using Photocatalysis. The optimum time, pH, dosage of H2O2, and mass of NPAC required for the effective treatment using photocatalysis were found to be 60 mins, 8, 0.2 mg.L-1, and 1g. 100 mL-1, respectively. Although the efficiency of homogeneous photocatalysis was found to be higher than that of heterogeneous photocatalysis, the biodegradability was higher in the latter, with a value of 0.26. The experimental results have proved that photocatalysis could be a promising technology to reduce the refractory organics present in the tannery effluent.

In recent times, nanotechnology has experienced widespread acclaim across diverse sectors, including but not limited to tissue engineering, drug delivery systems, biosensors, and the mitigation and monitoring of environmental pollutants. The unique arrangement of carbon atoms in sp3 configurations within carbon nanomaterials endows them with exceptional physical, mechanical, and chemical characteristics, driving them to the forefront of materials research. Their appeal lies in their efficacy as superior adsorbents and their exceptional thermal resistance, making them versatile in various applications. The present review extensively explores a range of carbon-based nanomaterials, delving into their synthesis methods and examining their multifaceted applications in addressing environmental pollutants. It is crucial to emphasize that the popularity of carbon-based nanomaterials arises from their potential to serve as superior adsorbents, coupled with their outstanding thermal resistance properties. These attributes contribute to their applicability in diverse environmental contexts. Looking ahead, carbon-based nanomaterials are poised to emerge as environmentally friendly and cost-effective materials, representing promising and potential avenues for the advancement of sustainable technology.