环境•农林最新文献

This study investigates the impact of domestic sewage wastewater irrigation on the cultivation of cassava (Manihot esculenta Crantz) from selected agrofields of Palakkad, Kerala with a comparison of well-water-irrigated M. esculenta from the same area. For this, the physicochemical parameters of respective water and soil samples were analysed. Further, to understand the post-harvest crop quality which includes the peeled tuber, peel, leaf and stem proximate composition, and mineral contents including heavy metal composition and in vitro antioxidant potential. The results of the physicochemical parameters of both domestic sewage wastewater and well-water irrigated samples (both water and soil) were observed within the permissible limits according to the WHO/FAO suggested pattern. Interestingly, heavy metals such as Zn, Cd, Cr, Cu, and Ni were within the admissible limit in respective samples from both fields. In general, when compared with well-water irrigated cassava crop samples, the antioxidant potential was significantly higher (p < 0.05) in sewage wastewater irrigated cassava samples. The present study demonstrated that domestic sewage water was found to have promising physicochemical properties that allow for safe use for irrigation as liquid organic fertilizers and the cassava crop residues from such agrofields could also be exploited as potential animal feed.

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The activity of six essential oils was investigated against eight fungal isolates (four Aspergillus and four Penicillium species) isolated from cultural heritage conservation premises in Serbia. To analyze the chemical composition of essential oils (EOs), gas chromatography coupled with mass spectrometry was employed. The antifungal activity of selected EOs was investigated using microdilution and microatmosphere methods while the commercial biocide benzalkonium chloride (BAC) was used as a control. Furthermore, molecular docking was used as an efficacious in silico method for the determination of interaction between dominant EO compounds and enzyme CYP51, essential for fungal ergosterol synthesis. It was demonstrated that BAC, Cinnamomum zeylanicum, and Gaultheria procumbens EOs had the strongest antifungal activity, which is in concordance with the results of molecular docking. Namely, the highest energy of enzyme–cofactor interaction was obtained for eugenol (the dominant component of Syzygium aromaticum and C. zeylanicum EOs). Moreover, it was found that the most resistant fungal isolates were A. flavus and A. niger, while A. sydowii and P. citrinum were the most susceptible. The results of our study point to the possibility of using studied environmentally friendly biocides of biological origin for the preservation of historical monuments and artifacts.

The issue of plastic waste has increased substantially due to the extensive employment of man-made polymers across multiple industries. These plastics derived from fossil fuels, such as polyethylene, polystyrene, and polypropylene, are difficult for nature to break down independently. Fortuitously, some microbes have developed the potential through evolutionary adaptation to break down these long-lasting synthetic compounds. Certain microorganisms have evolved the ability to decompose these durable polymers. Some beneficial soil bacteria called plant growth-promoting bacteria have shown promise in both supporting plant growth and development and degrading plastics. Various species of Bacillus and Pseudomonas contain enzymes enabling them to metabolize polyethylene. Rhodococcus species possess similar complimentary enzyme complexes suited for polypropylene degradation. These microbes employ hydrolytic and oxidative enzymes to initiate the plastic breakdown process. Additional soil organisms then further facilitate the mineralization of the fragmented polymers. The nitrogen-fixing Rhizobium can attack polystyrene. The multi-step mechanism often starts with surface oxidation catalyzed by bacterial enzymes. Multiple studies have isolated strains like Brevibacillus borstelensis and photosynthetic Rhodopseudomonas able to consume polyethylene. Meanwhile, certain Streptomyces also have polypropylene depolymerization potential. Overall, applying plastic-eating microbes offers hope for plastic waste management while lessening environmental harm and propelling the shift to a circular economy.

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The present study aimed to use Eucalyptus leaves extract for the green synthesis of ZnO oxide (ZnO) nanorods (NRs) using the hydrothermal method. The X-ray diffraction (XRD) patterns confirmed that the ZnO NRs had a hexagonal crystal structure with high crystal quality. FTIR analysis revealed the presence of functional groups associated to the formation of ZnO NRs. The optical band gap was calculated using the Tauc plot. Scanning electron microscopy (SEM) revealed rod-like morphology of the as-fabricated ZnO, which is further confirmed by the transmission electron microscopy (TEM) analysis. Furthermore, the biosynthesized ZnO NRs were used as photocatalysts for degradation of Rhodamine B (RhB) dye under ultraviolet radiation. Based on these results, ZnO NRs with a concentration of 20 mL of the eucalyptus extract revealed exceptional performance with a photocatalytic degradation rate of 94.77% under UV irradiation for 90 min. According to these results, wastewater can be treated effectively via the designed catalysts using the green and facile synthesis techniques.

The molybdenum doped mixed metal oxides such as zinc and cobalt (Mo/ZnCo₂O₄) were synthesized in a simple hydrothermal procedure that required no use of an expensive and toxic solvent but it exhibited the low photocatalytic efficiency. As-produced Mo/ZnCo₂O₄ were hybridized with reduced rGO to form Mo/ZnCo₂O₄/rGO nanoarray to remove above mentioned issues. Methylene blue (MB) was used in photocatalytic research because it is a common organic contaminant and create very detrimental effect on the living and environmental components. Degradation percentages for ZnCo₂O₄, Mo/ZnCo₂O₄, and Mo/ZnCo₂O₄/rGO nanocomposites were determined to be 41.17, 78.45 and 91.47%, respectively. As per the findings, the aqueous MB dye underwent oxidation primarily due to the presence of the superoxide (({O}_{2}^{bullet -})) radical. The nanocomposite photocatalysts exhibited photodegradation efficiency exceeding 91.47% and displayed remarkable stability, as evidenced by the absence of any noticeable decline in activity indicated by the repeatability test (five cycles). Furthermore, Mo/ZnCo₂O₄/rGO displays excellent antimicrobial activity toward the S.aureus and E.coli species. Our finding suggests that the Mo/ZnCo₂O₄/rGO nanostructure can act as a potential antimicrobial and photocatalytic agent.

The main aim of this study was the removal of heavy metal ions, namely aluminium (Al³⁺), chromium (Cr³⁺), zinc (Zn⁺²), lead (Pb²⁺) and arsenic (As³⁺) from metal plating wastewater using electrocoagulation (EC) technique. The Fe–Fe and Fe-Cu electrode pair configuration was used in the reactor. The influence of electrode material, EC time and wastewater pH on removal performance was investigated. The results showed that the heavy metal removal efficiency was higher when using the Fe-Cu electrode pair. Over 90% of heavy metal ions (Cr³⁺, Zn⁺², Pb²⁺ and As³⁺) were removed efficiently by conducting the EC treatment at current density (CD) of 12.6 mA/cm², pH of 6.2 and EC time of 30 min. These operating conditions led to specific energy consumption and specific amount of dissolved electrodes of around 20 kWh/m³ and 0.87 kg/m³, respectively. The kinetic study showed that the removal of such heavy metal ions follows pseudo first-order model.

Microplastics (MPs) and heavy metals are significant pollutants affecting aquatic ecosystems in Bangladesh, with potential ecological and human health implications. This study investigates the occurrence and characteristics of MPs and heavy metal contamination in Tenualosa ilisha (riverine shad) from the Meghna River Estuary in the northern Bay of Bengal. MPs abundance varied from 17 to 38 particles/fish sample with a mean of 10 items/fish sample. MPs show variations in shape, size, and color. The occurrence of 189 MPs from the visually identified 210 microplastic-like particles were confirmed by µ-Fourier Transformed Infrared Spectroscope (µ-FTIR). In addition, 12 heavy metals, including arsenic (As), lead (Pb), cadmium (Cd), and iron (Fe), were quantified in different body parts (head, flesh, and bones). The concentration was found as As ˃ Fe ˃ Mn ˃ Cu ˃ Ni ˃ Pb ˃ Mg ˃ Se ˃ Co ˃ Zn ˃ Cd ˃ Hg in all parts (head, flesh and bones) of the fish samples. Significant differences in MPs and metal concentrations were observed based on fish size and body part. PCA analysis revealed distinct patterns of metal accumulation across different body parts and fish sizes, with larger fish showing higher levels of Pb and Cu, indicating prolonged exposure. Hierarchical clustering further highlighted similarities in metal distribution, grouping metals such as Pb and Cd due to common sources or pathways of accumulation. The results emphasize the potential health risks associated with consuming larger Hilsa fish due to the occurrence of elevated levels of heavy metal and MPs. To tackle this, the need for regular monitoring of both MPs and heavy metals in anadromous fish species in Bangladesh's aquatic environments is quite apparent.

This study investigated river foam that accumulated on river edges and amongst in-stream debris in the Belubula River, an endangered ecological community and known habitat for platypus, draining a mostly agricultural catchment to the west of the Great Dividing Range in NSW. Samples of both water and accumulated foam from the river were tested for 15 metals and five per- and poly fluoroalkyl substances (PFAS) of which only perfluorooctane sulfonate (PFOS) was detected. The concentration of PFOS in foam (median 375,000 ng/L) was 18,750 times greater than in water (20 ng/L). Metals in river foam were more abundant than in river water. The median copper in river water was 3 µg/L and nearly 1000 times greater in river foam (median 2900 µg/L). Several metal toxicants (including mercury, cadmium, selenium and lead) were only detected in river foam where they were orders of magnitude higher than ecosystem protection levels. We speculate that aeration of river flow through rapids and waterfalls contributed air bubbles that produced surface foam in a similar process to foam fractionation. Although foam containing PFOS has previously been documented within a freshwater lake, the hyperaccumulation of metals within PFOS-enriched foam on the surface of a river appears to be a novel phenomenon and warrants further investigation to determine the bioavailability of the hyperaccumulated chemicals. In addition to the potential ecological impacts from such highly contaminated foam, it also poses potential human-health and agricultural pollution risks.

Microplastics have increasingly become a global menace, pervading aquatic ecosystems and exerting profound biological impacts on marine life. The breakdown of synthetic fabrics, consumer plastics and industrial trash is the source of these contaminants. Due to an inappropriate disposal and fragmentation procedures, these plastic waste materials end in aquatic bodies. While numerous studies have focused on studying the effects of various plastics, limited research has focused on low-density polyethylene (LDPE) MPs and their unique way of interaction with biota. In this study, pigmented LDPE plastics were separated into three distinct size ranges (> 10 µm, 10–15 µm, and 15–25 µm), characterized and exposed to zebrafish for 48 h at a concentration of 1 µg/ml. The following developmental endpoints were analyzed and assessed: histopathological changes, gastrointestinal enzyme activity (trypsin, chymotrypsin, carboxypeptidase A, α-amylase, and lipase), biochemical responses (superoxide dismutase, lipid peroxidation, and catalase) and embryo survival and hatching rates. Although LDPE MP exposure did not cause embryo death, it did cause a decrease in hatching rate, an increase in heart rate, a considerable accumulation of MPs in the gut and significant tissue damage, especially by the smallest particle size. These results demonstrate how colored LDPE MPs may jeopardize aquatic creatures’ biological integrity, posing a growing risk to aquatic ecosystems and public health.