Sacred groves are small or large patches of forest and are rich in biodiversity, store carbon (C) in biomass and soil, besides providing important ecosystem services. However, the information on tree species diversity, biomass, and C storage in sacred groves of Central India, Madhya Pradesh is elusive and fragmented. In the present study, 41 sacred groves were inventoried for tree species diversity, biomass, and C storage in vegetation and soil. A total of 103 tree species from 81 genera belonging to 37 families were recorded. Shannon’s diversity, Dominance, Fisher’s alpha, and species evenness indices for trees varied: 0.77–2.53, 0.07–0.64, 1.58–20.37, and 0.28–0.90 respectively. Tree density ranged 75–675 no. of stems ha⁻¹ with a mean of 271 no. of stems ha⁻¹, while basal area ranged 6.8–47 m² ha⁻¹ with a mean value of 27 m² ha⁻¹. Tree biomass ranged 34.9–409.8 Mg ha⁻¹ with a mean value of 194.01 Mg ha⁻¹, while, tree C ranged between 17.5 and 204.9 Mg C ha⁻¹ with a mean value of 97.0 Mg C ha⁻¹. The total soil organic carbon stock (0–30 cm) ranged from 22.4 to 112.5 Mg C ha⁻¹ with the mean value of 62 Mg C ha⁻¹. Biomass C and SOC contributed 61% and 39% of the total C stocks, respectively. Tree C stock showed a significant positive relationship with tree basal area (R² = 0.968). A total of five tree species belonging to four families were found to be vulnerable in Central India. The present study reveals that the sacred groves of Central India are species rich, have higher C stocks and sequestration potential in both vegetation and soil, and calls for an immediate attention for conservation and planning for long-term C sequestration.

This study was performed to evaluate the toxic effects of aflatoxin B₂ (AFB₂) on antioxidant-oxidant balance and vital parameters such as physiological, cytogenetic, and anatomical alterations in Allium cepa L. root tip cells. Toxic effects of AFB₂ on vital parameters were investigated by using the changes in weight gain, germination percentage, chromosomal aberrations (CAs), mitotic index (MI), micronucleus frequency (MN), and anatomical structure. Malondialdehyde (MDA) and reduced glutathion (GSH) levels and superoxide dismutase (SOD) and catalase (CAT) activities in root cells were investigated as antioxidant-oxidant parameters. For this aim, A. cepa bulbs were seperated into five groups as negative control, positive control, and AFB₂ treatment groups. In results, while the rate of germination percentage, weight gain, and MI rates decreased, MN and CA frequency increased in AFB₂-treated groups compared with the negative control. Most common CAs observed in AFB₂-treated groups were fragment and chromosome bridges. It was determined that in 160 μg L⁻¹ AFB₂-treated group there was a 70.8% increase in MDA and a 78.1% decrease in GSH level compared with the negative control group and these changes indicate oxidative damage. In 160 μg L⁻¹ AFB₂ treatment group, SOD and CAT activities decreased importantly due to inhibition. In anatomical examinations, it was determined that AFB₂ treatment caused some anatomical damages in A. cepa root cells such as necrosis, cell deformation, and thickening in cell wall. This study showed that AFB₂, which has the least data among aflatoxins, causes serious in vivo toxic effects in A. cepa root cells.

Spent pot liner (SPL) is a toxic solid waste generated in the aluminum mining and processing industry. SPL is considered as an environmental pollution agent when is dumped on environment. Thus, it is important to access its toxicological risk for the exposed organisms. The comet assay and micronucleus test are efficient tests to detect genotoxic/mutagenic compounds by DNA damage observation. Therefore, in the present study, the genotoxic potential of SPL was evaluated through the micronucleus and comet assay on human leukocytes. After ethics committee approval (COEP—UFLA n°. CAAE 11355312.8.0000.5060), blood aliquots collected from healthy volunteers were exposed to increasing concentrations of SPL (from 0.1 to 80 g L⁻¹). All SPL treatments, including the lowest concentration applied (0.1 g L⁻¹), significantly increased the micronucleus frequency. The frequency of DNA damage was determined by visual scores (from 0 to 4) and the results were expressed on percentage of damage and arbitrary units (AU). CaCl₂ (0.01 M) was applied as negative control (NC) and doxorubicin (10 μg mL⁻¹) as positive control (PC). It was observed a dose-dependency between SPL treatments: as SPL concentration for cell incubation increases, the frequency of damage on DNA also increases. Cells incubated on the NC presented nucleoids class 0 to 2, while those exposed to SPL presents nucleoids class 0 to 4. SPL-incubated cells increasing significantly the frequency of nucleoids class 4. For the PC, the UA of damage was 267.74, which is lower than the one observed for the treatments with high doses of SPL (40–287.40 g L⁻¹ and 80–315.30 g L⁻¹). Thus, it was demonstrated that the SPL is a genotoxic agent that induces DNA damage on exposed organisms.

Urban plants can improve several environmental pollution problems in cities, especially dust prevention, noise reduction, purification of the atmosphere, etc. To explore the influence of dust deposition on the spectral characteristics of the leaf, a foliar dust deposition prediction model based on high-spectrum data was established. Taking Euonymus japonicus L., the common greening tree species in Beijing, as the research object, high (T1), medium (T2), and low (T3) dust pollution gradients were set and hyperspectral data were collected. Results showed that: (1) in the dust-contaminated environment with different concentrations, the trend of the reflectance curve of the leaves of Euonymus japonicus L. was generally consistent. The spectral reflectance of the leaf surface was positively correlated with the amount of leaf dust. (2) There were five obvious reflection peaks and five main absorption valleys with the same positions and ranges in the 350–2500 nm range. (3) The spectral reflectance of leaf flour dust particles of Euonymus japonicus L. was significantly different before and after dusting, and its size was generally clean leaves > dust-depositing leaves. The sensitive range of its spectral response was 695–1400 nm. (4) The overall trend of the first derivative spectrum was basically the same. The red edge slope and the blue edge slope appeared as T3 > T2 > T1, the red edge position and the blue edge position appeared as T1 < T2 < T3. The red edge position of the leaf surface after dust deposition had an obvious "blueshift", and the moving distance increases with the increase of dust retention on leaf surface. (5) The leaf water index (y = − 1.18x² + 0.5424x + 0.9917, R² = 0.8030, RMSE = 0.187) had the highest accuracy in the regression model of leaf surface dust deposition using spectral parameters. The test showed that the R² reached 0.9019, which indicated that the model has a good fitting effect. This prediction model can effectively estimate the dust deposition of the leaf surface of Euonymus japonicus L.

This study investigated the impact of adding zeolite (F), superphosphate (G), and ferrous sulfate (L) in various combinations on reducing greenhouse gas (GHG) emission and improving nitrogen conservation during factory-scale chicken manure composting, aimed to identify the combination that optimizes the performance of the process. Chicken manure was mixed with F, G, FL, or FGL and subjected to windrow composting for 46 days. Results showed that global warming potential (GWP) was reduced by 21.9% (F), 22.8% (FL), 36.1% (G), and 39.3% (FGL). Further, the nitrogen content in the final composting product increased by 27.25%, 9.45%, and 21.86% in G, FL, and FGL amendments, respectively. The fertilizer efficiency of the compost product was assessed by measuring the biomass of plants grown in it, and it was consistent with the nitrogen content. N₂O emission was negligible during composting, and 98% of the released GHGs comprised CO₂ and CH₄. Reduction in GHG emission was mainly achieved by reducing CH₄ emission. The addition of FL, G, and FGL caused a clear shift in the abundance of dominant methanogens; particularly, the abundance of Methanobrevibacter decreased and that of Methanobacterium and Methanocella increased, which was correlated with CH₄ emissions. Meanwhile, the changes in moisture content, NH₄⁺-N content, and pH level also played an important role in the reduction of GHG emission. Based on the effects of nitrogen conservation, fertilizer efficiency improvement, and GHG emission reduction, we conclude that G and FGL are more beneficial than F or FL and suggest these additives for efficient chicken manure composting.

In this study, the growth and high-valued products accumulation characteristics of three common high-valued microalgae (Chlorella sp. HQ, Scenedesmus sp. LX1, and Chlorella vulgaris) in saline-alkali leachate were compared to select the species with greatest utilization potential. The results showed that after 28 days of cultivation, among three microalgae, Chlorella sp. HQ grew best with its maximum density at peak of 1.16 × 10⁷ cells mL⁻¹ and lipid production per unit cell (0.047 ± 0.006 × 10⁻⁷ mg cell⁻¹) and lipid content (18.18 ± 3.14%) were largest. The triacylglycerol (TAG) yield and content of Scenedesmus sp. LX1 were the highest, reaching 0.005 ± 0.000 × 10⁻⁷ mg cell⁻¹ and 19.74 ± 2.53%, respectively, which was slightly higher than those of Chlorella sp. HQ. According to comprehensive comparison, Chlorella sp. HQ was most suitable to grow in the saline-alkali leachate in terms of algal density, lipid yield, and content. The potential comparison and effects of salinity on the high-valued products accumulation of Chlorella sp. HQ compared with those in SE standard medium, reclaimed water, and tap water were further carried out. It was found that the density order of Chlorella was saline-alkali leachate > SE medium > reclaimed water > tap water. And the Chlorella density in the leachate with a salinity of 0.14% was greater than the other three salinities (0.32%, 0.45%, and 0.6%) at the end of cultivation. While the maximum lipid yield per unit cell and lipid content of Chlorella occurred in the salinity of 0.6%, which indicated that high salinity promoted the accumulation of lipid. Furthermore, other high-valued products (including starch, protein, total sugar, and photosynthetic pigments) accumulation characteristics were analyzed and found that they were all superior than those in SE medium. And with the salinity decreased, the microalgal protein and starch contents decreased. The contents of photosynthetic pigment and total sugar reached a maximum at salinities of 0.32% and 0.45%, respectively.

The alkaline nature of biochar provides a potential for soil arsenic (As) mobilization and, hence, enhancing efficiency of As phytoextraction by combining with As hyperaccumulator. To testify the feasibility and potential risk of the above strategy, biochar effect on As transfer in a paddy soil and accumulation in P. vittata was investigated in a pot experiment. By leaching soil (total As concentration 141.17 mg/kg) with simulated acid rain (pH 4.2), As the concentration in leaching eluate increased proportionally with increasing biochar ratio. Coincident with elevated soil As mobility, apparent enhancement in As uptake and translocation in P. vittata was determined with 1–5% biochar amendment after 40 days of plant growth. Furthermore, diffusive gradients in thin film (DGT) technique were employed to characterize any potential risk in vertical downward migration of As at 2-mm resolution. A significantly increasing profile of DGT-As ranging from on average 20 μg/L in CK to 50–100 μg/L in 1–3% biochar treatments was recorded over 0–60 mm depth, with 25–71% lower labile As in the rhizosphere than non-rhizosphere zone with few exceptions. As compared to Chinese quality standard for groundwater (Class IV 50 μg/L), biochar ratio at ≤ 1% was suggested for local water safety while actual application should take the physicochemical characteristic of tested soil into account. Our results demonstrated the biochar-assisted P. vittata phytoremediation can serve as an emerging pathway to enhance efficiency of soil As phytoextraction. The combination of DGT techniques and greenhouse assay provided a powerful tool for evaluating the gradient distribution of heavy metal in rhizosphere and accessing corresponding ecological risk at more precise scale.

Based on the compartment and exponential models, the distribution of Fukushima-derived ¹³⁷Cs was evaluated at four sampling dates in undisturbed coniferous forest soil. The compartment model was employed to evaluate the dynamic of ¹³⁷Cs in the three sub-sections of the forest floor (FF), namely undergrowth (UG), litter layer (OL), and fragmented litter layer (OF), while the exponential model was administrated to describe its distribution below the FF. According to the compartment model, the derived ecological half-life of ¹³⁷Cs in the UG, OL, and OF layers was 0.97, 1.1, and 4.9 years, respectively, indicating ¹³⁷Cs resides much longer in the OF layer. Hence, this soil section remains a potential source of radiation dose mainly due to its high ¹³⁷Cs content associated with low attenuation effect. Below the OF layer, the ¹³⁷Cs distribution was well described by exponential model and its derived relaxation lengths were in the range of 0.8–1.4 cm, implying the migration of ¹³⁷Cs in mineral soil is very slow and almost intact during the observation time. Collectively, our results highlighted that the compartment model for the FF and the exponential model for the soil below the FF are adequate enough to generate essential information. Thus, the potential decontamination measures should have to be chosen on their effect on the FF’s ¹³⁷Cs. Graphical abstract

Ammoniacal nitrogen is considered as one of the major pollutants of the leachate generated from the landfill site and has the potential to deteriorate the environment as well as health. Considering this, locally available agricultural waste, i.e., sugarcane bagasse ash, was employed as an adsorbent for the removal of ammoniacal nitrogen from landfill leachate. Batch-mode experiments were conducted to see the effect of dose (2–60 g L⁻¹), pH (2–12), and temperature (20–60 °C) on ammoniacal nitrogen adsorption. Application of sugarcane bagasse ash showed 60% removal of ammoniacal nitrogen (50 mg L⁻¹ strength) at an optimum dose of 20 g L⁻¹ and 180 min of contact time with an adsorption capacity of 0.31 mg g⁻¹. The Langmuir adsorption model was found to be best fit at 40 °C with R² = 0.944, depicting a monolayer coverage of ammoniacal nitrogen onto sugarcane bagasse ash. According to the result, solute uptake rate could be well described by the pseudo-second-order model (R² = 0.928), whereas the intraparticle diffusion model and Boyd plot indicated that the overall adsorption rate is governed by the external mass transfer. Thermodynamic studies revealed that adsorption is feasible, spontaneous, and endothermic in nature. Hence, the study shows that sugarcane bagasse ash could turn out to be a cost-effective adsorbent for the removal of ammoniacal nitrogen from leachate

Three sequential extraction procedures (SEPs), modified Tessier, modified BCR, and CIEMAT, were compared for mercury fractionation in polluted soils. With satisfactory total mercury recovery, the modified Tessier and modified BCR SEPs were comparable with each other in terms of extraction efficiency in equivalent mercury fractions, whereas both SEPs were not as efficient as the CIEMAT SEP. However, the CIEMAT SEP might underestimate the oxidizable mercury fractions due to the humic and fulvic complexes instead of the organic matter of the other two SEPs. For mercury bioavailability identification, based on Pearson correlation analysis, all fractions in each SEP were significantly correlated with mercury uptake in Ipomoea aquatica, causing difficulty in comparison. Partial correlation analysis indicated that the mobile mercury fractions extracted by the first step in all three SEPs had a positive correlation with mercury uptake by plant, while mercury bound to organic matter extracted by both modified Tessier and modified BCR SEPs presented negative correlation with mercury uptake by plant which was in contrast to CIEMAT SEP. Meanwhile, clearly positive correlations between mercury fractions extracted by the former three steps of CIEMAT SEP and mercury uptake in Ipomoea aquatica were observed, demonstrating that CIEMAT SEP provided more accurate results related to Hg bioavailability than did the other two SEPs.