In this study, palm oil mill sludge was used as a precursor to prepare biochar using conventional pyrolysis. Palm oil mill sludge biochar (POSB) was prepared at different preparation variables, i.e., heating temperature (300–800 °C), heating rate (10–20 °C/min) and holding time (60–120 min). The prepared biochars were tested for sulfur dioxide (SO₂) adsorption in a fixed bed reactor using 300 ppm of SO₂ gas at 300 ml/min (with N₂ gas as balance). Response surface central composite experimental design was used to optimize the production of biochar versus SO₂ removal. A quadratic model was developed in order to correlate the effect of variable parameters on the optimum adsorption capacity of SO₂ gas. The experimental values and the predicted results of the model were found to show satisfactory agreement. The optimum conditions for biochar preparation to yield the best SO₂ removal was found to be at 405 °C of heating temperature, 20 °C/min of heating rate and 88 min of holding time. At these conditions, the average yield of biochar and adsorption capacity for SO₂ gas was reported as 54.25 g and 9.75 mg/g, respectively. The structure of biochar and their roles in SO₂ adsorption were investigated by surface area, morphology images, infrared spectra, and proximate analysis, respectively. The characterization findings suggested that POSB adsorbs SO₂ mainly by the functional groups.

The soil ecosystem is critical for agricultural production, affecting many aspects of human health. Soil has more unknown biodiversity and edaphic parameters than any other ecosystem especially when polluted. Metagenomics and metatranscriptomics were applied to research on toxicological characteristics of Pb and resistance mechanism of flavonols. Rhizosphere microorganisms–plants system, a unified system closely related to soil environment was taken as research object. Results emphasize gene expression changes in different test groups. Gene ontology enrichment and eggNOG showed that Pb has a toxic effect on gene and protein function which concentrated on ATPase and ATP-dependent activity. Differentially expressed genes in the flavonols group indicated that flavonols regulate amino acid transport and other transportation process related to Pb stress. Kegg analysis represents that Pb interferences energy production process via not only the upstream like glycolysis and tricarboxylic acid (TCA) circle but also oxidative phosphorylation process, which can also produce reactive oxygen species and impact the eliminating process. Flavonols have shown the ability in alleviating toxic effect of Pb and improving the resistance of plants. Flavonols can recover the electronic transmission and other process in TCA and oxidative phosphorylation via ascorbic acid-glutathione metabolism. Flavonols activated antioxidative process and non-specific immunity via vitamins B₂–B₆ metabolism.

The anaerobic digestion of food waste (FW) often leads to acidification inhibition owing to rapid biodegradation, resulting in system instability. In this study, distillers’ grains (DG) and food waste were mixed in accordance with volatile solid (VS) ratios of 0.9:0.1, 0.85:0.15, 0.8:0.2, and 0.7:0.3. The experimental groups adopted yeast to conduct ethanol pre-fermentation and then inoculated sludge to perform anaerobic digestion, while the control groups conducted anaerobic digestion without pre-treatment. Results showed that the experimental groups had lower propionic acid concentrations; higher alkalinities, pH values and methane production rates and shorter stagnation periods than the control groups regardless of the mixing ratio. Specifically, at the DG/FW ratio of 0.7:0.3, compared with the control group, the propionic acid concentration was reduced by 59.6%, the alkalinity was increased by 41.7%. Even under high organic loading, the propionic acid and VFA did not accumulate in the system after ethanol pre-fermentation, and the anaerobic digestion system remained stable. At DG/FW ratios of 0.9:0.1 and 0.85:0.15, a synergistic effect was observed during the co-digestion of DG and FW. And, the synergistic effect of EP was relatively high, especially when the DG/FW ratio was 0.9:0.1, and methane yield increased by 26.8%.

In arid and semiarid areas, which are characterized by fragile ecological systems, deforestation and tillage have resulted in a net loss of soil carbon to the atmosphere. Vegetation restoration has great potential to alter the soil carbon stock. Exploring sustainable vegetation restoration for carbon sequestration in soils requires adequate information on soil carbon and soil water. The vertical distribution of soil organic/inorganic carbon (SOC/SIC) and soil water in the 0–200 cm soil depth under cropland, forestland, shrubland, and grassland with restoration age (0–30 years) in Zhifanggou watershed on the Chinese Loess Plateau were investigated. The results showed that after 10 years vegetation restoration, SOC content at topsoil in forestland, shrubland, and grassland increased significantly, and SIC content at subsoil in shrubland and grassland increased significantly due to more pedogenic carbonate formed by Ca²⁺ derived from the decomposed litter and biogenic CO₂. The absolute values of the slopes of the linear regression patterns between SOC and SIC were in the order grassland > forestland and shrubland and indicate that under the grassland the increment in SIC is larger per unit decrement in SOC. After 20 years vegetation restoration, the soil water content under forestland and shrubland decreased to 4.74%–6.16 and 4.08%–5.21% which are close to the wilting coefficient (5%) for the sandy loam soil in Zhifanggou watershed, resulting in the obstacle to sustainable land use. The conversion from cropland to natural grassland kept the relatively high level of soil water and may be the sustainable vegetation restoration approach to increase soil carbon.

Mosquito-borne diseases lead to serious public health concerns in tropical and sub-tropical countries worldwide, due to development of mosquito resistance to synthetic pesticides, non-target effects of pesticides, and socioeconomic reasons. Currently, green nanotechnology is a promising research field, showing a wide range of potential applications in vector control programs. The employ of natural products as reducing agents to fabricate insecticidal nanocomposites is gaining research attention worldwide, due to low costs and high effectiveness. Interestingly, biophysical features of green-synthesized nanoparticles strongly differ when different botanicals are employed for nanosynthesis. In this study, a cheap Acacia caesia leaf extract was employed to fabricate silver nanoparticles (Ag NPs) with ovicidal, larvicidal, and adulticidal toxicity against three mosquito vectors, Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus. Ag NPs were analyzed by various biophysical methods, including spectroscopy (UV-visible spectrophotometry, XRD, FTIR, EDX) and microscopy (SEM, TEM, AFM) techniques. High acute larvicidal potential was observed against larvae of An. subpictus (LC₅₀ = 10.33 μg/ml), Ae. albopictus (LC₅₀ = 11.32 μg/ml), and Cx. tritaeniorhynchus (LC₅₀ = 12.35 μg/ml). Ag NPs completely inhibited egg hatchability on three vectors at 60, 75, and 90 μg/ml, respectively. In adulticidal assays, LD₅₀ values were 18.66, 20.94, and 22.63 μg/ml. If compared to mosquito larvae, Ag NPs were safer to three non-target aquatic biocontrol agents, with LC₅₀ ranging from 684 to 2245 μg/ml. Overall, our study highlights the potential of A. caesia as an abundant and cheap bioresource to fabricate biogenic Ag NPs effective against mosquito young instars and adults, with moderate impact on non-target aquatic biocontrol agents.

Radiocarbon (¹⁴C) is the most accurate tracer available for quantifying atmospheric CO₂ derived from fossil fuel (CO₂ff), but it is expensive and time-consuming to measure. Here, we used common hourly Air Quality Index (AQI) pollutants (AQI, PM₂.₅, PM₁₀, and CO) to indirectly trace diurnal CO₂ff variations during certain days at the urban sites in Beijing and Xiamen, China, based on linear relationships between AQI pollutants and CO₂ff traced by ¹⁴C ([Formula: see text]) for semimonthly samples obtained in 2014. We validated these indirectly traced CO₂ff (CO₂ff₋ᵢₙ) concentrations against [Formula: see text] concentrations traced by simultaneous diurnal ¹⁴CO₂ observations. Significant (p < 0.05) strong correlations were observed between each of the separate AQI pollutants and [Formula: see text] for the semimonthly samples. Diurnal variations in CO₂ff traced by each of the AQI pollutants generally showed similar trends to those of [Formula: see text], with high agreement at the sampling site in Beijing and relatively poor agreement at the sampling site in Xiamen. AQI pollutant tracers showed high normalized root-mean-square (NRMS) errors for the summer diurnal samples due to low [Formula: see text] concentrations. After the removal of these summer samples, the NRMS errors for AQI pollutant tracers were in the range of 31.6–64.2%. CO generally showed a high agreement and low NRMS errors among these indirect tracers. Based on these linear relationships, monthly CO₂ff averages at the sampling sites in Beijing and Xiamen were traced using CO concentration as a tracer. The monthly CO₂ff averages at the Beijing site showed a shallow U-type variation. These results indicate that CO can be used to trace CO₂ff variations in Chinese cities with CO₂ff concentrations above 5 ppm.

The interactions between antibiotics and microorganisms have attracted enormous research attentions. In this study, we investigated the effects of two typical aminoglycoside antibiotics on the aggregation of the model cyanobacterium, Synechococcus elongatus, and the dominating strain in algal blooms, Microcystis aeruginosa, via the analysis of zeta potentials, hydrophobicity, and extracellular polymeric substances (EPS) secretion. The results showed that low-level antibiotics promoted the aggregation of S. elongatus and M. aeruginosa by 40 and 18% under 0.10 and 0.02 μg/mL of kanamycin, respectively, which was mainly attributed to the combined effects of increased zeta potentials and the ratio between extracellular proteins and polysaccharides. Tobramycin exerted similar effects. Additionally, we discovered that at low pH (pH 5) and ionic strength (1 mM Na⁺ and 2 mM Mg²⁺), the inducing effects of antibiotics would be even larger than those with higher pH and ionic strength. As aggregation is important to cyanobacteria in either the basic physiology of biofilm formation or the algal bloom, our study demonstrated that low-level antibiotics exert ecological impacts via interfered aggregation. We believe this study will shed light on the mechanisms underlying antibiotic-induced biofilm formation and help with the evaluation of the environmental and ecological risks of antibiotics and other emerging pollutants.

Effects on soil Collembola of Cu, Zn, Pb, and Cd pollution from Cu smelters over 40 years were investigated in paddy fields from an area of Eastern China. We compared the field effects to those observed in single-species laboratory tests employing the hemiedaphic collembolan Folsomia candida and the epedaphic Sinella curviseta obtained from laboratory cultures and exposed to field-collected polluted soil. The results indicated that different collembolan species responded differently to the pollution in the fields and could be divided into sensitive, indifferent, and tolerant types accordingly. The abundance of sensitive species decreased as the pollution increased, but this was not the same for indifferent and tolerant species. The dominant species changed from sensitive to tolerant species as the pollution increased. The reproduction of F. candida and S. curviseta was most sensitive to the contaminated soil compared to growth and survival; the sensitivity of the two species was similar. The growth was more sensitive than the survival for F. candida but not for S. curviseta. The growth and survival of F. candida were much more sensitive than those of S. curviseta. Sensitivity of field populations of F. candida (EC₁₀ 31 [15–46]) and hemiedaphic species Folsomia quadrioculata (EC₁₀ 52 [0.7–102]) were comparable with sensitivity of the reproduction of F. candida in the single-species tests (EC₁₀ 21 [14–27]), suggesting that single-species test based on laboratory cultures and field soil could be used to link laboratory and field data and then reflect the field situation. S. curviseta could be used as an epedaphic species in single-species tests and F. quadrioculata as an indicator species for assessment of field effect.

Cadmium (Cd) may be toxic to aquatic plants even at modest concentrations, and excessive quantities of zinc (Zn) decrease plant performance. The Cd and Zn phytoremediation potential of several aquatic plant species (Thalia geniculate, Cyperus alternifolius, Canna indica, Eichhornia crassipes, Pistia stratiotes) and one grass species (Vetiveria zizanioides) was evaluated in hydroponic experiments. Vetiveria zizanioides, E. crassipes, and P. stratiotes experienced reduced growth performance in the presence of Cd as determined from biomass production, survival rate, and crown root number (CN); however, they accumulated high quantities of metals in their tissues, particularly in roots. Root accumulation is considered a key characteristic of so-called excluder species. In this study, only E. crassipes and P. stratiotes had bioconcentration factors and translocation factors (> 1000 and < 1, respectively) suitable for high phytostabilization of Cd. Furthermore, V. zizanioides and P. stratiotes showed the highest percent metal uptake from solution and removal capacity for Zn (~70% and ~2 mg d⁻¹ g⁻¹, respectively). Emergent aquatic species (particularly C. alternifolius and T. geniculate) adapted and lived well in Cd- and Zn-contaminated solution and took up high quantities of Cd and Zn in roots, and are therefore considered strong excluders. Beneficial uses of such species in contaminated wetlands include stabilizing toxic metals and limiting erosion. Plant tissue can be applied to other uses, including as a biomass fuel. In field situations, the candidate species may work best when grown together, since each plant genotype possesses a different potential to control Cd and Zn.

Cadmium (Cd) accumulation and internal Cd translocation in the peanut (Arachis hypogaea L.) are highly related to root uptake, which may largely depend on the cultivar variation and the depth of the Cd-contaminated soil. A split-column soil experiment was conducted using two common Chinese peanut cultivars (Huayu-20 and Huayu-23) known to relocate Cd to different tissues. The growth medium was separated into four layers and Cd solution was solely applied to one layer to determine the key depth affecting the Cd accumulation in a plant via root uptakes. The results showed that the biomass of Huayu-23 was significantly higher biomass (3.28–94.0%) than that of Huayu-20, especially in the aerial parts (stems and leaves) and kernels, implying the dilution of Cd. Following the addition of Cd to the soil, the Cd concentrations in peanut tissues increased on average by 28.9–172 and 28.3–111% in Huayu-20 and Huayu-23, respectively. The largest presence of Cd in a peanut plant was observed in the aerial parts, followed by the kernels. Huayu-20 accumulated more Cd in plant tissues than did Huayu-23 due to the former’s high Cd translocation. These findings imply that peanut cultivars vary widely in biomass, Cd accumulation, and the percentage distribution of Cd among various plant tissues, especially kernels. Different Cd treatments in the full depth of the root zone induced significant alterations in Cd accumulation of peanut tissues, especially kernels, for both cultivars. The percentage distribution of Cd accumulation by kernels was significantly higher in the deeper layer than in the top layer of the root zone for both peanut cultivars. This study suggests that soil modifications performed during agronomic activities should take into account the full depth of root exploration as well as the peanut cultivars to manage plant Cd uptake.