Agriculture-based climate change mitigation may occur through enhancing the carbon sink or through reducing greenhouse gases (GHGs) emissions from agricultural residue treatment, as open burning of agricultural residues produces millions of tons of GHGs and air pollutants annually worldwide. Charring slashed biomass, termed as slash-and-char, has been considered as a promising alternative to open burning in dealing with agricultural residues such as rice straw. Previous studies, however, focused on relatively sophisticated slash-and-char systems, which could not be practiced easily by smallholder farmers in developing countries. Here we introduce a simple slash-and-char system to mitigate the environmental problems associated with open burning of rice straw. This system could convert 30.7% of the initial carbon in rice straw into biochar, much higher than that retained in the ash generated by open burning (3.95%). It could also cut GHGs, particulate matters and polycyclic aromatic hydrocarbons (PAHs) emissions by 26.9%, 99.0% and 99.4%, respectively. If open burning of rice straw was replaced by the slash-and-char, the annual emissions of GHGs, particulate matters and PAHs in China would decrease by at least 15.4 Tg, 1.51 Tg and 1.27 Gg, correspondingly. This decrease is nearly twice the size of China's estimated forest C sink (8.81 Tg).

Sugars and n-alkanes are important organic constituents of atmospheric fine particulate matter (PM₂.₅). For better understanding their sources and seasonal variations in urban atmosphere, sugar compounds (anhydrosugars, sugars and sugar alcohols) and homologue n-alkanes (C₁₈–C₃₇) were studied in PM₂.₅ samples collected from September 2013 to July 2014 in Beijing, China. In general, all measured compounds showed the lowest levels in summer. Higher concentrations of sugar compounds and n-alkanes were observed in winter, probably due to elevated combustion emissions (e.g., coal, biofuel and agricultural residue burning) and stable meteorological conditions during heating season. Levoglucosan was the major sugar species in all seasons particularly in autumn and winter, highlighting the significant contribution of biomass burning to fine organic aerosols throughout the whole year especially in cold seasons. Plant waxes contributed to n-alkanes the most in late spring (54.5%) and the least in winter (11.6%); while fossil fuel combustion had the largest contribution in winter (385 ng m⁻³). The weak odd-carbon predominance of n-alkanes in wintertime aerosols also suggests fossil fuel combustion as the important source of organic aerosols in the heating season. Soil resuspension, fossil fuel combustion and biomass burning, and secondary sources are the main sources of OC in PM₂.₅ at Beijing. The seasonal variation in source contributions indicates that meteorological condition is a key factor in controlling PM₂.₅ levels. Furthermore, dust storms in spring can strongly enhance the atmospheric level of fine organic matter in Beijing.

Soil contamination with antibiotics and antibiotic resistant bacteria/genes (ARB/ARGs) has becoming an emerging environmental problem. Moreover, the mixed pollutants' transfer and accumulation from soil to tuberous vegetables has posed a great threat against food security and human health. In this work, the application of two absorbing materials (maize biochar and sulfate modified eggshell) was able to reduce the poisonous effect of soil antibiotics on potato root system by stimulate the dissipation of water-soluble antibiotics in soil; and also improve food quality by increasing potato starch, protein, fat, and vitamins. Meanwhile, both amendments could effectively decrease the classes and the accumulative abundance of ARB and ARGs (sulI, sulII, catI, catII, ermA, ermB) in the edible parts of potato. The lowest abundance of ARGs was detected in the biochar application treatment, with the accumulative ARG level of 8.9 × 10² and 7.2 × 10² copies mL⁻¹ in potato peel (sull + catI + ermA) and tuberous root (sulI), respectively. It is the first study to demonstrate the feasibility of biochar and eggshell derived from agricultural wastes as green absorbing materials to reduce soil antibiotic, ARB, and ARGs accumulation risk in tuberous vegetable.

The lotic habitats affected by trout farm waste are colonized with a particular invertebrate community of which chironomids are the most abundant group. However, there is little information available regarding how chironomid community structures respond to this type of pollution at the highest taxonomic resolution. Eight fish farms, together with their lotic systems as recipients, were used to test the variability of the chironomid community and its surrogates (taxonomic and functional metrics) across spatially arranged sampling sites to form a gradual decrease in the trout farm influence. The self organizing map (SOM) classified six different types of chironomid communities which were characteristic for both the control and affected habitats. The species indicator analyses listed 32 taxa as positive indicators of water pollution. The SOM and Kruskal-Wallis test revealed that the pattern of chironomid community structure obtained was mainly driven by six environmental parameters (Altitude, conductivity, distance from the outlet, hardness, HN₄-N, NO₃-N). Categorical principal components analysis (CATPCA) derived three models for each type of biotic metric, in which for diversity-, taxonomy- and functional feeding group-based metrics, the first two dimensions explained 55.2%, 58.3% and 55.4%, of the total variance respectively for 315 sampling sites. According to this analysis, the total number of taxa (S), abundance and the Shannon-Wiener index (H′) (as a diversity metric), as well as the proportion of Tanypodinae (as taxonomic group) and grazers/scraper (GRA) and gatherer collector (GAT)(as FFG metrics), were related to the outlet distance gradient, thus showing great potential to be used in the multimetric approach in bioassessment.

Rising prevalence of cardiovascular disease requires in-depth understanding of predisposing factors. Studies show an association between air pollution and CVD but this association is not well documented in southern Nigeria where the use of biomass fuels (BMF) for domestic purposes is prevalent.This study aimed to explore the association between household BMF use and blood pressure (BP) and carotid intima media thickness (CIMT) among rural-dwelling women.A cross-sectional study of 389 women aged 18 years and older. Questionnaires were used to obtain data on predominant fuel used and a brief medical history. Wood, charcoal and agricultural waste were classified as BMF while kerosene, bottled gas and electricity were classified as non-BMF. Blood pressure and CIMT were measured using standard protocols. Regression analysis was used to assess the relationship between fuel type and BP, CIMT, pre-hypertension and hypertension after adjusting for confounders.There was a significant difference in the mean (standard deviation) systolic BP (135.3, 26.7 mmHg vs 123.8, 22.6 mmHg; p < 0.01), diastolic BP (83.7, 18.5 mmHg vs 80.1, 13.8 mmHg; p = 0.043) and CIMT (0.63, 0.16 mm vs 0.56, 0.14 mm; p = 0.004) among BMF users compared to non-BMF users. In regression analysis, the use of BMF was significantly associated with 2.7 mmHg higher systolic BP (p = 0.040), 0.04 mm higher CIMT (p = 0.048) in addition to increased odds of pre-hypertension (OR 1.67 95% CI 1.56, 4.99, P = 0.035) but not hypertension (OR 1.23 95% CI 0.73, 2.07, P = 0.440).In this population, there was a significant association between BMF use and increased SBP, CIMT and pre-hypertension. This requires further exploration with a large-scale longitudinal study design because there are policy implications for countries like Nigeria where a large proportion of the population still rely on BMF for domestic energy.

The ability of the agricultural residue of Phragmites australis to serve as an absorbent material used to remove phenol from aqueous solutions in batch and continuous fixed-bed columns was investigated. Prepared adsorbents were characterized by SEM, FTIR, and pHpzc methods. The equilibrium adsorption (qe) of phenol was increased from 9.61 to 29.40 mg/g when the initial phenol concentrations increased from 50 to 150 mg/L. The max adsorption capacity of Phragmites australis was found to be 29.60 mg/g at 30 °C. In column studies, a higher flow rate, higher initial concentration of phenol, and shorter packing layer height increase the column adsorption capacity of phenol. In a batch and continuous fixed-bed column studies, the experiment data was evaluated by some classic models. Fitting degree between the experimental results shows that the pseudo-second-order adsorption kinetics and Langmuir model were the best. Thomas and Yoon-Nelson models were in good agreement with the experimental breakthrough curve data. Both batch and continuous investigation indicated that Phragmites australis could be used as a fine adsorbent to remove phenol and that the adsorption efficiency improved significantly in the column experiment.

Corncob is a kind of agricultural waste, mainly composed of cellulose and hemicellulose. In this study, anion adsorbent hyperbranched polyamide-modified corncob was synthesized by glutaraldehyde cross-linking, which has abundant terminal groups. Then, the effect of modification conditions for the adsorption of Cr (VI) onto modified material was studied. The structural characteristics and the functional properties of modified corncob (HPMC) were revealed by thermogravimetric analysis (TGA), scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). Experimental results show that the optimum modification conditions were as follows: oxidized corncob 1 g, glutaraldehyde 2.5 mL, hyperbranched polyamide 10 mL, and a reaction time of 4 h under 60 °C. The effect of reaction temperature (factor C) on the removal rate of HPMC for Cr (VI) was the largest and GA dosage was the least. The equilibrium adsorption capacity of modified corncob for Cr (VI) was 47.8 mg/g (pH = 2, initial Cr (VI) concentration 100 mg/L, dosage 2 g/L, 4.0 h). The content of functional groups (-NH₂) on the surface of modified materials was obviously increased, the surface became rougher, and the thermal stability was improved. The adsorption mechanism was mainly electrostatic gravitation and oxidation-reduction reaction between HPMC and Cr (VI).

This study reports on the feasibility of remediation of catechol- and resorcinol-contaminated water using low-cost sunflower seed hull activated carbon (SSHAC). Sunflower seed hull (SSH), an abundant agricultural waste in Malawi, was used as precursor to prepare highly porous activated carbon by physicochemical activation, with zinc chloride (ZnCl₂) as an activating agent. The activated carbon was characterized by FTIR, SEM-EDS, XRD and BET analyses. In this work, pertinent parameters that affect the adsorption efficiency—pH, initial adsorbate concentration, contact time, adsorbent dosage, and solution temperature—were investigated in batch mode. At the same experimental conditions, more catechol was adsorbed than resorcinol may be due to the compound’s affinity towards water and the position of the hydroxyl group on the benzene ring. A maximum equilibrium adsorption of 271 and 250 mg/g was obtained at pH 9.0 and pH 8.0 for catechol and resorcinol, respectively. The adsorption behaviour of both adsorbates (catechol and resorcinol) on SSHAC can be well described by Langmuir isotherm model and pseudo-second-order kinetic model. The value ∆G, ∆S and ∆H indicated spontaneous and endothermic adsorption process. The adsorption process was readily reversible allowing reusability of the adsorbate. This study’s outcome is value addition to this category of wastes for environmental protection.

Spent mushroom substrate (SMS) as an organic amendment to plant production has received increasing attention on soil phytoremediation. However, organic amendments are known to contribute to greenhouse gas (GHG) emission from soils. Castor oil plant has a high biomass production and phytoremediation potential for heavy metal-contaminated soils. In the present study, the roles of SMS on phytoremediation efficiency of castor oil plant (Ricinus communis L.) from cadmium (Cd) and nickel (Ni)-contaminated soils were investigated, and the impact of SMS application on methane emission from the contaminated soil were evaluated. Pot experiments with SMS-amended and unamended contaminated soils were conducted to investigate Cd and Ni accumulation in R. communis and CH₄ emission. After growing for 3 months in soils with the addition of Cd (10 mg/kg) and Ni (at rates of 200 and 600 mg/kg), the dry biomass and the concentrations of Cd and Ni in the R. communis were measured, and the mobility factors for Cd and Ni were calculated. To assess methane emission, CH₄ fluxes and potential rates of CH₄ production and oxidation were measured pre- and post-incubation. SMS addition significantly improved the growth of R. communis and gave 19.15~82.46% more dry weight as compared to the single plant cultivation in the contaminated soils. SMS also increased plant Cd uptake and the total amount of Cd accumulation in R. communis increased by 28.1–152.1%, respectively, in signal Cd treatment and Cd-Ni complexation treatment, as compared to the single plant cultivation. The high values of mobility factor for Cd in single plant cultivation and co-application of SMS and R. communis pointed to the potential of R. communis to the Cd mobilization from the contaminated soils. Moreover, the addition of SMS tended to stimulate CH₄ uptake that the average increases in CH₄ uptake rate were 3.84-fold (in controls) and 2.91-fold (in single Cd treated soils) by the co-application of SMS and R. communis as compared to the single plant cultivation. The results suggested that the application of SMS could improve the growth of R. communis in Cd and Ni-contaminated soil, enhance heavy metal bioaccumulation, and stimulate soil CH₄ uptake. Therefore, SMS might be useful for enhancing phytoremediation of heavy metals and mitigate CH₄ emission from the contaminated soil. In addition, results in the study implied that implementing carefully designed management strategies (e.g., application of organic residues) during contaminated soil remediation is a promising solution for agricultural waste management and soil phytoremediation.

Organic matter derived from living, or recently living plant and animal, which can be used as fuel is called as biomass. It includes wood and agricultural waste such as dead plant etc. In India, majority of population depends largely upon agriculture as their primary source of income. Following every harvest, a huge amount of biomass is generated. It is mostly discarded as “agro waste”; however, recently, several uses of biomass and its derivatives have been reported. Thermochemical processing of biomass in absence of oxygen produces biomass char and flue gases which are of economic importance. However, it is necessary to characterize the physical and chemical properties of these components so as to utilize their potential benefit to the fullest. In this study, six different biomass remains that include mustard plant, groundnut plant, cotton plant, wheat plant, pigeon peas, and groundnut shell were pyrolyzed at 650 °C, in vertical downdraft fixed-bed biomass reactor. The flue gases were characterized in detail by gas chromatography. X-ray fluorescence, proximate, and ultimate analyses were performed on all BMC (biomass char) samples, and properties such as porosity, particle density, bulk density, point of zero charge, surface pH, surface charges, water-absorption capacity, and BET surface area were determined. SEM and FTIR were also carried out on all BMC samples. Our results showed that the surface area of biomass char varies from 38 to 138 m²/g. The solution pH for all BMC exceeds 8.6, thus confirmed the alkaline nature. Comparison between combustion products produced in the presence (biomass ash) and absence of oxygen (biomass char) is presented. BMC finds applications in agriculture, soil neutralizer, adsorbent, and soil additive. They have high amount of carbon and can act as a rich carbon source for the soil. Flue gases released contain methane and hydrogen which can also improve economic value for the char formation process.