Amount Of Residues Research Articles

Analysis of Antibiotics in Milk from Smallholder Farmers from Kenya Shows Traces Above the Recommended Maximum Residue Limits

Antimicrobial resistance (AMR) is rising globally and is likely to cause more deaths because of antibiotic-resistant microbial infections and antibiotic residues in animal foods and products as a result of misuse of antibiotics in dairying. Thus, we determined the presence and quantities of sulfonamide, tetracycline, and beta-lactam drug residues in milk sampled in Nyandarua, Meru, and Kiambu counties in Kenya using the Charm TRIO® test kit and liquid chromatography (LC) coupled to the triple quadrupole mass spectroscopy (MS) (LC-MS/MS). The TRIO® test kit showed dicloxacillin as the most prevalent at 9.3%, followed by penicillin and cloxacillin at 3.7% each, and nafcillin at 0.9% among the beta-lactams. Among the tetracyclines, demeclocycline and tigecycline were the most prevalent at 10.3% each, followed by oxytetracycline at 9.3%, chlortetracycline at 7.5%, and doxycycline at 3.7%, while sulfaquinoxaline was the only sulfonamide drug detected at 4%. The LC-MS/MS detected the presence of all the tested β-lactam and tetracycline antimicrobial traces and all sulfonamide drugs except sulfamerazine in all three counties. All the tetracycline antibiotics recorded between 3 and 10.5% of antibiotic residues above the recommended Maximum Residue Levels (MRLs) in milk across all three counties, with beta-lactam antibiotics recording between 2 and 33.3%, indicating their misuse in the three counties. Sulfaquinoxaline was the only sulfonamide detected in milk samples above the recommended MRLs, indicating sulfonamides are less used in those counties. Therefore, it is important to enforce a regulatory framework to control antibiotic use in livestock to minimize potential health risks related to their traces in the foods.

Crop management strategies shape the shared temporal dynamics of soil food web structure and functioning

In recent decades, there has been growing interest in exploring the soil biota, highlighting the significance of soil organisms' networks in soil functioning. Here, we use a modeling approach to investigate how changes in cropping practices influence the soil food web dynamics and it relates to that of soil functioning. In an experimental trial, we tested for change in topsoil food webs after shift from conventional to alternative practices (changes in tillage intensity, amount of residues returned and N fertilization rate). Samplings were made in 16 plots of a randomized complete block design during spring of year 0, 2 and 4 after the onset of the trial. Microorganisms, microfauna, mesofauna and macrofauna were sampled, identified and grouped into trophic groups. We built a general soil food web describing plausible carbon flows between these trophic groups and computed several network indices. At the same dates, soil functions linked to C and N dynamics were measured from soil samples. We used a COSTATIS analysis to investigate relationships between temporal sequences of soil functions and soil food web indices. Significant interactive effects of the date and of agricultural systems were found on the mean and the maximum trophic level, the bacterial-to-fungal path ratio, the total biomass and the way biomass accumulates across trophic levels, the number of trophic groups and the functional redundancy in trophic groups. Similarly, organic matter transformations and enzymatic activities showed differences across date and agricultural systems. Results show that temporal changes in soil food web structure and in soil processes related to N and C cycling co-vary following changes in agricultural management practices. Management practices related to tillage exerted stronger effects on soil food web functioning than those related to the export of crop residues or reduction in mineral N fertiliser. For instance, reduced tillage lead to more complex food webs, with increased C and N mineralization in the upper soil layer (0–5 cm), in which most of the residues accumulate. Our results provide insights on soil food webs temporal dynamics, even within a restricted panel of agricultural practices. Our results suggest that changes in agricultural practices influence feedbacks between organisms and the functions they perform, so that a temporal co-structure can be observed in the studied site. Such work could help better understand the mechanisms of resistance or ecological debt during agroecological transition, which could limit or delay expected Nature-based solutions.

Development of transcriptional factor-based whole-cell biosensors to monitor and degrade antibiotics using mutant cells obtained via adaptive laboratory evolution

With the widespread use of antibiotics and increasing environmental concerns regarding antibiotic abuse, the detection and degradation of antibiotic residues in various samples has become a pressing issue. Transcriptional factor (TF)-based whole-cell biosensors are low-cost, easy-to-use, and flexible tools for detecting chemicals and controlling bioprocesses. However, because of cytotoxicity caused by antibiotics, the application of such biosensors is limited in the presence of antibiotics. In this study, we used antibiotic-tolerant mutants obtained via adaptive laboratory evolution (ALE) to develop TF-based whole-cell biosensors for antibiotic monitoring and degradation. The biosensors had high performance and stability in detecting relatively high concentrations of tetracycline (Tc) and nisin. The ALE mutant-based Tc biosensor exhibited a 10-fold larger linear detection range than the wild-type strain-based biosensor. Then, the Tc biosensor was employed to detect residual amounts of Tc in mouse stool, serum, and urine samples and facilitate Tc biodegradation in mouse stool, demonstrating its high utility. Considering that ALE has been demonstrated to enhance cell tolerance to various toxic chemicals, our strategy might facilitate the development of whole-cell biosensors for most antibiotics and other toxic ligands.

Pilot findings on the real-world performance of xylazine test strips for drug residue testing and the importance of secondary testing methods

BackgroundXylazine is a sedative found increasingly in the illicit fentanyl supply that can cause hypotension, bradycardia, necrosis and death. This pilot examined the real-world performance of BTNX xylazine test strips (XTS) in drug residue samples. MethodsThis study was nested within a drug checking service in Rhode Island. We tested unmeasured drug residue dissolved in 5mL of distilled water using XTS and Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-QTOF-MS). Analyses compared XTS and LC-QTOF-MS results to calculate XTS detection of xylazine in residue. ResultsAmong 41 residue samples, xylazine was detected in 11% by the XTS and 44 % by the laboratory. The LC-QTOF-MS detected xylazine in 18 samples: 4 major, 9 minor, 5 trace by volume relative to the whole sample. The XTS disagreed with the LC-QTOF-MS by indicating a negative result in 77.8 % (N=14) of the samples but never indicated a positive when the LC-QTOF-MS reported xylazine’s absence. The XTS correctly detected xylazine 22 % of the time, however, this increased to 100 % of the time if xylazine was a major active component. ConclusionsIn this study, the BTNX XTS often disagreed with LC-QTOF-MS by indicating a negative result, likely due to the dilution levels used and sample composition. The XTS may not be accurate in detecting residual amounts of xylazine, especially if xylazine is not a dominant component of the tested sample. Given the novelty of BTNX’s XTS products, we recommend XTS only be used in conjunction with other advanced drug checking modalities for residue testing.

Study on Hydrothermal Arsenic Fixation in H3AsO4-FeSO4-Na2SO4-H2O System

In this study, hydrothermal metallurgy technology was used to convert arsenic in the solution into a stable, dense, and granular arsenic-fixing mineral, scorodite (FeAsO4·2H2O), that is conducive to storage. The effect of Na+ on the precipitation rate of arsenic and iron, the phase composition, and the transformation of arsenic residue during the mineralization and arsenic precipitation of hydrothermal scorodite in the H3AsO4-FeSO4-Na2SO4-H2O system were studied. The results show that Fe3+ co-precipitates with As5+ to form scorodite (FeAsO4·2H2O). In the later stage of the reaction, Fe3+ and Na+ combine to precipitate in the form of sodium jarosite [NaFe3(SO4)2(OH)6]. Under the conditions of an initial Na+ concentration of 10 g/L, an arsenic concentration of 10 g/L, a molar ratio of iron to arsenic of 1.5, a pH of 1, a reaction temperature of 160 °C, a stirring speed of 500 r/min, a reaction time of 3 h, and an oxygen partial pressure of 0.6 MPa, the precipitation rates of arsenic and iron were 98.2% and 93.2%, respectively. The phase composition of the arsenic residue is mainly composed of large-grained polyhedral crystal scorodite, and a small amount of irregular, small-grained crystal sodium jarosite is dispersed in it. By controlling the initial molar ratio of iron to arsenic, the concentration of Na+, and prolonging the reaction time, the formation of the sodium jarosite phase can be inhibited, and the transformation of the sodium jarosite phase into the scorodite phase can be promoted, so as to realize the efficient precipitation of arsenic, reduce the amount of arsenic residue, ensure the stability of arsenic residue, and avoid potential environmental pollution risks.

Rapid testing of antibiotic residues to increase food safety awareness of animal origin.

Antibiotics are used to improve growth, reduce disease, and decrease mortality in animals grown for food. The government regulates and prohibits the use of antibiotics, in particular, the use of antibiotic growth promoter (AGP) in livestock; however, it is not yet known whether the use of antibiotics is in accordance with regulations so that there are no antibiotic residues in food of animal origin. To ensure food safety of animal origin and to raise awareness of food safety, it is necessary to detect antibiotic residues in fish, eggs, and chicken meat from Yogyakarta Special Province through monitoring and monitoring. To ensure food safety and regulatory compliance in food samples, antibiotic residue screening techniques are essential. A number of methods, such as time-consuming and costly chromatographic and spectroscopic methods, have been developed for the detection of antibiotic residues in food samples; however, not all laboratories have these facilities. Therefore, a rapid diagnosis of food of animal origin is required. The purpose of this study was to rapidly test antibiotic residues by using Premi®test kits (R-Biopharm AG, Germany) to increase awareness of food safety of animal origin. We tested 345 animal-based food samples from traditional markets, supermarkets, and central markets in five districts of Yogyakarta Special Province for antibiotic residues using rapid test kits and observation questionnaires to identify risk factors. The presence of antibiotic residues in food-animal origin samples from the Yogyakarta region had an antibiotic residue level of 9.28% (32/345), consisting of fish samples 11.3% (18/97), eggs 15.65% (1/114), and chicken meat samples 0.87% (13/102). The highest percentage of samples positive for residual antibiotics was 21.9% (7/32) from supermarket meat samples. The highest amounts of antibiotic residues were found in fish samples collected from Sleman Regency, up to 25% (8/32), whereas in supermarket fish samples, there were as high as 18.8% (6/32). Antibiotic residues in animal-based food can be attributed to various factors, including product source, transportation conditions, and environmental conditions. The widespread distribution of antibiotic residues in fish comes from environmental conditions during maintenance, distribution, and retailing. Monitoring antibiotic residue prevalence in food-animal origins, particularly chicken meat, eggs, and fish, is crucial for improving animal food quality and safety.

Comprehensive investigation of undesired substances and microbial contamination in plant-based drinks

There is a growing market relevance of non-dairy alternatives mainly driven by issues concerning an increasing prevalence of vegetarianism, awareness of animal welfare and ecological impact of food production. Among the most popular plant-based drinks (PBDs) are almond-, oat- and soy-based products. As the likeliness of contamination of PBDs varies markedly depending on their plant origin, in a survey of selected most common organic-products from the German market mycotoxins, residues of plant protection products, heavy metals, and microbial contamination have been monitored. The results showed that, with one exception, all products were commercially sterile, free of pathogenic microorganisms and contained at most trace amounts of plant protection agent residues. For nickel especially, soy-based drinks showed elevated levels of up to 315 μg/kg and these products also had the highest cadmium levels of up to 7.2 μg/kg. Oat and almond based drinks contained up to 159 and 54 μg/kg Ni and 1.4 and 0.6 μg/kg Cd respectively. By contrast, for mycotoxins, the soy-based drinks showed almost no detectable contamination, while up to 2.1 μg/L T2+HT2-toxin and 5.5 μg/L deoxynivalenol were quantified in oat-based drinks and up to 130 ng/L aflatoxin B1 (AFB1) were found in almond-based drinks. Additionally, oat- as well as almond-based drinks frequently contained up to 263 ng/L and 70 ng/L of the emerging mycotoxin and AFB1 precursor sterigmatocystin.In particular, the mycotoxins in oat- and almond-based drinks and heavy metals in soy-based drinks should be further investigated and minimized, as PBDs represent a novel and additional source of the overall human exposure to these contaminants.

Effects of food waste biogas residue composting on soil aggregates and its organic matter content in relocation site

Understanding the effects of food waste biogas residue composting and chemical amendments on soil aggregates composition of different particle sizes, stability, and organic matter distribution in relocation sites could provide primary data for improving soil quality and land utilization of food waste biogas residue composting. We analyzed the characteristics of soil aggregates distribution, stability of aggregates, and organic matter content in different particle sizes under treatments with different application amounts of food waste biogas residue composting, chemical amendments (β-cyclodextrin, calcium sulfate and ferric oxide were mixed at a mass ratio of 1:1:1), and control (100% soil). The results showed that 20% (soil: biogas residue composting=8:2) and 30% (soil: biogas residue composting =7:3) biogas residue composting significantly decreased the micro-aggregates content with the particle size of <0.106 mm and increased the large aggregates content with the particle size of 0.5-1.0 mm. All treatments significantly increased large aggregates content with the particle size of ≥2.0 mm, soil aggregate structure content, and mean weight diameter, but reduced the percentage of aggregate destruction. Among all the treatments, the effect of mixes application of 20% biogas residue composting and chemical amendments was the best. Biogas residue composting treatments significantly affected the distribution of organic matter in soil aggregates, with the strongest effect under 30% biogas residue composting treatment. Biogas residue composting treatments significantly increased soil organic matter content in all aggregates, with the maximal increase of organic matter content in soil micro-aggregates with the particle size of 0.106-0.25 mm. In conclusion, biogas residue composting could increase organic matter content of soil aggregates in different particle sizes, promote the formation of large soil aggregates, and improve the stability of aggregation. Specifically, the mixed application of biogas residue composting and chemical amendments performed better on soil improvement in relocation site.

Safety evaluation of the food enzyme cellobiose phosphorylase from the genetically modified Escherichia coli strain LE1B109-pPB130.

The food enzyme cellobiose phosphorylase (cellobiose: phosphate α-d-glucosyltransferase; EC 2.4.1.20) is produced with the genetically modified Escherichia coli strain LE1B109-pPB130 by c-LEcta GmbH. The genetic modifications do not give rise to safety concerns. The food enzyme is considered free from viable cells of the production organism and its DNA. It is intended to be used in combination with a sucrose phosphorylase in the production of the specialty carbohydrate cellobiose. Since residual amounts of total organic solids are removed by downstream purification steps, the Panel considered that toxicological studies other than assessment of allergenicity were unnecessary and a dietary exposure was not estimated. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions upon dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of a food enzyme with phospholipase A1 and lysophospholipase activities from the genetically modified Aspergillus niger strain PLN.

The food enzyme with phospholipase A1 (phosphatidycholine 1-acylhydrolase, EC 3.1.1.32) and lysophospholipase (2-lysophosphatidylcholine acylhydrolase, EC 3.1.1.5) activities is produced with the genetically modified Aspergillus niger strain PLN by DSM. The genetic modifications do not give rise to safety concerns. The food enzyme is free from viable cells of the production organism and its DNA. It is intended to be used for the production of refined edible fats and oils by degumming. Since residual amounts of total organic solids are removed during this process, dietary exposure was not calculated and toxicological studies were considered unnecessary for the assessment of this food enzyme. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no matches were found. The Panel considered that the risk of allergic reactions upon dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.

Safety evaluation of the food enzyme α-amylase from the non-genetically modified Bacillus licheniformis strain AE-TA.

The food enzyme α-amylase (4-α-d-glucan glucanohydrolase; EC 3.2.1.1) is produced with the non-genetically modified microorganism Bacillus licheniformis strain AE-TA by Amano Enzyme Inc. The food enzyme is intended to be used in eight food manufacturing processes. Since residual amounts of food enzyme-total organic solids (TOS) are removed in two food manufacturing processes, dietary exposure was calculated only for the remaining six processes. It was estimated to be up to 0.056 mg TOS/kg body weight per day in European populations. The production strain of the food enzyme fulfils the requirements for the qualified presumption of safety approach to safety assessment. Consequently, in the absence of other concerns, the Panel considered that toxicological studies were not needed for the safety assessment of this food enzyme. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and two matches with respiratory allergens were found. The Panel considered that the risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded (except for the production of distilled alcohol), but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme inulinase from the non-genetically modified Aspergillus welwitschiae strain NZYM-KF.

The food enzyme inulinase (1-β-d-fructan fructanohydrolase; EC 3.2.1.7) is produced with the non-genetically modified Aspergillus welwitschiae strain NZYM-KF by Novozymes A/S. The food enzyme is free from viable cells of the production organism. It is intended to be used in the processing of fructo-polysaccharides for the production of fructo-oligosaccharides. Since residual amounts of total organic solids (TOS) are removed during the food manufacturing process, toxicological studies other than allergenicity were considered unnecessary and dietary exposure was not calculated. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and two matches with tomato allergens were found. The Panel considered that the risk of allergic reactions upon dietary exposure to this food enzyme, particularly in individuals sensitised to tomato, cannot be excluded, but is expected not to exceed that of tomato. As the prevalence of allergic reactions to tomato is low, also the likelihood of such reactions to occur to the food enzyme is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.

Safety evaluation of a food enzyme containing bacillolysin and subtilisin activities from the non-genetically modified Bacillus amyloliquefaciens strain AR-383.

The food enzyme with two declared activities, bacillolysin (EC 3.4.24.28) and subtilisin (EC 3.4.21.62), is produced with the non-genetically modified Bacillus amyloliquefaciens strain AR-383 by AB Enzymes GmbH. The food enzyme is intended to be used in nine food manufacturing processes. Since residual amounts of total organic solids (TOS) are removed in the production of distilled alcohol, dietary exposure was calculated only for the remaining eight food manufacturing processes. Exposure was estimated to be up to 1.958 mg TOS/kg body weight per day in European populations. As the production strain qualifies for the qualified presumption of safety approach to safety assessment and no issues of concern arising from the production process of the food enzyme were identified, the Panel considered that no toxicological studies other than the assessment of allergenicity were necessary. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made, and 30 matches were found, including one food allergen (melon). The Panel considered that, under the intended conditions of use, the risk of allergic reactions by dietary exposure to this food enzyme cannot be excluded, but for individuals sensitised to melon, this would not exceed the risk of consuming melon. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme sucrose phosphorylase from the genetically modified Escherichia coli strain LE1B109-pPB129.

The food enzyme sucrose phosphorylase (sucrose: phosphate α- d-glucosyltransferase; EC 2.4.1.7) is produced with the genetically modified Escherichia coli strain LE1B109-pPB129 by c-LEcta GmbH. The genetic modifications do not give rise to safety concerns. The food enzyme was free from viable cells of the production organism. It is intended to be used in combination with a cellobiose phosphorylase in the production of the specialty carbohydrate cellobiose. Since residual amounts of food enzyme-total organic solids are removed by the downstream purification steps, the Panel considered that toxicological studies other than assessment of allergenicity were unnecessary and a dietary exposure was not estimated. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that the risk of allergic reactions upon dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Investigating the potential of mineral precipitation in co-pyrolysis biochar: Development of a novel Cd (II) adsorption material utilizing dual solid waste

Ionic cadmium (Cd (II)) in water is a significant threat to ecosystems, the environment, and human health. Research is currently focused on developing efficient adsorption materials to combat Cd (II) pollution in water. One promising solution involves co-pyrolyzing solid residue from anaerobic digestion of food waste with oil-based drill cuttings pyrolysis residue to create a biochar with high organic matter content. This biochar has a lower heavy metal content and leaching toxicity compared to China's national standards, making it both safe and resourceful. It exhibits a high adsorption capacity for Cd (II) in water, reaching up to 47.80 ± 0.37 mg/g. Raising the pyrolysis temperature above 600 °C and increasing the amount of pyrolysis residue beyond 30 % enhances the biochar's adsorption capacity. The adsorption process is primarily driven by mineral precipitation, offering a promising approach for dual waste resource management and reducing heavy metal pollution.

Gliphosate and aminomethylphosphonic acid in the environment and their microbial transformation

Analysis of domestic and international literature indicates that the global use of glyphosate (GP), due to its effectiveness, low price and creation of herbicide-resistant agricultural crop varieties, resulted in nearly universal presence of the rest quantities of the herbicide and its main metabolite, aminomethylphosphonic acid (АМPA) in the environment: air, soil, water and crop products. Scientific information on glyphosate influence on the environment and living organisms is presented in this paper. The necessity is substantiated for periodic remediation for reducing the negative consequences of the repeated application of herbicide and detoxification of its residual quantities with the use of destructor-bacteria, capable of decomposing glyphosate and AMPA to ecologically safe compounds. The ways for glyphosate microbial transformation are reviewed. Ecologically safe detoxification assumes the use of bacterial destructors, which are destroying the phosphonic bond in glyphosate molecule. Although the bacteria of different genera are showing capacity for GP biodegradation, commercial products for the safe detoxification of glyphosate have not yet been developed due to the high level of strain specificity associated with the different ways of GF catabolism. The most perspective is the search for GP and AMPA destructors among rhizosphere bacteria, intended for application as inoculants. Complexity of the problem of GP and AMPA detoxification as well as the high level of strain specificity of bacterial destructors significantly restrain development of commercial preparations for GP and AMPA detoxification.

Impact of different decontamination methods on the reduction of spiromesifen residue in chilli fruits

Chilli is an indispensable food item in the daily life of humans but it is affected by many insects, so various pesticides, including spiromesifen, are applied to chilli crops to protect this crop from insect infestation. However, the use of pesticides poses environmental and health issues. These issues have raised the demand for pesticide-free chillies among consumers. The primary aim of this study was to assess the efficacy of various decontamination methods in removing spiromesifen residues from chilli fruits. A randomized block design was employed to conduct a supervised field experiment at the Rajasthan Agricultural Research Institute in Durgapura, Jaipur, India. The samples of chillies treated with pesticides are subjected to seven different homemade techniques. The samples were extracted using the QuEChERS method, known for its efficiency, affordability, simplicity, robustness, and safety. The analysis of spiromesifen residues was conducted using gas chromatography (GC) equipped with an electron capture detector (ECD), and the results were verified using gas chromatography-mass spectrometry (GC-MS). Out of several decontamination methods, the lukewarm water treatment was more effective than any other decontamination method, which led to the highest elimination of spiromesifen residue, whereas rinsing with tap water eliminates the least amount of spiromesifen residue. So, the lukewarm water treatment is a safe, cost-effective, and eco-friendly approach to remove spiromesifen residues from Chilli.

Valorisation of bread wastes via the bacterial cellulose production

AbstractThe short shelf life of bread can be attributed to changes in its textural and sensory properties, a process termed staling, and large amounts of bread residue and waste are generated daily. Because the main component of bread is starch, the use of bread wastes as a substrate for bacterial cellulose (BC) production can significantly contribute to valorisation and reuse of wastes. This study aimed to investigate the BC production potential of various stale breads, convert these wastes into usable forms for food and other industries, and increase their economic value. Stale breads were hydrolyzed with dilute acid, and BC-producing bacteria from Kombucha tea were isolated and identified as Gluconobacter oxydans MG2021 (GO). BCs were produced from bread hydrolysates with GO and Komagataeibacter hansenii GA2016 (KH), and their properties were examined. The results indicated that stale breads represented a good source for BC production, as high BC yields were obtained using GO (8.81%–25.02%) and all BCs had superior properties such as high crystallinity (75.96%–91.39%), thermal stability, liquid holding capacity, and fine fibers (40.16–85.39 nm). This study demonstrated that bread wastes could be used as a low-cost substrate for large-scale BC production, and the abundance of bread wastes demonstrated their potential as a resource for commercial BC producers.

Effects of biodegradable (PBAT/PLA) and conventional (LDPE) mulch film residues on bacterial communities and metabolic functions in different agricultural soils

Soil health is a crucial aspect of sustainable agriculture and food production, necessitating attention to the ecological risks associated with substantial amounts of mulch film residues. Biodegradable mulch films (BDMs) carry the same risk of mulch film residues formation as low-density polyethylene (LDPE) mulch films during actual use. More information is needed to elucidate the specific impacts of mulch film residues on the soil environment. Integrated 16S rRNA gene sequencing and non-targeted metabolomics, this study revealed the response patterns of bacterial communities, metabolites, and metabolic functions in the soil from three different agricultural regions to the presence of mulch film residues. LDPE mulch film residues negatively impacted the bacterial communities in the soils of Heilongjiang (HLJ) and Yunnan (YN) and had a lesser impact on the metabolic spectrum in the soils of HLJ, YN, and Xinjiang (XJ). BDM residues had a greater negative impact on all three soils in terms of both the bacterial communities and metabolites. The impact of BDM treatment on the soils of HLJ, YN, and XJ increased sequentially in that order. It is recommended that, when promoting the use of biodegradable mulch films, a fuller assessment should be made, accounting for local soil properties.

Innovative synthesis of low-carbon cemented backfill materials through synergistic activation of solid wastes: An integrated assessment of economic and environmental impacts

The accumulation of large amounts of steel slag (SS) and oil shale residue (OSR) causes serious pollution due to the lack of effective ways to utilize them. In this study, OSR, SS, and soda residue (SR) were used to synergistically prepare all-solid-waste low-carbon cemented backfill material (ALCCB). No cement and chemical additives were added to this material, and synergistic activation enabled full utilization of the solid wastes. The total solid waste utilization rate was 100 %. The mechanical characteristics of the ALCCB and the heavy metal leaching rates were determined. The unconfined compression strength of the ALCCB after 28 days was 5.97 MPa, while the slump was 205 mm. These results met the performance requirements for a filling material. The leaching rates for the heavy metals after 28 days conformed to the guidelines for Class III groundwater quality. The mechanism underlying synergistic hydration of the solid wastes was analyzed at the micro- and macroscale with X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP). The results indicated that hydration of the ALCCB occurred continuously during curing, and the faster early hydration reaction stabilized heavy metal curing at 7 d. In addition, ALCCB offers greater economic and environmental advantages than cementitious materials. Notably, the economic and environmental benefits of ALCCB were found to supersede those of cement-based materials, with a cost reduction of 42.6 % and a CO2 emission reduction of 86.9 %. This innovative low-carbon mine backfill material effectively promotes the utilization of solid waste resources and supports sustainable development.