Disposal Strategies Research Articles

Fed-in-situ biological reduction treatment of food waste via high-temperature-resistant oil degrading microbial consortium

This study aims to construct a high-temperature-resistant microbial consortium to effectively degrade oily food waste by Fed-in-situ biological reduction treatment (FBRT). Oil degrading bacteria were screened under thermophilic conditions of mineral salt medium with increased oil content. The oil degradation and emulsification ability of each stain was evaluated and their synergetic improvement was further confirmed. Consortium of Bacillus tequilensis, Bacillus licheniformis, Bacillus sonorensis and Ureibacillus thermosphaericus was selected and applicated as bacterial agents in FBRT under 55 °C. Changes in pH, moisture, bacterial community and key components of food waste were monitored for 5 days during processing. Facilitated by the bacterial consortium, FBRT gave superior total mass reduction (86.61 ± 0.58% vs. 67.25 ± 1.63%) and non-volatile solids reduction (65.91 ± 1.53% vs. 28.53 ± 2.29%) compared with negative control, the feasibility and efficiency of present FBRT providing a promising in-situ disposal strategy for rapid reduction of oily food waste.

Confidence gap or timid trust building? The role of trust in the evolution of the nuclear waste governance in Germany

Nuclear waste disposal represents one of the biggest socio-economic challenges of this century and probably for many centuries to come. It is a highly complex issue due to the interrelated technical, material, social, economic and political dimensions as well as the real or perceived risks involved. Distrust in technology, institutions, industry and even experts and decision-making processes are some of the reasons for opposition to nuclear waste disposal strategies. Our contribution analyses the dynamics of trust and distrust in Germany over the evolution of the search for a nuclear waste repository site in the last 40 years, identifies major turning points and explores the main factors that shaped trust/distrust relations over time. Site selection conflicts have often provoked ‘confidence gaps’ and site selection policies depend heavily on relationships based on mutual recognition and trust. We select key factors considered necessary to build trust in institutions and siting selection procedures and review recent changes in the institutional setting, including the establishment of a National Civil Society Board and the attempt to design more participatory procedures. Twenty-one stakeholders and experts were asked to rate some of the identified factors necessary for building trust and whether the measures carried out so far are sufficient to enhance trust in the relevant institutions and procedures and increase public confidence. Without a trust-building process for the siting, development and operation of a risky asset, a short-term attenuation of long-lasting conflicts is unlikely. The legacy of the past still plays an inhibiting role. In addition to expert judgement, evidence was derived from document analysis and participatory observation in the works of the German ‘Commission on the Storage of High-level Radioactive Waste’ and of the ‘National Civil Society Board’ as well as of events of regulator and operator.

Effect of eggshell- and homo-type Ni/Al2O3 catalysts on the pyrolysis of food waste under CO2 atmosphere

This study highlights the potential of pyrolysis of food waste (FW) with Ni-based catalysts under CO2 atmosphere as an environmentally benign disposal technique. FW was pyrolyzed with homo-type Ni/Al2O3 (Ni–HO) or eggshell-type Ni/Al2O3 (Ni-EG) catalysts under flowing CO2 (50 mL/min) at temperatures from 500 to 700 °C for 1 h. A higher gas yield (42.05 wt%) and a lower condensable yield (36.28 wt%) were achieved for catalytic pyrolysis with Ni-EG than with Ni–HO (34.94 wt% and 40.06 wt%, respectively). In particular, the maximum volumetric content of H2 (21.48%) and CO (28.43%) and the lowest content of C2–C4 (19.22%) were obtained using the Ni-EG. The formation of cyclic species (e.g., benzene derivatives) in bio-oil was also effectively suppressed (24.87%) when the Ni-EG catalyst and CO2 medium were concurrently utilized for the FW pyrolysis. Accordingly, the simultaneous use of the Ni-EG catalyst and CO2 contributed to altering the carbon distribution of the pyrolytic products from condensable species to value-added gaseous products by facilitating ring-opening reactions and free radical mechanisms. This study should suggest that CO2-assisted catalytic pyrolysis over the Ni-EG catalyst would be an eco-friendly and sustainable strategy for disposal of FW which also provides a clean and high-quality source of energy.

Carbon Footprint of Surgical Masks Made in Taranto to Prevent SARS-CoV-2 Diffusion: A Preliminary Assessment

The international outbreak of the SARS-CoV-2 infection has put pressure on governments to find immediate solutions to the shortage of surgical masks and other protective equipment. To allow textile manufacturers producing surgical masks to avoid usual restrictions imposed on personal-protective-equipment producers, the Italian government issued a ministerial decree that was followed by technical guidelines provided by several universities. Starting from a hypothetical composition and design, we calculated the carbon footprint of surgical masks manufactured following technical guidelines, with the city of Taranto hosting the production facility. Results show that the production of textile sheets composing the masks and their disposal were the main contributors to emissions, followed by packaging and transportation. A strategy of reuse based on laundry operation was modelled, and the balance between disposal strategy and reuse with the laundry operation (which has environmental issues due to detergents and water use) was in favor of the second option. To reduce the carbon footprint, a minimized textiles area (by smart shaping) and reuse strategies result in the best options. Further reduction may be achieved by building up a recycling chain of disposed masks, activated by municipalities.

Response of the yellow mealworm (Tenebrio molitor) gut microbiome to diet shifts during polystyrene and polyethylene biodegradation

Plastic biodegradation by mealworm is regarded as an emerging strategy for plastic disposal. In this study, the polystyrene (PS) and low density polyethylene (LDPE) degradation efficiency by yellow mealworms (Tenebrio molitor larvae) supplemented with bran and the effects of plastics on the gut core microbiome were explored to construct a circular and continuous reactor for plastic biodegradation in the future. The gut microbiome was also investigated with dietary shift to explore the relationship between specific diets and gut microbes. The bran plus plastic (7:1 ratio, w/w) co-diet contributed to the mealworm survival and growth. The formation of −C˭O−/−C−O− groups in the plastic-fed mealworms frass represented the oxidation process of plastic biodegradation in the mealworm gut. The changes in molecular weights (Mw, Mn and Mz) of residual PS and LDPE in mealworms frass compared with that of PS and PE feedstock confirmed the plastic depolymerization and biodegradation. Lactobacillus and Mucispirillum were significantly associated with PE + bran diet compared to bran diet and PE diet, representing the response of mealworm gut microbiome to the bran and plastic mixture was distinguished from either bran or plastics alone. The gut microbiome changed substantially with the diet shift, indicating that microbial community assembly was a stochastic process and diverse plastic-degrading bacteria might occur in the mealworm gut.

Impact of different organic amendments on: hydrodynamic soil properties and olive tree behavior conducted under deficit irrigation

ABSTRACT Current trends in the intensification of olive cultivation including irrigation have dictated a need to reconsider amendment management practices. The addition of organic wastes to agricultural soils is becoming a common practice as a disposal strategy and to improve the physical and chemical soil properties This study examines physiological varieties of young olive trees (Olea europaea L.) grown on deficit irrigation under four different amended soil. We evaluated the short-term effect of different amended soil under deficit irrigation on soil, plant water status, level of soil, and leaf Nitrogen. Water stress was considered to be insignificant or absent with an irrigation amount of 50% of daily evapotranspiration. Leaf relative water content was between 65 and 88% for the Chemlali cultivar, while that of the Koroneiki was between 60 and 70%. Under conditions of water stress, photosynthesis of trees planted in soil amended with biochar decreased from 8.5 to 1.5 μmol.CO2.m−2s−1, compared to the control for both cultivars.To conclude, amendment addition, used as a tool for sustainable agriculture, could improve plant growth, although soil fertility. The type and amount of amendment should receive special attention to be efficient.

Blood flows: mapping journeys of menstrual waste in Blantyre, Malawi

ABSTRACT The interplay between menstrual waste and urban sanitation infrastructure is largely hidden from view. Qualitative research has highlighted socio-cultural aspects of menstruation, but few quantitative studies have mapped the physical situation at scale. This study surveyed 258 women in Blantyre, Malawi about their menstrual absorbent choices, disposal practices, and socio-demographic characteristics. A Sankey diagram visualised flows of menstrual waste in the urban environment and identified ultimate disposal points. Most participants used either disposable pads and/or old cloth and disposed of them by either burning and/or throwing in pit latrines. Pad and cloth use were associated with age, education, employment, marital status, and household wealth. Younger women’s preference for disposable pads suggests that demographic shifts may cause volumes of menstrual waste to increase. However, differences in waste volume produced by disposable and reusable absorbents was less than previously assumed. The volume of menstrual waste discarded in pit latrines, and cultural barriers to disposing it elsewhere, highlights challenges for the pit emptying industry and faecal sludge value recovery sector, with the problem anticipated to be most acute in high-density settlements. Widening access to sustainable disposal strategies, affordable reusable menstrual products, and tackling stigma, are key to addressing this social and environmental challenge.

Desalination Concentrate Quantification and Management Through Multi-Stage Biomass Production: A Conceptual Framework for Further Research

Global population growth and climate change are adding pressure on conventional water sources to meet the rising demand. Reliance on unconventional water sources utilizing desalination technologies is increasing to ensure water security. A major economic and environmental challenge in the sustainable adoption of desalination is the hypersaline concentrate that is generated as a byproduct. Brine quantification estimation process and disposal strategies along with the associated costs are provided. Brine re-use for biomass production offers a promising solution to help mitigate the environmental and economic challenges related to brine disposal. Soil salinization is a key issue with the land application of brine impacting its sustainability and applicability in the long run. The paper proposes a methodology for multi-stage biomass production using desalination brine. Added advantage of the proposed methodology is the potential to manage soil salinization, adopt sustainable agricultural practices such as crop rotation and enhancing biodiversity through inclusion of marshlands and wetlands as part of the brine disposal strategy. The paper also proposes an experimental setup for lab scale experimentation and identifies research priorities and provides recommendations for further evaluation.

Rubberized geopolymer composites: Effect of filler surface treatment

Existing waste tire management strategies such as landfill, warehousing, incineration, and pyrolysis are associated with significant emissions of hazardous compounds including gases, heavy metals, and oils. A sustainable rubber waste disposal strategy is immobilizing them in a crushed form in eco-friendly geopolymer (GP) matrices. However, the implementation of this approach is constrained by the strength degradation of rubberized geopolymer composites. In order to solve this problem, this article includes a comparative investigation of the effect of various physical and chemical pre-treatments of tire crumb rubber (CR) with NaOH, H2SO4, (CH3)2CO and KMnO₄ solutions, as well as ultraviolet radiation, on the mechanical performances and microstructure of rubberized fly ash-based GP composites. It has been established that the best effects are demonstrated by treatment with an aqueous solution of potassium permanganate; oxidative reactions with the solution lead to the formation of surface-active functional groups on the rubber. As a result, there is more than a twofold increase in the hydrophilicity of CR particles, estimated from the mass of adsorbed water vapor (from 1.5 to 3.3 wt%). This provides a strong adhesive contact of the filler with the geopolymer matrix, which favorably affects the change in the mechanical properties of the composites. The compressive strength in this case has been increased from 12.8 MPa (GP/untreated CR composite) to 15.5 MPa at addition of 10.0 wt% KMnO4 treated CR. Further optimization of the composition and of the curing mode of the geopolymer binder can potentially provide an additional positive effect in this aspect.

Availability of heavy metals to cabbage grown in sewage sludge amended calcareous soils under greenhouse conditions

Compared to noncalcareous soils, data on the soil-to-plant transfer of heavy metals and their response to sewage sludge (SS) in calcareous soils with diverse properties are limited. Cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) transfer from soil to cabbage (Brassica oleracea L. var. capitata) under greenhouse conditions in 30 diverse soils amended with two types of sewage sludge (non-spiked and spiked with heavy metals) were investigated. Three transfer factors were calculated for heavy metals in three treated soils including control soils (CS), soils treated with non-spiked SS (NSS), and soils treated with spiked SS (PSS). The bio-concentration factor of heavy metals from soil to root (BCFRoots) in cabbage in three treatments was as follows: CS: Pb > Cu > Co > Zn > Ni; NSS: Pb > Co > Cu ≥ Zn > Ni; and PSS: Pb > Cd > Zn > Co > Cu > Ni. The same order was found for the bio-concentration factor of heavy metals from soil to shoots (BCFShoots) in PSS, and in CS and NSS treatments except that the position of Co, Cu, and Zn was changed. Based on the heavy metals translocation from plant roots to shoots, Cd, Cu, and Zn were the heavy metals that posed the highest risk due to the higher shoot content in all treatments, whereas Ni and Pb posed relatively lesser risk. Generally, the percentage of sand and silt in BCFRoots and BCFShoots was quite effective for Co, Ni, and Zn and it seems that soil texture is an important variable in heavy metals bioavailability. In conclusion, our findings highlight the significance of using SS to increase cabbage growth in soils contaminated with heavy metals. Furthermore, cabbage may be a good choice for phytoremediation of heavy metal-contaminated calcareous soils in terms of soil remediation. Novelty statement In recent years, sewage sludge production has increased as well as related waste disposal strategies because of the increasing population and growing demand for agricultural products. Sewage sludge utilization as a low-cost fertilizer has spread in some parts of Iran and the world. On the other hand, unnecessary and unproductive use of sewage sludge results in the accumulation of heavy metals in soils, adding them to food and the potential risk to human health. Currently, work on the transfer of heavy metals from soil to plant after soil treated with sewage sludge has focused on the bioavailability of heavy metals using specific extractants. The assessment of the transfer of heavy metals from soil to different parts of plants using sewage sludge has been less studied. In this study, the transfer of heavy metals (Cd, Co, Cu, Ni, Pb, and Zn) from several soils (30 soils samples) having diverse physical and chemical properties to the tissues of the cabbage plant in control soils, and two types of sewage sludge (nonspiked and spiked with heavy metals) were investigated. The novelty of this study is that the measured bio-concentration factor of heavy metals from soil to root and from soil to shoot and translocation of heavy metals from plant roots to shoots and correlations between these parameters and soil properties are reported for the first time in diverse calcareous soils.

Fabrication and characterization of keratin starch biocomposite film from chicken feather waste and ginger starch

The disposal of chicken feather through burning or burying is not environmentally compliant due to the accompanying release of greenhouse gas and underground water contamination. Thus, the transformation of this bio-waste into a bio-composite film is considered not only a sustainable strategy for disposal of this solid wastes but also an attractive alternative to developing an efficient nanostructured biomaterial from renewable bio resource. In the present study keratin extracted from chicken feather waste in combination with ginger starch were fabricated into a bio-composite film. The fabricated bio-composite films were characterized, using different analytical techniques. The physicochemical characteristics of ginger starch showed a moisture content of 33.8%, pH of 6.21, amylose and amylopectin contents of 39.1% and 60.9%, respectively. The hydration capacity of the starch was 132.2% while its gelatinization temperature was 65.7 °C. Physical attributes of the bio-composite film, such as surface smoothness and tensile strength increased significantly (p < 0.05) with increasing keratin content, while its transparency and solubility showed significant (p < 0.05) decrease with increasing keratin level. The various blends of the bio-composite films decayed by over 50% of the original mass after 12 days of complete burial in soil. Based on the results obtained in this study, the addition of keratin to starch bio-composite showed remarkable improvement in mechanical properties, such as tensile strength and surface smoothness. The bio-composite film exhibited appropriate stability in water, although future study should be carried out to evaluate its thermal stability. Nonetheless, the fabricated keratin-starch bio-composite showed desirable characteristics that could be optimized for industrial applications.

Opportunities for improving opioid disposal practices in the Veterans Health Administration.

DisclaimerIn an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.PurposeThe potentially vast supply of unused opioids in Americans’ homes has long been a public health concern. We conducted a needs assessment of how Veterans Affairs (VA) facilities address and manage disposal of unused opioid medications to identify opportunities for improvement.MethodsWe used rapid qualitative content analysis methods with team consensus to synthesize findings. Data were collected in 2 waves: (1) semistructured interviews with 19 providers in October 2019 and (2) structured questions to 21 providers in March to April of 2020 addressing how coronavirus disease 2019 (COVID-19) changed disposal priorities.ResultsWhile many diverse strategies have been tried in the VA, we found limited standardization of advice on opioid disposal and practices nationally. Providers offered the following recommendations: target specific patient scenarios for enhanced disposal efforts, emphasize mail-back envelopes, keep recommendations to providers and patients consistent and reinforce existing guidance, explore virtual modalities to monitor disposal activity, prioritize access to viable disposal strategies, and transition from pull to push communication. These themes were identified in the fall of 2019 and remained salient in the context of the COVID-19 pandemic.ConclusionA centralized VA national approach could include proactive communication with patients and providers, interventions tailored to specific settings and populations, and facilitated access to disposal options. All of the above strategies are feasible in the context of an extended period of social distancing.

Reprocessing vs direct disposal of used nuclear fuels: The environmental impacts of future scenarios for the UK

The UK recently switched from a “nominal” twice-through cycle - whereby used nuclear fuels were reprocessed, but uranium and plutonium were not routinely reintroduced in the fuel cycle – to a once-through cycle, where used nuclear fuels are stored pending disposal. However, it is also the current strategy to keep other options open, including a twice-through cycle based on a different chemical separation process from the conventional PUREX. This article presents a comprehensive Life Cycle Assessment study of future scenarios for the back-end of the UK nuclear fuel cycle that aims at informing policy- and decision-makers. The study considers the direct disposal approach and four reprocessing scenarios envisaging different strategies for disposal and/or reuse of reprocessed uranium and plutonium, and adopts a consequential approach including only short-term effects. These primarily represent reductions in demand for uranium mining due to recycling of uranium and plutonium, and are modelled upon identification of a marginal technology. Several marginal technologies are explored because of the uncertainty regarding the actual response of the market. Results of the study show that recycling of uranium, but especially of plutonium is of paramount importance because of the avoided burdens associated with production of nuclear fuel from mined uranium. The reprocessing scenarios envisaging reprocessing of used nuclear fuels and recycling of both plutonium and uranium represent the most favourable options. The direct disposal approach may be advantageous only in terms of radiological impacts depending on the marginal technology chosen.

Efficient stabilization of arsenic in the arsenic-bearing lime-ferrate sludge by zero valent iron-enhanced hydrothermal treatment

• A new ZVI-enhanced hydrothermal method for effective arsenic stabilization. • Unstable arsenic was converted into well-crystallized lattice incorporated in Johnbaumite. • The hydrothermal treatment is necessary for the formation of Johnbaumite. Arsenic-bearing lime-ferrate sludge (ABLFS) is a common hazardous waste from nonferrous metallurgical industry. The leaching of arsenic from ABLFS during waste storage and disposal causes serious environmental pollution. In this study, a new method was developed to effectively stabilize arsenic in ABLFS by treating ABLFS with combined zero valent iron (ZVI) and hydrothermal treatment. The treatment converted the unstable arsenic adsorbed or complexed on ferrihydrite into well-crystallized lattice form in a highly stable natural mineral, Johnbaumite. When treated under the optimum conditions (ZVI dosage = 0.1 g/g-sludge, hydrothermal treatment at 150 °C for 12 h), the leachable arsenic concentration was decreased from 22.4 mg/L for untreated ABLFS to 0.015 mg/L, which is far below the Chinese regulatory level of 2.5 mg/L. XRD, FTIR, and TEM analyses were carried out to understand the phase evolution and the underlying arsenic stabilization mechanism. The results revealed three key steps: (i) ZVI-mediated reaction with arsenic-laden 2-line ferrihydrite (Fh) leading to the release of arsenate ions, (ii) hydrothermally facilitated phase transformation of gypsum causing the release of calcium ions, and (iii) hydrothermally enabled formation and crystal growth of Johnbaumite. This work provides a promising treatment strategy for the safe disposal of ABLFS.

Transmission of SARS-Cov-2 and other enveloped viruses to the environment through protective gear: a brief review

Over the past two decades, several deadly viral epidemics have emerged, which have placed humanity in danger. Previous investigations have suggested that viral diseases can spread through contaminants or contaminated surfaces. The transmission of viruses via polluted surfaces relies upon their capacity to maintain their infectivity while they are in the environment. Here, a range of materials that are widely used to manufacture personal protective equipment (PPE) are summarized, as these offer effective disinfection solutions and are the environmental variables that influence virus survival. Infection modes and prevention as well as disinfection and PPE disposal strategies are discussed. A coronavirus-like enveloped virus can live in the environment after being discharged from a host organism until it infects another healthy individual. Transmission of enveloped viruses such as SARS-CoV-2 can occur even without direct contact, although detailed knowledge of airborne routes and other indirect transmission paths is still lacking. Ground transmission of viruses is also possible via wastewater discharges. While enveloped viruses can contaminate potable water and wastewater through human excretions such as feces and droplets, careless PPE disposal can also lead to their transmission into our environment. This paper also highlights the possibility that viruses can be transmitted into the environment from PPE kits used by healthcare and emergency service personnel. A simulation-based approach was developed to understand the transport mechanism for coronavirus and similar enveloped viruses in the environment through porous media, and preliminary results from this model are presented here. Those results indicate that viruses can move through porous soil and eventually contaminate groundwater. This paper therefore underlines the importance of proper PPE disposal by healthcare workers in the Mediterranean region and around the world.

DESCARTE ADEQUADO DE MEDICAMENTOS: UMA ESTRATÉGIA INTEGRADA DE EDUCAÇÃO EM SAÚDE VOLTADA À COMUNIDADE ACADÊMICA

O farmacêutico é o profissional responsável por orientar a comunidade sobre o uso racional de medicamentos, por meio da atenção farmacêutica. A prática da automedicação está relacionada ao estoque em domicílio de medicamentos, que favorece à problemática de seu descarte incorreto. Quando vencidos ou fora de uso, os medicamentos são descartados, na maioria das vezes, em locais inapropriados, afetando o meio ambiente. O trabalho teve por objetivo elaborar uma estratégia de descarte consciente de medicamentos durante a semana científica em uma faculdade privada, na cidade de Natal, RN, bem como avaliar o perfil dos medicamentos descartados. Trata-se de um estudo quantitativo, observacional e descritivo. A coleta dos medicamentos ocorreu em junho de 2019, durante a semana científica. Posteriormente foi realizada a contagem dos medicamentos recolhidos, separando-os por forma farmacêutica e em seguida verificou-se o quantitativo de medicamentos genéricos. Um total de 303 medicamentos vencidos ou fora de uso foram recolhidos, sendo 220 na forma farmacêutica sólida, 66 líquidos, e 17 semissólidos. Do total recolhido, apenas 51 eram genéricos. O estabelecimento de estratégias que facilitem o descarte racional de medicamentos no âmbito acadêmico possibilita uma alternativa para diminuir o acúmulo de medicamentos vencidos ou fora de uso em domicílio, bem como evita que estes sejam descartados em locais inapropriados.

Unraveling the mechanism of latex clearing protein Lcp&lt;sub&gt;K30&lt;/sub&gt; catalysed oxidative cleavage of poly(&lt;italic&gt;cis&lt;/italic&gt;-1,4-isoprene)

<p indent="0mm">Natural rubber or synthetic rubber materials have been extensively used in our daily life and industrial production for more than <sc>100 years</sc> due to their unique physical properties. However, a amount of rubber waste has been released into the environment, posing great challenges to the disposal of these polymers. In contrast to the disposal strategies such as combustion or stockpiling, enzyme catalyzed rubber degradation constitutes an environmentally friendly strategy. Latex clearing protein (Lcp) is an iron-heme containing endotype dioxygenase that catalyses the oxidative cleavage of the chemically inert poly(<italic>cis</italic>-1,4-isoprene) which is the main component of rubber, affording the products of aldehyde and ketone. It was found that active site E148 residue is key to the reactivity of Lcp based on the mutation experiments. However, the role of E148 and the overall mechanism are still controversial. It is generally accepted that both of dioxygen atoms are incorporated into the substrate. In previous studies, two possible mechanisms of Lcp catalyzed cleavage of poly(<italic>cis</italic>-1,4-isoprene) are proposed. In the first one, the distal oxygen atom of Fe(III)−O₂⁻ complex attacks onto the C=C double bond, leading to a three-membered epoxide intermediate. This is followed by the attack of Fe=O complex on the epoxide intermediate and subsequent C−C bond cleavage, affording the final ketone and aldehyde products. While in the second one, the proximal oxygen atom of Fe(III)−O₂⁻ complex attacks onto the C=C double bond of the substrate, which is followed by the attack of the distal oxygen atom onto the substrate radical to generate a four-membered cyclic dioxetane intermediate. The final O−O as and C−C bond cleavage in the dioxetane intermediate would afford the final products. In this study, based on the crystal structure of Lcp_K30, the combined molecular dynamic (MD) simulations and quantum mechanics/molecular mechanics (QM/MM) calculations are performed to elucidate the catalytic mechanism of Lcp catalysed cleavage of central double bond of poly(<italic>cis</italic>-1,4-isoprene). Our study shows E148 is protonated during the reaction and forms stable H bond interactions with Fe(III)−O₂⁻ species. Thus, the plausible role of E148 is related to the positioning of both Fe(III)−O₂⁻ species and the substrate. Moreover, it can be ruled out that the E148 acts as a base to abstract the proton from the substrate. The proposed mechanism of Lcp works as follows. Firstly, the distal oxygen of Fe(III)−O₂⁻ attacks onto the carbon−carbon double bond to generate the peroxide alky radical intermediate. This is followed by the rebound of the proximal oxygen to the carbon radical to generate the dioxetane intermediate, with Fe(III) being reduced to Fe(II). The following O−O bond cleavage occurs via the Fe(II)-mediated reductive cleavage of O−O bond of the dioxetane intermediate, leading to the vicinal diol radical anion intermediate. Finally, a facile C−C cleavage is undergone to yield the ketone and aldehyde products. In particular, our calculations show that the direct O−O cleavage of the dioxetane intermediate in the absence of Fe(II) catalysis requires a remarkably high barrier of <sc>160 kJ/mol,</sc> indicating the Fe(II) catalysis is vital for the further transformation of the dioxetane intermediate. For comparison, we also investigated the previously proposed mechanism involving the three-membered epoxide intermediate. However, the attack of the epoxide by Fe^IV=O complex is found to be highly unfavourable thermodynamically and thus can be ruled out. As such, this study may not only expand our understanding of the catalytic mechanism of Lcp_K30, but also provide useful information for rational design or engineering of Lcp enzyme toward the degradation of synthetic rubber materials.

Biodegradation pathway of penicillins by β-lactamase encapsulated in metal-organic frameworks

The pollution caused by the abuse of antibiotics has posed a serious threat to the ecological environment and human health, so development of effective strategies for degradation and disposal of antibiotic residues is urgently needed. In this work, penicillinase, a kind of β-lactamase, was immobilized into zeolitic imidazolate framework-8 (ZIF-8) by self-assembly method and the catalytic performance of the β-lactamase@ZIF-8 porous materials for degradation of penicillins has been investigated by high performance liquid chromatography coupled with mass spectrometry. The results illustrated that the catalytic activity of the encapsulated enzyme was significantly enhanced comparing with that of free enzyme. Meanwhile, the β-lactamase@ZIF-8 exhibited excellent stability under denaturing conditions including high temperature, organic solvent and the enzyme inhibitor. The catalytic degradation mechanism of the β-lactamase@ZIF-8 for penicillins has been probed and verified, and it has been found that the Zn (II) ion on ZIF-8 frameworks could form the complex with the target molecule, which weakened the bond of the four-membered β-lactam ring in the penicillin molecule, and thus enhanced the degradation efficiency of the enzyme. This work provided a promising strategy for eliminating the penicillin residues in water environment.

Phytoremediation of contaminants of emerging concern from soil with industrial hemp (Cannabis sativa L.): a review

The presence of contaminants of emerging concern (CECs) in wastewater treatment plant effluents is a significant underlying health risk and environmental concern. CECs consist of a wide variety of contaminants, including pharmaceuticals and personal care products, hormones, steroids, alkyl-phenols, flame retardants and pesticides. Their impact is of particular relevance to agricultural settings due to CEC uptake and accumulation in food crops and consequent diffusion into the food-chain. Meanwhile, marijuana reform is accelerating in the US, based on the scope and pace of legalization efforts and on wider acceptance in polls of voters. In this review, the effectiveness of industrial hemp (Cannabis sativa L.) in phytoremediation and hyperaccumulation of organic contaminants (e.g., benzo(a)pyrene, Naphthalene, and Chrysene) and heavy metal (e.g., Selenium and Cobalt) from either aqueous solutions or contaminated soils has been reviewed. The potential of industrial hemp as a renewable resource to biodegrade and/or decontaminate CECs is explored. Disposal strategies of this new phytoremediation crop that promote circular economy are also discussed. According to this current review, we believe the use of industrial hemp for phytoremediation is promising to have a sustainable, environmentally friendly and economically viable future.

Managing Nonmedical Opioid Use Among Patients With Cancer Pain During the COVID-19 Pandemic Using the CHAT Model and Telehealth

Managing Nonmedical Opioid Use Among Patients With Cancer Pain During the COVID-19 Pandemic Using the CHAT Model and Telehealth