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Biofilms play a significant role in the biogeochemical processing of organic matter and the environmental fate of emerging pollutants. In this study, we investigated the occurrence and distribution of 32 endocrine-disrupting chemicals (EDCs), including 24 environmental corticosteroids (ECs) and 8 environmental estrogens (EEs), in natural biofilms from the Pearl River system. Their association between biofilms and water and environmental risk were assessed. The ECs and EEs ubiquitously occurred in the biofilms, ranging from <0.61–6.57 ng/g and <0.8–2535 ng/g, respectively. Temporally, there was no obvious variance in either ECs or EEs in the biofilms during the winter and summer, and their concentrations exhibited a spatial trend of upward to midstream, descending downstream, and then seaward attenuation at the estuary. For ECs and EEs, the similar levels of field-derived bioconcentration factors (BCFs) (logarithm values: 2.42–2.86 and 2.72–2.98, respectively) and biofilm organic carbon-normalized partitioning coefficients (K boc) (3.39–3.69 and 3.35–3.95) suggest the comparable potential of accumulation and sorption by biofilms between these two classes of EDCs. In addition, higher values of BCF and K boc for the EEs were found in winter and were correspondingly comparable to their distribution coefficients (K d) and K oc derived from suspended particles and sediment, revealing that biofilms are a competitive environmental compartment for capturing EDCs, particularly during the mature period. A positive log K boc -log K ow relationship suggests hydrophobic partitioning as a primary interaction mechanism between the biofilm and EEs. Moreover, high risks from biofilm-associated ECs and EEs might have posed to the fluvial ecosystem. This study provides original insights into the occurrence, fate, and risk of ECs in natural biofilms for the first time and demonstrates that biofilms may not only serve as reservoirs but also serve as sentinels for fluvial EDC contamination. These results contribute to the further understanding of the behavior and fate of EDCs in aquatic environments. [Display omitted] • Environmental corticosteroids (ECs) were first found in natural biofilms. • The ECs and environmental estrogens (EEs) ubiquitously occurred in the biofilms. • Biofilm exhibits its potential as sentinel of EDC pollution in aquatic environment. • In situ biofilm/water BCF and K oc for both ECs and EEs were determined. • Hydrophobic partitioning plays a primary role in biofilm sorption of EEs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Perforated fly ash cenospheres (PFACs) were used as an internal curing agent for developing printable cement-based materials. • Internal curing effect of PFACs can alleviates autogenous shrinkage strain by 81% in 3D printing component. • Effect of PFACs on the rheology of limestone calcined clay cement (LC3) was evaluated. • Fiber Bragg Grating technology was adopted to study autogenous shrinkage by monitoring the interlayer strain. • Incorporating 15 vol% PFAC to replace sand gives LC3 exceptional resistance to autogenous shrinkage and printability. The development of three-dimensional (3D) printing technology in the construction industry has coincided with growing attention on the investigation of printable cement-based composite. Meanwhile, the exploitation of high-performance and environmentally friendly printable cement-based composite is an inevitable path for the sustainable development of 3D printing in the construction industry. This study proposes the use of perforated fly ash cenospheres (PFACs) as internal curing (IC) agent into limestone calcined clay cement (LC3) mortar to develop a novel green printable cement-based composite. Rheological behavior of LC3 mortar containing PFACs has been shown to meet the requirements of 3D printing. The internal curing effect on autogenous shrinkage of mortar was studied by employing Fiber Bragg Grating (FBG) technology. Compressive and flexural strengths of LC3 mortar containing PFACs were evaluated. Additionally, microstructural investigation was analyzed through SEM, and the hydration products were studied by XRD and TG tests. Results suggest that shrinkage strain of LC3 mortar containing 15% PFAC was approximately 80% lower than that of mortar without PFAC, which indicates that PFAC in LC3 mortar can be effective in holding the mixing water for IC that can reduce the autogenous shrinkage. Furthermore, additional mechanical strength of mortar containing PFAC was generated through IC effect and the pozzolanic activity of PFAC, which can effectively compensate the strength loss caused by the PFAC. However, microstructural investigation indicated that the pozzolanic activity of PFAC has limited effect on cement hydration compared with the introduction of additional IC water. Consequently, this study reveals that it is effective to adopt PFAC as IC agent into LC3 mortar to develop high-performance and sustainable printable cement-based composite. [ABSTRACT FROM AUTHOR]

[Display omitted] • Feasibility of cathode ray tube (CRT) glass as geopolymer aggregate was studied. • Waste CRT glass can release PbO and retard in the hydration of geopolymer. • Waste CRT glass was immobilized by physical encapsulation effect of geopolymer. • Fly ash (FA) addition increased total porosity and Pb leaching concentration. • A mix proportion of 50 wt% FA and 50 wt% slag was proposed to recycle CRT glass. Stabilization/solidification (S/S) of lead in hazardous waste cathode ray tube (CRT) glass by using geopolymers is a promising disposal method for further construction use. In this study, the effects of fly ash addition and waste CRT glass aggregate on the properties of slag-based geopolymers were investigated. Results show that the addition of 50 wt% fly ash into the geopolymer containing 50 wt% waste CRT glass can mitigate the alkali-silica expansion by 61%, slightly decrease the compressive strength by 1.5 MPa and promote the generation of mullite. On the other hand, the PbO released from waste CRT glass can retard the hydration process, but without changing the crystalline phase composition and the aluminosilicate structure of geopolymers. Therefore, the S/S of waste CRT glass by geopolymers mainly depends on the physical encapsulation effect. Furthermore, fly ash addition can degrade the S/S performance of geopolymers due to the increase of the total porosity representing the channel number. Finally, based on the requirements of volume stability, compressive strength, and leaching concentration of Pb, a mix proportion of 50 wt% fly ash and 50 wt% slag can be proposed for recycling waste CRT glass in a non-hazardous way. Overall, this study is an innovative attempt to reveal the feasibility of utilizing waste CRT glass in geopolymers as fine aggregate. [ABSTRACT FROM AUTHOR]

[Display omitted] • Particle packing of quaternary composites was optimized for favorable printability. • Rheological behaviors of composites were studied for evaluating the printability. • High thixotropy of LC3 was found to be effective for buildability. • A novel low-carbon and low-energy printable composite was proposed. This study develops a modified limestone calcined clay cement (LC3) composite for 3D printing, by introducing silica fume (SF) and particle packing theory. Interactions between particle packing density, rheological properties, and printability of the composites were synergistically investigated. Moreover, the ratio of the sand-to-binder (S/B) was also analyzed to explore the performance response. Results show that when composites contain 33.33 wt% calcined clay, 16.67 wt% limestone powder and 5 wt% SF with S/B ratio of 2.5, the dynamic yield stress, static yield stress, and structural recovery can be significantly improved. The proposed mortar can be continuously extruded with few defects and exhibited an excellent shape retention during printing process. Furthermore, the embodied energy (EE) and embodied carbon emissions (ECO 2 e) per cubic meter of optimal mortar respectively decreased by 50.2% and 45.2% with respect to the plain mortar. Finally, the employment of LC3 containing SF together with optimum particle packing system mutually contributed to lower the cement content of composites that eventually led to the development of eco-efficient printable materials. [ABSTRACT FROM AUTHOR]

3D printing is becoming increasingly popular for construction owing to its reduced environmental impact and lower energy demand than conventional manufacturing. Rapid application of this technology relies largely on the development of high-performance cement-based composites compatible with 3D printers. This study aims to develop high-quality and sustainable cement-based composites containing microcrystalline cellulose (MCC) that can satisfy the requirements for 3D printing. The workability, rheological behavior, buildability, and mechanical properties of the cement-based composites for 3D printing were examined systematically. The rheological analysis revealed that the plastic viscosity and yield stress of mortars with 1 wt% MCC were increased by 20.9% and 190.0%, respectively, compared with those of mortars without MCC. The buildability of mortars with 1 wt% MCC was also improved, and the printed structure exhibited neither large cracks among the printed filaments nor distorted components in the printing process. Compared with the mortars without MCC, the 28-d compressive and flexural strengths of the mortars with 1 wt% MCC were increased by 18.6% and 12.5%, respectively. In addition, the carbon emissions from the overall life cycle of a printed residence were quantified by considering the material attributes of additive manufacturing and using software tools to conduct building information modeling (BIM)-enabled life cycle assessment (LCA) modeling. The results indicated that compared with the mortars without MCC at equivalent mechanical strengths, the mortars containing 1 wt% MCC could reduce the CO 2 emissions by 6.82%. The comprehensive improvement in rheological properties and buildability as well as the environmental benefits can promote the sustainable industrial utilization of MCC-reinforced cement-based materials in the 3D-printing industry. Image 1 1. Micro-crystalline cellulose (MCC) was evaluated in composites for 3D-printing 2. Printable MCC-reinforced composites exhibited good rheology and buildability 3. BIM and LCA tools were coupled to evaluate the environmental impact 4. Addition of MCC contributed to a reduction in CO 2 emissions from the composites 5. High-quality sustainable composites meeting 3D printing requirements were proposed [ABSTRACT FROM AUTHOR]

[Display omitted] • This paper presents a critical review on sustainable 3D printing concrete (3DPC). • The performance of 3DPC based on recycled aggregate and fibre is investigated. • Effect of fibre on mechanical and anisotropic properties of 3DPC is evaluated. • Structural behaviour, environmental impact and cost of 3D printed strucrure is given. This paper presents a critical review of reducing the life-cycle environmental impact of 3D printing concrete (3DPC) systems from the perspectives of material preparation, construction process and structure level. The material requirements of 3DPC are first introduced, then the utilization of low-carbon cementitious materials, recycled aggregates, admixture and fibres in 3DPC is explored, along with their effect on workability and mechanical property. The potential for improving the environmental benefits by applying better design and printing parameters are discussed in the subsequent part. Two main delivery systems and the effect of printing parameters (including printing speed, standoff distance) are presented. Finally, the behaviour of 3D printing components (beam, slab and column) is examined at the structural level. 3D printing technology has a high degree of freedom, thus better understanding of the component behaviour can save materials and improve strength. Finding a balance between component's performance and environmental impact is a crucial work in future. [ABSTRACT FROM AUTHOR]

• Recycling of hazardous cathode-ray tube (CRT) glass by fly ash-slag geopolymer mortar was studied. • Effect of alkali dosage and silica modulus on mechanical and Pb solidification performance was elaborated. • Higher alkali dosage results in weak interfacial transition zone (ITZ) and lower total porosity. • Increasing silica modulus improves physical encapsulation and chemical solidification of Pb. • The optimal alkali dosage and silica modulus are 6% and 1.5 for fly ash-slag geopolymer mortar containing CRT glass aggregate. Large amount of waste cathode ray tube (CRT) glass containing the hazardous heavy metal Pb, discarded at landfill sites without proper recycling method, poses a great threat to the environment and public health. It is urgent to develop an effective and efficient recycling method to minimize the quantity of these hazardous wastes. In the present study, recycling of waste CRT glass as fine aggregate through fly ash-slag geopolymer composite were studied. The compressive strength, alkali-silica reaction expansion (ASR expansion) and Pb leaching of fly ash-slag geopolymer mortars containing CRT glass (FSGM-CRT), considering influence of silica modulus and alkali dosage, were comprehensively studied through toxicity characteristic leaching procedure (TCLP) test, X-ray diffraction (XRD), thermogravimetry (TG), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM). The results showed that the solidification mechanism of geopolymer for waste CRT glass includes not only physical encapsulation, but also chemical solidification. As the silica modulus increased, the compressive strength and the ASR expansion first increased and then decreased, and the leached concentration of Pb significantly decreased. The increased silica modulus improves the chemical binding of Pb ions by generating lead silicate as it is resulted by microstructure evolution tests. Additionally, increase of silica modulus can significantly improve the interfacial transition zone (ITZ) and the total porosity, resulting in better physical encapsulation performance on the leached Pb ions. On the contrary, higher alkali dosage can hinder the polycondensation reaction of silicate and aluminum tetrahedrons, inhibiting the polymerisation of the geopolymer mortars, thus leading to weakening of both the solidification performance and the compressive strength of FSGM-CRT. Considering combined structural and solidification performance requirements on compressive strength, ASR expansion and Pb leaching limit, the optimal alkali dosage and silica modulus for recycling CRT with geopolymer is 6% and 1.5, respectively. [ABSTRACT FROM AUTHOR]

Shared bicycles are prevailing in China but the extent to which they contribute to maintaining and transmitting pathogens and antibiotic-resistant bacteria remain largely unknown. To fill the knowledge gap, herein, swab samples (n = 963) were collected from handlebars of shared bicycles in areas of hospital, school, metro station (n = 887) and riders (n = 76) in Chengdu, China. Staphylococci (n = 241) and Enterococci (n = 69) were widely distributed across sampling locations at a frequency of 2.3%–12.9%, and 0.08%–5.5%, respectively. Bicycle or rider-borne Gram-positive bacteria were frequently resistant to clinically important antibiotics including linezolid, fosfomycin, and vancomycin, and a significant portion of these isolates (3.4%–16.6% for Staphylococci and 0.1%–13.8% for Enterococci) indicated multidrug resistance. Nineteen Staphylococcus aureus isolates were identified in this collection and 52.6% of which were considered as methicillin-resistant S. aureus. Whole genome sequencing further characterized 26 antimicrobial resistance genes (ARGs) including fosB , fusB , and lnu (G) in S. aureus and 21 ARGs including optrA in Enterococci. Leveraging a complementary approach with conventional MLST, whole genome SNP and MLST analyses, we present that genetically closely-related bacteria were found in bicycles and riders across geographical-distinct locations suggesting bacterial transmission. Further, five new ST types 5697–5701 were firstly characterized in S. aureus. ST 942 and ST 1640 are new ST types observed in E. faecalis , and E. faecium , respectively. Our results highlighted the risk of shared bicycle system in disseminating pathogens and antibiotic resistance which warrants effective disinfections. Unlabelled Image • The dock-less shared bicycles may be a reservoir and vehicle in transmitting ARGs. • Isolates from shared bicycles were resistant against clinical antibiotics. • Shared bicycles may accelerate the spread of pathogens and ARGs. • Effective disinfection operations are needed to mitigate transmission. [ABSTRACT FROM AUTHOR]