The cement industry is the second largest source of anthropogenic mercury (Hg) emissions in Europe, accounting for 11% of global anthropogenic Hg emissions. The main objective of this study was to examine the influence of Hg emissions from the Salonit Anhovo cement plant on Hg levels measured in the ambient air at Vodarna, 1 km downwind from the flue gas chimney. The findings reveal that the plant raw mill operational status plays an important role in Hg concentrations in the flue gas emitted from the plant. Emitted total gaseous mercury was, on average, higher (49.4 μg/m³) when raw mills were in the direct mode (both raw mills-off) and lower (23.4 μg/m³) in the combined mode (both raw mills-on). The average Hg concentrations in Vodarna were 3.14 ng/m³ for gaseous elemental mercury, 53.7 pg/m³ for gaseous oxidised mercury, and 41.9 pg/m³ for particulate bound mercury for the whole measurement period. Atmospheric Hg speciation in Vodarna, coupled with plant emissions and wind data, has revealed that the total gaseous mercury emitted from the cement plant is clearly related to all Hg species measured in Vodarna. Wind blowing from the northeastern quadrant (mostly NE, ENE) is responsible for the elevated Hg levels in Vodarna, where gaseous oxidised mercury levels are highly linked to the cement plant emissions. However, elevated levels of Hg species in the absence of northeastern winds indicate potential inputs from other unknown local sources as well as inputs from regional and global transport mechanisms.

This study focused on the syngenetic control of polychlorinated-ρ-dibenzodioxins and dibenzofurans (PCDD/Fs) and heavy metals by field stabilization/solidification (S/S) treatment for municipal solid waste incineration fly ash (MSWIFA) and multi-step leachate treatment. Modified European Community Bureau of Reference (BCR) speciation analysis and risk assessment code (RAC) revealed the medium environment risk of Cd and Mn, indicating the necessity of S/S treatment for MSWIFA. S/S treatment significantly declined the mass/toxic concentrations of PCDD/Fs (i.e., from 7.21 to 4.25 μg/kg; from 0.32 to 0.20 μg I-TEQ/kg) and heavy metals in MSWIFA due to chemical fixation and dilution effect. The S/S mechanism of sodium dimethyldithiocarbamate (SDD) and cement was decreasing heavy metals in the mild acid-soluble fraction to reduce their mobility and bioavailability. Oxidation treatment of leachate reduced the PCDD/F concentration from 49.10 to 28.71 pg/L (i.e., from 1.60 to 0.98 pg I-TEQ/L) by suspension absorption or NaClO oxidation decomposition, whereas a so-called “memory effect” phenomena in the subsequent procedures (adsorption, press filtration, flocculating settling, slurry separation, and carbon filtration) increased it back to 38.60 pg/L (1.66 pg I-TEQ/L). Moreover, the multi-step leachate treatment also effectively reduced the concentrations of heavy metals to 1–4 orders of magnitude lower than the national emission standards. Furthermore, the PCDD/Fs and heavy metals in other multiple media (soil, landfill leachate, groundwater, and river water) and their spatial distribution characteristics site were also investigated. No evidence showed any influence of the landfill on the surrounding liquid media. The slightly higher concentration of PCDD/Fs in the soil samples was ascribed to other waste management processes (transportation and unloading) or other local source (hazardous incineration plant). Therefore, proper management of landfills and leachate has a negligible effect on the surrounding environment.

The Red Sea is exposed to metals from a large variety of natural and anthropogenic sources. In this study, we analyzed 19 common element concentrations in 14 Red Sea zooplankton samples using inductively coupled plasma-optical emission spectrometry (ICP-OES). The average metal or metalloid concentrations of the Red Sea zooplankton were: Ca > Sr > Fe > Al > Zn > As > Cu > Mn > Cr > Mo > Ni > Pb > Cd. The As, Ca, and Cu concentrations significantly increased with increasing latitude, while Cd concentrations decreased (p < 0.01). Our study indicated that anthropogenic activities (i.e., cement factories and oil refining industries) might be the predominant sources of significantly high Cr (1718 mg/kg), Fe (11,274 mg/kg), Mn (57.3 mg/kg), Mo (286 mg/kg), Ni (226 mg/kg), Pb (332 mg/kg), and Zn (17,046 mg/kg) concentrations that recorded in the Central to North Red Sea zooplankton.

Logistics network is one of the most important parts of supply chains with significant share in achieving sustainability across them. In this paper, we investigate a new multi-objective mixed integer linear programming model for the design of multimodal logistics network. A bi-objective mathematical model is introduced and two conflicting objectives including the minimization of total cost and the total environmental impact are taken into account. Effective environmental life cycle assessment–based method is incorporated in the model to estimate the relevant environmental impacts. Due to budget constraints, financing decisions for facility construction are considered in the proposed model. To cope with the model objective functions, the augmented ε-constraint method is applied. Computational analysis is also provided by using a cement multimodal rail-road logistics network case study to present the significance of the proposed model. Results show that utilizing the proposed multi-period optimization model influences the location of multimodal terminals and their construction time. Also, the results show that the use of the proposed model enhances the efficiency of terminals. On the other hand, computational results indicate that preferences of decision-makers and the importance of environmental objective have significant impacts on the topology of transportation network.

High-fluorine alkali-free liquid accelerator (AF₋ₕf, F⁻ concentration was about 2.31g/L) was still used in engineering because of its low cost, excellent stability, and coagulation-promoting effect. The main purpose of this study was to explore the leaching behavior of fluorine ions in shotcrete for tunnel lining with high-fluorine alkali-free liquid accelerator and whether there was fluoride pollution. The setting time and mechanical properties of cement paste and mortar with AF₋ₕf were tested. Under different environmental conditions, F⁻ leaching concentration from sprayed concrete was studied comparatively. Moreover, XRD and SEM were used to analyze the crystal composition and micro morphology of hydration products. The experimental results showed that with the increase of AF₋ₕf dosage, the setting time of cement paste was greatly shortened, and later strength of mortar and shotcrete could meet the construction requirements. In addition, when the leaching solution type (including Na₂CO₃, Na₃PO₄, Na₂SO₄, and NaNO₃) and testing conditions (particle size, soaking temperature, leaching solutions) were different, F⁻ leaching concentration changed regularly, and the minimum value was more than 20 mg/L, which might cause fluorine pollution to groundwater and soil. After shotcrete samples were soaked, the CaF₂ peaks’ intensity was relatively weaker and Ca(OH)₂ decreased obviously. Meanwhile, cement hydration products became looser and abundant of flaky C-S-H gel transformed into fibrous and chained structure.

This study aimed to evaluate the effect of using expanded vermiculite and its impact on the production of concrete roof tiles. The control treatment and replacement of 12.5, 25, 37.5, and 50% sand by vermiculite were evaluated. The concrete roof tiles were moulded by the simultaneous pressing and extrusion mechanical process. The control trace was comprised by 21.95% CPV-ARI cement, 65.85% sand, and 12.20% limestone. After production, the concrete roof tiles were cured for 28 days. The physical (roof tiles classification, samples dry weight, water absorption, and porosity), mechanical (splitting tensile strength), and microstructural properties were evaluated. All treatments were assessed before and after accelerated ageing. The thermal properties of the modification in the concrete roof tiles’ composition were also analysed. The evaluated amounts of vermiculite significantly affected the physical, mechanical, and thermal properties of concrete roof tiles. The use of vermiculite in concrete roof tiles reduced their dry weight and thermal conductivity, not impairing their durability. The use of 31.0% vermiculite in concrete roof tiles was suggested for better thermal insulation optimization (20.29% reduction) and weight reduction (7.92% and 7.94% at 28 days of curing and after accelerated ageing, respectively), along with adequate physical, mechanical, and durability properties.

The balanced amelioration of mechanical characteristics of fat clay with an additive refers to the attainment of high strength without compromising ductility, which is unattainable by solitary usage of a cementing additive. For this purpose, an amalgamated binary admixture (ABA) is proposed by assimilating shredded face mask (FM) waste, which is posing serious environmental concerns these days, with a cementitious waste material, i.e., silica fume (SF). However, for such ABA, the optimization of mix design is desirable because an excessive amount of one component could disturb the required balance. To address this issue, response surface methodology (RSM) is used in the current study, which is a strong technique used during the process of production to develop, improve, and optimize product inputs. Several experiments are designed and conducted to evaluate mechanical responses, i.e., unconfined compressive strength (qᵤ), brittleness index (IB), deformability index (ID), and California bearing ratio (CBR) value, of treated fat clay by varying mix designs of ABA. Based on the test results, mathematical models are developed which are found to be statistically valid to predict the subjected responses using SF and FM as inputs. Afterward, an optimized mix design is determined by integrating developed models with a desirability function model and setting maximization of strength and ductility as the optimization goals. An ABA having 7.9% SF and 1.2% FM is observed to provide the highest strength and ductility for multiple applications, i.e., road and buildings, with desirability factor close to unity; responses of which are also validated by performing tests. Furthermore, analysis of cleaning aspect shows that the use of optimized ABA in place of cement for subgrade improvement of 1 km two-lane road could avoid CO₂ emission of around 79,032 kg of C, save 42,720 kWh and 1174.8 GJ of electrical and thermal energy, respectively, and clean 43 Mg of FM waste; however, astute protocols of COVID-19 FM waste handling and disinfection are needed to be established and followed.

The treatment of coal gangue solid waste and microbially induced calcium carbonate precipitation (MICP) consolidate technology is a focus of research at home and abroad. MICP technology was used to solidify and cement coal gangue particles and endows them with a certain strength. The process does not use the traditional cementitious material (Portland cement) and is eco-friendly and pollution-free. The mechanical properties including unconfined compressive strength, CaCO₃ content, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and infrared spectroscopy (FTIR) were used for macroscopic and microscopic analyses. The results show that the average strength of CG-based bio-mineralized backfill materials reaches 1.55 MPa and the maximum strength is 2.17 MPa, suggesting the potential for its use as an underground fill. Compared with unmineralized gangue, the CaCO₃ crystal content in CG-based mineralized material is increased by 8.75% on average, and the maximum content is 13.34%. In the process of bacterial liquid perfusion, there is uneven distribution of bacteria in the material, which results in fewer CaCO₃ crystals being locally generated in the mineralized material and affects the overall compressive strength of gangue columns. Moreover, the greater the amount of calcium carbonate, the larger the strength of the mineralized material. SEM analysis results indicate that the gaps between gangue particles are filled with CaCO₃ crystals, and the calcium carbonate crystals are mostly polyhedral, showing stacked growth and contain a small number of spherical crystals that exist alone. The results of FTIR and EDS analysis show that the CaCO₃ crystals in the mineralized material are mainly in the form of calcite, followed by a small amount of vaterite. Comprehensive analysis demonstrates that the preparation of CG-based bio-mineralized backfilling materials is successful, and this experiment provides new ideas and methods for the treatment of solid waste such as coal gangue and building material waste.

Recycled aggregates (RA) from construction and demolition waste (CDW) instead of natural aggregates (NA) were analysed in the manufacture of new eco-friendly concrete. Fine (FRA) and coarse (CRA) recycled aggregates were used in different percentages as substitutes of natural sand and gravel, respectively. The results revealed that the use of RA in percentages of up to 50 wt.% is feasible. Additionally, RA were used to produce paving blocks in accordance with industrial requirements. Thus, values of water absorption lesser than 6.0% and tensile strength upper than 3.6 MPa were obtained, which are similar to those of a reference sample and within the limit values established by the regulations. These results were achieved by reducing the incorporation of cement, thereby saving production costs and minimizing environmental impact.

The objective of the current study is to investigate the natural radioactivity of some building materials, the resulting long-term external and internal effective dose equivalents (EEDE and IEDE) analysis followed by indoor radon measurements, and the assessment of some radiological risk indicators associated with radon exposure. A total of 37 samples of building materials were analyzed with a sodium iodide detector (NaI (Tl)), and the computer code RESRAD-BUILD was used for the analysis of the EEDE and IEDE of the structural elements of the houses (walls and floor). For indoor radon measurements, 140 houses were selected, and in each of them was placed 01 RADTRAK dosimeter. Inhalation dose, total dose, and some radiological risk indicators were calculated. The specific activities of ²²⁶Ra, ²³²Th, and ⁴⁰K for the overall sampled building materials were found to vary between 10 ± 2–52 ± 7, 10 ± 1–95 ± 10, and 31 ± 1–673 ± 20 Bq kg⁻¹, respectively. The dwelling types with bare brick walls, cement mortar plastered walls, and concrete floors show EEDE and IEDE values well below the recommended limits. The corresponding dwelling type contributions to the measured average indoor radon concentration (42 ± 12 Bq m⁻³) are 22%, 13%, and 16%, respectively. Inhalation dose resulting from the measured indoor radon concentrations varies from 0.35 to 3.24 mSv y⁻¹ with a mean value of 0.96 ± 0.55 mSv y⁻¹, which represents about 65% of the total dose simulated (1.49 ± 0.88 mSv y⁻¹) by the RESRAD-BUILD code. The overall analysis of indoor radon-related radiological risk indicators shows low levels of risk relative to permissible limits.