•PPE inhibited the development of glomeruli and promoted compensatory growth of renal tubules.•PPE at clinical dose disturbed fetal kidney development with a time-effect difference, manifested as ...full-term pregnancy exposure > early pregnancy exposure > mid-late pregnancy exposure.•The developmental toxicity of PPE on fetal kidney was more serious to the female fetuses than the males.
Prednisone is a synthetic glucocorticoid that is commonly used in both human and veterinary medication. Now, it is also recognized as an emerging environmental contaminant. Pregnant women may be exposed to prednisone actively or passively through multiple pathways and cause developmental toxicity to the fetus. However, the impact of prenatal prednisone exposure (PPE) on fetal kidney development remains unclear. In this study, pregnant mice were administered prednisone intragastrically during full-term pregnancy with different doses (0.25, 0.5, or 1 mg/(kg·day)), or at the dose of 1 mg/(kg·day) in different gestational days (GD) (GD0-9, GD10-18, or GD0-18). The pregnant mice were euthanized on GD18. HE staining revealed fetal kidney dysplasia, with an enlarged glomerular Bowman's capsule space and a reduced capillary network in the PPE groups. The expression of the podocyte and the mesangial cell marker genes was significantly reduced in the PPE groups. However, overall gene expression in renal tubules and collecting ducts were markedly increased. All of the above effects were more pronounced in high-dose, full-term pregnancy, and female fetuses. Studies on the mechanism of the female fetal kidney have revealed that PPE reduced the expression of Six2, increased the expression of Hnf1β, Hnf4α, and Wnt9b, and inhibited the expression of glial cell line-derived neurotrophic factor (GDNF) and Notch signaling pathways. In conclusion, this study demonstrated that there is a sex difference in the developmental toxicity of PPE to the fetal kidney, and the time effect is manifested as full-term pregnancy > early pregnancy > mid-late pregnancy.
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This research aimed to characterize the physical and chemical properties of municipal solid waste (MSW) incineration fly ash, as well as to investigate the leaching of heavy metals during toxicity ...characteristics leaching procedure (TCLP) process. To understand the leaching behaviour, concentrations of heavy metals, chloride, sulphate and calcium at various leaching, time was monitored together with pH of the leaching solution. Results showed that the chemical compositions of fly ashes led to differences in leaching environment. For the two fly ashes under study, one resulted in a leaching environment with pH of 10?12 while the other had pH about 6?7. Based on pH, anions and cations concentrations, Minteq software was employed to investigate the speciation of heavy metals. Results showed that the shift in precipitation/dissolution balance of carbonate and hydroxides of heavy metals could explain the fluctuation in metal concentrations during the leaching process, which indicates that leaching was probably controlled by these reactions. On the other hand, addition of EDTA changed the controlling reactions. Chelating reactions between heavy metals and EDTA led to much higher leaching toxicity due to the presence of heavy metals, showing that the presence of chelating organics in natural environment may facilitate heavy metal leaching.
New Sustainable with no CO2 emission cold mix asphalt (CMA) for road and highways surfacing is successfully developed from wastewater sludge ash normally sent to landfills. The Paper reports; ...durability in terms of water sensitivity, aging and contamination levels of heavy metals of the new developed novel CMA containing upgraded fly and bottom ash secondary cementitious materials from United Utilities fly and bottom ashes. Road engineers currently restricted the use of conventional CMA containing conventional limestone fillers (LF) for use in walkways and light trafficked roads only, as these mixtures needs from 2 to 24 months for curing. Conventional CMA mixtures also have high voidage contents and thus low traffic bearing capacity. The durability of these mixes is low especially in the UK and European countries where the climate is predominantly wet and cold.In Germany and France, ordinary Portland cement (OPC) replaced the filler used in traditional CMA. Although this allows the new CMA to be used in roads for light and heavy trafficked loads. The materials are not environmentally friendly, as one tone of cement releases approximately one tone of CO2 emission during their manufacturing process.
The results of the new developed CMA are satisfying the British and European codes of practices requirements. The new novel mixtures are also; highly cost-effective compared with the use of Hot Mix Asphalt (HMA), has no CO2 emission during mixing construction, and has no health and safety issues compared with the HMA manufacturing and application process.
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•Sustainable concrete produced with coal bottom ash and fly ash as substitute for fine aggregate and OPC, respectively.•Compressive strength, sulfate attack, acid attack and elevated ...temperature effects on the coal ash concrete are determined.•Pulse velocity, reduction in mass, change in strength and micro-structural tests are performed.•TCLP test is performed to analyze the leaching behavior of BA, FA and coal ash concrete.
The main aim of this study was to investigate the toxicity characteristics and durability of concrete containing bottom ash (BA) and fly ash (FA), as partial or total replacement of fine aggregate and Ordinary Portland cement (OPC), respectively. Concrete mixtures were prepared containing 0, 20, 50, 75 and 100% of BA as a substitute for river sand and 20% of FA as a replacement for OPC. Tests carried out were Toxicity Characteristics Leaching Procedure (TCLP), sulfate and acid attack (change in compressive strength, microstructure and weight) and elevated temperature effects (loss in compressive strength and mass as well as change in pulse velocity). Results showed that submerging coal ash concrete (CAC) mixtures in 5% sulfuric acid solution resulted in less reduction of compressive strength and mass loss compare to that of the control concrete. Moreover, sulfate resistance tests on concrete mixtures indicated that there were no mass loss and no reduction in compressive strength of all the mixtures after submersion in 5% magnesium sulfate solution. CAC showed higher weight loss and greater compressive strength reduction at elevated temperatures. From TCLP results, it is concluded that none of the elements leached higher than the maximum concentration of contaminants for toxicity characteristics. It indicates that transportation, disposal and utilization of BA and FA as clean construction material’s replacement could be utilized to reduce their environmental problems, increase efficiency and reduced unit cost production of concrete.
•The novel Posslite LWAC produced from LWA made from lime-treated SS and POFA.•Dense shell and rough surface of Posslite LWA enhanced the strength of LWAC.•Presence of crystals prevents Posslite LWA ...from decay in concrete.•Workability of Posslite LWAC is comparable with NWAC and yet it is 15% lighter than NWAC.•The mechanical and durability performance of Posslite LWAC is comparable to NWAC.
This paper reports the investigation on toxicity characteristics, microstructure, physical and mechanical properties of artificial Posslite lightweight aggregate (LWA) made from lime-treated sewage sludge (SS) and palm oil fuel ash (POFA). The presence of crystals and a dense shell of Posslite LWA enhanced its strength and the rounded shape of LWA enhanced the workability of fresh lightweight aggregate concrete (LWAC). Results showed that mechanical and durability properties of Posslite LWAC were comparable to normal weight aggregate concrete (NWAC). Posslite LWAC possesses compressive strength, VPV, sorptivity, chloride diffusion of 50.4 MPa, 8.7%, 0.0151 mm/s0.5 and 2.12 × 10−11 m2/s, respectively.
While several research studies considered the utilization of reclaimed asphalt pavement (RAP) aggregates for asphalt and concrete pavements, very few attempted its possible utilization for precast ...concrete applications like concrete paver blocks (CPBs). Moreover, few attempts made in the recent past to improve the strength properties of RAP inclusive concrete mixes by incorporating certain supplementary cementitious materials (SCMs) have reported an insignificant or marginal effect. The present study attempts to comprehensively investigate the utilization potential of some locally and abundantly available materials having suitable physicochemical properties to improve the performance of a zero-slump CPB mix containing 50% RAP aggregates. The studied filler materials, namely, wollastonite (naturally occurring calcium metasilicate mineral) and jarosite (hazardous zinc industry waste), were used to replace 5–15% and 10–20% by volume of Portland cement in the 50% RAP CPB mix. Apart from their individual effects, the efficacy of wollastonite-jarosite blends was also investigated. Considering the lack of indoor storage facilities and economic aspects of CPBs, the influence of water spray curing regime on the performance of the RAP CPB mixes was studied and compared to that of continuous water curing regime. Inclusion of the considered fillers was found to statistically and significantly enhance the flexural strength, tensile splitting strength, and abrasion resistance of the 50% RAP CPB mix; however, the compressive strength (in most cases), permeable voids, water absorption, and water permeability properties showed an insignificant improvement. Results of thermogravimetric analysis confirmed the occurrence of pozzolanic reactivity, and microstructure analysis revealed improvements in packing of concrete matrix and ITZ with filler inclusion qualitatively substantiating the improvements in strength and durability characteristics. The toxicity characteristics of heavy metals that may leach from the hazardous jarosite-based RAP CPB mixes were found to be within permissible limits. Based on the performance requirements specified by IS, IRC, and ASTM standards, all the RAP CPB mixes with filler inclusions fulfilled the acceptance criteria for heavy traffic applications, and water spray curing can enact as an alternate method for curing these mixes. However, to avail maximum performance benefits, it is recommended to use 5% wollastonite, 15% jarosite, and a combination of 10% wollastonite and 10% jarosite as a Portland cement substitute to produce sustainable eco-friendly RAP CPB mixes.
Understanding the effects of oxalic acid (OA) on the immobilization of Pb(II) in contaminated soils by phosphate materials, has considerable benefits for risk assessment and remediation strategies ...for the soil. A series of phosphate amendments with/without oxalic acid were applied to two anthropogenic contaminated soils. We investigated the immobilization of Pb(II) by KH2PO4, phosphate rock (PR), activated phosphate rock (APR) and synthetic hydroxyapatite (HAP) at different phosphate:Pb (P:Pb) molar ratios (0, 0.6, 2.0 and 4.0) in the presence/absence of 50mmol oxalic acid/kg soil, respectively. The effects of treatments were evaluated using single extraction with deionized water or CaCl2, Community Bureau of Reference (BCR) sequential extraction and toxicity characteristic leaching procedure (TCLP) methods. Our results showed that the concentration of water extractable, exchangeable and TCLP-Pb all decreased with incubation time. The concentration of water-extractable Pb after 120days was reduced by 100% when soils were amended with APR, HAP and HAP+OA, and the TCLP-Pb was <5mg/L for the red soil at P:Pb molar ratio 4.0. Water-soluble Pb could not be detected and the TCLP-Pb was <5mg/L at all treatments applied to the yellow-brown soil. BCR results indicated that APR was most effective, although a slight enhancement of water-soluble phosphate was detected at the P:Pb molar ratio 4.0 at the beginning of incubation. Oxalic acid activated phosphates, and so mixing insoluble phosphates with oxalic acid may be a useful strategy to improve their effectiveness in reducing Pb bioavailability.
The fly ash, generated at the coal-based thermal power plant, is always a cause of concern to environmentalists owing to its adverse impact on air, water and land. There exists a high environmental ...risk when it is disposed to the environment. Thus, two different type of fly ash samples (FA-1 and FA-2) have been considered in this study to examine the leaching potential of the elements magnesium, aluminium, silicon, calcium, titanium, vanadium, chromium, manganese, iron, nickel, cobalt, copper, zinc, arsenic, selenium, strontium, cadmium, barium and lead for different types of leachant. Toxicity characteristics leaching procedure and ASTM tests have been performed in the laboratory to simulate different natural leaching scenarios. Characterisation of samples have been done through X-ray diffraction and field emission gun scanning electron microscope. The effect of different liquid to solid ratios (i.e. 5, 10, 20 and 50) on the mobilisation of elements has been analysed. The results indicated that the maximum leaching of all elements occurred at a liquid to solid ratio of 5 except for arsenic, barium and silicon. The groundwater analysis has also been done to understand the actual effects of leachate. The elements presenting the highest leachability in the two fly ash samples under all tested conditions were magnesium, aluminium, silicon and calcium. It has been observed that calcium exhibits greater leaching effects than all other constituents. The study presented here has been found very useful for assessing contamination levels in groundwater owing to leaching effects of fly ash under different scenarios, which can be helpful to prevent spreading of the contaminants by efficient management of fly ash.
Magnetic fractions (MFs) in fly ashes from eight coal-burning power plants were extracted by magnetic separation procedure. Their mineralogy and potential leachability of heavy metals were analyzed ...using rock magnetism, X-ray diffraction (XRD), scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM/EDX) and leaching procedures (toxicity characteristics leaching procedure by the United States Environmental Protection Agency, TCLP, and gastric juice simulation test, GJST). Results show that the MFs in the fly ashes range between 2.2 and 16.3
wt%, and are generally composed of magnetite, hematite, quartz and mullite. Thermomagnetic analysis and SEM/EDX indicate that the main magnetic carrier magnetite is substituted with small amounts of impure ions, and its structures are featured by rough, dendritic and granular iron spherules. The MFs are found to be rich in Fe, Mn, Cr, Cu, Cd and Pb. Compared with the non-magnetic fractions (NMFs), the MFs have about 5 times higher iron, and 1.6 times higher Mn, Cr, Cu and Cd concentrations. The TCLP test shows that the TCLP-extractable Cr, Cu, and Pb concentrations in the MFs are higher than those in the NMFs, while the TCLP-extractable Cd concentration in the MFs and NMFs is below the detection limit (<0.1
mg/L). The GJST-extractable Cd, Cr, Cu, and Pb concentrations in the MFs are higher those in the NMFs. No significant difference in the leachability ratio of Cr, Cu and Pb with TCLP and GJST is found in the MFs and NMFs. However, the GJST test showed that Pb has higher leachability in MFs than that in NMFs. The leachability ratio of heavy metals has an order of Cu
>
Cr
>
Pb
>
Cd. The heavy metals of fly ashes have a great potential to be released into the environment under acid environment.
The supply of light-emitting diode (LED) lamps has been expanding as lighting devices to replace fluorescent lamps. Accordingly, it is expected that a large amount of end-of-life LED lamps will be ...generated. Among various types of LED lamps, liner LED lamps are generally used. Since linear LED lamps have been reported to use hazardous materials such as As and Pb, the hazardous characteristics of end-of-life LED lamps were estimated. To verify the hazardous characteristics of end-of-life linear LED lamps, leaching tests such as Korea Extraction Test (KET) and Toxicity Characteristics Leaching Procedure (TCLP) were carried out for the overall mixture and the each component of end-of-life linear LED lamps. The linear LED lamp is generally composed of cover, frame, LED, the driver and others. The portions of LED and the driver in linear LED lamp are only about 1% and 10%, respectively. End-of-life linear LED lamp can be non-hazardous waste because leaching concentrations of heavy metals in the overall mixture of end-of-life linear LED lamp were lower than the regulatory level. Since leaching concentrations of As, Pb and Cu in LED and the driver were higher than the regulatory level, however, LED and the driver can be classified as the hazardous waste.
