Dysfunction of Nrf2-regulated cellular defence system and JNK activation induced by high dose of fly Ash particles are associated with pulmonary injury in mouse lungs.

The mechanisms of the exposure to fine particulate matter (PM) as a risk factor for pulmonary injury are not fully understood. The transcription factor, NF-E2-related factor 2 (Nrf2), plays a key role in protection lung against PM insult and cancer chemoprevention. In this study, F3-S fly ash particles from a municipal waste incinerator were evaluated as a PM model. We found that F3-S triggered hierarchical oxidative stress responses involving the prolonged activation of the cytoprotective Nrf2 transcriptional program via Keap1 Cys151 modification, and c-Jun NH2-terminal kinase (JNK) phosphorylation at higher doses. In mouse lungs exposed to fly ash particles at a low dose (10-20 mg/kg), Nrf2 signalling was upregulated, while in those exposed to a high fly ash particle dose (40 mg/kg), there was significant activation of JNK, and this correlated with Nrf2 phosphorylation and the downregulation of antioxidant response element (ARE)-driven genes. The JNK inhibitor, SP600125, reversed Nrf2 phosphorylation, and downregulation of detoxifying enzymes. Silencing JNK expression in mouse lungs using adenoviral shRNA inhibited JNK activation and Nrf2 phosphorylation, promoted ARE-driven gene expression, and reduced pulmonary injury. Furthermore, we found that the 452-515 amino acid region within the Neh1 domain of Nrf2 was required for its interaction with P-JNK. We demonstrated that Nrf2 was an important P-JNK target in fly ash-induced pulmonary toxicity. JNK phosphorylated Nrf2, leading to a dysfunction of the Nrf2-mediated defence system.

Decreased immune response in undernourished rats after air pollution exposure.

Children are highly vulnerable subpopulation to malnutrition and air pollution. We investigate, in a rat nutritional growth retardation (NGR) model, the impact of Residual Oil Fly Ash (ROFA) on the lung immune response using in vitro and ex vivo methods. In vitro: Alveolar macrophages (AM) were isolated from Control (C) and NGR animals, cultured and treated with ROFA (1-100 µg/ml) for 24 h. Ex vivo: C and NGR rats were intranasally instilled with ROFA (1 mg/kg BW) or PBS. 24 h post-exposure AM were isolated and cultured. ROFA-treatment increased superoxide anion production and TNFα secretion in C-AM in vitro, though for NGR-AM this response was lower. A similar pattern was observed for TNFα and IL-6 secretion in ex vivo experiments. Regarding the antioxidant response, although NGR-AM showed increased Nrf2, after ROFA instillation an attenuated activation was observed. To conclude, chronic undernutrition altered AM response to ROFA affecting immune responsiveness to air pollutants.

Comparative toxicity of coal and coal ash: Assessing biological impacts and potential mechanisms through in vitro and in vivo testing.

BACKGROUND: Coal and coal ash present inorganic elements associated with negative impacts on environment and human health. The objective of this study was to compare the toxicity of coal and coal ash from a power plant, assess their inorganic components, and investigate the biological impacts and potential mechanisms through in vitro and in vivo testing. METHODS: Particle-Induced X-ray Emission method was used to quantify inorganic elements and the toxicity was evaluated in Caenorhabditis elegans and Daphnia magna in acute and chronic procedures. The genotoxic potential was assessed using alkaline and FPG-modified Comet assay in HepG2 cells and mutagenicity was evaluated using Salmonella/microsome assay in TA97a, TA100, and TA102 strains. RESULTS: Inorganic elements such as aluminum (Al) and chromium (Cr) were detected at higher concentrations in coal ash compared to coal. These elements were found to be associated with increased toxicity of coal ash in both Caenorhabditis elegans and Daphnia magna. Coal and coal ash did not induce gene mutations, but showed genotoxic effects in HepG2 cells, which were increased using the FPG enzyme, indicating DNA oxidative damage. CONCLUSIONS: The combined findings from bioassays using C. elegans and D. magna support the higher toxicity of coal ash, which can be attributed to its elevated levels of inorganic elements. The genotoxicity observed in HepG2 cells confirms these results. This study highlights the need for continuous monitoring in areas affected by environmental degradation caused by coal power plants. Additionally, the analysis reveals significantly higher concentrations of various inorganic elements in coal ash compared to coal, providing insight into the specific elemental composition contributing to its increased toxicity.

Effect of bacteria on strength properties and toxicity of incinerated biomedical waste ash concrete.

A large amount of biomedical waste is generated worldwide, and this waste is hazardous and infectious. The ultimate solution for the issue of disposal of such waste is incineration and then landfill. This incinerated waste is called incinerated biomedical waste ash (IBWA). After incineration, the IBWA is still toxic because of the presence of heavy metals and alkaline metals as they get leached out and have a lethal effect on the environment. This study aims at the use of IBWA in concrete as fine aggregate replacement material. The IBWA was given bacterial treatment to stabilise it against alkalinity and heavy metals leaching. Fine aggregate was replaced with IBWA with ratios having replacement levels from 0%, 5%, 10%, 15%, and 20%. Strength tests performed were compressive strength and splitting tensile strength up to the age of 365 days. United States Environmental Protection Agency's (U.S. EPA) toxicity characteristic leaching procedure, SEM-EDS, and XRD tests were performed. Leachate generated from the concrete mix incorporating IBWA (with and without bacterial treatment) was studied, and the aim was to bind the metals to ensure that the metals leached out are within permissible limits.

Does exposure to weathered coal ash with an enhanced content of uranium-series radionuclides affect flora? Changes in the physiological indicators of five referent plant species.

Coal ash deposited in open landfills is a potential source of environmental pollutants due to the contained toxic element content. The weathered coal ash used in this study additionally contains enhanced activity concentrations of 238U series radionuclides. This study aimed to determine the physiological effects of enhanced ionizing radiation and toxic elements on five plant species (smilo grass, sticky fleabane, blackberry, mastic and pine tree) inhabiting the coal ash disposal site. Among the potentially toxic measured elements, contents of Sb, As and especially V significantly exceeded their respective levels at the control site, as well as the content of 238U and its progenies. Significant changes in photosynthetic pigments were recorded following chronic exposure to the plants growing on the coal ash site. Different responses were also observed in the plant species regarding the activity of catalase and glutathione-S-transferase (GST). The level of lipid peroxidation markedly increased in plants from the disposal site, except in blackberry, wherein GST activity was the strongest, indicating an important role of that enzyme in the adaptation to coal ash pollutants. The results of this study suggest that the modulation of the studied biochemical parameters in plants growing on coal ash is primarily species-dependent.

Exposure to coal ash and depression in children aged 6-14 years old.

BACKGROUND: When coal is burned for energy, coal ash, a hazardous waste product, is generated. Throughout the world, over 1 billion tons of coal ash is produced yearly. In the United States, over 78 million tons of coal ash was produced in 2019. Fly ash, the main component of coal ash contains neurotoxic metal (loid)s that may affect children's neurodevelopment and mental health. The objective of this study was to investigate the association between fly ash and depressive problems in children aged 6-14 years old. METHODS: Children and their parents/guardians were recruited from 2015 to 2020. Tobit regression and logistic regression were used to assess the association between coal fly ash and depressive problems. To determine fly ash presence, Scanning Electron Microscopy was conducted on polycarbonate filters containing PM10 from the homes of the study participants. Depressive problems in children were measured using the Depressive Problems DSM and withdrawn/depressed syndromic problem scales of the Child Behavior Checklist. RESULTS: In covariate-adjusted Tobit regression models, children with fly ash on the filter had higher scores on the DSM Depressive Problems (3.13 points; 95% CI = 0.39, 5.88) compared with children who did not have fly ash on the filter. Logistic regression supported these findings. CONCLUSION: Coal ash is one of the largest waste streams in the U.S, but it is not classified as a hazardous waste by the Environmental Protection Agency. To our knowledge, no studies have assessed the impact of coal ash on children's mental health. This study highlights the need for further research into the effects of coal ash exposure on children's mental health, and improved regulations on release and storage of coal ash.

Cytotoxicity of stabilized/solidified municipal solid waste incineration fly ash.

Low-carbon stabilization/solidification (S/S) is of increasing importance as an option for the treatment of municipal solid waste incineration fly ash (MIFA). This study tailored four binders (e.g., ordinary Portland cement (OPC), calcium aluminate cement (CAC), phosphate-modified OPC, and phosphate-modified CAC) for S/S of MIFA and evaluated the cytotoxicity of treated MIFA by using A549 cell-based in-vitro assay. After S/S treatment, the leachability of Cr, Cu, Zn and Pb from MIFA decreased by 76.1%, 93.4%, 69.6%, and 85.5%, respectively. Spectroscopic analysis indicated that the hydration products determined the immobilization efficiencies of various binders, and strong bonding between metallic cations and phosphate enhanced the immobilization efficiency. The treated MIFA showed significantly lower cellular reactive oxygen species (ROS)-inducing abilities than original MIFA, in which with phosphate-modified OPC treated MIFA showed the lowest ROS levels. Intracellular ROS and multicytotoxicity results also revealed that the treated MIFA not only decreased the cytotoxicity-inducing capability but also enhanced the tolerant dosage of cytotoxicity, in which phosphate-modified S/S treatments showed more effective mitigation (25% less cytotoxicity) than plain cement treatments due to the high-efficiency immobilization of potentially toxic elements. This study develops a pioneering assessment protocol to measure the success of sustainable treatment of MIFA in human health perspective.

Toxicity effects of size fractions of incinerated sewage sludge bottom ash on human cell lines.

Sewage sludge bottom ash (SSBA) from the incineration plant used for the production of construction materials possibly possess heavy metals which might cause a negative impact on human health. Considering biosafety, we investigated the toxicity effects of 0.5-2 mm (aggregate substitute) and < 0.075 mm (cement substitute) in its solid and leachate form on human lung fibroblast cells (MRC-5) and human skin epidermal cells (HaCaT) on exposure through contact. MTS assay revealed the cellular responses of lung and skin cell lines to the leachates showing that the skin cells, which often interact with the external environment displayed better tolerance than the lung cells, whereas solid ash showed a concentration and size-dependent toxicity. Solid ash was found to downregulate the intracellular glutathione/superoxide dismutase activities and upregulate lactate dehydrogenase/lipid peroxidation activities thus inducing oxidative stress to the cell and subsequently resulting in the cell membrane leakage, destructive mitochondrial membrane potential (Δψm), apoptosis, and DNA damage, which is nearly 7-fold higher than the negative control. At a high concentration, DNA damage index of 1.09 and 1.29 was observed for the 0.5-2 mm sized ash leachate on skin cells and lung cells respectively, whereas for ash (<0.075 mm size) leachate, this fraction was 1.29 and 2.96, respectively. Overall, the ash leachate is found to be safer/biocompatible if they come in contact with humans as compared to SSBA in its solid form.

Environmental potential assessment of MSWI bottom ash-based alkali-activated binders.

Alkali-activated binders (AABs) stand out as a sustainable alternative to ordinary Portland cement (OPC) as they can be formulated using by-products or waste as raw materials. However, the presence of hazardous compounds in residues can lead to an increase in AABs' toxicity due to the highly alkaline media. Therefore, it is extremely important to evaluate their environmental risks to validate their use as building materials. This study environmentally assessed AABs prepared with two different fractions (0-30 mm and 8-30 mm) of weathered bottom ash (AA-WBA) from WtE plants. The potential leachate toxicity of AA-WBA was assessed using granular and monolithic leaching tests that simulated end-of-life and service life scenarios, respectively. Furthermore, an acute toxicity test with crustacean Daphnia magna as model organisms was conducted to determine the relationship between the leachate metal(loid) concentrations and the ecotoxicity of AA-WBA. The results showed higher metal(loid) concentrations in AA-WBA specimens prepared with the 0-30 mm fraction of WBA. The service life scenario revealed multiple metal(loid)-release mechanisms. The 48 h EC50 value (close to 10%; moderate toxicity) indicated that the use of the coarse fraction of WBA increased the immobilisation of the metal(loid)s. Finally, the correlation between the concentrations of some of the metal(loid)s and toxicity was demonstrated.

Isoleucilactucin Ameliorates Coal Fly Ash-Induced Inflammation through the NF-κB and MAPK Pathways in MH-S Cells.

We investigated whether isoleucilactucin, an active constituent of Ixeridium dentatum, reduces inflammation caused by coal fly ash (CFA) in alveolar macrophages (MH-S). The anti-inflammatory effects of isoleucilactucin were assessed by measuring the concentration of nitric oxide (NO) and the expression of pro-inflammatory mediators in MH-S cells exposed to CFA-induced inflammation. We found that isoleucilactucin reduced CFA-induced NO generation dose-dependently in MH-S cells. Moreover, isoleucilactucin suppressed CFA-activated proinflammatory mediators, including cyclooxygenase-2 (COX2) and inducible NO synthase (iNOS), and the proinflammatory cytokines such as interleukin-(IL)-1ß, IL-6, and tumor necrosis factor (TNF-α). The inhibiting properties of isoleucilactucin on the nuclear translocation of phosphorylated nuclear factor-kappa B (p-NF-κB) were observed. The effects of isoleucilactucin on the NF-κB and mitogen-activated protein kinase (MAPK) pathways were also measured in CFA-stimulated MH-S cells. These results indicate that isoleucilactucin suppressed CFA-stimulated inflammation in MH-S cells by inhibiting the NF-κB and MAPK pathways, which suggest it might exert anti-inflammatory properties in the lung.

Comparative Toxicity of Fly Ash: An In Vitro Study.

Fly ash produced during coal combustion is one of the major sources of air and water pollution, but the data on the impact of micrometer-size fly ash particles on human cells is still incomplete. Fly ash samples were collected from several electric power stations in the United States (Rockdale, TX; Dolet Hill, Mansfield, LA; Rockport, IN; Muskogee, OK) and from a metallurgic plant located in the Russian Federation (Chelyabinsk Electro-Metallurgical Works OJSC). The particles were characterized using dynamic light scattering, atomic force, and hyperspectral microscopy. According to chemical composition, the fly ash studied was ferro-alumino-silicate mineral containing substantial quantities of Ca, Mg, and a negligible concentration of K, Na, Mn, and Sr. The toxicity of the fly ash microparticles was assessed in vitro using HeLa cells (human cervical cancer cells) and Jurkat cells (immortalized human T lymphocytes). Incubation of cells with different concentrations of fly ash resulted in a dose-dependent decrease in cell viability for all fly ash variants. The most prominent cytotoxic effect in HeLa cells was produced by the ash particles from Rockdale, while the least was produced by the fly ash from Chelyabinsk. In Jurkat cells, the lowest toxicity was observed for fly ash collected from Rockport, Dolet Hill and Muscogee plants. The fly ash from Rockdale and Chelyabinsk induced DNA damage in HeLa cells, as revealed by the single cell electrophoresis, and disrupted the normal nuclear morphology. The interaction of fly ash microparticles of different origins with cells was visualized using dark-field microscopy and hyperspectral imaging. The size of ash particles appeared to be an important determinant of their toxicity, and the smallest fly ash particles from Chelyabinsk turned out to be the most cytotoxic to Jukart cells and the most genotoxic to HeLa cells.

[Emission Characteristics and Toxicity Effects of Halogenated Polycyclic Aromatic Hydrocarbons from Coal-Fired and Waste Incineration Power Plants].

Coal-fired power plants (CFPPs) and waste incineration power plants (WIPPs) represent a large portion of polycyclic aromatic hydrocarbons (PAHs) sources in the environment, among which halogenated PAHs (HPAHs) are more toxic to the human body compared with their corresponding parent PAHs. In the current work, we investigated the occurrence, formation mechanism, and toxicity effects of HPAHs in the coal and waste combustion products from three CFPPs and one WIPP. The results indicate that the contents of chlorinated PAHs (Cl-PAHs) in the fly ash from the CFPPs and WIPP were 1.06-1.67 ng·g-1 and 2.76 ng·g-1, respectively, and the contents of brominated PAHs (Br-PAHs) in the fly ash from the CFPPs and WIPP were 26.4-44.2 ng·g-1 and 6.31 ng·g-1, respectively. The HPAH contents in the fly ash from the WIPP were significantly higher than those from the CFPPs primarily due to the abundant plastics in the domestic waste, represented by polyvinyl chloride, resulting in the formation of Cl-PAHs during combustion. The HPAH contents in the fly ash from the pulverized coal-fired (PC) boiler were significantly higher than those from the circulating fluidized bed (CFB) boiler mostly due to the higher combustion temperature operated in the PC boiler. The HPAHs in the fly ash from coal combustion were predominantly 7-BrBaA and 9-ClPhe, and those from domestic combustion were predominantly 9-BrPhe and 2-ClAnt. In addition, the contents of 7-BrBaA and 9,10-Br2 Ant in the coal combustion fly ash were significantly higher than those in domestic waste combustion fly ash, whereas 2-BrFle exhibited a contrasting profile. The content of Br-PAHs in the fly ash treated by semi-dry deacidification was twice that in dust removal fly ash but significantly increased in the chelating agent stabilization fly ash. The Pearson correlation analysis indicated the the formation mechanism of Cl-PAHs and Br-PAHs were the same but a secondary formation of HPAHs during the chelating agent stabilization of the fly ash was deduced. The TEQ values of the HPAHs in the fly ash (8.87×10-3-15.0×10-3 ng·g-1) from the WIPP were similar to those in the fly ash from the CFPPs (10.0×10-3 ng·g-1), which were significantly reduced in the fly ash treated by semi-dry deacidification due to the removal of 7-BrBaA. Moreover, the TEQ values of the HPAHs in the fly ash increased 5.4 times after the chelating agent stabilization. The ecological risk should be considered for the CFPP fly ash due to their massive amount of discharge and high TEQ values.

Incinerated Sewage Sludge Bottom Ash- Chemical processing, Leaching patterns and Toxicity testing.

Sewage sludge bottom ash, which is the major fraction obtained from the incineration of sewage sludge was treated with various organic and inorganic acids for heavy metal removal, along with a comparative phosphate treatment for heavy metal fixation. Malonic acid, an organic acid, was found to remove heavy metals better as compared to nitric acid, a strong inorganic acid. The acid treated samples were further examined for heavy metal leaching, followed by marine toxicity/abnormality testing of the leachates, where acid treated and phosphate treated ash leachate displayed higher (with malonic acid proving to be most toxic) and similar toxicity profiles as compared to raw ash leachate respectively. Raw ash was tested for its leaching patterns at different liquid/solid ratios(L/S = 5 and 10), salinities and time points (24, 48 and 72 h), where the leaching was found to saturate at L/S = 5 and at 24 h with varied salinity effecting the leaching insignificantly. When raw ash was benchmarked against concrete sand for marine toxicity, a material commonly used for land reclamation, acute toxicity patterns were found to be mostly similar except in case of the sea urchin embryonic assay, where toxicity was detected, indicating the sensitivity of the assay to residual levels of heavy metals. The raw ash was also tested against human cell lines where it displayed size and dose-dependent toxicity. To enable the use of ash for environment applications such as coastal reclamation, appropriate treatments are required to minimize leaching of potential harmful contaminants and this study demonstrates the importance of post-treatment of ash on its subsequent toxicity to organisms.

NADPH oxidase and mitochondria are relevant sources of superoxide anion in the oxinflammatory response of macrophages exposed to airborne particulate matter.

Exposure to ambient air particulate matter (PM) is associated with increased cardiorespiratory morbidity and mortality. In this context, alveolar macrophages exhibit proinflammatory and oxidative responses as a result of the clearance of particles, thus contributing to lung injury. However, the mechanisms linking these pathways are not completely clarified. Therefore, the oxinflammation phenomenon was studied in RAW 264.7 macrophages exposed to Residual Oil Fly Ash (ROFA), a PM surrogate rich in transition metals. While cell viability was not compromised under the experimental conditions, a proinflammatory phenotype was observed in cells incubated with ROFA 100 µg/mL, characterized by increased levels of TNF-α and NO production, together with PM uptake. This inflammatory response seems to precede alterations in redox metabolism, characterized by augmented levels of H2O2, diminished GSH/GSSG ratio, and increased SOD activity. This scenario resulted in increased oxidative damage to phospholipids. Moreover, alterations in mitochondrial respiration were observed following ROFA incubation, such as diminished coupling efficiency and spare respiratory capacity, together with augmented proton leak. These findings were accompanied by a decrease in mitochondrial membrane potential. Finally, NADPH oxidase (NOX) and mitochondria were identified as the main sources of superoxide anion () in our model. These results indicate that PM exposure induces direct activation of macrophages, leading to inflammation and increased reactive oxygen species production through NOX and mitochondria, which impairs antioxidant defense and may cause mitochondrial dysfunction.

Feeding inhibition following in-situ and laboratory exposure as an indicator of ecotoxic impacts of wildfires in affected waterbodies.

Among the various environmental disturbances caused by wildfires, their impacts within burnt areas and on the downhill aquatic ecosystems has been receiving increased attention. Post-fire rainfalls and subsequent runoffs play an important role in transporting ash and soil to aquatic systems within the burnt areas. These runoffs can be a diffuse source of toxic substances such as metals. The present work aims at assessing the effects of ash-loaded runoff on feeding rates of three representative aquatic invertebrates (Daphnia magna, Corbicula fluminea and Atyaephyra desmarestii) and the mosquitofish, Gambusia holbrooki, through post-exposure feeding inhibition bioassays carried out in-situ and in the laboratory using water collected from the experimental field sites. Four sites were selected in a partially burnt basin for bioassay deployment and sample collection: one site upstream of the burnt area (RUS); three sites receiving runoff directly from the burnt area, one immediately downstream of the burnt area (RDS) and two in permanent tributary streams within the burnt area (BS1 and BS2). The in-situ exposure lasted four days and began following the first post-fire major rain events. At sites affected by the wildfire, post-exposure feeding rates for D. magna, A. desmarestii and G. holbrooki were lower, which is consistent with the highest levels of metals found at these sites compared to the unaffected site, although the individual concentrations of each metal were generally below corresponding ecological safety benchmarks. Thus, interactions between metals and/or between metals and other environmental parameters certainly played a role in modulating the ecotoxic effects of the runoffs; this was further supported by a Toxic Units Summation exercise. Even if direct causal links between the ecotoxicological effects observed in D. magna, A. desmarestii and G. holbrooki and the physicochemical parameters of the water samples could not be established, the results suggest an important role of major and trace elements in explaining post-exposure feeding rate variation.

The Effect of Dietary Exposure to Coal Ash Contaminants within Food Ration on Growth and Reproduction in Daphnia magna.

Coal ash contains numerous contaminants and is the focus of regulatory actions and risk assessments due to environmental spills. We exposed Daphnia magna to a gradient of coal ash contamination under high and low food rations to assess the sublethal effects of dietary exposures. Whereas exposure to contaminants resulted in significant reductions in growth and reproduction in daphnids, low, environmentally relevant food rations had a much greater effect on these endpoints. Environ Toxicol Chem 2020;39:1998-2007. © 2020 SETAC.

Solidification and multi-cytotoxicity evaluation of thermally treated MSWI fly ash.

Municipal solid waste incineration (MSWI) fly ash produced in waste-to-energy plants possesses a serious threat to human health. Although the traditional methods including toxicity characteristic leaching procedure and sequential extraction approach can partially evaluate the reduction of heavy metals leaching from thermally treated MSWI fly ash, the potential threat towards organisms is frequently ignored in previous literature. Considering this, herein we systematically assess the cytotoxicity of heat-treated samples using multiple cells from different biological tissues/organs for the first time. The results indicate that the leachability and transferability of heavy metals are declined after treatment. The biological assays demonstrate that the leachates from the treated residues induce lower phytotoxicity and cytotoxicity compared with the original samples. Moreover, according to the cellular responses of multiple cells to the leachates, normal cells (MC3T3-E1, HUVEC, and L929) are more tolerant to the leachates than cancerous cells (4T1, MG63), and the skin fibroblasts (L929), which often interact with the external circumstance, have the best cellular tolerance. This work provides a novel platform to determine the potential biosecurity of MSWI fly ash-derived products towards organisms, when they are served as secondary building materials in the constructional industry that may be contact with animals and human beings.

Sex differences in the association between exposure to indoor particulate matter and cognitive control among children (age 6-14 years) living near coal-fired power plants.

Coal fly ash consists of inhalable particulate matter with varying concentrations of neurotoxic metals. Children living near coal-fired power plants with coal fly ash storage facilities may be exposed to coal fly ash when it escapes as fugitive dust emissions into surrounding communities. Previous research on outdoor particulate matter air pollution of similar aerodynamic diameter (PM10) suggests exposure may be associated with impaired cognitive control. The purpose of this research was to investigate sex-differences in the association between exposure to indoor PM10 and cognitive control among children (n = 221), ages 6-14 years, living near coal-fired power plants with fly ash storage facilities. In an ongoing community-based study, we measured indoor PM10 concentrations in participants' housing units and used performance measures from the BARS (Behavior Assessment and Research System) Continuous Performance Test (CPT) and Selective Attention Test (SAT) to assess neurotoxic effects on cognitive control. In adjusted negative binomial regression models, we found children living in housing units with higher indoor PM10 concentrations had a higher risk of commission errors on the CPT (incidence rate ratio (IRR) = 1.22 per interquartile range difference (IQR = 0.72 µg/m3) in natural log-transformed PM10 concentrations; 95% CI = 1.01, 1.46) and SAT (IRR = 1.14; 95% CI = 1.01, 1.28). Furthermore, child sex modified the association between PM10 concentration and CPT commission errors. Among females, higher PM10 concentration was associated with higher risk of CPT commission errors (IRR = 1.39; 95% CI = 1.06, 1.82), but we found no association among males (IRR = 1.01; 95% CI = 0.79, 1.30). We found no association between PM10 concentrations and CPT or SAT response latency. Our results suggest females living near coal-fired plants with coal fly ash storage facilities may be more susceptible to impaired cognitive control associated with particulate matter exposure. Children living near coal-fired power plants with coal fly ash storage facilities who are exposed to particulate matter may have an increased risk of impulse control problems.

Human exposure and risk assessment of recycling incineration bottom ash for land reclamation: A showcase coupling studies of leachability, transport modeling and bioaccumulation.

Incineration bottom ash (IBA) faces challenges for its sustainable recycling due to the absence of scenario-specific risk assessment. Environmental risk assessment was carried out via a case study incorporating key factors to dominate human exposures during IBA utilization in land reclamation. Three research components echoing respective IBA leaching, exposures, and consequences were performed under a supportive framework to elaborate these interlinked key factors and unveil the potential environmental risks. IBA leachability was firstly investigated using various laboratory standard leaching methods while conducted a large-scale field trial experiment for mutual confirmation, suggesting that maximum leached amounts may be achieved when liquid to solid (L/S) ratio increases to 10. Dilution and transportation models were both developed to discriminate the mitigation of IBA leachate between two periods i.e. during and after land reclamation, suggesting that dilution rather than transportation may dominate the environmental impact for metal exposures. Metal bioaccumulation from a typical mollusk species was performed coupling the calculated dietary safety limits based on Singaporean diet intake for development of the threshold of toxicology concerns on human exposures. With such, IBA benign usage in land reclamation was also conferred in the form of distance and dilution factor.

Microbial induced solidification and stabilization of municipal solid waste incineration fly ash with high alkalinity and heavy metal toxicity.

This paper presents an experimental study on the applicability of microbial induced carbonate precipitation (MICP) to treat municipal solid waste incineration (MSWI) fly ash with high alkalinity and heavy metal toxicity. The experiments were carried out on fly ashes A and B produced from incineration processes of mechanical grate furnace and circulating fluidized bed, respectively. The results showed that both types of fly ashes contained high CaO content, which could supply sufficient endogenous Ca for MICP treatment. Moreover, S. pasteurii can survive from high alkalinity and heavy metal toxicity of fly ash solution. Further, the unconfined compressive strength (UCS) of MICP treated fly ashes A and B reached 0.385MPa and 0.709 MPa, respectively. The MICP treatment also resulted in a reduction in the leaching toxicity of heavy metals, especially for Cu, Pb and Hg. MICP had a higher solidification and stabilization effect on fly ash B, which has finer particle size and higher Ca content. These findings shone a light on the possibility of using MICP technique as a suitable and efficient tool to treat the MSWI fly ash.