Toxic Chemical Emissions Research Articles

Dental plaque quantitation by light induced fluorescence technology in exclusive Electronic Nicotine Delivery Systems (ENDS) users

ObjectivesIn comparison to conventional combustible cigarettes, Electronic Nicotine Delivery Systems (ENDS) including both e-cigarettes (ECs) and heated tobacco products (HTPs) significantly reduce exposure to toxic chemical emissions. However, their impact on dental plaque remains unclear. This study measures dental plaque in ENDS (ECs and HTPs) users using quantitative light-induced fluorescence (QLF) technology, comparing them with current, former, and never smokers. MethodsThis cross-sectional study compared dental plaque measurements using QLF technology (Q-ray cam™ Pro) among current smokers (≥10 cigarettes/day), former smokers (quit ≥6 months), never smokers, and exclusive ENDS users (quit ≥6 months). Dental plaque measurements were expressed as ΔR30 (total area of mature dental plaque) and ΔR120 (greater plaque thickness/maturation-calculus). The Simple Oral Hygiene (SOH) score was calculated by the QLF proprietary software. Statistical analyses including ANCOVA was performed by R version (4.2.3) with p < 0.05. ResultsA total 30 smokers, 24 former smokers, 29 never smokers, and 53 ENDS users were included. Current smokers had significantly higher ΔR30 and ΔR120 values compared to other groups (p < 0.001). ENDS users showed plaque levels similar to never and former smokers (p > 0.05) but significantly lower than current smokers (p < 0.01). Although ENDS users showed a lower SOH score than smokers, this difference was not statistically significant. Daily toothbrushing and mouthwash usage were significant covariates. ConclusionENDS users exhibited reduced accumulation of dental plaque and calculus compared with current smokers. Clinical significanceExclusive ENDS use could less impact dental plaque accumulation compared to cigarette smoking. Further research is needed to confirm these findings and fully understand ENDS impact on dental plaque formation.

Hydrogenation of the benzene rings in PET degraded chemicals over meso-HZSM-5 supported Ru catalyst

Chemical upcycling of waste polyethylene terephthalate (PET) to value-added products can reduce the emission of CO2, microplastics and toxic chemicals. In this work, mesoporous H-type Zeolite Socony Mobil-5 (HZSM-5) supported Ru catalyst (Ru/m-HZSM-5) was synthesized and tested in the hydrogenation of PET degraded chemicals (bis(2-hydroxyethyl) terephthalate, dimethyl terephthalate, diethyl terephthalate, and terephthalic acid). Characterizations disclosed that Ru/m-HZSM-5 catalyst possesses mesopores (a dominant channel of 5.32 nm), enlarged specific surface area (404 m2·g−1), and Ru NPs dispersed highly (40.6 %) compared to that of Ru/HZSM-5. And also, it was found that Ru/m-HZSM-5 was capable for the hydrogenation of benzene rings in these PET degraded chemicals with large sizes (1.09–1.82 nm). In particular, the conversion of BHET and the selectivity of BHCD over Ru/m-HZSM-5 reached 95.5 % and 95.6 % at 120 °C within 2 h. And Ru/m-HZSM-5 could be recycled at least five times without obvious loss of activity and selectivity.

Associations between toxicity-weighted concentrations and dementia risk: Results from the Cardiovascular Health Cognition Study

BackgroundAir pollution is a modifiable risk factor for dementia. Yet, studies on specific sources of air pollution (i.e., toxic chemical emissions from industrial facilities) and dementia risk are scarce. We examined associations between toxicity-weighted concentrations of industrial pollution and dementia outcomes among a large, multi-site cohort of older adults. MethodsParticipants (n = 2770) were ≥ 65 years old (Mean = 75.3, SD = 5.1 years) from the Cardiovascular Health Cognition Study (1992–1999). Toxicity-weighted concentrations were estimated using the Risk Screening Environmental Indicator (RSEI) model which incorporates total reported chemical emissions with toxicity, fate, and transport models. Estimates were aggregated to participants' baseline census tract, averaged across 1988–1992, and log2-transformed. Dementia status was clinically adjudicated in 1998–1999 and categorized by subtype (Alzheimer's, vascular, mixed). We assessed whether RSEI-estimated toxicity-weighted concentrations were associated with 1) odds of prevalent dementia and 2) incident dementia risk by subtype. ResultsAfter adjusting for individual and census-tract level covariates, a doubling in toxicity-weighted concentrations was associated with 9 % higher odds of prevalent dementia (OR = 1.09, 95 % CI: 1.00, 1.19). In discrete-time survival models, each doubling in toxicity-weighted concentrations was associated with a 16 % greater hazard of vascular dementia (HR = 1.16, 95 % CI: 1.01, 1.34) but was not significantly associated with all-cause, Alzheimer's disease, or mixed dementia (p's > 0.05). DiscussionLiving in regions with higher toxicity-weighted concentrations was associated with higher odds of prevalent dementia and a higher risk of incident vascular dementia in this large, community-based cohort of older adults. These findings support the need for additional studies to examine whether toxic chemical emissions from industrial and federal facilities may be a modifiable target for dementia prevention.

Bacterial nano-factories as a tool for the biosynthesis of TiO2 nanoparticles: characterization and potential application in wastewater treatment.

The development of reliable and eco-conscious processes for nanoparticle synthesis constitutes a significant element in nanotechnology. TiO2 nanoparticles (NPs) are becoming essential due to their potential uses in dentistry, surgery, agriculture, and pharmacy. This leads to the development of various procedures for producing TiO2 NPs using various physicochemical methods. Still, the drawbacks of these conventional methods are associated with the emission of toxic chemicals into the atmosphere and high energy demands in production, hence endangering the health and the environment. Problems issued are solved by green nanotechnology, which offers tools as nano-factories by utilizing biological sources to subside the improper effects of conventional methods and produces nanoparticles through synthesis methods that are clean, safe, energy-efficient, and cost-effective. Among the biogenic sources, microbial cells such as bacteria possess intrinsic pathways of converting metallic salt to nanoparticles due to their ability to produce reductase enzymes. Also, they can offer features to products such as high dispersity and produce sustainable nanoparticles at a large scale. Biosynthesized TiO2 NPs have high oxidizing potential and a wide range of applications, specifically as photosensitizers and antimicrobial agents. This review will address bacterial nano-factories that can be utilized for the biosynthesis of TiO2 NPs, the characterization of biosynthesized nanoparticles, and their potential application in wastewater treatment.

TOXIC CHEMICAL EMISSIONS AND DEMENTIA RISK: RESULTS FROM THE CARDIOVASCULAR HEALTH COGNITION STUDY

Abstract Air pollution is a modifiable risk factor for dementia. Yet, studies on specific forms of air pollution (e.g., toxic chemical emissions from industrial facilities) and dementia risk are underexplored. We examined associations between toxicity-weighted concentrations of industrial pollution and dementia outcomes among a large, multi-site cohort of older adults. Participants (n=2,770) were ≥ 65 years old (M=75.3, SD=5.1 years) from the Cardiovascular Health Cognition Study. Toxicity-weighted concentrations were estimated using the Risk Screening Environmental Indicator (RSEI) model which incorporates total reported chemical emissions with toxicity, fate, and transport models. Estimates were aggregated to participants’ baseline census tract, averaged across 1988-1992, and log10-transformed. Dementia status was clinically adjudicated in 1998-1999 (M=5.2 person-periods) by subtype (all-cause, Alzheimer’s, vascular, mixed). We assessed whether RSEI-estimated toxicity-weighted concentrations were associated with: 1) odds of prevalent dementia and 2) incident dementia risk by subtype. After adjusting for individual and neighborhood-level covariates, a 1-unit increase in log10-toxicity was associated with a 34% increase in the odds of prevalent dementia (OR=1.34, 95% CI: 1.01, 1.78). In discrete-time survival models, each 1-unit increase in log10-toxicity was associated with a 65% increased hazard of vascular dementia (HR=1.65, 95% CI: 1.04, 2.61) but was not significantly associated with all-cause, Alzheimer’s disease, or mixed dementia. Living in regions with higher toxic air emissions was associated with greater odds of prevalent dementia and a heightened risk of incident vascular dementia. Results suggest that the RSEI model may be a novel screening tool for examining associations between toxic chemical releases and dementia risk.

Trends of sustainable recycling technology for lithium‐ion batteries: Metal recovery from conventional metallurgical processes to innovative direct recycling

AbstractThe remarkable market growth of lithium‐ion batteries (LIBs) for various applications has been witnessed in the past two decades. However, as a retirement wave of more and more LIBs approaches, the disposed end‐of‐life batteries represent a growing hazard to ecosystem and human health. Recycling valuable metals from those spent LIBs still remain challenging because the current conventional metallurgical recycling processes involve the emission of toxic gas and waste chemicals as well as intensive energy consumption. These processes are not considered as green recycling approaches that contradict with the principles of carbon neutrality and circular economy embraced by the world. Hence, implementing green and sustainable recycling technologies of spent LIBs, especially for cathode materials, is an urgent need. This review provides a comprehensive understanding and critical evaluation of traditional pyrometallurgy, hydrometallurgy, and state‐of‐the‐art direct recycling for recovering valuable metal materials from the spent LIB cathode. The fundamentals, methods, efficiencies, and feasibility of the three recycling approaches are also assessed. In addition, the recent progress for green innovation of hydrometallurgical and direct recycling processes as well as the potential research tendency for spent LIBs are discussed.

EPA targets toxic chemical plant emissions

EPA targets toxic chemical plant emissions

Ecological unequal exchange: quantifying emissions of toxic chemicals embodied in the global trade of chemicals, products, and waste

Ecologically unequal exchange arises if more developed economies (‘core’) shift the environmental burden of their consumption and capital accumulation to less developed economies (‘periphery’/‘semi-core’). Here we demonstrate that human populations in core regions can benefit from the use of products containing toxic chemicals while transferring to the periphery the risk of human and ecological exposure to emissions associated with manufacturing and waste disposal. We use a global scale substance flow analysis approach to quantify the emissions of polybrominated diphenyl ethers (PBDEs), a group of flame retardants added to consumer products, that are embodied in the trade of chemicals, products and wastes between seven world regions over the 2000–2020 time period. We find that core regions have off-loaded PBDE emissions, mostly associated with the disposal of electrical and electronic waste (e-waste), to semi-core and peripheral regions in mainland China and the Global South. In core regions this results in small emissions that mostly occur during the product use phase, whereas in peripheral regions emissions are much higher and dominated by end of life disposal. The transfer of toxic chemical emissions between core and periphery can be quantified and should be accounted for when appraising the costs and benefits of global trade relationships.

Invited Perspective: Oil and Gas Development and Adverse Birth Outcomes: What More Do We Need to Know?

Invited Perspective: Oil and Gas Development and Adverse Birth Outcomes: What More Do We Need to Know?

Particle/gas partitioning for semi-volatile organic compounds (SVOCs) in level III multimedia fugacity models: Both gaseous and particulate emissions

Multimedia fugacity models have long been used to address the fate of toxic organic chemical emissions by providing a quantitative account of the sources, transport processes, and sinks. Recently, we have examined three level-III fugacity models (E4F (equilibrium six-compartment four-fugacity), S6F (steady-state six-compartment six-fugacity) and S4F (steady-state six-compartment four-fugacity) Models), in the context of their performance set against real-world data, and their practicality of application. Here, we discuss how the balance between gaseous and aerosol phases of emissions assumed for initial conditions affects the different model outcomes. Our results show that the S6F Model predictions closely match those of the S4F Model when chemical emissions are entirely in the gas-phase. As the particulate proportion of the emission increases, the S6F Model predictions diverge from those of the S4F Model and approach those of the E4F Model. Once the particulate portion reaches 100%, the S6F and E4F Models produce identical results: an internally inconsistent system where chemicals are not in a steady state between air and aerosols, and mass balance for both air and aerosols is not achieved. Thus, in terms of practicality, internal consistency, chemical mass balance and agreement with observations, the S4F Model is clearly the best choice.

Gulls foraging in landfills: Does atmospheric exposure to halogenated flame retardants result in bioaccumulation?

Several bird species have adapted to foraging in landfills, although these sites are known to represent significant sources of emissions of toxic semi-volatile chemicals including the halogenated flame retardants (HFRs) (e.g., polybrominated diphenyl ethers (PBDEs) and emerging compounds). The objective of this study was to investigate the association between atmospheric exposure to PBDEs and selected emerging HFRs and their bioaccumulation in landfill-foraging birds. We determined HFR concentrations in liver of 58 GPS-tagged ring-billed gulls (Larus delawarensis) breeding in a colony near Montreal (Canada) as well as their atmospheric exposure determined using a miniature bird-borne passive air sampler. PBDE mixtures were the most abundant HFRs determined in passive air samplers (daily exposure rates of ∑9PentaBDE: 47.4 ± 6.5 pg/day; DecaBDE: 36.0 ± 6.3 pg/day, and ∑3OctaBDE: 3.4 ± 0.5 pg/day) and liver (∑9PentaBDE: 68.1 ± 8.9 ng/g ww; DecaBDE: 52.3 ± 8.1 ng/g ww, and ∑3OctaBDE: 12.8 ± 2.1 ng/g ww), and their concentrations increased with the presence probability of gulls in landfills. We found a spatial relationship between the local sources of atmospheric exposure to PBDEs and the sites associated with greatest PBDE concentrations in liver. Specifically, the atmospheric exposure index was correlated with the bioaccumulation index (Pearson r for ∑9PentaBDE: r = 0.63, p < 0.001; DecaBDE: r = 0.66, p < 0.001, and ∑3OctaBDE: r = 0.42, p < 0.001). However, we found no correlation at the individual level between daily exposure rates of HFRs in passive air samplers and their liver concentrations. This suggests that complex exposure pathways combined with toxicokinetic factors shaped HFR profiles in gull liver, potentially confounding the relationships with atmospheric exposure.

Hazardous air pollutant emissions implications under 2018 guidance on U.S. Clean Air Act requirements for major sources

ABSTRACT On January 25, 2018, the United States Environmental Protection Agency withdrew a 1995 policy that mandates the use of maximum achievable control technology (MACT) to regulate emissions from major sources of hazardous air pollutants (HAPs), a category of toxic chemicals that may be carcinogenic, mutagenic, or cause other adverse health effects. To better understand the implications and scope of the change in regulatory guidance for HAP emissions of major sources that may reclassify as area sources, the increase in emissions that could legally occur under the new policy is assessed here. Based on facility-level data from a 2014 HAP national emissions inventory, it is estimated that 70% of major sources of HAPs qualify for reclassification as area sources, which could result in a maximum of 35,030 tons per year (tpy) of additional HAP emissions if all sources successfully reclassified. This amount would nearly triple the total volume of HAPs that qualifying major sources emitted in 2014. On average, qualifying sources could emit individually an additional 18.4 tpy. In the 21 states and territories that follow only federal guidelines for controlling HAPs, it is more likely that the estimates presented here could materialize compared to states that have additional guidelines for area sources of HAPs. The quantitative analysis of the potential emission changes resulting from regulatory change is instructive for industry, state and federal decisionmakers, and interested members of the public looking to understand and anticipate how relevant stakeholders will be affected by this policy change. Implications: Withdrawal of a U.S. Environmental Protection Agency policy that mandates the use of maximum achievable control technology (MACT) to regulate emissions from major sources of hazardous air pollutants (HAPs) could result in higher emissions of toxic chemicals that may be carcinogenic, mutagenic, or cause other adverse health effects. Analysis of potential emission changes resulting from regulatory change is instructive for industry, state, and federal decisionmakers, and interested members of the public looking to understand and anticipate how relevant stakeholders will be affected by this policy change.

Green Hedge Fund Activists

We examine the environmental impact of hedge fund activism. We find that firms targeted by hedge fund activism reduce toxic chemical emissions. In particular, target firms close heavy polluting plants and investing in green pollution-reduction technologies to reduce toxic emissions. We also find that target firms with the larger decreases in toxic chemical emissions experience higher stock returns after activism.

Capitalizing on Sustainability: Value of Going Green

We investigate how corporate environmental responsibility (CER) actions affect firm value. We adopt an event studies approach using two narrowly-decided 5-to-4 Supreme Court rulings and show that firms gain value when they are expected to increase their CER activities. The market reactions are larger for firms that are affected to a greater extent by the Court decisions. These return patterns are more pronounced among firms in regions with high levels of social trust. Firms that reduced toxic chemical emissions show positive earnings surprises, higher revenue and profitability, and greater capital inflow from institutional investors with longer horizons. In sum, we present empirical evidence consistent with the market viewing CER as leading to higher firm value.

Combustibility and characteristics of wood-fiber insulation boards prepared with four different adhesives

Wood-fiber insulation boards can be utilized as a core construction material. They provide a comfortable and safe residential space and reduce energy consumption because of the ecofriendly nature and high heat insulation. In this study, wood-fiber insulation boards were prepared with different types of adhesive (melamine-urea-formaldehyde (MUF), phenol-formaldehyde (PF), emulsifiable 4,4’ methylene diisocyanate (eMDI), and latex resins), and the physical and heat insulation properties, toxic chemical emissions, and combustion characteristics were analyzed. The different adhesive types had no major effects on the insulation. With regard to the toxic emissions, all wood-fiber insulation boards showed the best rating possible except for the PF resin. In the cone-calorimeter test, the wood-fiber insulation board prepared with MUF showed a lower total heat release, mean heat release rate, smoke release, and CO and CO2 yields than the other samples because of the early formation of the carbonized layer. Based on the comprehensive evaluation, the MUF adhesive is the best choice for wood-fiber insulation boards.

Risk assessment in case of toxic chemical emission at railway transport

Risk assessment during emission of toxic chemicals at railway transport is the problem of great scientific interest. To make such assessment we need special computer models. At present, in Ukraine,we have lack of such models. The authors present numerical models for territorial risk assessment in case of organized emissionsat railway transport (for example, emissions during locomotive movement) and in case of accident emissions (accident spills of dangerous cargo, emissions of NH3 from railway tank, etc.). The basis of the developed numerical models is the system of fundamental equations of fluid dynamics. These equations are solved numerically using implicit schemes of splitting. The developed models allow to take into account some important factors which influence the territorial risk value: probability of atmosphere conditions, train route, transport infrastructure at railway stations, probability of emission site.Also the process of pollutant chemical transformation in the atmosphere is taken into account in the developed models. The developed models allow to predict territorial risk in case of moving source of emission (moving damaged railway tank).The results of numerical experiments are presented. These results illustrate territorial risk maps for different sites near Prydniprovska railway.

A Mini-Review on Organic synthesis in Water

The use of water as solvent in organic synthesis is one of the most powerful tool of green chemistry as it reduces emission of toxic chemicals in the environment thereby reducing pollution Reactions can be carried out under mild conditions minimizing chemical waste with easy work up procedure enabling recycling of the catalyst This review briefly highlights some important reactions carried out recently in water

Pediatric Environmental Health: Using Data on Toxic Chemical Emissions in Practice

Children's unique behavioral and physiological characteristics can increase their exposure and susceptibility to environmental chemicals. The link between exposure to environmental chemicals and specific health outcomes, however, is often uncertain. This article introduces several resources to help health practitioners identify potential environmental exposures and risks related to toxic chemicals. It focuses on the U.S. Environmental Protection Agency's (EPA's) free and public environmental data, including the Toxics Release Inventory (TRI) data that contain information about toxics released to the environment. Three hypothetical case studies are presented to demonstrate how these data can help answer environmental exposure questions. The first case study illustrates a scenario where multiple patients in an area exhibit the same symptoms with a suspected link to environmental chemicals. The second case study illustrates a scenario where a patient with a confirmed exposure to a toxic chemical needs assistance with identifying potential environmental sources. And the third case study illustrates a scenario where a patient is concerned about the potential for future exposure to an environmental contaminant in a particular geographic area. Each case study includes contacts for follow-up questions, including the Pediatric Environmental Health Specialty Units (PEHSUs), EPA regional staff, state environmental agencies, and local health departments. These resources can help practitioners access and interpret environmental data, answer questions about potential exposures, and inform next steps if necessary.

Numerical analysis of the interaction between high-pressure resin spray and wood chips in a vapour stream

This article investigates the interaction between the resin spray and the wood chips in a vapour stream using a multi-phase multi-component computational fluid dynamics approach. The interaction between the spray and the chips is one of the main issues in the industrial process for manufacturing medium density fibre boards. Thus, the optimization of this process can lead to important benefits, such as the reduction in the emission of formaldehyde-based toxic chemicals, the reduction in energy consumption in the blending process and energy saving in the fibreboard drying process. First step of the study is the numerical analysis of the resin injector in order to extend the experimental measurements carried out with water to the resin spray. The effects of the injector’s geometrical features on the spray formation are highlighted under different injection pressure values and needle displacements. Afterwards, the results obtained in the analysis of the single injector are used for the complete simulation of multi-injector rail where the mixing of the resin spray and wood chips takes place. The influence of the main operating conditions, such as the vapour and the wood chip flow rates, on the resin distribution is addressed in order to optimize the resination process.

Pollution havens and the trade in toxic chemicals: Evidence from U.S. trade flows

National registries of toxic chemical emissions and facilities are increasingly used to raise public awareness of potential health hazards in local areas, but an unintended consequence may be the offshoring of production to less regulated countries. Using disaggregated U.S. trade data, this study examines the impact of registry listing on subsequent bilateral trade flows. Estimates from a difference-in-differences model indicate a significant shift toward imports from poorer countries following registry listing. Assuming that environmental protection is a normal good, this result suggests the emergence of pollution havens due to more stringent U.S. environmental regulation.