Hazardous Waste Remediation Research Articles

Assessment of Innovative Technologies for Hazardous Waste Treatment and Remediation Review: A Sustainable Approach for Environmental Protection

<p>The management of hazardous waste is a critical environmental challenge that requires innovative and sustainable solutions to mitigate adverse impacts on ecosystems and human health. This research project aims to assess and evaluate cutting-edge technologies for the treatment and remediation of hazardous waste, focusing on their sustainability and effectiveness in environmental protection. The study will investigate various innovative methods such as advanced oxidation processes, bioremediation techniques, nanotechnology applications, and green chemistry strategies. These technologies offer promising opportunities to address hazardous waste contamination while minimizing resource consumption and environmental footprints. The research will include a comprehensive review of existing literature, case studies, and technical reports to gather insights into the performance, cost-effectiveness, and environmental benefits of these innovative technologies. Special emphasis will be placed on evaluating their applicability across different types of hazardous waste, ranging from industrial chemicals and pollutants to electronic waste and persistent organic pollutants. Furthermore, the study will analyze regulatory frameworks, policy implications, and socio-economic factors influencing the adoption and implementation of these technologies in diverse industrial sectors and geographical regions. Through rigorous assessment and analysis, this research aims to provide valuable insights and recommendations for stakeholders, policymakers, and environmental practitioners involved in hazardous waste management. The findings will contribute to advancing sustainable approaches for addressing hazardous waste challenges, promoting environmental protection, and fostering a circular economy mindset in waste management practices.</p>

A new molecular thermodynamic model of liquid-liquid interfacial tension

• A new molecular thermodynamic model of interfacial tension is derived. • This model yields satisfactory prediction results for interfacial tension. • It doesn't require mutual solubility data for interfacial tension predictions. • This model is simple in implementation and reliable in application. Interfacial tension between water and organic liquids plays an important role in the design and optimization of various processes, such as enhanced oil recovery, the entrapment and migration of non-aqueous phase liquid (NAPL), chemical separation technology (liquid-liquid extraction) relevant to ex-situ hazardous waste remediation and chemical processing. A new molecular thermodynamic approach of monolayer interface model was developed in this work, in which the total interfacial energy includes contributions from the excess interface cohesive energy and excess interface entropy (entropy from partially mixing and entropy from free volume change). The accuracy of this model in the prediction of interfacial tension for water-organic liquid and mercury-nonmetallic liquid systems has been examined with satisfactory results. The investigation results indicates that for water-organic liquid systems, the excess interface entropy term makes considerable contribution (9.5%∼46.6%) to the total interfacial energy, which may result in the interaction parameter of Girifalco and Good model being greater than unity (1.04≤ Φ ≤1.15) for water-alcohols; while for mercury-nonmetallic liquid systems, the contribution to the total interfacial energy from interfacial entropy is negligible (1.2%∼2.7%), the difference in cohesive energy of molecules between the bulk phase and interfacial phase dominates the wetting process. This method doesn't require measured mutual solubility data for interfacial tension predictions, which is simple in implementation and reliable in application.

Bioprocess development as a sustainable platform for eco-friendly alkaline phosphatase production: an approach towards crab shells waste management

BackgroundThere are substantial environmental and health risks associated with the seafood industry's waste of crab shells. In light of these facts, shellfish waste management is critical for environmental protection against hazardous waste produced from the processing industries. Undoubtedly, improved green production strategies, which are based on the notion of "Green Chemistry," are receiving a lot of attention. Therefore, this investigation shed light on green remediation of the potential hazardous crab shell waste for eco-friendly production of bacterial alkaline phosphatase (ALP) through bioprocessing development strategies.ResultsIt was discovered that by utilizing sequential statistical experimental designs, commencing with Plackett–Burman design and ending with spherical central composite design, and then followed by pH-uncontrolled cultivation conditions in a 7 L bench-top bioreactor, an innovative medium formulation could be developed that boosted ALP production from Bacillus licheniformis strain ALP3 to 212 U L−1. The highest yield of ALP was obtained after 22 h of incubation time with yield coefficient Yp/s of 795 U g−1, which was 4.35-fold higher than those obtained in the shake-flask system. ALP activity has a substantial impact on the volatilization of crab shell particles, as shown by the results of several analytical techniques such as atomic absorption spectrometry, TGA, DSC, EDS, FTIR, and XRD.ConclusionsWe highlighted in the current study that the biovalorization of crab shell waste and the production of cost-effective ALP were being combined and that this was accomplished via the use of a new and innovative medium formulation design for seafood waste management as well as scaling up production of ALP on the bench-top scale.

Destructing surfactant network in nanoemulsions by positively charged magnetic nanorods to enhance oil-water separation

The separation of ultrafine oil droplets from wasted nanoemulsions stabilized with high concentration of surfactants is precondition for oil reuse and the safe discharge of effluent. However, the double barriers of the interfacial film and network structures formed by surfactants in nanoemulsions significantly impede the oil-water separation. To destroy these surfactant protective layers, we proposed a newly-developed polyethyleneimine micelle template approach to achieve simultaneous surface charge manipulation and morphology transformation of magnetic nanospheres to magnetic nanorods. The results revealed that positively charged magnetic nanospheres exhibited limited separation performance of nanoemulsions, with a maximum chemical oxygen demand (COD) removal of 50%, whereas magnetic nanorods achieved more than 95% COD removal in less than 30 s. The magnetic nanorods were also applicable to wasted nanoemulsions from different sources and exhibited excellent resistance to wide pH changes. Owing to their unique one-dimensional structure, the interfacial dispersion of magnetic nanorods was significantly promoted, leading to the efficient capture of surfactants and widespread destruction of both the interfacial film and network structure, which facilitated droplet merging into the oil phase. The easy-to-prepare and easy-to-tune strategy in this study paves a feasible avenue to simultaneously tailor surface charge and morphology of magnetic nanoparticles, and reveals the huge potential of morphology manipulation for producing high-performance nanomaterials to be applied in complex interfacial interaction process. We believe that the newly-developed magnetic-nanorods significantly contribute to hazardous oily waste remediation and advances technology evolution toward problematic oil-pollution control.

Exposure to combustion derived particulate matter exacerbates influenza infection in neonatal mice by inhibiting IL22 production

BackgroundParticulate matter (PM) containing environmentally persistent free radicals (EPFRs) are formed during various combustion processes, including the thermal remediation of hazardous wastes. Exposure to PM adversely affects respiratory health in infants and is associated with increased morbidity and mortality due to acute lower respiratory tract infections. We previously reported that early-life exposure to PM damages the lung epithelium and suppresses immune responses to influenza virus (Flu) infection, thereby enhancing Flu severity. Interleukin 22 (IL22) is important in resolving lung injury following Flu infection. In the current study, we determined the effects of PM exposure on pulmonary IL22 responses using our neonatal mouse model of Flu infection.ResultsExposure to PM resulted in an immediate (0.5–1-day post-exposure; dpe) increase in IL22 expression in the lungs of C57BL/6 neonatal mice; however, this IL22 expression was not maintained and failed to increase with either continued exposure to PM or subsequent Flu infection of PM-exposed mice. This contrasts with increased IL22 expression in age-matched mice exposed to vehicle and Flu infected. Activation of the aryl hydrocarbon receptor (AhR), which mediates the induction and release of IL22 from immune cells, was also transiently increased with PM exposure. The microbiome plays a major role in maintaining epithelial integrity and immune responses by producing various metabolites that act as ligands for AhR. Exposure to PM induced lung microbiota dysbiosis and altered the levels of indole, a microbial metabolite. Treatment with recombinant IL22 or indole-3-carboxaldehyde (I3A) prevented PM associated lung injury. In addition, I3A treatment also protected against increased mortality in Flu-infected mice exposed to PMs.ConclusionsTogether, these data suggest that exposure to PMs results in failure to sustain IL22 levels and an inability to induce IL22 upon Flu infection. Insufficient levels of IL22 may be responsible for aberrant epithelial repair and immune responses, leading to increased Flu severity in areas of high PM.

Mission net-zero America: The nation-building path to a prosperous, net-zero emissions economy

Jesse D. Jenkins is an assistant professor at Princeton University in the department of mechanical and aerospace engineering and the Andlinger Center for Energy and the Environment. He is a macro-scale energy systems engineer with a focus on the rapidly evolving electricity sector and leads the Princeton ZERO Lab, which focuses on improving and applying optimization-based energy systems models to evaluate low-carbon energy technologies and generate insights to guide policy and planning decisions. Jesse earned a PhD and SM from the Massachusetts Institute of Technology and was previously a postdoctoral environmental fellow at Harvard University. Erin N. Mayfield is an assistant professor at the Thayer School of Engineering at Dartmouth College focusing her research on sustainable-systems engineering and public policy. She develops and applies multi-objective computational models that integrate techno-economic, environmental, and social equity objectives to inform energy and industrial infrastructure transitions. Prior to her academic research career, her work with other organizations included regulatory assessments of environmental rule-makings, hazardous waste remediation in environmental justice communities, and ecosystem services valuation related to petrochemical and pesticide contamination. Erin has a PhD in engineering and public policy from Carnegie Mellon University and was previously a postdoctoral scholar at Princeton University. Eric Larson is a senior research engineer at Princeton University leading the Energy Systems Analysis Group in the Andlinger Center for Energy and the Environment. He holds courtesy appointments with the High Meadows Environmental Institute and the Center for Policy Research on Energy and the Environment in the School of Public and International Affairs. His research, intersecting engineering, environmental science, economics, and public policy, aims to identify sustainable, engineering-based solutions to major energy-related problems and to help inform public and private decision-making in the U.S. and elsewhere. Eric has a PhD in mechanical engineering from the University of Minnesota. Stephen Pacala is the Frederick D. Petrie professor in ecology and evolutionary biology at Princeton University and director of the Princeton Carbon Mitigation Initiative. His research interests are in the design and testing of mathematical models to investigate interactions between greenhouse gases, climate, and the biosphere and to predict their effects on local and global ecosystems. He is a member of the U.S. National Academy of Sciences, the American Association for the Advancement of Science, and the American Academy of Arts and Sciences. Steve has a PhD in biology from Stanford University. Chris Greig is the Theodora D. and William H. Walton III senior research scientist in the Andlinger Center for Energy and the Environment at Princeton University. His research interests lie in energy transitions, economics, and policy; capital project investment decision-making and implementation; and carbon capture, utilization, and storage. Chris has a PhD in chemical engineering from the University of Queensland and is a fellow of the Australian Academy of Technology and Engineering. His academic career was preceded by 25 years in senior project and executive roles in the resources and energy sectors.

Landfilled coal ash for carbon dioxide capture and its potential as a geopolymer binder for hazardous waste remediation

The legacy of global fossil fuel usage is not just the increase in global warming due to CO2 production, but also the billions of tons of toxic coal ash disposed in landfills. This investigation evaluates the merits of using high-calcium landfilled coal fly ash of different disposal durations and granulated blast furnace (GBF) slag as primary raw materials for production of a new class of geopolymer binder. Processing of landfilled coal fly ash, GBF slag and supplementary raw materials into a geopolymer binder was accomplished by a simple, scalable milling process in the absence of heating under a carbon dioxide environment. The resultant geopolymer cement binders were tested for carbon dioxide uptake, compressive strength, and heavy metal stabilization. The geopolymer binder demonstrated a desired balance of carbon dioxide uptake, strength and safety. These results also indicate that the performance of the geopolymer binder depends on the landfill disposal age of the coal fly ash.

(Invited) Oxidation of Alloy-X in Near Supercritical and Supercritical Water

Supercritical water is a growing medium for power production, hazardous waste remediation, and chemical synthesis. These broad applications require robust materials that can withstand exposure to the high operating temperatures and pressures of supercritical water, while achieving these conditions necessitates that water transitions from the subcritical state to the higher enthalpy supercritical state. This region of transition has been observed to be the region with the greatest variation in thermophysical properties, with reports of a local maximum in corrosion rate. Experimental procedures have been employed to study the effects of exposure of Alloy X to the near supercritical and supercritical region in the supercritical water loop at The University of Nevada, Reno, which is of a design that allows for controlled exposure to the transition region between subcritical and supercritical water. An investigation into the oxidation of Alloy X included characterization by Raman spectroscopy, X-ray diffraction pattern analysis, scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. Observation and characterization of the oxidation as a result of exposure will allow for the evaluation of Alloy X as a candidate for application in processes utilizing supercritical water, as well as increased understanding of the specific demands of exposure to the transition region between subcritical and supercritical water.Acknowledgements: The SCWL was funded by the Department of Energy through a Nuclear Energy grant: DE-NE0000454. Kenny Osborne serves as the program manager for the DOE award. This work was performed under the auspices of the US Nuclear Regulatory Commission Faculty Development Program under contract NRC-HQ-11-G-0039. Nancy Hebron-Isreal serves as the grants program officer for the NRC award.

Synthesis and mechanical properties of Bi2O3-Al4Bi2O9 nanopowders

As a result of great surface area and a great number of energetic sites, ceramic nanocomposites are being considered as good adsorbents and catalysts. Al2O3 nanoparticles are widely used in high-tech applications owing to their excellent properties. Besides, Bi-based oxides have been the center of attention for applications such as remediation of hazardous wastes and wastewater photochemical degradation of organic contaminants and remediation of hazardous wastes. In this research, the synthesis of Bi2O3-Al4Bi2O9 nanocomposite and its mechanical properties as a novel composition were investigated. The results showed that the prepared Bi2O3-Al4Bi2O9 sample exhibited the Al4Bi2O9 crystalline peaks. Additionally, the prepared nanocomposite showed no impurities. The mechanical properties of the Bi2O3-Al4Bi2O9 sample were improved in comparison with Al2O3, Bi2O3, and Bi2O3- Al2O3, which offer it as a promising alternative to Bi2O3-Al2O3 composite ceramic.

Microbial Electro-Remediation (MER) of hazardous waste in aid of sustainable energy generation and resource recovery

Abstract In recent years, bioelectrochemical hybrid technology has emerged as an alternative energy conversion device for bioelectricity generation with concurrent waste remediation. The major attractions of this bioelectrochemical technology are eco-friendly nature, energy-saving, and energy transformation with reduced sludge generation. A wide variety of substrates, including complex wastewater, can be employed as a potential substrate to operate the bioelectrochemical cells (BEC). Hence, microbial electro-remediation technologies are aimed towards the enhancement of the metabolic activity of electrochemically active biocatalyst by supplying organic/inorganic nutrients, electron acceptors, or donors, thus stimulating oxidation or reduction of contaminants. In this regard, BEC has gained much attention, in which the control environment is feasible by means of electrical current/voltage that serves as a donor or acceptor for hazardous waste remediation. In the present review, we mainly emphasize the developments and advancements of microbial electro-remediation technologies in the direction of complex hazardous waste remediation. We reviewed and discussed various BEC mediated complex pollutants remediation (ex: aromatics, dye, nitrogen compounds, heavy metals etc.) and its limitations. In conclusion, the future perspectives in the BEC for bioenergy generation with concurrent waste remediation are proposed through numerous aspects and approaches to afford clean energy and the environment.

A Water-Stable Ionic MOF for the Selective Capture of Toxic Oxoanions of SeVI and AsV and Crystallographic Insight into the Ion-Exchange Mechanism.

Selectively capturing toxic oxoanions of selenium and arsenic is highly desired for the remediation of hazardous waste. Ionic metal-organic frameworks (iMOFs) especially cationic MOFs (iMOF-C) as ion-exchange materials, featuring aqueous phase stability, present a robust pathway for sequestration of the oxoanions owing to their ability to prevent leaching because of their ionic nature. On account of scarcity of water-stable cationic MOFs, the capture of oxoanions of selenium and arsenic has been a major challenge and has not been investigated using iMOFs. Herein, we demonstrate large scale synthesis of cationic MOF, viz. iMOF-1C that exhibits selective capture of oxoanions of SeVI (SeO42- ) and AsV (HAsO42- ) in water with a maximum sorption capacity of 100 and 85 mg g-1 , respectively. This represents among the highest uptake capacities observed for selenate oxoanion in MOFs. Further, the ion-exchange mechanism was directly unveiled by single crystal analysis, which revealed variable modes of host-guest binding.

A Water‐Stable Ionic MOF for the Selective Capture of Toxic Oxoanions of SeVI and AsV and Crystallographic Insight into the Ion‐Exchange Mechanism

AbstractSelectively capturing toxic oxoanions of selenium and arsenic is highly desired for the remediation of hazardous waste. Ionic metal–organic frameworks (iMOFs) especially cationic MOFs (iMOF‐C) as ion‐exchange materials, featuring aqueous phase stability, present a robust pathway for sequestration of the oxoanions owing to their ability to prevent leaching because of their ionic nature. On account of scarcity of water‐stable cationic MOFs, the capture of oxoanions of selenium and arsenic has been a major challenge and has not been investigated using iMOFs. Herein, we demonstrate large scale synthesis of cationic MOF, viz. iMOF‐1C that exhibits selective capture of oxoanions of SeVI (SeO42−) and AsV (HAsO42−) in water with a maximum sorption capacity of 100 and 85 mg g−1, respectively. This represents among the highest uptake capacities observed for selenate oxoanion in MOFs. Further, the ion‐exchange mechanism was directly unveiled by single crystal analysis, which revealed variable modes of host–guest binding.

Advancing science in rapidly changing environments: opportunities for the Central and Eastern European Conference on Health and the Environment to connect to other networks.

The Central and Eastern Europe region is faced with longstanding environmental health problems as well as emerging health threats from pollution caused by the region's recent period of rapid industrialization. As researchers in the region continue to work to address these problems, they could find unique approaches by increasing collaborations between biomedical and non-biomedical scientists and by more closely following the Superfund Research Program model of pursuing basic research, then connecting with stakeholders in the region to share and apply new knowledge. To build upon and leverage research in the region, researchers and stakeholders should work to formalize the bi-annual meeting of the Central and Eastern European Conference on Health and the Environment into a more cohesive organization and make efforts to connect to broader global networks that aim to spread research results and applications around the world. By taking these steps to connect to the broader world of environmental health research, the CEE region stakeholders can reduce pollution-related disease, minimize costs of hazardous waste remediation, and help grow the economy in their region.

Radical containing combustion derived particulate matter enhance pulmonary Th17 inflammation via the aryl hydrocarbon receptor

BackgroundPollutant particles containing environmentally persistent free radicals (EPFRs) are formed during many combustion processes (e.g. thermal remediation of hazardous wastes, diesel/gasoline combustion, wood smoke, cigarette smoke, etc.). Our previous studies demonstrated that acute exposure to EPFRs results in dendritic cell maturation and Th17-biased pulmonary immune responses. Further, in a mouse model of asthma, these responses were enhanced suggesting exposure to EPFRs as a risk factor for the development and/or exacerbation of asthma. The aryl hydrocarbon receptor (AHR) has been shown to play a role in the differentiation of Th17 cells. In the current study, we determined whether exposure to EPFRs results in Th17 polarization in an AHR dependent manner.ResultsExposure to EPFRs resulted in Th17 and IL17A dependent pulmonary immune responses including airway neutrophilia. EPFR exposure caused a significant increase in pulmonary Th17 cytokines such as IL6, IL17A, IL22, IL1β, KC, MCP-1, IL31 and IL33. To understand the role of AHR activation in EPFR-induced Th17 inflammation, A549 epithelial cells and mouse bone marrow-derived dendritic cells (BMDCs) were exposed to EPFRs and expression of Cyp1a1 and Cyp1b1, markers for AHR activation, was measured. A significant increase in Cyp1a1 and Cyp1b1 gene expression was observed in pulmonary epithelial cells and BMDCs in an oxidative stress and AHR dependent manner. Further, in vivo exposure of mice to EPFRs resulted in oxidative stress and increased Cyp1a1 and Cyp1b1 pulmonary gene expression. To further confirm the role of AHR activation in pulmonary Th17 immune responses, mice were exposed to EPFRs in the presence or absence of AHR antagonist. EPFR exposure resulted in a significant increase in pulmonary Th17 cells and neutrophilic inflammation, whereas a significant decrease in the percentage of Th17 cells and neutrophilic inflammation was observed in mice treated with AHR antagonist.ConclusionExposure to EPFRs results in AHR activation and induction of Cyp1a1 and in vitro this is dependent on oxidative stress. Further, our in vivo studies demonstrated a role for AHR in EPFR-induced pulmonary Th17 responses including neutrophilic inflammation.

Smart Kd-values, their uncertainties and sensitivities - Applying a new approach for realistic distribution coefficients in geochemical modeling of complex systems

One natural retardation process to be considered in risk assessment for contaminants in the environment is sorption on mineral surfaces. A realistic geochemical modeling is of high relevance in many application areas such as groundwater protection, environmental remediation, or disposal of hazardous waste. Most often concepts with constant distribution coefficients (Kd-values) are applied in geochemical modeling with the advantage to be simple and computationally fast, but not reflecting changes in geochemical conditions.In this paper, we describe an innovative and efficient method, where the smart Kd-concept, a mechanistic approach mainly based on surface complexation modeling, is used (and modified for complex geochemical models) to calculate and apply realistic distribution coefficients. Using the geochemical speciation code PHREEQC, multidimensional smart Kd-matrices are computed as a function of varying (or uncertain) environmental conditions. On the one hand, sensitivity and uncertainty statements for the distribution coefficients can be derived. On the other hand, smart Kd-matrices can be used in reactive transport (or migration) codes (not shown here). This strategy has various benefits: (1) rapid computation of Kd-values for large numbers of environmental parameter combinations; (2) variable geochemistry is taken into account more realistically; (3) efficiency in computing time is ensured, and (4) uncertainty and sensitivity analysis are accessible.Results are presented exemplarily for the sorption of uranium(VI) onto a natural sandy aquifer material and are compared to results based on the conventional Kd-concept. In general, the sorption behavior of U(VI) in dependence of changing geochemical conditions is described quite well.

Environmentally Sustainable Visible Photocatalytic Nanostructured ZnS Doped with CuS for Chemical Effluent Treatment Applications

Owing part of the innovative research concerning the degradation of the chemical industry pollutants was notably focused on photocatalysis process, in order to meet the strict pollution abatement legislation required by environmental protection agencies worldwide. Nanostructured TiO2, ZnO and ZnS as a semiconductor photocatalysts have proved to be effective and more suitable for the widespread environmental application, such as air purification, water disinfection, hazardous waste remediation and water purification. In the present investigation, CuS doped ZnS nanopowders have been synthesized by simple and cost effective sol-gel process. The dried powders have been sintered and the visible photocatalytic property of the pure ZnS and CuS doped in ZnS have been tested for the degradation of standard dyes along with chemical effluent. The samples have been characterized for their structural, chemical and morphological properties by employing X-ray Diffraction (XRD), X-Ray Photoelectron spectroscopy (XPS) and Scanning Electron Microscopy (SEM) techniques, respectively in order to understand the structure–property relationship.

Three-dimensional (3D) palladium-zinc oxide nanowire nanofiber as photo-catalyst for water treatment

Zinc Oxide Nano Wires (ZNWs) has been considered as a promising material for purification and disinfection of water and remediation of hazardous waste owing to its high activity and lower cost. In this study, three-dimensional (3D) structured palladium (Pd)/ZNWs were synthesized on the fabricated electrospun nanofibers and explored for enhancement of organic matter (OM) removal efficiency in water by suppressing electron–hole recombination during photocatalytic activity and increased surface area. The densely populated ZNWs were fabricated on the electrospun nanofiber by electroless plating (EP) and hydrothermal synthesis. In order to improve photocatalytic efficiency, a thin layer of Pd was coated prior to ZNWs growth to induce suppression of electron hole recombination produced during catalyst activity. The creation of a highly porous network of nanofibers decorated with ZNWs resulted in an increase of specific removal rate (SRR) of OM from 0.0249 to 0.0377 mg CODCr removed/mg ZNWs-hr when ZNW were grown on a Pd layer. It is believed that the demonstration of OM removal in the water through Pd/ZNWs membrane and enhanced photocatalytic activity under UV irradiation from layered structure can broaden potential applicability of Pd/ZNWs membranes for various photo catalytic water treatment.

Abstract P060: Reduction of Cardiovascular Mortality in the United States Population, 1988-2004: A Larger Contribution of Declining Exposures to Cadmium and Lead Compared to Traditional Cardiovascular Risk Factors

Introduction: Lead and cadmium exposures have markedly declined in the US following the banning of lead in gasoline and the implementation of tobacco control, air pollution reduction, and hazardous waste remediation policies since the mid 1970s. While lead and cadmium have been proposed as cardiovascular disease risk factors, little is known about their potential contribution to the decline in cardiovascular mortality in US adults. Hypothesis: We assessed the hypothesis that lead and cadmium exposure reductions partly explain the decreasing trend in cardiovascular mortality that occurred in the US from 1988-1994 to 1999-2004, after controlling for traditional cardiovascular risk factors including smoking, obesity, physical inactivity, hypertension, diabetes, chronic kidney disease, and dyslipidemia. Methods: Cohort study of 15,421 men and women ≥40 years old participating in the National Health and Nutrition Examination Survey (NHANES) 1988-1994 and 1999-2004. We implemented a mediation approach with additive hazard models to estimate the reductions in cardiovascular disease (CVD) mortality rates over time explained through changes in urine cadmium and blood lead concentrations. Results: After adjusting for age, sex, race and smoking, urine cadmium and blood lead concentrations decreased by 20.4 and 38.2%, respectively, between 1988-1934 and 1999-2004. Age-adjusted CVD mortality rates in the US decreased from 712.0 to 356.8 /100.000 person-years comparing 1988-1994 to 1999-2004. Changes in traditional CVD risk factors explained 16% of this decline. The observed reductions in urine cadmium and blood lead levels explained an additional 27.6% of this decline. Conclusions: The net impact of declining cadmium and lead exposures on mortality changes in the US was larger compared to traditional risk factors. These findings support that reducing cadmium and lead exposures resulted in a major public health achievement. The general population, however, remains exposed to cadmium and lead at concentrations that have been associated to CVD in the US population. Preventive strategies to enable additional reductions in exposure to cadmium and lead are needed.

Superfund Chaos Theory: What Happens When the Lower Federal Courts Don't Follow the Supreme Court

There is legal chaos in the national Superfund. The Supreme Court reversed decisions of eleven federal circuit courts in United States v. Atlantic Research Corp. There is no instance in modern Supreme Court history where the Court reversed every federal circuit court in the country, as it did in Atlantic Research. The Supreme Court’s reversal was through a unanimous decision. This was extraordinary: It not only reversed the entire legal interpretation of one of America’s most critical statutes, but also re-allocated billions of dollars among private parties. The Supreme Court, when it rendered its decision, seemed to be rectifying a bottleneck in Superfund remediation of hazardous waste. However, in the decade since this Supreme Court decision, several federal trial and circuit courts have circumvented the Supreme Court command. This article illustrates how the lower federal courts have done this without violating Article III of the Constitution, by re-defining a one-word term. The practical impact has been chaos in hazardous substance remediation across the U.S., affecting an estimated 600,000 contaminated waste sites. There are huge dollar impacts: addressing the 350,000 remaining contaminated sites in the U.S. would cost up to one-quarter trillion dollars, or an expenditure of $6-8 billion annually. This Article analyzes how the lower federal courts have circumvented the Supreme Court decisions, with particular focus on decisions and legal prestidigitation in the most recent four years. This lower court inversion of the law is without much basis in law, and resurrects exactly what the Supreme Court thought it had overruled unanimously. What transpired in enforcement in the lower courts is not what the Supreme Court’s opinion contemplated. This Article examines the method by which the lower federal courts have created an ongoing legal mechanism to circumvent the most important Supreme Court holding in a critical area of the economy.

Effect of aspect ratio and surface defects on the photocatalytic activity of ZnO nanorods

ZnO, aside from TiO2, has been considered as a promising material for purification and disinfection of water and air, and remediation of hazardous waste, owing to its high activity, environment-friendly feature and lower cost. However, their poor visible light utilization greatly limited their practical applications. Herein, we demonstrate the fabrication of different aspect ratios of the ZnO nanorods with surface defects by mechanical-assisted thermal decomposition method. The experiments revealed that ZnO nanorods with higher aspect ratio and surface defects show significantly higher photocatalytic performances.