scholarly journals Behavior of Pb During Coal Combustion: An Overview

2019 ◽  
Vol 11 (21) ◽  
pp. 6061 ◽  
Author(s):  
Bartoňová ◽  
Raclavská ◽  
Čech ◽  
Kucbel
Keyword(s):  
Heavy Metals ◽  
Coal Combustion ◽  
Control Device ◽  
Health Concern ◽  
Condensed Phases ◽  
Gaseous Emissions ◽  
Fluidized Bed Combustion ◽  
Pulverized Fuel ◽  
Pass Through ◽  
Particulate Control

Despite the progress in understanding heavy metals behavior during coal combustion, mitigation of heavy metals emissions is still a tough challenge due to a complex character of this phenomenon. Several lists of potentially toxic elements have been presented; in most cases, Pb belongs to the elements with the greatest environmental and human-health concern. The review paper is focused upon the behavior of Pb during coal combustion. with particular attention paid to decreasing its emissions. It summarizes the dominant parameters affecting its redistribution among coal combustion streams. As gaseous emissions can quite easily pass through the particulate control device, attention was paid primarily to Pb distribution between condensed and volatilized phases. A crucial factor enhancing Pb volatility is the presence of organic or inorganic chlorides, which is discussed in detail, including their chlorination mechanisms and interactions with other fuel/flue gas species. Components decreasing Pb volatility and promoting the formation of condensed phases are also discussed (higher levels of moisture, Na, O2 etc.). Factors enhancing Pb volatility, as well as factors facilitating Pb retention, are discussed with the view of fluidized-bed combustion, pulverized-fuel combustion, or co-combustion of coal with wastes.

Performance Characteristics of Concrete Produced with Fluidized Bed Combustion Ash Residue

1988 ◽  
Vol 136 ◽  
Author(s):  
A. E. Bland ◽  
C. E. Jones ◽  
J. G. Rose ◽  
J. L. Harness
Keyword(s):  
Fluidized Bed ◽  
Performance Characteristics ◽  
Strength Development ◽  
Fluidized Bed Combustion ◽  
Portland Cement Concrete ◽  
Conventional Concrete ◽  
Setting Times ◽  
Pulverized Fuel ◽  
Tennessee Valley ◽  
Pulverized Fuel Ash

ABSTRACTOver the last five years, the Kentucky Energy Cabinet (KEC) and the Tennessee Valley Authority (TVA) have developed and demonstrated the production of concrete from atmospheric fluidized bed combustion (AFBC) spent bed (SB) ash, and pulverized fuel ash (PFA). This AFBC concrete contains no cement and relies on the reaction of residual lime in the SB ash to react with the pozzolan PFA to form cementitious products. The SB ash is prehydrated in order to reduce exothermic lime hydration reactions and minimize molar volume expansion. Laboratory tests were conducted to establish the performance characteristics of AFBC concretes relative to conventional concrete. AFBC concretes exhibit slower strength gain characteristics, but long term (60 day), unconfined compressive strengths of 5,000 psi have been documented. This slow strength development is typical of pozzolanic concretes. AFBC concrete is more flexible and less brittle than conventional Portland cement concrete, as evidenced by its much lower modulus of elasticity. Setting times for AFBC concretes are extended, requiring the use of accelerators under certain applications. Field demonstrations of the AFBC concretes in ready mix concrete, masonry units, and road base applications have indicated excellent workability and finishing characteristics and confirm the laboratory performance characteristics.The paper describes the results of the testing program with emphasis on the ash chemistry/conditioning, the performance characteristics and field demonstrations.

scholarly journals Excretion of Heavy Metals and Glyphosate in Urine and Hair Before and After Long-Term Fasting in Humans

2021 ◽  
Vol 8 ◽  
Author(s):  
Franziska Grundler ◽  
Gilles-Eric Séralini ◽  
Robin Mesnage ◽  
Vincent Peynet ◽  
Françoise Wilhelmi de Toledo
Keyword(s):  
Heavy Metals ◽  
Environmental Pollutants ◽  
Dietary Exposure ◽  
The Body ◽  
Health Concern ◽  
Obese People ◽  
Clinical Trial Registration ◽  
Reduced Body ◽  
Before And After

Background: Dietary exposure to environmental pollutants in humans is an important public health concern. While long-term fasting interrupts the dietary exposure to these substances, fat mobilization as an energy source may also release bioaccumulated substances. This was, to our knowledge, only investigated in obese people decades ago. This study explored the effects of 10-days fasting on the excretion of heavy metals and glyphosate.Methods: Urinary levels of arsenic, chromium, cobalt, lead, nickel, mercury and glyphosate were measured before and after 10 fasting days in 109 healthy subjects. Additionally, hair analysis was done before and ten weeks after fasting in 22 subjects.Results: Fasting caused a decrease in body weight, and in urinary arsenic (by 72%) and nickel (by 15%) concentrations. A decrease in lead hair concentrations (by 30%) was documented. Urinary mercury levels were unchanged for chromium, cobalt and glyphosate, which were undetectable in most of the subjects. Additionally, fatigue, sleep disorders, headache and hunger were reduced. Body discomfort symptoms diminished four weeks after food reintroduction.Conclusions: The results of this study provide the first insights into the changes in heavy metal excretion caused by long-term fasting. Further studies focusing on the kinetics of efflux between different compartments of the body are needed.Clinical Trial Registration:https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00016657, identifier: DRKS00016657.

scholarly journals Levels of some heavy metals in vegetables from artisanal mining sites of Dilimi River, Bukuru and Barkin Ladi North Central Nigeria: any public health concern?

2018 ◽  
Vol 69 (4) ◽  
pp. 335-345 ◽  
Author(s):  
Orish Ebere Orisakwe ◽  
Emmanuel Ayuba Dagur ◽  
Herbert Orji Chidi Mbagwu ◽  
Nnaemeka Arinze Udowelle ◽  
Samuel James Offor
Keyword(s):  
Public Health ◽  
Heavy Metals ◽  
Health Concern ◽  
Public Health Concern ◽  
North Central ◽  
Artisanal Mining ◽  
Mining Sites

Assessment of Adverse Effects of Lead, Nickel and Cadmium on Biochemical Parameters, Antioxidants Status and Metallothionein Expression in Buffaloes Slaughtered at Local Abattoir

2021 ◽  
Author(s):  
Himalaya Bhardwaj ◽  
Chanchal Singh ◽  
Shashi Nayyar
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Adverse Effects ◽  
Biochemical Parameters ◽  
Maximum Level ◽  
Lactic Dehydrogenase ◽  
Atomic Absorption Spectrophotometry ◽  
Health Concern ◽  
Control Group ◽  
Lead Nickel

Background: With the pace of industrialization, heavy metal level has been increasing in animals thereby causing deleterious effects, which emanate as public health concern, associated with their accumulation in food chain. The present study was undertaken to assess the systemic damage caused by heavy metals in buffaloes. Methods: The assessment of adverse effects of the lead (Pb), nickel (Ni) and cadmium (Cd), in blood was determined by monitoring the levels of biochemical parameters, antioxidants and expression of metallothionein in buffaloes. Blood and tissue (liver, kidney, pancreas and ovary) samples (n=50) were collected from local abattoir to estimate the levels of lead, nickel and cadmium using atomic absorption spectrophotometry. Antioxidants and biochemical parameters were estimated using standard procedures and while the expression of metallothionein-2 was analyzed using real-time PCR.Result: After determining the concentration of heavy metals in samples the buffaloes were classified as heavy metal exposed and non-exposed groups. The plasma level of heavy metals were found to be significantly (p less than 0.05) higher than the permissible limit in exposed buffaloes. In tissues, heavy metals levels were within the permissible limits. Malondialdehyde level in each of lead, nickel and cadmium exposed groups was significantly (p less than 0.05) higher than the non-exposed, control group. The antioxidant activity of superoxide dismutase, catalase and glutathione was found to be increased significantly (p less than 0.05) in exposed groups. Also, plasma glucose, cholesterol, aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), lactic dehydrogenase (LDH), creatine kinase (CK), urea and creatinine levels were found to be significantly higher (p less than 0.05) in the blood of the animal model used for the study. The fold change expression of MT-2 in blood was found to be at maximum level in cadmium and minimum in nickel exposed buffaloes. It can be concluded from the results of the experiment that heavy metals affect major organs (liver, kidney and muscle etc.) as evident by altered intracellular expression of MT-2, antioxidants and biochemical parameters.

scholarly journals Bacterially generated Fe2(SO4)3 from pyrite, as a leaching agent for heavy metals from lignite ash

2007 ◽  
Vol 72 (6) ◽  
pp. 615-619 ◽  
Author(s):  
Jelena Jekic ◽  
Vladimir Beskoski ◽  
Gordana Gojgic-Cvijovic ◽  
Mirjana Grbavcic ◽  
Miroslav Vrvic
Keyword(s):  
Heavy Metals ◽  
Environmental Protection ◽  
Coal Combustion ◽  
Shake Flask ◽  
Metal Leaching ◽  
Testing Technique ◽  
Leaching Experiment ◽  
Leaching Efficiency ◽  
Oxidation Agent ◽  
Ash Leaching

Investigations of heavy metals from lignite ash, which is a coal combustion by-product, have for years been very interesting from different aspects of environmental protection. In this study, the possibility of microbiological ash leaching, with a strong oxidation agent, bacterially generated Fe2(SO4)3 was investigated in order to minimize the concentration of toxic ash elements. Leaching experiment by the shake flask testing technique was performed during a period of 20 d at a temperature of 28?C. The results obtained show 5- to 22-fold (for Cd and Ni approx. 5, Zn approx. 6, Mn approx. 8, Cr approx. 13 and Cu approx. 22) higher metal leaching efficiency in the suspension with bacterially generated Fe2(SO4)3 than in the control suspension. .

Emission fluxes of heavy metals from the fluidized bed combustion of fossil fuels

1995 ◽  
Vol 26 ◽  
pp. S655-S656
Author(s):  
J Smolík ◽  
M Hartman ◽  
I Sýkorová ◽  
J Kučera
Keyword(s):  
Heavy Metals ◽  
Fluidized Bed ◽  
Fossil Fuels ◽  
Fluidized Bed Combustion ◽  
Emission Fluxes

scholarly journals Consumption of Raw Herbal Medicines Is Associated with Major Public Health Risks amongst Ugandans

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Fred Ssempijja ◽  
Keneth Iceland Kasozi ◽  
Ejike Daniel Eze ◽  
Andrew Tamale ◽  
Sylvia Anurika Ewuzie ◽  
...  
Keyword(s):  
Public Health ◽  
Heavy Metals ◽  
Developing Countries ◽  
Health Risks ◽  
Daily Intake ◽  
Herbal Medicines ◽  
World Health ◽  
Health Concern ◽  
Vernonia Amygdalina ◽  
Increased Risk

Background. Community consumption of herbal plants in developing countries is a common practice, however, scarcity of information on their physiochemical composition is a major public health concern. In Uganda, Vernonia amygdalina is of interest in rural communities due to its therapeutical action on both bacterial and protozoal parasites, however no studies have been conducted to assess the heavy metal concentrations in traditional plants used in alternative medicine. The aim of the study was to establish concentrations of heavy metals in Vernonia amygdalina, model the estimated daily intake (EDI), and assess both the non-cancer-related health risk using the target hazard quotient (THQ), and the risk related to cancer through the incremental lifetime cancer risk (ILCR) for the Ugandan population. Methods. Leaves of Vernonia amygdalina were collected from 20 georeferenced villages and processed into powder in the laboratory using standard methods. These were then analyzed in the laboratory using an atomic absorption spectrometer for lead (Pb), chromium (Cr), copper (Cu), zinc (Zn), cobalt (Co), iron (Fe), cadmium (Cd), and nickel (Ni). Concentrations were compared against the World Health Organization (WHO) limits. The EDI, THQ, and ILCR were modelled and significance was measured at 95% confidence. Results. The study showed that mean ± SEM concentrations of heavy metals were highest in the order of Cr, 121.8 ± 4.291 ppm > Ni, 84.09 ± 2.725 ppm > Zn, 53.87 ± 2.277 ppm > Pb, 40.61 ± 3.891 ppm > Cu, 28.75 ± 2.202 ppm > Fe, 14.15 ± 0.7271 ppm > Co, 7.923 ± 0.7674 ppm > Cd, 0.1163 ± 0.005714 ppm. Concentrations of Pb, Cr, Zn, Co, and Ni were significantly higher than the WHO limits. The EDI was significantly higher in children than in adults, demonstrating an increased risk of toxicity in children. The THQ and ILCR were over 1000 times higher in all Ugandans, demonstrating the undesirable health risks following oral consumption of Vernonia amygdalina due to very high Cr and Ni toxicities, respectively. Conclusion. Consumption of raw Vernonia amygdalina was associated with a high carcinogenic risk, demonstrating a need to enact policies to promote physiochemical screening of herbal medicines used in developing countries against toxic compounds.

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