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Author: Huan Xia
Publisher:
ISBN:
Category :
Languages : en
Pages : 500
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Book Description
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic contaminants that are widely distributed in soils. Some PAHs are potent human carcinogens. When released into soils, PAHs are often emitted within a certain source matrix (e.g. soot, coal tar or oils). In addition to the diversity of the PAH source matrix, soils are also very heterogeneous mixtures containing many different components, such as sand, clay, organic matter and black carbon which can have varying capacity and affinity for sorbing hydrophobic organic contaminants. Together, these different matrices in soil control the PAH bioavailability to receptors such as soil invertebrates and human beings via various exposure pathways. In terms of soil remediation, numerous recent studies have demonstrated the prominent effectiveness of condensed, black carbon particles, such as biochar or activated carbon (AC), in reducing the bioavailability of hydrophobic contaminants in ecological receptors.
Author: Huan Xia
Publisher:
ISBN:
Category :
Languages : en
Pages : 500
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Book Description
Polycyclic aromatic hydrocarbons (PAHs) are a group of organic contaminants that are widely distributed in soils. Some PAHs are potent human carcinogens. When released into soils, PAHs are often emitted within a certain source matrix (e.g. soot, coal tar or oils). In addition to the diversity of the PAH source matrix, soils are also very heterogeneous mixtures containing many different components, such as sand, clay, organic matter and black carbon which can have varying capacity and affinity for sorbing hydrophobic organic contaminants. Together, these different matrices in soil control the PAH bioavailability to receptors such as soil invertebrates and human beings via various exposure pathways. In terms of soil remediation, numerous recent studies have demonstrated the prominent effectiveness of condensed, black carbon particles, such as biochar or activated carbon (AC), in reducing the bioavailability of hydrophobic contaminants in ecological receptors.
Author: Jose Luis Gomez Eyles
Publisher:
ISBN:
Category : Bioavailability
Languages : en
Pages :
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Book Description
A large number of chemical methods to measure the bioavailability of polycyclic aromatic hydrocarbons (PAHs) have been proposed over the last decades. The main aim of this thesis is to evaluate the ability of these chemical methods to predict PAH bioavailability to earthworms and plants.
Author: Jose luis Gomez Eyles
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309086256
Category : Technology & Engineering
Languages : en
Pages : 433
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Book Description
Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.
Author: Joseph Paul Kreitinger
Publisher:
ISBN:
Category :
Languages : en
Pages : 350
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment and have been shown to elicit toxicity in humans and other organisms. Therefore, it is important to monitor environmental concentrations of PAHs. Toxicologically, we are concerned not only with the total PAH concentration but, with that fraction available to partition into an organism (bioavailable fraction). This research fits within three areas concerning bioavailability of PAHs including; 1) development of methods to measure bioavailability in the field, 2) identification and characterization of mechanisms controlling bioavailability and, 3) development of models to predict bioavailability in the natural environment. In the first phase of this research, the role of black carbon (BC) in the bioavailability of PAHs in soil and sediment was examined by measuring sorption in systems containing BC, natural organic matter (NOM), and microorganisms. A model was developed to predict the bioavailable fraction of PAHs and factors that may alter sorption in the natural environment from that predicted by laboratory models were examined. In the second phase of this research, a novel passive sampling device was developed to monitor truly dissolved PAH concentrations in water. Sorption isotherms of pyrene-d10 were measured for diesel soot (DS), Suwannee River NOM, Leonardite humic acids (HA), DS previously exposed to NOM and HA, in binary systems containing both DS and NOM, and to DS exposed to lake water. When DS was previously exposed to NOM, competition for sorption sites was observed. However, when both pyrene-d10 and NOM were introduced to DS simultaneously, less competition occurred and sorption was predicted within 92% of observed values using additive sorption models (based on the unit-normalized Freundlich model and Polyani-Dubinin-Manes model). Weathering of DS significantly reduced adsorption capacity but many strong sorption sites still remained, possibly due to renewal of sorption sites b.
Author:
Publisher: World Health Organization
ISBN:
Category : House & Home
Languages : en
Pages : 488
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Book Description
This book presents WHO guidelines for the protection of public health from risks due to a number of chemicals commonly present in indoor air. The substances considered in this review, i.e. benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons (especially benzo[a]pyrene), radon, trichloroethylene and tetrachloroethylene, have indoor sources, are known in respect of their hazardousness to health and are often found indoors in concentrations of health concern. The guidelines are targeted at public health professionals involved in preventing health risks of environmental exposures, as well as specialists and authorities involved in the design and use of buildings, indoor materials and products. They provide a scientific basis for legally enforceable standards.
Author: Insoo Joo
Publisher:
ISBN:
Category :
Languages : en
Pages : 198
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Book Description
The bioavailability of polycyclic aromatic hydrocarbons (PAHs) in coal-tar contaminated soils plays an important role in determining the risk of these compounds to the environment and humans. Developing an understanding of organic compounds bioavailability will assist in improving risk assessment and developing bioremediation strategies. In the first part of study, the degradation of 16 EPA priority PAHs in soil slurry reactors were investigated along with the change in microbial population. Using DAPI-stained organisms, maximum microbial populations were found to correspond with the depletion of 2- and 3-ring PAHs. Degradation of PAHs was sequential with the 2- and 3-ring PAHs degrading first, followed by the 4- and 5-ring PAHs. There was negligible degradation of 6-ring PAHs. The Modified Gompertz equation, an empirical model, was used to estimate the lag phase, degradation rate, and maximum degraded fraction of individual PAHs. The Monod equation was also applied but did not model the experimental data well especially the change in microorganism population. In the second part of study, several chemical methods were performed to assess the bioavailability of PAHs in three coal-tar contaminated soils from former manufactured gas plant (FMGP) sites. The methods tested were hydroxypropyl-[beta]-cyclodextrin (HPCD), persulfate oxidation, acetone-water mixture extraction, butanol extraction, and solid phase extraction using XAD-2. Residual PAHs in each soil following extraction were compared with the PAHs remaining after biodegradation in soil slurry reactors. Of the five methods tested, the XAD-2 desorption method was determined to the best method for predicting the bioavailability in coal-tar contaminated soils.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309168961
Category : Technology & Engineering
Languages : en
Pages : 432
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Book Description
Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.
Author:
Publisher:
ISBN:
Category : Polycyclic aromatic hydrocarbons
Languages : en
Pages : 500
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Book Description
