Effect of Soot Aerosols on Animals
The Study of Deposition and Pathogenic Effect of Soot Aggregates Aerosols in Laboratory Animals
Tech Area / Field
- ENV-APC/Air Pollution and Control/Environment
- ENV-EHS/Environmental Health and Safety/Environment
3 Approved without Funding
State Research Center of Virology and Biotechnology VECTOR, Russia, Novosibirsk reg., Koltsovo
- Institute of Chemical Kinetics and Combustion, Russia, Novosibirsk reg., Novosibirsk
- Lovelace Respiratory Research Institute, USA, NM, Albuquerque
Project summaryBackground information.
The health of the planet’s population largely depends on the quality of the inhaled air. Soot is one of the major atmospheric pollutants. Sources releasing soot into the atmosphere include Diesel engines, aviation turbines, thermal power plants, forest fires, etc. The concentration of soot particles in the oceanic atmosphere is 0.5 mg/m3, while in the on-land layer of atmosphere of industrially developed regions it reaches 30 mg/m3.
Combustion of hydrocarbon fuels is accompanied by the formation of various products of complete and incomplete combustion including toxic ones: carbon oxides, acrolein, formaldehyde, benzopyrene and others. Many combustion products adversely influence human and animal organisms, besides, they can cause climatic changes on the Earth. Polycyclic aromatic hydrocarbons formed in combustion processes are well known to produce mutagenic and carcinogenic effects on human beings.
Due to their branched surface, soot particles can adsorb significant amounts of various compounds, including polyaromatic ones. Thus, soot plays an important role in the transfer of harmful substances in atmosphere. That’s why a great attention is paid worldwide to the questions of formation of soot particles in different technological processes and evaluation of toxic effect produced by these particles. However, these studies pay too little attention to the mechanisms of formation of particle aggregates and deposition of the formed aggregates in the respiratory tract while the lack of exact data on the site of soot aggregates deposition in the respiratory tract does not allow evaluation of the effects of the received of toxicant doses on a macroorganism.
Charged carbon particles are very important for the process of soot formation. Primary soot particles (10-150 nm) formed immediately after combustion often form long aerosol chains (1 – 3 mm or longer ones) owing to electrostatic interaction in the air. Under certain conditions the chain aggregates can roll up into balls (compact aggregates). Due to their form the chain aggregates have an aerodynamic diameter, which is considerably smaller than 1 mm on account of the small fractal particle size. That’s why they can easily penetrate and most likely apply to the mucous membrane of the lower sections of human and animal respiratory tracts on account of difficulties associated with removal of elongated particles at exhalation. However, the patterns of deposition, retention and removal of such aerosol particles in/from human and animal respiratory tracts are unknown. Besides, the question of the effect of soot aggregates that get into lungs as aerosol (including the whole complex of toxicants adsorbed on the aggregates surface) on a macroorganism remains unelucidated.
The Project’s Goals:
- Determine the rate of primary deposition of soot aggregates in different sections of the laboratory animal’s respiratory tract;
- Determine the rate of removal of primarily deposited soot particles from different sections of the laboratory animal’s respiratory tract;
- Carry out evaluation of pathologic effect on a macroorganism of applied soot aerosol in the laboratory animal’s respiratory tract.
The following results are to be achieved during the two years of the Project implementation:
- An aerosol plant for carrying out research in animals with soot aerosols by modifying the particles size and morphology will be prepared (quarter 2);
- Methods for evaluating the sites of localization and concentration of soot particles in the laboratory animal’s organs and tissues will be developed (quarter 2);
- The sites of primary deposition of soot aggregates (quarter 6) and the rates of their removal from the laboratory animal’s respiratory tract will be determined (quarter 8);
- Carcinogenic and toxic effects of soot aerosol on the animals and its effect on the immune system organs and the animals’ resistance to a respiratory infection will be evaluated (quarter 8).
The new experimental results are fundamentally important for understanding of:
- The mechanisms of deposition and removal of a soot aggregates particles from the macroorganism’s respiratory tract;
- The mechanisms of their reaction with the respiratory tract cells;
- The role of the primary localization of such soot particles in the macroorganism’s respiratory tract at the disease onset and in its course.
The above results can find practical application in the following fields:
- Ecology – for evaluating the risk of induction of oncology and other diseases by soot aerosols in regions with increased concentration of such particles.
- Pathophysiology – for studying the pathogenesis events of diseases caused by soot and silicon particles using the scientific-methodical and technical basis to be created in the Project implementation.
- Virology and microbiology – for evaluating the peculiarities of infectious processes in macroorganisms exposed to soot aerosols.
- Medicine – for selecting more efficient tactics for prevention and treatment of diseases caused by soot aerosols based on the disease pathogenesis data obtained in the Project implementation.
The methodology of research work is based on the use of a plant developed at the Institute of Chemical Kinetics and Combustion, Siberian Branch of Russian Academy of Sciences, which allows controlling the size and morphology of soot particles by varying the coagulation period of soot particles and the parameters of the flame burning. Hydrocarbon fuel burnt in oxygen-depleted air is supposed to be used as a source for producing soot particles. Electron microscopy methods will be employed to determine the application sites of soot aerosol particles and the dynamics of their removal from the respiratory tracts of model laboratory animals. Pathologic effects of aerosols of the soot aggregates on the macroorganism will be evaluated by the results of experiments in mice using certain generally-accepted evaluation methods:
1. Acute and chronic toxicity;
2. Histological changes in organ and tissues;
3. Oncogenic effect;
4. Renal indices;
5. Concentration of immunocompetent cells in the respiratory tract and their activity;
6. Production of superoxide radical anions;
7. Phagocytic activity of alveolar macrophages and neutrophils;
8. Changes in the animals’ resistance to a respiratory infection (taking the influenza as an example).
Evaluation of these indices will be performed in comparative experiments involving a group of animals treated only with gases produced in hydrocarbon fuel combustion.
The following scope of participation of the Collaborator is planned:
- Discussion of obtained results;
- Information exchange during all the stages of the Project implementation;
- Commenting quarter, annual, and final technical reports.
- Organizing joint symposia and work seminars.
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