The main research activities in the Environmental Toxicology program are as follows:
1. Effects of Environmental Pollutants and Industrial Chemicals as Modifiers of Physiological and Pathological Status
The project broadly aims to evaluate the possible harmful effects of environmental pollutants and industrial chemicals on health. Two types of studies have been initiated:
Study in the animal model, where animals are exposed (acute to subchronic) to various levels of chemicals. Effects on hepatic biotransformation leading to activation and inactivation of chemicals are evaluated under various pathological conditions of the host.
Assessment of the possible harmful effects on human health by studying the relationship between the extent of exposure, level of damage and individual susceptibility through the use of biological markers.
Two specific examples include:
AIR POLLUTION: Emphasis has been placed on the assessment of exposure and health impacts of urban air pollution, particularly carcinogenic compounds such as PAHs, benzene and 1,3-butadiene, in various susceptible groups of the population.
ARSENIC: Arsenic is an environmental pollutant with known carcinogenic properties. Chronic arsenic exposure in Ron Pibul district in Southern Thailand has been well documented since 1987. The laboratory has initiated a study on cellular responses to arsenic exposure in this population.
2. Study of The Effects of Nutritional Deficiencies as Modulating Factors in Carcinogenesis and Toxicity of Chemicals
Many forms of nutritional deficiencies are still prevalent in Thailand and Southeast Asia. Among the micronutrients, deficiencies of vitamins, particularly the B vitamin family, are still common and can occur rapidly after inadequate intake of food containing vitamins. The effects of the vitamin B deficiencies on toxicity of industrial chemicals and carcinogens, such as acrylonitrile, styrene, benzene and dimethylnitrosamine, have been studied.
3. Impacts of Industrial Chemicals on The Environment and Health of Workers and Population in Industrial Communities
To address long-term health concerns and improve the quality of life of industrial workers, and communities living in industrial areas, a project has been initiated to study the impacts on the environment of potentially toxic chemicals in industry, with regard to their chronic effect on the health of workers and on people living near industrial areas.
The research includes:
Monitoring of pollutant levels in the environment and workplace. Air and waste water samples as well as emission gases from selected factories involved in petrochemical and chemical industries will be collected and analysed for levels of volatile organic compounds (VOCs).
Analysis of biomarkers of chemical exposure, biological effects and susceptibility as well as other indices of adverse effects on specific organ systems in the blood and urine of workers and population living in the industrial community. With these research goals, it will be possible to evaluate the negative impacts of toxic chemicals on the environment and the risk to human health.
4. Detection of Environmental Toxicants by Dielectrophoresis (DEP)
Current methods for the detection of toxic substances in bodies of water, ground water and the public water supply rely upon specific laboratory tests and biological tests using aquatic organisms, which have some disadvantages. The rapid detection of environmental toxicants is a key aspect, not only for basic research but also for environmental and industrial monitoring and the enforcement of environmental and health standards. The ability to conduct rapid tests on multiple samples in the field would therefore represent a significant step forward for environmental research and monitoring.
This project, a collaboration with the University of Texas, M.D. Anderson Cancer Center, USA , aims at utilizing the technique of dielectrophoresis in detection of low levels of pollutants arising from industrial and agricultural sources in the water supply. Dielectrophoresis is the motion of particles induced by non-uniform, oscillating electric fields. Subtle responses of cells to agents include alterations in membrane capacitance and membrane conductance, which are two parameters easily assessed by dielectrophoresis.
Dielectrophoresis has been used to study, manipulate and separate both particles and cells. This technique is applied as a contact-free way to sense changes in the plasma membrane capacitances and conductivities of cells. The phenomenon depends on the capacitance, conductivity and size of the biological cells, the frequency of the applied field, and the electrical properties of the suspending medium. DEP has been shown to respond to minute changes in cell properties. However, DEP alone have some drawbacks such as time consuming, tedious work, and impractical for routine measurement. The developed dielectrophoresis field–flow fractionation or dFFF was established to solve said problems.
By applying this technique, it is hoped that a new, low-cost and rapid method of detection of toxic chemicals in the water supply can be developed.