|As one of the top 150 World’s best program in Environmental Science (QS World University Rankings) for 7 consecutive years, the Department of Environmental Science at Chulalongkorn University provides high quality learning environment for its students. The program offers various courses that expose students to scientific principles, laboratory and field practice, and real-world situations related to environmental issues. Armed with knowledge and working skills in environmental science, students who graduate from this program are qualified for positions in most industrial and governmental sectors and most graduate programs in renowned institutes. Overall, we aim at producing graduates that are not only employable and academically successful but they should also become motivated to lead the society to sustainability.
Previously, the department was known as Department of General Science. The Environmental Science program was first offered in 2005. The department was renamed as Department of Environmental Science on April 1, 2011. As of 2017, there are 15 faculty members with a wide range of expertise and have conducted several research projects which culminated into publications in national and international peer-reviewed journals. This book contains selected research abstracts by our faculty members which are grouped into 10 broad categories in environmental science as follows.
1) Natural Resource Management
This field concentrates on scientific understanding of biological mechanisms and ecological processes in natural ecosystems including plants, soil, water, land and animals. The major aims of this type of research is managing how humans and natural ecosystems interact in ways that lead to conservation and sustainability of the natural resources. In the 21st century, the studies of natural resources have become a significant research area. In our department, we have a wide range of interests ranging from soils assessment, watershed management, forest ecosystem, urban trees, and coastal environment. Some of these studies show a linkage between natural resources and community as well as an integration of different technological applications. Other research examples comprise estimating the value of ecosystem services in a mixed-use watershed based on a choice experimental approach, assessing the influence of environmental variability on silicate exchange rates between sediment and water in a shallow-water coastal ecosystem, studying responses of water use by urban trees in different environmental conditions, assessing impacts of artificial soil drought on above ground biomass, interpolating and simulating soil properties distribution, and studying factors impacted soil fertility.
2) Environmental Health Risk Assessment
In our environmental health research, advanced tools of American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD) modeling and Geographical Information System (GIS) krigging interpolation were applied to estimate exposure metrics of ambient air toxicants such as NO2, SO2, PM10, PM2.5, CO, and O3 in communities by traffic, forest fire and industrial emissions. Target population included in studies ranging from school children, farm residents, children to elderly in villages. Spatial and temporal toxicant mapping and fluctuations were discussed regarding source locations, metrological factors and season. The Environmental Protection Agency (EPA) health risk model was occasionally integrated in studies to characterize community cancer and non-cancer risks. In addition, a logistic regression model under environmental epidemiology designs was fitted in some works to confirm an association between ambient toxicants and adverse health effects in sensitive population.
3) Occupational Health Risk Assessment
Faculty members have investigated occupational health inhalation and skin absorption exposure of volatile organic compounds (VOCs) including Benzene, Xylene, Toluene, Ethylbenzene, carbonyl compounds, particulate matters and other toxicants using standard analytical methods with GC-FID, HPLC-UV and a microbalance. The occupational health risk in both cancer and non-cancer effects regarding exposure to such toxicants were estimated in various working environments including indoor (gas station, hospital, furniture factory, office, toll way station, parking, temple etc.) and outdoor (polices, street venders, motorcycle drivers, etc.) settings. Some works investigated the correlation between breathing zone exposure of airborne toxicants of interest and their biomarkers to determine if evidence of occupational airborne hazards exist. The results were then applied for better occupational control measures.
4) Environmental toxicology
This field investigates the effects of toxicants, chemical pollution and other stressors on the ecosystems. The research presented here involves identifying spatial distributions and mobility factor of heavy metal contamination in soils. One study examined such variations of Pb ore in the soils near abandoned dressing plant, indicating that the contamination was caused by anthropogenic mining activity. According to the Pb characterization, the dominant chemical fraction of sediment was in reducible form in upstream and was oxidizable and in residual forms in downstream. Further risk assessments revealed that the contamination levels of agricultural and ore dressing plant areas were exhibited low to medium potential ecological risk. Another study showed that organic waste from the yellowtail cage farm exerted dramatic impacts on the surface and the bottom water of coastal area. The findings from these studies can be used to make predictions in order to design effective strategies for site remediation.
Bioremediation is known as an alternative method using organisms, such as bacteria, fungi, yeast, and plants, to neutralize or degrade contaminants that pose environmental and human risks. The applications can be either in situ or ex situ. Several advantages of using bioremediation process include cost effective, environmentally-friendly technique, and less energy requirement. Our research focuses on phytoremediation. For example, chlorpyrifos removal was markedly facilitated by the presence of a root-associated bacterium. In this study, an application of water hyacinth and plant-associated bacteria provided an efficient and ecological alternative to accelerate removal of chlorpyrifos pollution from water. Besides water hyacinth, the use of electrokinetic enhancement (EK)-phytoremediation significantly increased the accumulation of zinc and decreased the residual zinc levels in soil when compared to the use of Ruzi grass alone. For an indoor pollution, all plants exposed to formaldehyde had a reduction in measured leaf chlorophyll by 14-35%. The application of air plant can also be developed to plant-based remediation system for other atmospheric contaminants. Thus, phytoremediation is viewed as efficient clean technology for a variety of organic and inorganic pollutants.
6) Wastewater Control and Management
This topic includes application of biomass residues and chemical substances in wastewater treatment to convert wastewater to effluent returned to the water cycle with minimal environmental contamination. Recently, various methods have been developed for heavy metal removal from wastewater, but none of the available technologies are sustainable for the environment. In the present research projects, various types of biomass (filamentous fungi, cuttlebone, etc.) are used and improved for heavy metal removal from wastewater. The publications showed that the bio-sorbents are the effective, environmentally-friendly and economic technologies to reduce Pb, Cd, Zn, Cu, Cr, As and Ni in wastewater.
7) Waste Utilization
This topic comprises utilization of sludge, dredged sediment, municipal solid waste, agricultural residues, and industrial waste to produce construction materials, fuel for energy recovery and compost and using Life-Cycle Assessment (LCA) to determine the environmental impacts and energy or resource consumption of the products over their life cycles to improve products for environmentally friendliness. Examples of our research in this area include finding the optimum condition to fabricate activated charcoal that can adsorb a volatile organic compound (BTEX) released from water and oil base paints; development of geopolymer bricks that were synthetized from fly ash mixed with concrete residue as required by the TIS 168-2546 standard; management guidelines for dredged sediment from Lumsai Canal and rice straw through the production of bricks, fuel briquettes and organic fertilizer and using Life Cycle Assessment (LCA) to evaluate the environmental impact; using dredged sediments with waste glasses as raw materials to produce facing bricks; the application of rice husk and cabbage market waste for charcoal production.
8) Air Pollution Characterization and Modelling
The research focuses on measuring and characterizing significant ambient air pollutants such as PM10, PM2.5, O3, NOX and VOC from various sources of forest fire, traffic, industrial complex and urban activities. Published works also include how these air pollutants behave, disperse, transport to receptors by different modelling approaches. Their known physical and chemical characterizations are helpful in terms of prediction of ecological and residential health effects. Climate change by its fluctuating meteorological variables also significantly contribute to the ambient and indoor concentrations. The meteorological variables can be modelled to forecast those air pollutants and the significant meteorological variables can be addressed.
9) Environmental Science Communication
This research topic involves diverse synthesis of communication theory and environmental theory that examines the role, techniques, and influence of communication among environmental affairs. One approach is to enhance collaborations between researchers and the community through specific projects. Our research includes joint work between the research team, which mostly consisted of our faculty members, and the local community to develop a Reduce-Reuse-Recycle (RRR) communication strategy through environmental camp for elementary school students at Koh Si Chang. Another project showed the implementation of science camp approach and cartoon books to improve communication and education in the topic on ‘Noise’ for elementary students at Wat Hau Lampong school.
10) Environmental Materials
In a modern world, there is still room for innovation where the development of novel environmentally-friendly materials is contributing new challenges for material scientists. The research topic in this field is broad and touches on some relatively in-depth aspects of structure, physical-chemical properties, or product design. Research examples in our department show various types of research studies. One of these studies found the use of polystyrene nanoparticles and chitosan solution can increase the anti-bacterial activity on cotton fabric. The percentage bacterial reductions ranged from 65.5 to 90.8%. In addition, the study of encapsulated eucalyptus oil in ionically cross-linked alginate microcapsules indicated the optimum conditions for preparing the microcapsules, oil loading efficiency, and controlled release of the encapsulated eucalyptus oil from the microcapsules as a function of time at 40oC. The release rate was directly influenced by the ionic cross-link density between the alginate and Ca2+ ions. Because hemicellulose and cellulose as major compositions of cassava can be used to produce bio-based products, another study therefore focuses on hydrochar and liquid fraction from hydrothermal carbonization of cassava rhizome to improve the optimal conditions.