The School of Environmental Science and Management-University of the Philippines Los Baños (SESAM-UPLB), resumed its Living Dangerously Seminar Series with the webinar entitled “Iodine-129 for determining the origin of salinity in groundwater in Pampanga, Philippines”, last 13 May 2020. It was the 3rd seminar of the lecture series aimed to discuss environmental challenges that societies face.
During the webinar, Dr. Angel T. Bautista VII, a Senior Science Research Specialist from the Nuclear Analytical Techniques Application Section of the Philippine Nuclear Research Institute of the Department of Science and Technology, and Dr. Sunshine V. Tan, an affiliate of the Environmental Engineering Program of the University of the Philippines Diliman, shared their findings on groundwater salinity tracing that was conducted in Pampanga, Philippines using 129I, a radioisotope of iodine.
The paper emphasized that with the ongoing water crisis in the Philippines, it is necessary to check if groundwaters are contaminated with salt-water. The study was published by the Journal of Environmental Radioactivity Volume 218 in March 2020.
The possible sources of groundwater salinity, the resource speakers said, could be saltwater intrusion, which results from excessive pumping of wells; brine fossil water, which is trapped old marine water; and it could also be non-marine in origin, such as natural weathering, evaporation, and wastewater.
Salinity origin, according to Dr. Bautista, could be investigated using iodine-129 and iodine-127 isotopes integrated with hydro-geochemical (mainly Cl) and stable water isotopes parameters by generating two graphs: 129I vs. chloride and 129I/127I ratio vs. 1/127I. Dr. Tan concluded that 129I vs. Cl graph was capable of displaying clear distinction among different salinity origins. The interpretations are that high concentrations of Cl and high 129I indicate that salinity may be influenced by seawater while increasing Cl with low to high 129I, depending on the exposure to human sources, depicts evaporated water. Very high Cl and low 129I, on the other hand, could be brine fossil water.
The methods as well as the results of such studies can benefit the government, civil society, and other organizations, especially in regions that are encountering water salinization problems and in areas that are vulnerable to the challenges of this phenomenon. With the ongoing water crisis, this is a timely initiative as this can provide the necessary techniques and information for appropriate assessment, monitoring and management actions vital to the provision of adequate and good quality freshwater for communities.
The webinar, with 145 participants, was enabled with the use of a video conferencing software app. It was facilitated by the Continuing Education Division of UPLB-SESAM, with technical support from the Information Technology Center of UPLB. This webinar was also in collaboration with the Rushurgent Working Group, Tectonics and Geodynamics Laboratory of the National Institute of Geological Sciences, University of the Philippines Diliman and the Philippine Environmental Science Association. (Cherry S. Padilla and Thaddeus P. Lawas)
