The 99th RIHN seminar

Date: 19 December 2013 (Tue.)
Time: 12:15 –13:15
Place: Seminar room 3&4( → Access)
Title: Occurrence and levels of major ions in Laguna Lake: Impacts on drinking water production
Speaker: Dr. ESPINO, Maria Pythias Baradero (Associate Professor, Institute of Chemistry, University of the Philippines) .


This study aimed to determine the levels of bromide, chloride, fluoride, nitrate, nitrite, sulphate, phosphate, sodium, potassium, magnesium and calcium ions in the surface water of Laguna Lake in the Philippines. The lake has many uses including aquaculture, recreation and transportation path, water reservoir and sink, as well as water source for power generation, cooling industrial processes and potable water production.
Because it is used as a supply for drinking water production, ions contamination must be studied. The ions in the water of the lake and its tributary rivers were analyzed by ion chromatography with conductivity detection. The concentrations of chloride, sulphate, nitrate, phosphate and sodium were relatively high in some areas of the lake. Nitrate, phosphate and chloride concentrations, however, did not exceed the Class C water quality criteria stipulated in the 1990 Administrative Order No. 34 of the Department of Environment and Natural Resources. Chloride and sodium ion concentrations were high in the tributary rivers located in densely populated areas around Laguna Lake. This suggests inputs from domestic and industrial activities in buildup areas which can affect the lake’s water quality. The occurrence of chloride and bromide in the lake water is a concern because these ions, along with dissolved organic matter, are precursors of disinfection by-products formed during water treatment processes. Disinfection by-products are harmful to human health and are not routinely monitored in the drinking water supplies in the Philippines. This six months study showed temporal variations in the ions’ concentrations.
Longer term studies including temporal and spatial trends in terms of ions contamination are needed to assess the suitability of the lake as a source for drinking water production.

Brief Curriculum Vitae:

Dr. Maria Pythias Espino earned her PhD in Chemistry in 2000 at the Ateneo de Manila University in the Philippines. She conducted part of her PhD research on organophosphorus pesticides in water at the Swiss Federal
Institute of Aquatic Science and Technology (EAWAG) in Switzerland.
In 2003-4, she did her postdoctoral study on UV radiation treatment of persistent organic pollutants in Tokyo University of Agriculture and Technology. She has received research scholarships including a UNESCO fellowship at the Danish Hydraulics Institute-Water and Environment in Copenhagen, an OPCW grant at the Karl-Franzens University in Austria, and a Fulbright scholarship in Duke University in the US. She is an associate professor at the University of the Philippines Institute of Chemistry where she teaches analytical chemistry. Her research involves fate and behavior of environmental pollutants, disinfection by-products in drinking water, and hazardous chemicals from waste electronic and electrical equipment.

KURATA Takashi (Associate Professor, RIHN)
Research Institute for Humanity and Nature
457-4 Motoyama, Kamigamo, Kita-ku, Kyoto, 603-8047, Japan
Phone : +81-75-707-2382
Fax : +81-75-707-2513