DAVAO CITY, Philippines (Philippines News Agency) — A study conducted by a university in Mindanao has raised health concerns after tilapia from the Gibong River in Agusan del Sur province were found to contain high levels of mercury.
The study was made by Rose D. Arquion of the Philippine Normal University Mindanao in Prosperidad, Agusan del Sur, and Ryan Paul M. Vales of Tagbina National High School in Surigao del Sur. It was presented at the ongoing 3rd International Research Conference on Diversity in Education facilitated by the Consortium of Asia-Pacific Education Universities (CAPEU) at the Grand Regal Hotel here.
Interviewed on the sidelines of the event, Arquion warned local people to limit their consumption of tilapia caught from the Gibong River after their study found 283 mg/kg of mercury in the flesh of tilapia samples caught in the river.
A value of 283 mg/kg is very close to the provisional tolerance weekly intake (PTWI) of 300 mg/kg/week for the total mercury in diet, as provided for by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO), Arquion said.
”It is already risky for human health,” she said.
Noting that their study covered the Gibong River, the Agusan Marsh, and the Agusan River, Arquion said the high mercury content was found only in the tilapia from the Gibong River.
Tilapia found in the Agusan Marsh contained only 039 mg/kg of mercury while those in the Agusan River had 083 mg/kg.
The study also made some recommendations to protect the health of consumers in the towns of Esperanza and Prosperidad, such as the monitoring of heavy metal in fish, which should be done at least twice a year, during the wet and dry seasons, by concerned agencies at all levels; and the involvement of the local government units (LGUs) in monitoring heavy metal in fish and in developing and disseminating advisories to the local communities.
The study also called on concerned authorities to make an inventory and assessment of potential sources of mercury in the river and marsh, such as industrial sources.
Arquion said she has heard of continuing small-scale mining in the upland areas of the Gibong River, which she suspected to be one of the sources of the mercury in the river.
She however clarified that the possible source of mercury was not part of their study as they do not want to meddle with economic activities, whatever they may be, in the upper areas of Gibong River.
“From the mountains, the rocks and soils contain mercury and due to erosion and the siltation process, this mercury now is driven down to the river system where the Phytoplanktons are found,” Arquion said.
She added that mercury is then mixed with microscopic plants called Phytoplanktons that serve as food of the tilapia.
“The mercury contained in Phytoplanktons will accumulate in the body of the tilapia. And once the tilapia is eaten by humans, the mercury will also accumulate in the human body,” she said.
The repeated act of eating contaminated tilapia would endanger human health, she emphasized.
Arquion said they are about to present the results of the study to the provincial government as well as the LGUs in Prosperidad and Esperanza.
“I still need to see the mayor of Prosperidad and the provincial leadership of Agusan del Sur on this. Right now I have not yet presented to them the result of the study,” she said.
The CAPEU was established in April 2013 as a non-profit consortium of education universities in the Asia-Pacific region. The group envisions changes and innovations in education, teacher training, research and community services among education universities in Asia and the Pacific.