The Department of Environment and Natural Resources (DENR) has slammed the study that branded Pasig River as the supposed top ocean plastic pollution-contributor among rivers in the world, likening it to a mere product of guesswork.
"Sad to say, these are all information substantiated actual research or actual data," DENR Undersecretary Benny Antiporda said in a virtual press conference Monday, June 28, referring to the study, "More than 1000 rivers account for 80% of global riverine plastic emissions into the ocean" done by the group called The Ocean Cleanup.
"Ang ginawa po nila dito ay probabilistic ...tinancha lang po nila yung data nila na hindi po naging malinaw (What they did here is a probabilistic study...they just estimated their data and it wasn't so clear)," he said.
Antiporda said the DENR particularly took issue with The Ocean Cleanup's claim that Pasig River was no.1 in terms of riverine plastic emissions to the ocean.
Local media outlets picked up the results of the group's study early this month, highlighting Pasig River's newfound infamy. But Antiporda said the DENR took its time in responding to the issue as it conferred with "international experts" first regarding the veracity of the study.
"Basically the people were misled when it comes to the publication of this issue saying that plastic emission all over the world...an in-depth review and assessment of this study and of data of governmental efforts under the current DENR leadership showed a different conclusion," he said.
"To clarify the results of the study and its methodology, the Environmental Management Bureau (EMB) requested the assistance of international experts to help Philippine decisionmakers objectively understand what data, assumptions, methodology and scope the authors employed as reported in the full and supplemental publications," he said.
One of the experts tapped by the DENR was Dr. Vesna Lavtizar, the Healthy Oceans and Clean Cities Initiatives (HOCCI) lead for the Institute for Global Environmental Strategies (IGES).
"Both EMB and IGES confirmed that the Meijer study used a probabilistic approach which the study also claimed. In using the said model/approach, the probabilities were derived from physical and environmental characteristics including precipitation, wind, terrain slope, land use, distance to river, river discharge, distance to the ocean, and the corresponding mobilization and transport probabilities," Antiporda said.
It is for the reason that the DENR official described the study as not being based on hard data. He further said that the study "has assumed that those sections closer to the river mouth contribute significantly to plastic reaching the ocean."
"The method used did not reflect the actual condition on the site. Plastic waste which came from lands going to these rivers may have huge variation during the summer-low discharge rate and rainy-high discharge rate," Antiporda noted.
"This accounts for erroneous results which is far from the current condition of Philippine river systems especially in Pasig River, numerous activities and rehabilitations since 2019," he added.
As for The Ocean Cleanup, Antiporda said the group "claims to be a non-profit organization which are developing technologies to address plastic pollution in the ocean."
He also said that the details of the study was contrary to an international award that the Pasig River received in 2018. "It was awarded the Asia River Prize by the International River Foundation lauding the effort of the Philippine government in the restoration, protection, and sustainable management of Pasig River."
"Since 2019, the DENR has strengthened its campaign to save our rivers from further environmental degradation. It has also focused on addressing the solid waste management issue, including plastic waste, among others," the undersecretary said.
"Let me reiterate this: The Meijer study is silent on the aspects of strong leadership and efforts to mitigate pollution under the term of the present administration. We are of strong opinion that if these aspects were taken into consideration, the study would show a different result," he said.
It should be noted that the assailed study named six other Philippine rivers among its Top 10 ocean plastic pollution-contributors. These are Agno River (10th), Rio Grande de Mindanao (9th), Libmanan (7th), Pampanga (6th), Meycauyan (5th), and Tullahan (2nd).