(STAR) By Katherine Adraneda and Dino Balabo - A New York City-based environmental group has named the river system traversing Meycauayan City and Marilao town in Bulacan as among the 30 dirtiest in the world, posing a danger to human health.

In its World’s Worst Polluted Places 2007, the Blacksmith Institute described the Meycauayan-Marilao river system as “extremely polluted” due to haphazard dumping of industrial waste.

But the Department of Environment and Natural Resources-Environmental Management Bureau (DENR-EMB) questioned the report, pointing out that the determination of water quality is based on several criteria, with tests going beyond one-time sampling and may even take years.

Experts of the EMB’s water division said

Blacksmith should specify the criteria it used in declaring the river system among the worst in the world.

Water quality, according to them, is determined through certain criteria such as, principally, dissolved oxygen (DO) and biochemical oxygen demand (BOD), and total suspended solids (TSS) and total dissolved solids (TDS).

Engineer Jun Rivera, of the DENR-EMB, said it might not be possible to find one river as “worst” on both the DO and BDO criteria since each criterion has a different parameter.

“A river may be declared worst, but that should be qualified in terms of the level or parameter used,” Rivera said.

“Even the sampling, it cannot be a one-time sampling because there should be an established trend first considering that water samples may vary due to certain factors like rain, which can definitely affect the water in the river,” he added.

According to the Blacksmith report, industrial waste is indiscriminately dumped into the Meycauayan-Marilao river system, a source of drinking and agricultural water for 250,000 people. The river also traverses Obando town.

Blacksmith blamed the river system’s pollution on small-scale lead recycling facilities and tanneries that dump untreated “hexavalent chromium-laced” wastewater into the waterway.

“The river system is extremely polluted due to wastes received from tanneries, gold and precious metals refineries, the largest lead smelter in the Philippines, and numerous municipal dumpsites,” it said.

Blacksmith said the dumping of toxic waste into the river has severely affected the health of residents, who have complained of nausea, eye irritation and respiratory ailments.

It further noted that the river system eventually contaminates fishing areas around Manila Bay since it feeds directly into it, further endangering the health of more people.

Other places listed in Blacksmith’s “Dirty 30” were two sites in Africa, six in China, 10 in Eastern Europe and Central Asia, six in Latin America and the Caribbean, and five in South Asia.

“Toxic pollution in these sites has resulted from sources as diverse as massive industrial estates, large-scale mining and smelting operations and even Cold War era chemical weapons production,” Blacksmith said.

In the National Water Quality Status Report 2001-2005 of the DENR-EMB, the Meycauayan-Marilao river system was listed as among the 19 priority water sources for cleanup and rehabilitation.

Chief News Editor: Sol Jose Vanzi

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