DAVAO CITY—Rising levels of nitrate and phosphate in a river that drains into one of the city’s major sources of drinking water are prompting environmentalists to raise health concerns here.
If not immediately addressed, the high levels of nitrate and phosphate could degrade water quality at Panigan River and may cause health problems to water consumers here, said one of the environmental groups, Bantayo Aweg, a Bagobo term for water guardians.
Aian Gumapac of Bantayo Aweg said a six-year monitoring they conducted on the water in Panigan River, an important catchment basin for the city’s aquifer, showed that its nitrate level has gone up to 2.53 milligrams per liter, higher than the allowable 1 mg per liter for top quality water; while phosphate level was at 0.23 mg per liter, which is higher than the 0.1 mg per liter for top quality water category.
Under the standards used by the Environmental Management Bureau (EMB) of the Department of Environment and Natural Resources (DENR), the level of nitrate in Panigan River placed its water quality in the Class C category while its phosphate content placed it under the EMB’s Class B category, which makes water good for “recreational purposes only.”
Gumapac said their study showed that except for the rising nitrate and phosphate levels, the river’s color, temperature, dissolved oxygen content and water acidity were still within the ideal range for water organisms to survive.
But Gumapac said the situation could worsen if the contaminants were not addressed from its source.
“The river is still clear and has enough oxygen to support fishes but we are concerned about the levels of phosphate and nitrate in the water,” said Gumapac.
Ann Fuentes, environment research specialist for Interface Development Intervention, said the high level of phosphate and nitrate found in the river could have come from pesticides and fertilizers.
Gumapac said monocrop plantations and small farms dotted the river.
Gumapac said the solution to the rising levels of nitrate and phosphate is to implement the city’s watershed code, which banned single crop plantations and farms from the watershed areas or its periphery.
City Agriculturist Leonardo Avila admitted that the code, approved in 2008, has yet to be fully enforced. (Germelina Lacorte, Inquirer Mindanao)