While debates flame around whether or not to fluoridate drinking water, the Portland Water Bureau’s Lusted Hill treatment facility in Gresham hums along, shaded by Douglas fir and alder. This is where fluoridation will happen if voters approve it May 21.
Knowing how and why other chemicals are added at the Lusted Hill plant helps clarify questions about fluoridation.
Portland’s impassioned attachment to its water began in 1895 when the city first piped it from Bull Run Lake on Mount Hood, advertising the clean mountain water like fine wine.
Water that didn’t make people sick was rare, until chlorination was invented to disinfect it. But Bull Run water didn’t need it. By 1927 Portland and Spokane were the only U.S. cities that didn’t chlorinate.
Chlorine never aroused the contention that fluoride has. In 1931 when someone asked the chief engineer of the Portland Water Bureau about chlorine, he told The Oregonian, “we’ve been putting chlorine in the water for years.” Records show chlorine was first added in 1928, without fanfare or voter input.
Chlorine was blended in where the pipe started, at Bull Run Lake. With it came a dose of ammonia that bound to chlorine and kept it from evaporating.
Better disinfection was needed, though. Chlorine is a stronger microbe-killer before ammonia binds to it. So Lusted Hill was built downstream to allow more time between the chlorine and ammonia.
Lusted Hill’s ammonia room holds two 7000-gallon tanks as big as small houses. Six wall monitors — one active and one backup for each of the three pipelines from Bull Run — control the ratio of ammonia to water, a mere 0.4 parts per million.
Instruments for drinking water additives cannot get stuck in the “on” position, according to Andrew Degner, water treatment operations supervisor at Lusted Hill.
In the next room at Lusted Hill, which also has two giant tanks with meters and controls, sodium hydroxide is mixed in to make the water less acid. Bull Run water is acidic enough to leach lead from pipes. To reduce harmful lead levels in children, the Environmental Protection Agency in 1994 required water purveyors nationwide to alkalinize water.
If voters pass Measure 26-151, a fluoridation room will become part of the process at Lusted Hill. Two enormous tanks will hold liquid fluoride and arrays of controls will adjust the amount.
“Fluoride won’t be more difficult to manage than what we already manage,” says David Peters, water bureau principal engineer.
It may come as a surprise that sometimes Portland’s water supply does contain fluoride.
Bull Run water contains little or none. But 25 wells near the Columbia River do. They are tapped to meet high water demand in summer and when Bull Run is unavailable, such as during maintenance. The well water contains 0.16 parts per million of fluoride, about one-fifth the 0.7 parts per million recommended by the U.S. Department of Health and Human Services.
Wells draw water up from mineral-rich underground aquifers, explains Ben Perkins, professor of geology at Portland State University. Minerals dissolve over many years from the rocks that contain the aquifer. Lakes and rivers don’t carry minerals as much.
Perkins, a hydrogeologist, collects data on minerals in water all over Oregon. Northwest Oregon’s underground water sources contains from 0.1 to 0.3 parts per million of fluoride, he says.
Beaverton, Hillsboro, Salem, Corvallis, McMinnville, and Coos Bay are among the Oregon cities that add fluoride. Across the Columbia River, so does Vancouver.
The Tualatin Valley Water District, the second largest water provider in Oregon after Portland, serves parts of Tigard, Portland, Beaverton, Hillsboro and unincorporated Washington County. The district has fluoridated since 1964. If Portland elects to fluoridate, it would use liquid fluorosilicic acid as does Salem, which has floridated for 60 years. It comes from the mineral apatite, mostly calcium and phosphate, with three percent fluoride. When dissolved in sulfuric acid, apatite releases fluoride as a gas that’s captured with silica and water.
The major product of apatite is phosphate fertilizer, which aids root growth. On a bag of fertilizer, it’s usually listed as N (nitrogen), P (phosphate) and K (potassium).
Fluorosilicic acid is a byproduct, made by processses that mainly make something else.
“We use byproducts every day,” says Corby G. Anderson of the Colorado School of Mines. “From a process standpoint, it’s just another product you make,” he says.
In much of the country, fluoride is not an issue because it occurs naturally in underground aquifers tapped for water. Midwestern aquifers in general carry middling levels of fluoride, enough to help teeth resist cavities but not enough to stain them, a sign of too much fluoride. Granite aquifers in Colorado can carry high levels of fluoride. In Colorado Springs, for example, discolored but cavity-resistant teeth led to the discovery of fluoride’s effects.
In Africa’s Rift Valley and parts of China and India, underground water naturally contains extremely high fluoride, 20 to 30 parts per million, versus the 0.7 parts per million that Portland would use. Chronic intake of so much fluoride by people with malnutrition causes a crippling disease, skeletal fluorosis. In the developed world, with better nutrition and resources to find wholesome water, this disease essentially does not exist.
The three chemicals added to Bull Run water at the Lusted Hill plant keep it clean, safe and healthy to drink. On May 21 Portland voters will decide whether to add a fourth one, flouride.
Other Oregon cities signed up to fluoridate years ago. The still-to-come debate will determine whether Portland joins them.
–Merilee D. Karr
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