Corrosion Control Program

Salem Installs Corrosion Controls Salem’s Corrosion Control Program Effects of Corrosion Control on Drinking Water Chemistry Effects on Customers Facts about Corrosion Control More about Soda Ash Risks of Handling Sodium Carbonate (soda ash) Risks of Sodium for Human Consumption To Learn More… Lead and Copper Rule

Salem’s Corrosion Control Program

New corrosion control equipment is being installed at Salem’s Geren Island Water Treatment Facility. Soda ash (Na₂ Co₃) will be added in very small doses to help raise the pH of the drinking water delivered to Salem’s customers, reducing the amount of lead and copper leaching from household plumbing.

Soda ash (Na₂ Co₃ ) will be stored at the Geren Island facility in an 8-foot-diameter cylindrical tank. Soda ash is a relatively innocuous chemical that can be easily, safely and cleanly handled, and stored in bulk for long time periods. The chemical will be added to Salem’s drinking water at a solution of up to 9 mg/L.

The new corrosion control system is currently under construction. Equipment will be installed and tested in spring 2006. The system is scheduled to be in operation by summer.

The exceptionally low mineral content in Salem’s drinking water makes the water "soft," but also makes household plumbing vulnerable to lead and copper corrosion. Salem’s drinking water is high quality, and lead has never been detected in our source water. Unfortunately, plumbing and piping inside some homes have lead solder and other sources of lead that can get in to the drinking water. Testing of water from the taps of Salem homes has consistently revealed the drinking water in a very few homes have a lead content above the standard set by the U.S. Environmental Protection Agency (EPA).

EPA and Oregon’s Drinking Water Program are taking action to address these very low levels of lead. They have mandated that the City of Salem treat its drinking water, installing corrosion controls to lessen the potential for lead and copper to leach from household plumbing.

Other corrosion control methods were also considered. Water treatment with lime and caustic soda (sodium hydroxide) were considered—and rejected—because these chemicals are dangerous and hard to handle. Another option, using corrosion inhibitors, can be effective in water transmission lines—but doesn’t work well in home plumbing, where lead enters Salem’s water. Top

Effects of Corrosion Control on Drinking Water Chemistry

Soda ash is added during the drinking water treatment process to adjust pH and alkalinity for corrosion control. Generally, somewhere between 1 ppm and 40 ppm of sodium carbonate is added to water for purposes of corrosion control. These additions are very small compared to naturally-occurring sodium and carbonate found naturally in food, beverages and natural waters, or quantities ordinarily added to food and beverages for other purposes.

The average pH of Salem’s drinking water is expected to change from 7.1 to 7.8—making it slightly more basic. The pH will remain well within EPA standards of 6.5 to 8.5 for drinking water. Certain water-related activities or hobbies may be affected by changes in pH—swimming pools, hot tubs, beer or winemaking, and aquariums, for example. Salem water customers should follow instructions from product manufacturers and professionals. Top

Effects on Customers

At home, Salem’s residential customers won’t notice anything different. Corrosion control will reduce the potential for lead and copper contamination of drinking water—even at very low levels.

Some business customers may need to pay attention. Businesses should be aware even these subtle changes in water chemistry may affect their processes. Salem’s Public Works Department is contacting selected business and institutional customers, including: food processors, bottlers, wineries and breweries, kidney dialysis centers, hospitals and clinics, and aquarium shops.

Installation of the corrosion control system will cost approximately $700,000. Operating costs are estimated to be $200,000 per year. These costs are included in Salem’s current water rates, and will be shared by all residential and business customers. Salem’s water system now serves a population of about 180,000. Top

Facts about Corrosion Control

• Soda ash—its chemical name is sodium carbonate—is a relatively harmless chemical that is an important ingredient in many household products: toothpaste, skin care lotions, food and beverages.
  
• The average pH of Salem’s drinking water is expected to change from 7.1 to 7.8—making it slightly more basic. The pH will remain well within EPA standards of 6.5 to 8.5 for drinking water.
  
• These modifications to the water treatment process will reduce the amount of lead and copper in customers’ drinking water.
  
• The change in water chemistry will not affect human health. The soda ash will add a very small amount  of sodium. However, Salem’s water will still be rated as "sodium free" under federal guidelines.
  
• Fish and other pets will not be harmed. Top

More about Soda Ash

Soda ash (Na₂ Co₃)—its chemical name is sodium carbonate—is a relatively harmless chemical that is an important ingredient in many household products. Soda ash is an odorless white powder. The chemical is mined from the earth in solid form, and is also extracted from various brines and industrial processes. It is used in cosmetic products ranging from toothpaste to skin care products and lotions, and in food and beverages for the adjustment of acidity and as a stabilizer. It is also a component of over-the-counter and prescription medications such as antacids. Soda ash is often used in spas and swimming pools to adjust acidity of the water. It is also used in many industrial processes including manufacturing glass, paper and in mining processes.

Soda ash can be handled easily, safely and cleanly, and stored in bulk. Soda ash will not affect the taste, smell, or color of Salem’s drinking water.

Sodium carbonate is often naturally present in drinking water, because sodium and carbonates are common minerals naturally present in soils, and found in many sources of surface water and groundwater, and in plants and animals. Water supplies in limestone areas have high levels of sodium carbonate—sometimes too high to use for drinking water.

In its various forms and products, sodium carbonate has many common synonyms: soda ash, soda, sal soda, washing soda, carbonic acid, trona, disodium carbonate, Solvay soda, crystal carbonate, natrium carbonicum and Snowlite. Top

Risks of Handling Sodium Carbonate (Soda Ash)

Sodium carbonate is potentially harmful only in its solid form or in a very concentrated solution. Direct skin or eye contact, or inhalation of powder or crystals can produce irritation, rash and sometimes burns. Household cleaning and laundry solutions contain sodium carbonate at levels of 10% (100,000 ppm) or greater, and are moderately irritating to bare skin after prolonged contact. Undiluted cleaning products with 50% (500,000 ppm) or greater concentrations of sodium carbonate can react chemically with and burn skin and mucous membranes.

Ingestion of the concentrated salt or cleaning solutions can cause nausea, vomiting, stomachache, diarrhea, and burns to the mouth and throat. Solutions or concentrations at or below 10% (100,000 ppm) are safe for skin contact and can be handled without adverse effects. Top

Risks of Sodium for Human Consumption

Knowing how much sodium is in your water may be important to your health—particularly for people who need to watch their sodium intake. Too much sodium has been identified as a risk factor for high blood pressure, which affects one in four Americans. To prevent or reduce high blood pressure, a low sodium diet is usually recommended, along with exercise, weight control and medication.

Sodium content in drinking water is measured in milligrams (mg) per liter (L). Current (2004) sodium levels in Salem’s drinking water are 4.18 mg/L. The soda ash will add 3.2 mg/L of sodium, for a total of 7.4 mg/L. The American Heart Association’s recommended maximum level is 20 mg/L for persons on a restricted low sodium diet. Here’s another way to measure the sodium content: Salem’s drinking water currently contains 1.05 mg of sodium per 8 oz. serving.

After soda ash is introduced, the sodium level in Salem’s water will rise to 1.85 mg per serving. For comparison, high sodium foods—pickles, cured meats, potato chips—contain sodium levels from 600 ppm (parts per million) to several thousand ppm. Soft drinks contain 80 to 250 ppm of sodium. Milk has 125 mg of sodium per cup, fish or meat has about 75 mg per serving, fresh vegetables have 35 mg. According to guidelines set by the U.S. Food and Drug Administration (FDA), Salem’s water will still be rated as "sodium free" after corrosion controls are installed.

Carbonate levels in food and drink also vary widely. Carbonated soft drinks (the fizzy kind!) contain from 2,700 to more than 10,000 ppm carbonate ion. Commercial bottled water contains from about 10 ppm to 3,000 ppm carbonate. For comparison, carbonate levels in any water source exposed to air may form carbonate levels between 10 ppm and 250 ppm. Top

To Learn More…

Customers who have questions about corrosion control or changes in Salem’s drinking water chemistry should contact Jason Pulley, Water Quality Supervisor, at 503-588-6398 or e-mail jpulley@cityofsalem.net .

For additional information, go to http://www.epa.gov/safewater/lead/index.html or call:

Consumer Information: 1-800-424-LEAD.

Safe Drinking Water Hotline: 1-800-426-4791. Top