Sunday, March 1, 2009

Are You Concerned About Lead in Your Drinking Water? Here's Some Things You Can Do

This entry was updated on May 23, 2010:

DC drinking water should be lead-free (or close to it) if your plumbing has no lead-bearing components. But if you have:
  • A lead service line (full or partial)
  • Lead solder connecting your pipes
  • Leaded brass fixtures, or
  • Galvanized iron pipes (and your home has or had a full or partial lead service line)
your tap water may dispense lead. Virtually all DC plumbing systems have leaded brass. Lead solder was very common in homes built before 1987. And more than 30,000 DC residents have lead pipes (intact or partially replaced) in front of their homes.

The lead in our drinking water can come in two forms:
  • Soluble (like dissolved sugar), and
  • Particulate (small pieces of lead solder or detaching lead rust)
Orthophosphate, the chemical treatment that was added in DC water in 2004 to control lead leaching, helps control soluble lead, but its effect on lead particles is uncertain.

For children or pregnant women, the Centers for Disease Control and Prevention (CDC) recommends using only bottled water for cooking, drinking, and baby formula preparation, if water lead concentrations exceed 15 parts per billion.

If you are concerned about lead in your drinking water, you can:

1. Have your water tested by an independent EPA-accredited lab

Look for an NLLAP lab that does water testing.

Make sure that the test kit sent to you includes two bottles, for both a 1st and 2nd draw sample. The bottles should be large enough (1/4 of a liter) and their opening should be wide enough to allow sampling at a flow rate that resembles the way you usually fill a glass of water or a pan for cooking. Water corrosion expert at Virginia Tech, Marc Edwards, recommends that when you mail bottles back to the lab, you request that they use 2% nitric acid in the first step (prior to the mandatory holding time of the acidified bottles), instead of the specified 0.15% nitric acid (pH less than 2). Use of a stronger acid is allowed by EPA and makes it more likely that lead particles will not be missed.

One thing to keep in mind: the release of lead particles tends to be erratic. If your plumbing releases lead particles, you may or may not capture any in the two samples you take for analysis. This means that if you are really concerned about lead in your water, you may want to take precautions even if your test results indicate water lead levels below 15 parts per billion.

2. Take precautions

To reduce lead in water, EPA recommends the following:
  • When a tap has not been used for several hours, run the water until you feel the temperature change before cooking, drinking, or brushing teeth
  • Use only cold water for cooking and drinking
  • Never cook or mix infant formula with hot tap water
Additionally, you can use bottled water, or a water treatment device that is certified by the National Sanitation Foundation to reduce lead. NSF Standard 53 certification for lead reduction means that the certified device reduces 150 parts per billion lead to 10 parts per billion or less for the product's stated service cycle in gallons. For lead reduction, NSF certifies three different types of devices:
  • Distillation
  • Filtration
  • Reverse osmosis
At this time, the only pitcher-style filter certified by NSF to remove both soluble and particulate lead is ZP-001 by Zero Technologies. The Zero Technologies website says that this filter is sold at Target and Walgreens. It costs approximately $40.

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