Testing can determine whether water contains too much lead


June 25, 1991|By Dr. Simeon Margolis

Q: Recent news stories have said that our water supply may be contaminated with excessive amounts of lead. How can I find out if there is too much lead in the water my family is drinking?

A: The water stored in public reservoirs is not contaminated with lead because almost all of it is removed by treatments required by law. The problem is that lead may enter the water as it passes through the pipes connecting the public water supply to your own house or apartment. Until the practice was banned in 1986, many such systems used lead pipes or connected pipes with lead solder.

Corrosion of lead plumbing allows it to enter the water. Soft water is slightly acidic and more prone to leach lead from pipes. The bottom line: Lots of us are drinking water containing rather high levels of lead, which cannot be detected by appearance, taste or smell.

You might consider testing the amount of lead in your drinking water, especially if there are preschool-age children or pregnant women in the household. Although lead can injure many organs in both children and adults, young children and fetuses are particularly susceptible to brain damage and later learning disabilities from excessive lead intake.

You can get information about a reliable testing laboratory by calling the Safe Drinking Water Hotline of the Environmental Protection Agency, (800) 426-4791. Water should be tested first thing in the morning when lead levels are highest. Although the Federal Safe Drinking Water Act set 50 parts per billion as the maximal level of lead in our water, the EPA has proposed that the level should not exceed 20 ppb.

The amount of lead in the water can often be reduced to acceptable levels by flushing out the water that has been sitting in contact with lead pipes overnight. First thing in the morning, before it is used for drinking or cooking, run the tap water for 3 to 5 minutes or for as long as it continues to get colder. Water treatment systems may be needed if such flushing does not reduce the lead content enough.

Dr. Margolis is professor of medicine and biological chemistry at the Johns Hopkins School of Medicine and associate dean for faculty affairs at the school.

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