Extension and Ag Research News


Lead Can Be Found in Drinking Water

An NDSU water quality expert offers people advice on reducing the amount of lead they ingest through drinking water.

Recent recalls of children’s toys have raised concerns about lead poisoning from paint.

But paint is not the only source of potential danger from lead. The Environmental Protection Agency states that 10 percent to 20 percent of human exposure may come from drinking water.

“Rarely do we find lead in naturally occurring water, such as rivers and lakes, but it may leach into your water through pipes, solder, fixtures and faucets in homes, causing corrosion,” says Roxanne Johnson, North Dakota State University Extension Service water quality associate.

In the past, lead pipes connected houses and buildings to water mains, and the use of lead-based solder to join copper pipe, brass and chrome-plated brass faucets was common.

Brass materials still are used in nearly 100 percent of all residential, commercial and municipal water distribution systems. However, since 1986, Congress has restricted lead content to 8 percent in pipes, faucets and other plumbing materials and banned the use of solder containing more than 0.2 percent lead.

Corrosion occurs more often in water having a pH (acidity level) of less than 8 or low total dissolved solids content, or high amounts of dissolved oxygen or carbon dioxide, according to Johnson. If the water is not corrosive, minerals form a scale lining on the inside of the pipes. This scale lining, which may take up to five years to accumulate, will protect the water from lead contamination.

Treating naturally hard water with an ion exchange water softening, reverse osmosis or distillation unit can prevent or dissolve the scale, eliminating its possible protective effect.

Low levels of lead ingestion maybe not produce symptoms, and only a blood test will confirm its presence in the human body. Children under the age of 6 are at the highest risk because their bodies are growing at the fastest rate.

Irreversible damage to the brain, red blood cells and kidneys may be the result of the cumulative effect of lead poisoning. Low levels can cause a low IQ, hearing impairment, reduced attention span and increased behavior problems. A nutritious, low-fat diet containing foods high in iron and calcium, such as spinach and dairy products, is beneficial because it helps the body absorb less lead.

Research at the University of Nebraska, Lincoln, has found that lead in drinking water is not the predominant source of lead poisoning, but it can increase total lead exposure, particularly the exposure of infants who drink baby formulas and juices mixed with water. Pregnant women and their fetuses are vulnerable, exhibiting low birthweights and delayed mental and physical development. Adults may display high blood pressure, kidney problems and even cancer, according to EPA findings.

Detection of lead in drinking water cannot be based on its smell, color or taste, Johnson says. Municipalities and rural water systems include lead testing in their routine monitoring. If they find levels greater than 15 ppb (parts per billion), they note it in their annual testing report. This “action level” for public water suppliers triggers EPA-required measures. Those actions may include additional screening or treatment.

Many cities in North Dakota also routinely monitor old and new homes for high levels of lead. But that testing only is on public water sources.

“Remember, if your source for drinking water is a private well, you are responsible for testing,” Johnson says.

People with concerns about lead contamination in their water system should have it checked by a certified laboratory. Labs in North Dakota certified for lead testing are the Fargo Cass Public Health Environmental Laboratory, which charges a $22 test fee, and the North Dakota Department of Health, which charges $33. Additional information on these labs can be found at http://www.ag.ndsu.nodak.edu/abeng/waterquality.htm.

Johnson recommends taking two samples to detect the source of the lead. Take a first-draw sample after allowing the water to sit in the pipes for at least six hours, and always test cold water because warm water dissolves lead from pipes more quickly. A test of that sample will tell you if the lead source is in the pipes of your home, perhaps from lead-containing brass in faucets and lead pipes or copper pipes with solder.

Take the second sample after flushing your system, which means you let the cold water run for 15 to 30 seconds before sampling. This sample flushes water within the house and allows you to test water from outside your home.

If the tests find high levels of lead, drinking water users can follow EPA guidelines, taking into account the health risks, costs and benefits of reducing the lead concentration, Johnson says.

Some suggestions for reducing the ingestion of lead are:

  • Run the cold water tap for 15 to 30 seconds to remove water that sat in the pipes for more than six hours.
  • Use only cold water for cooking.
  • Install a reverse osmosis or filtration system for your main source of drinking water.
  • Purchase bottled water for drinking.
  • Remove loose lead solder and debris from plumbing materials installed in newly constructed homes or homes in which the plumbing has been replaced recently. To do that, remove the faucet strainers from all taps and run the water for three to five minutes. Follow up by flushing the strainers periodically.

For more information, contact Johnson at (701) 231-8926 or mailto:roxanne.m.johnson@ndsu.edu.

NDSU Agriculture Communication

Source:Roxanne Johnson, (701) 231-8926, roxanne.m.johnson@ndsu.edu Editor: :Ellen Crawford, (701) 231-5391, ellen.crawford@ndsu.edu
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