| Lead Poisoning: Statistics and Prevention
Lead poisoning is one of the most serious diseases that can occur as a result of drinking water contamination. Below is a fact sheet regarding this condition, including health effects, levels of incidence, and prevention methods.
What is lead and what is its purpose?
Lead is a naturally occurring metal, generally found in deposits of ores containing other elements. It has been commonly used as a solder in home plumbing systems and in water service pipes designed to transport water from municipal water mains into homes. At one time, lead was also a common element in many household products, including lead-based paints and ceramic glazes.
What is lead poisoning?
Lead poisoning (also known as plumbism or painter's colic) is a toxic condition that occurs when an individual is consistently exposed to levels of lead above the federally defined Maximum Contaminant Level (MCL). Lead poisoning primarily affects red blood cell chemistry and the nervous system.
What are the health effects of lead poisoning?
Increased blood serum levels of lead have been shown to cause reduced IQ, learning disabilities, and retarded physical and mental development. The most obvious symptoms include excessive lethargy or hyperactivity, reduced appetite, nausea, headache, and abdominal pain. An increased level of lead in the blood is also a leading cause of anemia, a condition that currently affects more than 3.5 million people in the United States.
What is the biological role of lead in the body?
Lead has no biological role in the body. However, when it is ingested, lead has the ability to mimic other, more necessary metals, such as iron and zinc. This mimicry allows lead to bind with vital proteins and molecules in the body and to disrupt their functioning. Lead most commonly disrupts the production of hemoglobin, a fundamental ingredient for proper red blood cell chemistry.
Who is at most risk of lead poisoning?
Lead poisoning most commonly affects children under the age of 12. Young toddlers under the age of two are particularly at risk for lead poisoning, as they come into more contact with lead through household dust and increased water intake.
How much lead is too much?
Government and health officials have had a difficult time defining a legally safe level of lead in the body. Because young children are at most risk of lead poisoning, the bulk of the research has pointed toward them to determine contaminant thresholds. The original threshold below which lead was not a significant adverse factor in the blood was 25 ug/dL. Scientists are now suggesting this number should be moved to 10 ug/dL, but many health officials believe even this number may not represent a safe threshold for lead in the blood of small children. What is the national incidence of lead poisoning? According to a recent report from the Centers for Disease Control (CDC), 310,000 children in the U.S. have elevated levels of lead in their blood. While this number may not seem terribly significant, the U.S. EPA recently named childhood lead poisoning “A major environmental health problem in the U.S.”
In what ways does lead exposure occur?
Lead can be present in nearly any home, regardless of location or age; it can occur in outside soil, household dust, food, some types of ceramic and pottery, and in water. The most common sources of lead exposure are contact with peeling lead paint or lead paint dust. However, any contact with lead can increase the overall amount of lead in the blood and cause lead poisoning.
How does lead occur in drinking water?
Lead most commonly occurs in drinking water as a result of the corrosion of lead-soldered pipes. In homes built before 1978, such lead-soldered pipes are quite common. Household electrical systems grounded to the plumbing generally increase the corrosion of these pipes. Lead may also occur in drinking water as a result of source water contamination. Source water contamination is rare, but it may occur in areas where lead is mined or used to smelt other metals. Due to local mining operations, the largest releases of lead into source water occur in Missouri, Arizona, and Montana.
What are the federal regulations regarding lead in drinking water?
In 1974, the U.S. Congress passed the Safe Drinking Water Act, requiring the EPA to set federal regulatory levels for safe levels of lead in public drinking water systems. The EPA has set its most recent MCL for lead at 15 parts per billion (ppb). However, as no definitive safe threshold for lead in drinking water has been determined, the Maximum Contaminant Level Goal (MCLG) for lead in drinking water is 0. All public drinking water facilities are required to test for lead in the water at levels above 15 ppb twice each year.
Why is lead still a concern?
Despite federal and municipal efforts to limit lead in drinking water (including limits on the use of leaded gasoline and lead-based paint), lead may still be present in many U.S. homes. Houses built before 1978 are more likely to have lead-soldered pipes, but many newer houses may also be at risk of lead contamination. Even plumbing that has legally been termed “lead-free” may consist of up to 8% lead. Chrome-plated brass fixtures, fittings, and pipes also leach lead into water, especially if hot water is used.
How can lead poisoning be prevented?
Lead poisoning is one of the most easily preventable pediatric diseases. Below are simple measures you can take to reduce or even eliminate lead in your home's water:
- Have your drinking water tested. If the test yields results of greater than 15 ppb lead contamination, take immediate action. However, even lower levels can add to your overall lead intake and produce harmful effects.
- Flush your system before using water for drinking or cooking. If a tap has gone unused for more than six hours, lead can begin to build up in the water. Run cold water through the tap for 1-2 minutes before using the water for cooking or drinking.
- As often as possible, use only cold water for cooking and drinking. Hot water can corrode lead from the plumbing more easily than cold water. If you need hot water, heat cold water on the stove rather than using hot water from the tap.
- Replace any lead-soldered pipes in your home. If you have brass fixtures, be sure to flush water through them before using them for cooking or drinking.
- Have an electrician check the wiring in your home. More lead may leach into water if the wiring has been grounded to a lead-soldered pipe. If that is the case, consider relocating the wires.
- Filter your water before using it for drinking or cooking. A water filter reduces lead in your water water at the point of use, where the possibility of re-contamination is least likely. However, some water filters may exacerbate the problem by using brass fixtures to dispense filtered water. Be sure to check independent testing and performance data sheets to verify that your water filter reduces lead. Also, look for water filters that use ion exchange processes to filter lead. Simple, mechanical filtration will not reduce dissolved lead in water.
This fact sheet is for informational purposes only and should not be used as a means of diagnosis or as a substitute for consultation with a health professional.
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