Lead contamination poses a serious threat to drinking water safety. Both U.S. Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) agree that Lead is harmful to health, especially for children. There is no known safe level of lead in a child’s blood. Taking action to reduce these exposures can improve outcomes.
Where does lead come from?
The chemical symbol for lead is Pb. It comes from the Latin plumbum, the root for “plumbing”. Lead is an element that does not break down into less harmful substances. Lead has been used as an ingredient of gasoline, paint, glassware, metal pipes, and food containers. All of these have contained varying amounts of lead. Therefore, even though lead has been banned from gasoline and most paint and is no longer used in food containers, some lead can be found in the food, paint, soil, dust, housewares, and drinking water of many American homes.
Lead paint and dust are the primary source of lead exposure, especially in older homes. Leaded gasoline has caused lead contamination of soil near roadways and in urban areas. However, it has been largely replaced by unleaded mixtures since the 1970s. Drinking water is usually a smaller source of exposure to lead, but this varies greatly among homes, schools, and other buildings, and can add to other lead sources.
How does lead get into water?
We know lead has been used as an ingredient in a variety of products. How does lead get into water? In rare cases, lead gets into water as a result of pesticides that were used decades ago or industrial activities that contaminated soil and groundwater. In other words, lead rarely naturally occurs in groundwater.
Lead is much more likely to enter water from household plumbing, especially for homes with lead pipes, faucets, and fixtures. For this reason, lead is a potential concern for all homes whether you are on a public water supply or private wells. Laws have restricted the amount of lead allowed in new pipes, fixtures, and solder, but many homes contain older materials. Lead pipes are more likely to be found in older cities and homes built before 1986. For homes without lead pipes, the most common problem is with brass or chrome-plated brass faucets and plumbing with lead solder.
Water Corrosivity plays a key factor!
Corrosivity describes how aggressive water is at corroding pipes and fixtures. Corrosive water can cause lead and copper in pipes to leach into drinking water and can eventually cause leaks in plumbing. Surface water and groundwater, both sources of drinking water, can potentially be corrosive.
Water corrosivity is controlled primarily by the water acidity and calcium carbonate content. In general, acidic water that has a pH less than 7 is more corrosive than water that pH is higher than 7. Water that is low in calcium carbonate is more corrosive than water that is high in calcium carbonate.
In addition to acidity and calcium carbonate, many other factors can influence water’s corrosivity. Soft water (low in dissolved solids like calcium and magnesium) tends to be more corrosive than hard water (with high concentrations of calcium and magnesium), and warm water is more corrosive than cold water.
These are just general rules. Keep in mind, any kind of water – hard, soft, acidic, or non-acidic – can contain dangerous amounts of lead.
How much lead in water is too much?
Guidance from the Centers for Disease Control and Prevention suggests that blood lead concentrations over 5 micrograms per deciliter of blood (µg/dL) may indicate lead poisoning. 3.5 micrograms per deciliter (µg/dL) is used to identify children with blood lead levels that are higher than most children’s levels. Various studies have found that blood lead concentrations are positively and significantly related to the amount of lead in drinking water.
The U.S. EPA set the maximum allowable concentration of lead in public drinking water at 15 micrograms per liter (µg/L). Florida set the drinking water standard for lead the same as the EPA standard of 15 µg/L. Since lead serves no beneficial purpose in the human body, it is the best if drinking water contains no lead.
What are the regulations related to lead in drinking water?
The maximum contaminant levels are set by the Safe Drinking Water Act. It was originally passed by Congress in 1974 and amended several times. The 2011 federal Reduction of Lead in Drinking Water Act redefined “lead-free” to up to 0.25% lead on surfaces in contact with drinking water for consumption, with solder still less than 0.2% lead. This redefined lead free based on the 1986 federal Safe Drinking Water Act, which defined “lead-free” as less than 8% lead in pipes or fixtures and less than 0.2% in solder.
How is lead in drinking water monitored?
Public water systems are required to perform routine water quality testing to ensure that the water they are providing their customers meets state and federal standards. In Florida, lead is monitored under two separate regulations. The Inorganics Monitoring Rule requires community water systems and non-community water systems to monitor for lead at each point of entry to its distribution system. In other words, after the water leaves the treatment plant, but before it reaches the water system’s first customer. A “community water system” means a public water system which serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents. Non-community water systems are still public water systems, but serve less than 15 service connections.
The other rule in Florida is “The Lead and Copper Rule” (LCR). It requires community water systems and non-community water systems to collect first-draw samples from water taps in homes or buildings that may be or are at an elevated risk of lead and copper contamination.
What can well owners do to make sure the water is safe to drink?
Different from public water system, private wells are not regulated. The management and protection of well water depends on well owners. Annual water testing needs to be a routine. The basic water testing includes bacteria, nitrate, lead and any contaminants of local concern.
You may need to test more than once a year, if:
- A change in the taste, odor, or appearance of the well water, or if a problem occurs such as a broken well cap, inundation by floodwaters, or a new contamination source.
- The well has a history of bacterial contamination.
- The septic system has recently malfunctioned.
- Family members or house guests have recurrent incidents of gastrointestinal illness.
- An infant is living in the home.
How should I test lead in my drinking water?
Although regulations are in place to control lead in drinking water, the only way to know if your tap water contains lead or not is to have it tested no matter you use a public or a private water supply. Because of the large variability in lead levels among homes, you should have your water tested for lead no matter what the levels in neighboring houses. Click here to find a state certified drinking water lab.
A “first draw” sample is need to test lead in drinking water. First draw means the water has sat in the plumbing system overnight or at least 6 hours without any activities. This sample determines if lead accumulates in your water as it sits in contact with the plumbing system.
What should I do if I have elevated lead in my drinking water?
If your first-draw water test result is greater than 15 µg/L:
- Stop using it immediately;
- Find an alternate source of water until the problem is resolved.
The most effective and most expensive lead removal method is to replace the leaded components in the plumbing system with newer, non-leaded components. This procedure most often involves replacing copper pipes and lead solder with certified non-leaded pipes. When it is not possible to eliminate sources of lead contamination, the best option is to use an alternate source of drinking water (such as bottled water) or install a treatment system on one faucet in the home and collect water for drinking and cooking from that faucet only. Flush your plumbing systems can reduce the amount of lead in your water. The amount of time to run the water will depend on whether your home has a lead service line or not, and the length of the lead service line.
Lead in drinking water presents a complex problem for both public and private water users. If you have any questions about lead in your drinking water, contact your local health department.
Lead in Drinking Water Webinar
Watch the webinar recording to learn more about Lead in Drinking Water. This webinar was conducted in 2021, as part of the Florida Well Owner Network webinar series.
If you like our webinar, please share with your family and friends. We would also greatly appreciate if you could complete the evaluation survey and tell us how we can improve our series. Link to the survey: https://ufl.qualtrics.com/jfe/form/SV_aWRDK1pBqIt9gEu
- Florida Department of Health: http://www.floridahealth.gov/environmental-health/lead-poisoning/index.html
- Centers of Disease Control and Prevention: https://www.cdc.gov/nceh/lead/prevention/default.htm
- U.S. EPA: https://www.epa.gov/ground-water-and-drinking-water/basic-information-about-lead-drinking-water
Posted: June 13, 2022
Source: UF/IFAS Alert – https://blogs.ifas.ufl.edu/