drinking water analysisIs my tap water contaminated with lead? If it is, should I be concerned? How did the lead get into my tap water in the first place? These are questions that the residents of Flint, Michigan are currently seeking answers to. The effects of lead poisoning have made recent news headlines, as a result of switching the city’s water supply source from Lake Huron to Flint River. The corrosive nature of the water from Flint River has caused lead to leach from many of the pipes that deliver water to residential neighborhoods.

How Does Lead Affect Your Health?

In my previous blog, titled Top Four Toxic Metals in Water, you may have read how bad the four metals (arsenic, cadmium, lead, and mercury) are for health.

Lead (Pb) is a well-known toxin that affects almost every organ system in the human body. The most severe effects are often neurological, resulting in stunted cognitive development. Babies and children absorb toxins faster than adults, making them more vulnerable to lead poisoning effects. This is also true of pregnant women, as the toxins are passed directly to the unborn fetus. Some of the effects from lead poisoning are categorized below:

  • Newborn babies: stunted growth and learning difficulties
  • Kids: weight loss, lack of appetite, fatigue, vomiting, constipation, and hearing loss
  • Adults: high blood pressure, pains (headache, abdomen, muscles and joints), kidney damage, mental problems and memory loss

How High is Too High?

Since lead is so toxic and can exist in drinking water (from both natural and anthropogenic sources), it is strictly regulated by the EPA via the Lead and Copper Rule (LCR). This mandate was published in 1991 and required large public systems to have proper corrosion control protocols in place by 1998 to reduce contamination from water pipe corrosion.

The EPA sets the Minimum Contaminant Level Goals (MCLG) for lead at zero parts per billion (ppb). Since the source of lead is often due to corrosion of residential plumbing systems, the EPA has established a Minimum Contaminant Level (MCL) for lead, with an associated action level (the current action level is set at 15 ppb). Under this guideline, when more than 10% of the water samples from a public water system contain more than 15 ppb of lead, that water treatment facility is mandated to put a treatment plan into place to reduce the lead to an acceptable concentration.

In the spring of 2015, tap water was tested in over 270 homes located in Flint. In addition to these tests, repeat water samples were collected at varying water flow rates to determine whether the rate of water coming out of the faucet had an effect on the amount of lead that was transferred into the water. Test results varied widely, with the lowest concentration found at 200 ppb. Many of the samples, particularly those collected at higher water flow rates, contained 1000 ppb of Pb. The water sample that was determined to be the most contaminated was found to contain 13,000 ppb of Pb. For reference, the EPA defines water as toxic waste when it contains more than 5000 ppb of Pb.

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How Do You Test For Lead?

Public water systems are required to quantify more than 90 contaminants in drinking water to meet National Primary Drinking Water Regulations (NPDWR). All analyses have to be performed in compliance with the appropriate regulatory methods. Multiple methods are applicable to the analysis of lead; however, EPA Methods 200.8 (using ICP-MS) and 200.9 (using graphite furnace atomic absorption spectrometry) are often used for analysis due to their high sensitivity and low detection limits. Since trace levels of lead (sub ppb to ppb level concentrations) can be detected, care must be taken during sample preparation to make sure the preparation procedure does not inadvertently contaminate the samples with lead. For instance, avoid using open digestion systems. All flasks, beakers, pipettes and other preparation equipment should be rinsed well with high-purity diluted nitric acid before use.

In the case of the Flint incident, it is critical to know whether children are being affected by the lead-contaminated drinking water. Their blood and urine needs to be checked for the presence of lead and compared to the lead level from children who have not consumed water containing high levels of lead. You can read our application note as a demonstration on how lead in blood is measured by ICP-MS.

What Can we Learn from This?

The incident in Flint highlights the importance of contaminant regulation and monitoring. Consistent and accurate water testing provides us with the confidence that our drinking water is safe for consumption. Furthermore, consistent testing at various parts of the distribution systems is important for peace of mind.

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If you are involved in drinking water analysis, we would like to hear your thoughts.

Maura Rury coauthored this post. Maura currently provides marketing for trace elemental analysis in the Chromatography and Mass Spectrometry group at Thermo Fisher Scientific, Inc.