shutterstock_1013160If you search “lead in public school drinking water” you may see news every day on either lead contamination or actions taken in a particular state to measure lead levels in school drinking water. In the wake of the Flint drinking water crisis due to contamination from poisonous lead, more and more public schools are conducting lead testing in their drinking water. Many of the test results show much higher lead levels than the action level (AL) from the federal regulation known as the Lead and Copper Rule (LCR). As a result, some states, such as New Jersey and New York, have made legislation to require schools to test the drinking water for lead.

Lead Regulations: The Lead and Copper Rule and School Lead Testing

The Safe Drinking Water Act (SDWA) established in 1974 requires the EPA to set regulatory standards including the non-enforceable Maximum Contaminant Level Goal (MCLG) and enforceable Maximum Contaminant Level (MCL) for primary drinking water contaminants. The MCLG, which is based solely on health risk, is set to zero for lead. The MCL is set to be as close to the MCLG as practically possible, while considering the cost and benefit for detecting and removing the contaminant using suitable technologies. Because lead contamination usually occurs at the end user’s tap due to plumbing pipe corrosion –  rather than at the treated water distributed by public water systems (PWS) – the action level for treatment technique regulation for PWS, not MCL, was established for lead in the LCR. PWS are required to take samples periodically to monitor lead in tap water at their served sites where plumbing corrosion is more likely to happen. Amongst the samples taken, if 10 percent of them exceed the AL of lead (0.015 mg/L or 15 ppb), the PWS must take action to lower lead contamination for regulatory compliance. These actions include water quality parameter monitoring, source water testing, corrosion control treatment, and lead service line replacement if other actions will not lower the lead levels to meet the LCR requirement.

For school drinking water safety, in 1989 the EPA provided a protocol for testing water for lead  and recommended 20 ppb or lower for lead concentration in drinking water at fixtures. This level is actually 12 ppb, even lower than the AL (at 15 ppb) for PWS, considering the different sampling size used for these two types of testing.

Although the states are not required to set up the testing programs, they are not restricted from developing testing and assisting programs for lead testing in schools. Indeed, many states have developed programs for lead testing to improve drinking water safety in schools. For instance, California’s water resources control board requires community water systems to test lead in public school drinking water within three months if the school officials put a written request.  If the water system receives a lab report with lead level over 15 ppb, the school needs to be notified within two business days. The community water systems are responsible for the costs for sample collection, testing, and result reporting.  After the Flint lead-contamination incident, more and more state legislators are making lead testing a requirement for school drinking water.

Why public school drinking water? Why now?

Testing the public school drinking water for lead is critical because children are especially vulnerable to lead which, even at very low levels. can damage their neurological development and learning capability. Some public schools have their own drinking water supply and are required to test their drinking water regularly to be in compliance with the LCR. However, most public schools and daycare centers get their water from PWS and only PWS, not the schools, are required to do the drinking water testing. Although the drinking water provided by the PWS may meet the regulatory standards, the public school drinking water may contain higher levels of lead than that at the entry point of PWS due to lead leaching from the transporting plumbing pipes to the schools. Because water testing for these schools is voluntary, the students in these schools may drink water which exceeds the action level for lead without even knowing it.

After many students in Flint, Michigan were found to have elevated levels of lead in their blood due to high level of lead in the drinking water, many public schools requested to test their on-site drinking water. In some areas, more than half of the schools showed elevated levels of lead–even 15 times higher than the lead AL. Now it is time to address drinking water testing in public schools and day care facilities to make sure students are not exposed to dangerous levels of lead anymore! You can refer to the EPA’s quick guide for schools and child care facilities for lead testing in compliance with LCR.

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Sampling and Testing for Lead

Incorrectly sampling drinking water may generate misleading testing results. It is important to utilize the required sampling methods for testing so that reliable results can be directly compared and evaluated. Once the samples are taken, they must be sent to state certified labs for regulatory compliance testing. Although ease-of-use kits are available for residence lead testing, these kits may only be used to test higher levels of lead for informational purposes as they are not sensitive enough to be used for meeting the strict regulatory compliance.

The two most commonly used lead testing methods that are approved by EPA for regulatory compliance are EPA Methods 200.8 and 200.9. EPA Method 200.8 uses inductively coupled plasma mass spectrometry (ICP-MS) while EPA Method 200.9 uses graphite furnace atomic absorption (GFAA). Both methods can achieve a detection limit that is sufficient for measuring lead at or above the AL.

Despite their low detection limit, the determination of lead in drinking water using either ICP-MS or GFAA is challenging because a variety of chemical and physical interferences have to be overcome to measure trace levels of lead. In addition, sample collection, transport and laboratory treatment must be done carefully to avoid possible contamination.

As for which instruments or methods are chosen, if only lead or a few other elements are measured, GFAA can be a cost-effective tool with great sensitivity. However, if lead and many other metals, especially the metals with lower maximum contaminant levels (such as Cd and As) are also required to be measured and a large number of samples are to be analyzed, ICP-MS is an excellent choice. But do bear in mind, collision cell technology, which helps provide more accurate results for As in particular, has not yet been approved for EPA Method 200.8, although the EPA is currently evaluating the technology for drinking water analysis.

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