return to Research Projects
Testing for Lead in Drinking Water in Addison Central School District
This work is supported by Middlebury College Department of Chemistry & Biochemistry and the Senior Work Fund
This project lies at the intersection of my personal and professional worlds. As a parent and an environmental chemist who teaches and conducts research related to environmental pollution and environmental health, I followed the national stories about lead in drinking water closely. The toxicity of Flint’s water was initially detected because of its off-color, bad taste, illnesses, and a host of issues like hair loss and skin rashes — and of course because of the heroic work of its citizens and community organizers. Lead itself, however, cannot be seen or tasted directly, nor are its toxic effects immediately obvious. The quiet, incremental, and cumulative nature of lead as a neurotoxin is part of its danger.
But however extreme, tragic, and frustratingly preventable the situation was in Flint, contamination of drinking water with lead is not unique to Flint. Lead pipes and lead-containing solder, faucets, and spigots represent an invisible toxic legacy that communities all across the country (and world) are facing. And yet, out-of-sight is rarely out-of-mind for a chemist. My role as an environmental chemist is to make the invisible world of atoms and molecules visible and, in doing so, hopefully promote human and environmental health.
And so…I test water.
I started the project with no particular notion that there was a lead problem in our local schools, I simply wanted to know. But more than that, I wanted to make any problems visible so that they could be fixed. The Addison Central School District (ACSD) has a been a great partner on this project. They have embraced the project and are acting on its findings.
Background on Health Effects of Lead
Health effects of lead exposure include irreversible developmental neurotoxicity, disruption of the hormone and reproductive systems (Sanborn et al.), and gastrointestinal and cardiovascular issues. Even at low levels, lead has been known to decrease IQ scores. Lead exposures occur through various means, including from dust and soil contamination from earlier use of lead-based paint and leaded gasoline. The EPA estimates that ~20% of lead exposure is through drinking water. While no level of lead exposure is considered to be safe for anyone, exposure of children to lead is particularly concerning. Children absorb into their bodies a higher fraction of ingested lead and the detrimental effects of developmental exposures can be irreversible (Ellenhorn et al.). Because developing children spend much of their time at school, exposure to lead through drinking water in schools is an important issue (Edwards and Best; Laidlaw et al.). Ultimately, it is the amount of lead in a person’s blood that is considered the best indicator of potential health concerns. Vermont considers blood lead levels >5 ug/dL (micrograms per deciliter) to be elevated. Steady progress is being made on reducing the number of children with elevated levels. Between 2006 and 2017, the fraction of 1-2 year olds with elevated blood lead dropped from ~19-20% to 4-5%.
Between 2017 and 2019, we worked with Addison Central School District (ACSD) to test all water outlets in each of its schools. The types of outlets vary by school, but include sink faucets, drinking fountains, kitchen sprayers, showers, bottle fillers, chillers, and even ice machines. For each outlet, we took two types of samples — the first provides information about lead levels, the second provides information on the source of lead (if any).
Context for Lead Testing Results
Lead levels: Initially, we evaluate measured levels relative to two voluntary standards: the EPA action level for residential water and the American Academy of Pediatrics (AAP) recommended safety level for drinking water in schools.
The EPA action level — 15 parts-per-billion (ppb) — is a regulatory level that water suppliers must meet in 90% of its users’ water (they measure lead in a small number of residences each year). It doesn’t pertain to schools per se and is not a safety level. It’s simply a level that, if it occurs too frequently, forces a municipal water supplier to do something about it (i.e., add/revise pipe anti-corrosive measures). If the level is exceeded in <10% of the residential samples taken, it doesn’t necessarily mean residents have safe water, it simply means any problem is the resident’s responsibility to fix.
The AAP safety level — 1 ppb — is a readily achievable health-based standard recommended specifically for school water fountains; this matches Vermont’s health advisory level for lead in drinking water. In our work, we applied this standard to any outlet that might reasonably be used for consumption, including bottle fillers, sinks where kids might fill water bottles, sinks that are used for food preparation, etc. You may wonder about the fact that there is no known safe level of lead and yet the safety level is 1 ppb? Why isn’t the safety level ZERO? Well, to be a scientific stickler about it …scientists can’t prove zero. The best scientists can do is to tell you “lead is not detectable” in a given sample. But the level of lead that is detectable is dictated by the sensitivity of the methods used. So, to be pragmatic about it — 1 ppb is very low, achievable in updated water systems/fixtures, and also readily quantified. If we can get water lead levels down to this level, our resources would be much more wisely spent reducing lead exposures elsewhere (e.g., dust from lead paint in homes) than they would be getting water levels even lower.
For some schools, we reported the data relative to the anticipated or actual Vermont standard for schools. In February 2019 the Vermont Senate unanimously voted to require schools to test all of their outlets that are potentially used for consumption and to remediate any that hit a 3-ppb action level. I was invited to testify before the Senate Education Committee on this bill (S.40). Here are links to my testimony:
In February 2019, the House Education Committee took up the bill and invited me to testify. Below are links to that testimony and additional commentary I provided in response to suggestions that the House weaken the health protections provided for in the Senate version of the bill.
- Costanza-Robinson_Vt House Testimony on S.40_Feb 26 2019
- CostanzaRobinson_S.40. Supplemental Testimony_Mar13_2019
Ultimately, lawmakers passed consensus legislation requiring schools to remediate any outlets that hit a 4-ppb action level. This is now the law of the land and although the action level is higher than pediatricians recommend, it still represents a major step forward for VT. It stands as the most health-protective state law in the U.S. related to lead in school drinking water.
Sources of lead in drinking water: three potential sources are considered: the incoming water supply; the fixture itself (i.e., the actual faucet, spigot, showerhead, etc.); and the pipes and connections deeper in the water system.
For each school, a brief summary of findings and links to a full report and to a technical summary are posted.
Summaries: provide the main findings with community members in mind. See also the section above for background information you may find helpful, or the FAQs below.
Full reports: include background on lead and lead testing, details of the school (number of water outlets, age of building, etc.), description of the sampling and analytical methods employed, and a full description and interpretation of the findings. The purpose of the full report is to fully document the work, its methods and findings. The report may make your eyes glaze over or cure your insomnia, but in the name of transparency, it’s there for anyone who wants it.
Technical summaries: provide little to no background or explanatory information, and focus instead on a condensed reporting of the location and lead levels for water outlets prioritized for remediation. Think of it as a to-do list for the schools.
Lead Testing Results by School
Bridport Central School (BCS). Most outlets (79%) met the AAP recommended safety level. Two outlets exceeded the EPA action level, including a classroom water fountain and a classroom sink, and were considered as a highest priority for remediation. Three other classroom or office sinks exceeded the AAP recommended safety level and were considered a high priority for remediation. Findings suggested that the predominant source of lead is the fixtures or their immediate connections, rather than more distal pipes or the incoming water supply. BCS_Full Report | BCS_Technical Summary
(Cornwall) Bingham Memorial School (BMS). Most outlets (63%) exceeded the AAP recommended safety level. One classroom sink (18 ppb) exceeded the EPA action level and is considered a highest priority for remediation. Three kitchen sinks or sprayers (3-11 ppb) and a water fountain in a classroom (7 ppb) are also considered a highest priority for remediation, because they are intended for consumption or food preparation and exceeded the Vermont action level and/or the AAP safety level. Eight classroom or bathroom sinks (2-8 ppb) exceeded either the AAP safety level or Vermont action level and are considered a high priority for remediation. One outlet within the mechanical closet (2126 ppb) exceeded the EPA action level, but is considered a low priority for remediation because it is not used for any regular purpose and neither students nor staff have access to it. Testing suggests that the predominant source of lead is the fixtures or their immediate connections, rather than more distal pipes or the incoming water supply, although two outlets may have some fixture connections or pipes that are contributing some lead. BMS_Full Report | BMS_Technical Summary
Mary Hogan Elementary School (MHES). More than half of the outlets (54%) exceeded the AAP recommended safety level, of which three also exceeded the 15-ppb EPA action level. All bottle fillers and most water fountains met the AAP recommended safety level; however, 6 water fountains and 46 sinks exceeded the AAP level (2-10 ppb) and 2 utility sinks and the health office shower exceeded the EPA 15-ppb action level (18-71 ppb). We categorized the six water fountains and two kitchen sinks that exceeded the AAP recommendation as highest priority for remediation due to their use for direct consumption or food preparation. Most other sinks as a high priority due to their potential use for consumption. Remaining outlets that exceeded the AAP recommendation or EPA action level, but which are not likely to be used for consumption (e.g., utility sinks in custodial closets) were considered as a low priority for remediation. Results suggested that the predominant source of lead is the fixtures or their immediate connections, but that more distal pipes or connections may also contain lead and contribute to lead levels in water. MHES_Full Report | MHES_Technical Summary
Middlebury Union High School (MUHS). Twelve of the 122 outlets sampled exceeded the 15-ppb EPA action level, including 1 food preparation sink (26 ppb), 8 classroom/office sinks (16-41 ppb), and 3 bathroom sinks (15-20 ppb), all of which we considered a highest priority for remediation. A total of 84 outlets (69%) exceeded the AAP safety level (but not the EPA action level) (2-14 ppb), including 3 water fountains, 8 kitchen sinks/sprayers, 35 classroom/office sinks, 36 bathroom sinks, and 2 utility sinks. We considered water fountains, kitchen, and food preparation sinks/sprayers that exceeded the AAP or EPA levels as highest priority for remediation due to their intended use for direct consumption or for food preparation. Bathroom and classroom/office sinks that exceeded the AAP but not the EPA action level were considered a high priority for remediation. The utility sinks were considered a low priority for remediation, because they are contained within a custodial closet and not likely to be used for consumption. Results suggested that the predominant source of lead is the fixtures or their immediate connections, but that more distal pipes or connections may also contain lead and contribute to lead levels in water. MUHS_Full Report | MUHS_Technical Summary | MUHS corrective measures updates_Jan2018
Middlebury Union Middle School (MUMS). Roughly, 1/3 of outlets (35%) produced water samples that met the AAP recommended safety level. Roughly a quarter of the FD samples hit the 4-ppb VT action level for lead, including 4 kitchen sinks/sprayers (4-9 ppb), 10 classroom or office sinks (4-80 ppb), 6 showers (19-391 ppb), and 4 utility sinks (4-55 ppb). The classroom, office, and kitchen sinks require remediation according to state law due to their reasonable or known use for consumption and are considered a highest priority. We considered the showers and utility sinks a medium and low priority, respectively for remediation, because of their low likelihood of use for consumption but rather high lead levels. An additional quarter of outlets produced water samples that exceeded the 1-ppb AAP safety level but were below the VT Action Level (i.e., 2-3 ppb), including 1 kitchen sink/sprayer; 21 classroom, bathroom, or office sinks; and 1 shower. Despite not triggering required action via state law, the kitchen sink is consider a highest priority for remediation due to its use for consumption and/or food preparation; the classroom, office, and bathroom sinks are considered a high priority for remediation due to their reasonable or known use for consumption. These low shower levels are considered a low priority for remediation. Testing suggests that the predominant source of lead is the fixtures or their immediate connections, rather than more distal pipes or the incoming water supply. MUMS_Full Report | MUMS_Technical Summary
Ripton Elementary School (RES). Most outlets (91%, 20 of 22 total) met the 1 ppb AAP recommended safety level. A kitchen sprayer (>50 ppb) exceeded the 15-ppb EPA action level and is considered a highest priority for remediation due to its use for consumption or food preparation. The “source sample” (closest outlet to the water entry point in the school, 5 ppb) exceeded the anticipated 3-ppb Vermont action level. This outlet is considered a low priority for remediation, because it is not used for any regular purpose, nor do children or staff have access to it. Results suggests that the predominant source of lead is the fixtures or their immediate connections, rather than more distal pipes or the incoming water supply. RES_Full Report | RES Technical Summary
Salisbury Central School (SCS). Roughly half of the outlets (46%) met the American Academy of Pediatrics (AAP) recommended safety level of 1 ppb for lead in school drinking water. A source sample and health office shower exceeded the EPA action level (15 ppb) but are considered a low and medium priority for remediation, respectively, due to their non-use by students. Four kitchen sinks delivered water that exceeded the AAP safety level (2-7 ppb) and are considered a highest priority for remediation due to their intended use for consumption or food preparation. An additional 11 classroom and bathroom sinks exceeded the AAP safety level (2-12 ppb) and are considered a high priority for remediation due to their accessibility and convenience for consumption. Two utility sinks located within custodial closets (5 ppb) were considered a low priority for remediation due to their inaccessibility for consumption. Testing suggests that the predominant source of lead is the fixtures or their immediate connections, rather than more distal pipes or the incoming water supply. SCS_Full Report | SCS Technical Summary
Shoreham Elementary School (SES). Most of the 28 outlets sampled (75%) met the AAP recommended safety level. Seven sinks, including two in the kitchen, four in classrooms or offices, and a utility sink in a custodial closet exceeded the AAP recommendation, with lead concentrations ranging from 2 to 14 ppb. We categorized the kitchen sinks as highest priority for remediation due to their use for direct consumption or food preparation. The classroom or office sinks were categorized as a high priority for remediation due to their potential use for consumption, and the utility sink was considered a low priority for remediation because it is unlikely to be used for consumption. Results suggests that the predominant source of lead is the fixtures or their immediate connections, rather than more distal pipes or the incoming water supply. SES_Full Report | SES Technical Summary
Weybridge Elementary School (WES). Roughly one-third of outlets (32%) met the American Academy of Pediatrics (AAP) recommended safety level of 1 ppb for lead in school drinking water. One classroom storage sink exceeded the EPA action level (46 ppb) and two kitchen sinks/sprayers exceeded the AAP safety level (7-8 ppb); these three outlets are considered a highest priority for remediation based on lead levels and potential use for consumption or for food preparation. Nine classroom, office, and bathroom sinks (2-9 ppb) were considered a high priority for remediation because they are accessible and convenient for use for consumption. High lead levels in the source and utility sinks were considered a low priority for remediation because they are not used for consumption and neither students nor regular staff have access to the outlets. High lead levels were observed in the health office shower, presumably due to its non-use. Because it is not in use and is not used for consumption, this outlet was considered a medium priority for consumption. WES_Full Report | WES_Technical Summary
Frequently Asked Questions
- Aren’t water suppliers required to test for lead and ensure that drinking water is safe? Yes and No. Public water suppliers are required to monitor for lead in drinking water. If lead concentrations exceed 15 ppb action level (parts-per-billion) in more than 10% of customer taps sampled, public water suppliers must take action to control corrosion and inform the public about steps they should take to protect their health. Importantly, the 15-ppb action level is used to evaluate community exposure but is not a health-based standard.
- What level of lead exposure is considered safe? ZERO. There is no known safe level of lead exposure. The American Academy of Pediatrics has issued a health-based recommendation that water fountains in schools not deliver water exceeding 1 ppb lead (AAP). The EPA has issued a maximum contaminant level goal (MCLG) and the state of Vermont a Health Advisory Level, both health-based non-enforceable goals, for lead in drinking water of zero.
- Aren’t schools required to test for lead and ensure that drinking water in schools is safe? Yes and no. Federal law does not require schools to test for lead in drinking water unless they rely on a private water supply and serve more than 25 people daily. Before 2019, the state of Vermont required drinking water only in early education classrooms (e.g., pre-K) to be tested for lead and meet a 15-ppb action level. In 2019, the state of Vermont passed the most health-protective state law in the nation with regard to testing school water for lead. Going forward, schools will need to test and remediate or disconnect any outlets that hit a 4-ppb action level.
- If the incoming water supply is low in lead, does this mean the water in a building/school is safe? Not necessarily. While municipal water must be tested for lead at the site of distribution and at a small number of end-user (typically residential) outlets, lead can leach into the water at various points within the system, including from lead-containing pipes, solder, and individual outlet fixtures. Testing of water from individual outlets is the only way to understand the potential for lead exposure through drinking water.
- If “lead-free” pipes, fixtures, and solder are used, is the water also lead-free? Not necessarily. The federal 1986 Safe Drinking Water Act and later revisions limit the use of lead pipes and lead-containing solders in new drinking water systems, but the definition of “lead free” has been lowered over time. Before 2014, “lead-free” referred to products containing less than “0.2% lead for solders and fluxes and not more than 8% lead for pipes and pipe fittings.” For products installed after 2014 “lead free” means that wetted surfaces of a pipe contain a weighted average of 0.25% lead and the wetted surfaces of solder and flux contain a weighted average of 0.2% lead. Because of shifting “lead free” definitions, specific exemptions from lead-free requirements (e.g., for outlets used for irrigation), and uncertainty regarding individual pipe and fixture composition and installation dates, testing of water from individual outlets is the only way to understand the potential for lead exposure through drinking water.
- Is lead exposure through drinking water a problem in Vermont schools? Possibly, but there’s little data to go on. Data from the Vermont State Health Lab in 2015 indicate that ~5% of blood samples from Vermont children age 2-and-under exceed Vermont’s 5 µg/dL standard. In 2017, the Vermont Department of Health and Agencies of Education and Natural Resources launched a pilot project to test all drinking water outlets in 16 Vermont public schools that are on municipal water supplies. Results of that pilot showed substantial differences across schools in the frequency of lead detection and in lead levels. Schools ranged from having 0% up to 54% of outlets exceeding the EPA action level for lead, and from 3-88% of outlets exceeding AAP safety level of 1-ppb. The Addison Central School District performed by the Costanza-Robinson lab, as well as a handful of other towns who have voluntarily tested, provide the only other data to-date, where all water outlets in schools have been tested.
- Was it expected that would lead will be found in Vermont schools’ drinking water? Yes and no. While we didn’t have specific evidence suggesting a problem existed, it was not surprising to find some water outlets delivering water with unsafe lead levels. The older infrastructure of many Vermont schools, coupled with data from elsewhere, suggest that lead is likely to be detected in at least some outlets in most schools.
- What will happen if elevated lead levels are found in my/my child’s school? ACSD has voluntarily committed to reducing lead exposure through drinking water at its schools by taking steps to address outlets deemed a priority through our work. Based on the new Vermont lead law, they will be required to re-test every couple of years, each time demonstrating either that the water meets the standard or that remediation strategies have been successful at bringing the outlet into compliance.
- Is the lead testing being conducted by a certified laboratory and can we trust the results? No and Yes. No, the Robinson Lab at Middlebury College is not a certified laboratory — few academic research laboratories are. You can trust the data, because we adhere to industry-accepted quality assurance and quality control protocols and criteria, including those used by certified laboratories. These include, but are not limited to, daily calibration of analytical instruments (r2>0.99; all calibration standards within 10% of known values), sample analysis in triplicate (<10% variation), and analysis of a National Institutes of Standards and Technology certified reference material (within 10% of certified 12 .1 ppb value for lead) before/after every 10 samples and at the end of the run. We have confirmed the lead levels, and thereby our methods, in ~10% of samples by analyzing them using an independent analytical technique (also with its associated QA/QC); values from the two techniques agree to within 10% and typically to within 1 ppb. Finally, we have sent ~10 samples to a certified laboratory for fully independent analysis; our values agree with certified laboratory values to within 10% and typically within 1 ppb. Dr. Costanza-Robinson has a Ph.D. in Analytical Chemistry and Soil, Water and Environmental Science; has taught Environmental Chemistry, Environmental Analytical Chemistry, and Instrumental Analysis courses at the college level for more than 15 years; and regularly publishes in top peer-reviewed environmental chemistry journals. Dr. Costanza-Robinson personally supervises and independently verifies every aspect of the work.
- What if I am concerned about lead in my home’s drinking water? If you are concerned or simply want to know the lead levels in your home’s drinking water, you can have it tested. The Vermont State Health Lab conducts test — for lead alone, it costs $12/sample. You will typically want to collect 2 samples for each outlet/faucet you want to test, so $24. Instructions on how to collect the sample are provided by the state, but last I checked they were designed for municipal sample collection. Here are the Collecting Water Samples_Home Lead Testing (and used for ACSD schools) for lead testing in your home. Here’s the order form you would send in with your samples.
Past and present members of the Robinson Lab lead team, affectionately known as Team Pb&Fun, include Gabrielle Davis (ES-Chemistry ’19), Jennifer Ortega (ES-Chemistry ’18), Sarah Kotin (ES-Chemistry ’20), Mairin Wilson (ES-Chemistry ‘17.5), and Nina Buzby (ES-Chemistry ’17). Members of the CHEM 311 Instrumental Analysis Laboratory Fall 18 class have also contributed.
The Robinson Lab is grateful to Mr. Eric Warren, ACSD Facilities Manager, and Mr. Bruce MacIntire, ACSD Director of Facilities, for providing access to and technical and historical information about ACSD schools, and for assisting in communicating with the school community about the project. We thank Dr. Peter Burrows, ACSD Superintendent, for his support of the work. We gratefully acknowledge the assistance of Jody Smith, Senior Instrument Technician at Middlebury College, for instrument support, maintenance, and student training and Carl Robinson for aid in sample collection.
We are grateful for the ongoing communication between our lab and the Vermont Department of Health regarding lead testing in schools, including regarding best practices for communicating findings with the public.
References for sources not available freely online
AAP (2016). “Prevention of childhood lead toxicity.” Pediatrics 138:17, DOI: 10.1542/peds.2016-1493.
Edwards, M., T. S. and D. Best (2009). “Elevated blood lead in young children due to lead-contaminated drinking water: Washington dc 2001-2004.” Environmental Science & Technology 43:1618-1623,
Ellenhorn, M. (1997). Lead epidemiology, industrial exposure, immunotoxicology. Ellenhorn’s medical toxicology, diagnosis and treatment of human poisoning. Philadelphia, Williams & Wilkins: 159-160.
Laidlaw, M., G. Filippelli, R. Sadler, C. Gonzales, A. Ball and H. Mielke (2016). “Children’s blood lead seasonality in flint, mi (USA), and soil-sourced lead hazard risks.” International Journal of Environmental Research and Public Health 13:358.
Lambrinidou, Y., S. Triantafyllidou and M. Edwards (2010). “Failing our children: Lead in u.S. School drinking water.” New Solutions 20:25-47.
Sanborn, M., A. Abelsohn, M. Campbell and E. Weir (2002). “Identifying and managing adverse environmental health effects: 3. Lead exposure.” Canadian Medical Association Journal 166:1287-1292,