In New York
Test Method Minimized Lead Levels in Schools’ Water?
Chronicle News Services
NEW YORK--When the results of tests for lead in the water at more than 1,500 New York City school buildings were announced in July, officials said that fewer than 1 percent of all the samples taken showed lead concentrations that exceeded Environmental Protection Agency guidelines. Given other safety measures in place, officials assured parents, the water was safe to drink.
But a review of how the testing was conducted suggests that the amount of lead in the water that students consume could be greater than the results indicate.
According to the city, every water outlet in each school was turned on fully for two hours the night before the samples were taken--a practice known as prestagnation flushing that cleans most soluble lead and lead particles from pipes and thus reduces lead levels temporarily.
In February, the E.P.A. recommended against the use of prestagnation flushing when sampling water in homes, saying that the step “may potentially lower the lead levels as compared to when it is not practiced.”
Because the E.P.A. does not regulate the testing of water in schools, its guidance on pre-stagnation flushing does not apply directly to New York’s procedures. But the agency’s voluntary guidelines for schools do not recommend such flushing and generally direct schools to mimic normal consumption patterns when taking samples.
“The results should be thrown into the garbage, and the city should start over,” said Marc Edwards, a civil engineering professor at Virginia Tech who helped uncover dangerously high lead levels in the water in Flint, Mich., touching off scrutiny of drinking water across the country.
Yanna Lambrinidou, an anthropologist who has worked with Dr. Edwards to expose lead continuation in water in Washington, D.C., and elsewhere, and an affiliate faculty member at Virginia Tech’s Department of Science and Technology in Society, said in an email that New York City’s schools “may have just broken the national record for flawed testing.”
“Flushing is inappropriate anytime you want to assess lead concentrations coming out of individual taps,” Dr. Lambrinidou wrote in the email. She said that water in schools is often stagnant for long periods of time--after school hours and on weekends, holidays and other breaks--and that the idea is to test it under conditions similar to those in effect when children might drink it. “Unless N.Y.C. schools flush every drinking water tap every evening for 2 hours routinely, their sampling technique is both unreliable and scientifically and morally indefensible,” she wrote.
Dan Kass, a deputy commissioner in the city’s Department of Health and Mental Hygiene, defended the process used to test the water. In an interview last week, he said the most important thing when sampling for lead was to have a period of stagnation, and that whether the water was flushed before that period began, and for how long, would not affect the results.
The purpose of a stagnation period, Mr. Kass said, “is that it essentially acknowledges that there’s going to be use of water the day before.” He continued, “Whether it’s flushing or actual use, it’s just use, and that’s entirely what’s intended by the overall testing protocol.”
Mr. Kass also said the flushing was intended to create a consistent baseline for the tests, regardless of whether the samples were taken on a Monday morning after a building had not been used over the weekend or collected on another day of the week.
At the city’s schools, contractors, after finishing the flushing, left for roughly eight hours and returned around 5 a.m. At each outlet to be tested, a sample was taken of the first water out of the tap, known as the first draw. The water was then run for 30 seconds and another sample--known as the second draw--was taken. A second-draw sample that shows an elevated lead concentration indicates a problem not simply with a fixture but a more sustained source of lead in the plumbing.
Over all, 510 of the city’s 1,520 occupied school buildings had at least one outlet where the first-draw water sample had a lead concentration over 15 parts per billion, the E.P.A.’s “action level” for lead in municipal water systems. And 153 buildings had at least one outlet where the second-draw sample exceeded the cutoff. Eight buildings had at least one outlet where a first- or second-draw sample had a lead concentration over 500 parts per billion.
Public School 254 in Sheepshead Bay, Brooklyn, which had more than 700 students in kindergarten through fifth grade, was among the schools with the most samples showing elevated lead levels: 13 first-draw samples and five second-draw samples had concentrations over 15 parts per billion. The first draw sample at one water fountain had a concentration of 712 parts per billion; the second-draw sample had a concentration of 348 parts per billion.
Public School 42 on Staten Island. Water samples taken from a drinking fountain there showed concentrations of lead far above Environmental Protection Agency guidelines for what is considered safe.
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