A closer look at lead contamination tests conducted at New York City schools shows a much higher risk than originally thought. Initially, officials reported that fewer than 1 percent of water samples from 1,500 NYC school buildings showed lead concentrations exceeding Environmental Protection Agency (EPA) guidelines. However, it has come to light that the process used to obtain samples may have resulted in test results that reflected a much lower risk than the city’s school children are actually facing.

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City officials revealed that a process called pre-stagnation flushing was used, wherein every water fixture at each school was turned on fully for two hours the night before the samples were taken. This practice cleans most lead particles from pipes and leads to test results showing temporarily lower lead levels, which is the main reason the EPA warned against it with a memo issued in February. By flushing the pipes prior to collecting water samples, test results do not give a clear picture of the risks associated with ordinary use of those same water fixtures.

Related: Federal prosecutors look into lead exposure and other health issues in NYC public housing

School buildings are outside the EPA’s official scope of regulation, though, so city officials were not required to follow EPA standards for sample collecting or testing. The agency does outline voluntary guidelines for schools, which do not include provisions for pre-stagnation flushing and instead recommend collecting samples under circumstances that most closely mimic regular usage. Not surprisingly, the city has defended its testing methods despite the elevated safety concerns.

Now, many water quality experts are calling on the city to do another round of testing, without flushing pipes prior to collecting samples. “The results should be thrown into the garbage, and the city should start over,” Marc Edwards, a civil engineering professor at Virginia Tech told the New York Times. Edwards was one of the first to uncover dangerously high lead levels in the water in Flint, Mich.

Via The New York Times

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