The Santa Rosa well on the Superfund site, from which water has been distributed by the Puerto Rican water utility, contained only trace amounts of PCE, an industrial chemical, according to the tests run by the Virginia Tech Water Quality Lab. The other two wells at the Dorado Superfund site, called Maguayo 2 and Maguayo 4, showed no signs of industrial contamination.
Marc Edwards, the professor at Virginia Tech who conducted the tests for CNN, said the low level of contamination put even the Santa Rosa well safely within clean drinking water standards. All three wells are safe, he said. "I would drink" this water, he told CNN on Thursday.
"This water you sent me is meeting all federal safe drinking water standards," said Edwards. "How that happened? It could be the way the water flows on the ground (that's) not bringing contamination from the Superfund site to the well. Or maybe they are using some sort of treatment technology."
is an environmental engineer and water quality specialist who also conducted testing on water in Flint, Michigan.
Last week, CNN reported
locals had been drinking from at least two wells on the Dorado Groundwater Contamination Site
, west of San Juan, the capital. That area was designated as a Superfund site by the US Environmental Protection Agency in September 2016.
"Sampling at the site has found chemical contamination that is impacting wells used to supply drinking water to the local communities," the EPA said at the time. "Drinking water with the solvents, which include tetrachloroethylene and trichloroethylene, can have serious health impacts including damage to the liver and increasing the risk of cancer."
This island was pummeled by Hurricane Maria on September 20, leaving about 1 million people without running water, even more than one month after the storm. CNN talked to locals who said they were desperate for water and were willing to take what they perceived as risks by drinking water from a location designated as a hazardous-waste site by the government.
The tests by Virginia Tech were not conducted according to the strictest of protocols. CNN producers collected water samples on Sunday in glass Perrier bottles and shipped them, in a cooler with ice, from Puerto Rico to the lab in Virginia. In the absence of specialized equipment in a disaster zone, the crew used alternate methods suggested by Edwards.
An unopened bottle of Perrier was sent for testing to control for any contamination.
These methods may produce slightly cleaner results than normal, Edwards said, but the levels of contamination were so low that they do not concern him.
The Santa Rosa well showed 0.7 parts per billion of PCE, the industrial contaminant, which is also known as tetrachloroethylene, Edwards said. Drinking water standards in the United States say water is safe below 5 parts per billion, he said.
The lab did not test for bacteria, which is another concern after hurricanes. But the samples showed levels of chlorine, a disinfectant, that make Edwards confident they are safe.