ANCHORAGE — The only school in one of Alaska’s most eroded communities is among 28 public and private entities in the state whose water systems recently exceeded federal lead limits.

An Associated Press analysis of Environmental Protection Agency data shows the state-owned school in Newtok was significantly over the federal lead limit in 2013. The EPA calls for systems to keep levels below 15 parts per billion.

Testing at the school showed lead levels of more than 161 parts per billion. That figure was skewed by an isolated sample taken from the kitchen sink that tested out at 317 parts per billion, Cindy Christian, drinking water program manager for the Alaska Department of Environmental Conservation, said. Five samples were collected altogether, with three of them testing at zero and one at 5.6 parts per billion.

No amount of lead exposure is considered safe. Lead contamination has been linked to problems such as learning disabilities.

AP’s analysis found nearly 1,400 water systems across the country had samples exceeding the limit at least once between Jan. 1, 2013, and Sept. 30, 2015. The affected systems include 278 that are owned and operated by schools and day care centers in 41 states, including Alaska, which had eight schools on the list.

The groundwater itself is typically free of the toxin in Alaska, and lead found in drinking water usually comes from materials existing in older pipes and fixtures, Christian said.

In Newtok’s case, a high reading came from a kitchen sink used to wash dishes, and potentially, prepare food, according to officials with the Lower Kuskokwim School District, which operates the Newtok school. The system serves a 175-person population, according to the EPA data.

Officials downplayed the excessive level found, saying suppliers are required to collect samples from taps not used for at least six hours, which allows higher concentrations of the contaminant than would be found after the water is running for a while. In Newtok’s case, the source of the lead was determined to be an old faucet, which was promptly replaced, according to officials.

“It’s an incident, an isolated incident, nothing to be addressed districtwide” plant facilities manager James Mikesell said.

Newtok tribal leaders didn’t respond to multiple requests for comment.

Because lead exposure builds up over time, it’s difficult to predict the long-term effects, Christian said. However, she added, “if you’ve exceeded an action level in the case of lead, we wouldn’t recommend that you drink the water without some kind of treatment.”

If more than 10 percent of samples are above the EPA level, water providers must inform users and increase water sampling. Sometimes suppliers must take actions like adding corrosion-control chemicals.

Newtok, a Yup’ik Eskimo community of about 380, has had corrosion-control measures in place for about a decade. But after the high test result, state regulators worked with the system operators to adjust corrosion controls, Christian said. That was the third and final time the village 480 miles west of Anchorage exceeded the action level in its history.

The public was notified in February 2014 through an information sheet posted at the school and distributed to Newtok staffers, Christian said. District officials say parents were not directly notified.

Christian said there’s no record of the Department of Environmental Conservation receiving any calls from concerned Newtok parents that would have been fielded at the agency’s Anchorage office.

The department stepped-up monitoring at the school in 2014. Subsequent water samples show the school has registered at zero or below the action limit since then, Christian said. Samples were last taken last October, when the kitchen sink with the earlier high reading registered at 1.5 parts per billion.

“The school did what they were supposed to do,” Christian said. “They worked with us. They made sure that they got their samples and they did a very good job in addressing the problem.”

Newtok is among Alaska’s most imperiled communities because of aggressive erosion, and it is the only community that has begun a physical relocation to higher ground. The conditions in the village are not believed to have contributed to the lead problem, Christian said.

Other water systems in Alaska exceeding federal limits, according to the AP data review, include local government or tribal water systems in Kake, Seldovia, Kipnuk, Sleetmute, Beaver and Unalakleet, as well as systems connected to the Pogo Mine near Delta Junction and a now-inactive work camp in the North Slope for drilling contractor Nabors Alaska. Water systems in Sleetmute, Seldovia and Beaver are among 19 systems the Department of Environmental Conservation lists as currently exceeding the federal lead limit.