NEWARK - Some 17,000 children will be tested for potential lead poisoning after high levels of the chemical were found in nearly half of the its schools, officials revealed today.

Newark Department of Health Director Dr. Hanaa Hamdi told members of the City Council Tuesday that the tests will begin with approximately 2,000 toddlers who attend early childhood centers located at the 30 buildings were elevated levels of lead were found.

Once those have been completed, the city will set up a number of sites outside of schools to test the remaining students. Parents who do not wish for their children to be tested will be given the opportunity to opt out, according to Hamdi.

City spokeswoman Marjorie Harris said the testing will be led by the state Department of Health and Department of Environmental Protection, with the city serving in a supporting role.

The move is the latest attempt to gain a fuller picture of just how children have been affected by the tainted water. Officials have urged calm and caution in the week since it was first revealed, saying the levels found in the schools do not compare to those making national headlines in Flint, Mich.

Central Ward Councilwoman Gayle Chaneyfield Jenkins questioned the plan to prioritize children in the early childhood centers, saying they were more likely to drink prepackaged water or be overseen by an adult when utilizing drinking fountains.

"The teenagers, the young people who regularly walk over to a water fountain themselves....they were the ones drinking directly from the source," she said.

"The fact the city is taking that approach, I have to be critical of it. It's mind-boggling to me."

Hamdi defended the plan, however, saying that children between 1 and 6 were in the most danger if they ingested lead-contaminated water.

"It doesn't mean the other students are not our priority," she said. "If we can look at those toddlers first, we'll be able to gauge whether they're safe or not."

No clear timetable for the testing was offered, but Hamdi said officials with the school district and various faith and community-based organizations had offered their assistance as plans take shape.

Though school officials have acknowledged they have long been aware of potential lead-related risks at many of Newark's aging school buildings, it remains unclear just how long children may have been exposed to the high concentration of lead. On Monday, the city's teachers union released photos of what it claims are expired lead reduction filters in at least 10 of the city's schools.

In response to the council announcement Tuesday, school officials released a statement saying the testing would not impact school operations or instructional time.

"We look forward to learning more about their plan for implementation and partnering with (the city) to get the testing information to our students and families," the statement said.

Students and faculty in the 30 affected schools are depending on bottled water for drinking and cooking.

Any calls about potential lead poisoning related to water in Newark schools may be directed to the New Jersey Poison Center at (800) 222-1222.

Dan Ivers may be reached at divers@njadvancemedia.com. Follow him on Twitter at @DanIversNJ. Find NJ.com on Facebook.