Students who drank lead-contaminated water in Seattle public schools would not have suffered detectable or lasting health problems, a panel of scientists that reviewed a district water study has concluded.

Seattle-based Intertox, which conducted the study for the Seattle School District, said that even under a "worst-case" scenario, the most lead-concentrated water sample collected would not have raised the lead level in a child's blood enough to be considered lead poisoning.

The peer-review panel assessed the integrity of Intertox's report. Among the panelists was a state Department of Health toxicologist and three University of Washington scientists.

The report said the worst-case sample was drawn from standing water from a fountain in Room 5 at Alternative Elementary #2 (AE2) at Decatur. It measured 1,600 parts per billion (ppb) of lead, which could raise a typical child's blood lead level to 8.6 micrograms per deciliter (mcg/dL). The federal concern level is 10 mcg/dL.

And a blood lead level of 8.6 mcg/dL would have been unlikely, according to Intertox's report, which was released yesterday. That's because the scenario assumes that the child drank water only from the Room 5 fountain every day for two school years and that half of the water consistently contained 1,600 ppb lead.

The study's findings may settle an emotional debate over health risks that has continued since January 2004, when the district began supplying bottled water to most schools and testing drinking fountains and sinks for lead, cadmium and other contaminants.

The tests showed that about a quarter of the district's drinking-water outlets exceeded the federal "action level" for lead in water of 20 parts per billion. Though fewer than 5 percent of the outlets exceeded the action level after being flushed for 30 seconds, district officials can't document whether those outlets were being flushed regularly.

The Seattle district plans to spend about $18 million to clean up its water. A School Board policy now limits drinking-water lead levels to 10 ppb, a level also adopted by Shoreline and Portland schools, and also regulates cadmium, copper and iron contamination.

Blood lead levels are still of concern to parents. Children in the United States between ages 6 and 11 typically have blood lead levels of 1.5 mcg/dL, on average, which Intertox assumed also was the typical level for Seattle students from normal exposure to the city's air, soil and water.

But as the lead in a young child's blood rises above 1 mcg/dL, the impact on the child's IQ increases, Cornell University researchers say, and with a lead level of 10 mcg/dL, a child's IQ could fall by 7 points. The Cornell study documented that effect in children as they aged from 3 to 5.

Intertox examined data from more than 2,000 district fountains and predicted that, under a worst-case scenario, students at four schools — AE2, Wedgwood Elementary, the Boren interim school site and Lincoln High School — might have blood lead levels above 5 mcg/dL.

The study's worst-case scenario pertained to students ages 5 to 7, so older students at Boren and Lincoln are expected to have been affected even less than predicted, said Rick Pleus of Intertox.

"I am confident that no child experienced the level of sustained exposure that would be necessary to cause any significant effect on mental development," wrote David Eaton, a UW toxicology expert who reviewed Intertox's study.

He cited three reasons: Studies done by Intertox and the UW's pediatric environmental-health specialty unit both showed the health risks to Seattle students were extremely low, partly because of the students' age. Exposure to lead is most hazardous from birth to age 4, a critical period of brain development. And the students also weren't drinking school water year-round, given summer and winter breaks and weekends.

However, the experts noted that the study couldn't accurately predict the risk or the blood lead levels for individual students because circumstances — such as medical conditions, or certain students drinking extraordinary amounts of water — can vary.

It's possible, they said, that students exposed to lead from paint or drinking water in their homes could suffer lead poisoning with the additional exposure at school.

"Nevertheless, I do not believe that school drinking water could have produced blood lead levels sufficient to produce any detectable or lasting impact on health in any child," wrote Bryan Hardin, a panel member whose Redmond firm, GlobalTox, coordinated the peer review for $15,000.

An oversight committee appointed by the School Board to monitor water-quality improvements met yesterday to receive Intertox's report. A fact sheet will be sent to parents next week.

Intertox did not predict the blood lead levels of children in Head Start, which serves 3- and 4-year-olds from low-income families at about a dozen Seattle schools. Pleus said the district didn't ask Intertox to study the exposure to children under age 5. He said he would expect younger children's lead levels to be higher, but he didn't know by how much.

Sanjay Bhatt: 206-464-3103