The latest round of testing for the city of Flint’s drinking water shows a rise in lead levels.
Michigan’s state environmental agency has been closely watching lead levels in Flint’s drinking water since 2016, with regular testing of properties with lead service lines.
Flint’s lead testing data for the first six months of 2022 showed the 90th percentile calculation for the samples collected is at 10 parts per billion (ppb) for lead.
While being below the state and federal action levels for lead in drinking water, 10 parts per billion is still a big increase over recent years.
In the last six months of 2021, testing showed 7 parts per billion in the 90th percentile. In the first six months of 2021, the number was 3 parts per billion.
In fact, the last time the lead test results were higher was in 2016.
Scott Dean is a spokesman for the Michigan Department of Environment, Great Lakes and Energy. He said one reason behind the increase might be the properties being tested.
Dean pointed out that the properties being tested now tend to fall into what is called “tier 2” — homes and businesses with relatively little water use. Most "tier 1" homes in Flint have had their lead and galvanized service lines replaced by now, and are no longer part of the survey.
Dean said “tier 2” homes and businesses usually use much less water, which can lead to higher readings.
“The longer water stagnates the more likely it is to absorb lead and other minerals,” said Dean.
He said Flint’s water quality is improving due to infrastructure improvements and the replacement of lead service lines.
Despite the increase, Flint is now in its sixth year of meeting state and federal standards for lead in drinking water.
Still, there is no safe level of lead in drinking water.
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