Flint’s water woes lingered

Just five days into 2016, Michigan Governor Rick Snyder declared a state of emergency in Genesee County in response to high lead levels in the city of Flint’s drinking water. This declaration followed months of work by scientists and activists to alert government officials that something was wrong with Flint’s water.

The city’s water woes started back in 2014 when it stopped taking treated water from the Detroit Water & Sewerage Department and instead began treating water from the nearby Flint River. The city’s treatment plant didn’t effectively optimize this new source of water to prevent it from corroding pipes in the city’s distribution system. This corrosion leeched lead into the drinking water.

The entire crisis might have been avoided if the city had added an orthophosphate corrosion inhibitor to the water, says Marc A. Edwards, a Virginia Tech environmental engineer who led a team that studied Flint’s water problems. Other factors contributing to the water’s corrosiveness were a relatively low pH and high chloride levels.

Edwards’s team also determined this year that outbreaks of Legionnaires’ disease in Flint in June 2014 and May 2015 were likely linked to the city’s corrosive water (Environ. Sci. Technol. Lett. 2016, DOI: 10.1021/acs.estlett.6b00192). The lung infection is caused by Legionella bacteria that can lurk in drinking water systems. Flint’s corrosive drinking water leeched iron out of city pipes, which could have fed the bacteria’s growth and reacted with and eliminated chlorine disinfectant.

Flint is back to taking water from Detroit. Recent measurements by the Michigan Department of Environmental Quality and Edwards’s team show that lead levels in the city’s water are dropping. Some homes still have levels above a regulatory limit set by the Environmental Protection Agency.

The city hopes to replace lead pipes throughout its distribution system. But a study this year from researchers at Dalhousie University suggested that for such replacements to effectively lower lead levels, they must be complete—all pipes must be replaced between water mains and a home, not just up to homeowners’ property lines (Environ. Sci. Technol. 2016, DOI: 10.1021/acs.est.6b01912). Partial replacements can actually increase lead levels because of electrochemical reactions that corrode the lead, the study found.