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Credit: Charles Maldonado / Verite

Officials in the New Orleans area are closely watching a slow-moving salt wedge creeping its way up the Mississippi River. Salt water is expected to reach Jefferson and Orleans parishes by late October, threatening the drinking water supply of two of the state’s most populous parishes. As of last week, residents were hitting grocery stores to stock up on bottled water. 

At a press conference on Friday, state Health Officer Dr. Joseph Kanter confirmed health concerns from exposure to salt water mainly for seniors, pregnant women and infants who might be more sensitive to salt exposure. 

But he also raised an additional worry: the corrosive effect of salt on lead pipes. 

“We also are concerned for corrosion of pipes, and leaching out of heavy metals,” said Kanter in an interview with Verite. “It’s very, very challenging to predict that,” noting that the effect of salt water on each parish’s systems will vary. 

According to the EPA, even at low levels, lead exposure can cause behavior and learning problems, slowed growth, and hyperactivity in children. Large, older water systems like that in New Orleans could be particularly vulnerable to heavy metal contamination. On Friday, after signing an emergency declaration, Mayor LaToya Cantrell said the city and the Sewerage & Water Board are monitoring thousands of lead pipes around the city.  

The Army Corps of Engineers is continuing to expand a salt water sill meant to slow the progress of the wedge, and barging in water as needed to create a mixture in water processing facilities in the parishes that is safe for drinking. But the problem will not be solved as long as persistent droughts continue in the Midwest, upriver from Louisiana, lowering the river level and allowing saltwater intrusion. “Without significant rain in the immediate future. The augmented saltwater sill will too be overtopped,” said Col. Cullen Jones, the corps’ New Orleans district commander, who also noted that this intrusion event could last several weeks. 

Experts say it will be difficult to predict the effect that salt water will have on New Orleans’ pipes, but that any amount of additional salt could have corrosive effects. 

“It’s going to be very important for water systems as this wedge goes forward in partnership with the Department of Health to conduct very frequent testing of the water,” Kanter said. “Very frequent testing in responding to heavy metals.”

The Sewerage & Water Board has more than 1,500 miles of pipes delivering water to residents, many of them built in the early 20th century, when lead was a relatively common construction material. But the utility does not know where all of them are. 

“New Orleans, like most cities in the nation, lacks an updated comprehensive map of where lead water pipes are located,” reads the Sewerage & Water Board’s release this spring on their efforts to map out the city’s lead lines.

But portions of lead service lines — as well as interior lead fixtures — are located on private property. 

“Plumbing materials and age will vary by home … that can impact what leaches into water as well,” said Adrienne Katner, professor of environmental and occupational health at LSU, whose research has evaluated New Orleans water lead levels. 

Responding to questions from Verite News, the Sewerage & Water Board said that it is evaluating their options to address the salt water issue, with daily monitoring for salinity levels, and will be using calcium hydroxide to raise the pH level of the drinking water. The water utility says this will reduce potential for lead to enter drinking water, noting that the impacts will be difficult to predict. 

“Any speculation about impacts is premature,” the Sewerage & Water Board said in a statement to Verite. “But we are working diligently with top experts at Louisiana Dept. of Health … and the Environmental Protection Agency … to prepare to increase our frequency of lead testing and address impacts swiftly with a full range of resources.”

Concerns over lead exposure are not new in New Orleans, where generations of youth have been exposed to lead in public housing. The period of hurricane Katrina brought concerns over the distribution of lead in silt from destroyed houses and scattered debris. Concerns over lead in the drinking water are also not new, with a 2016 investigation by NBC indicating that federal tests were missing high levels of lead in the water. 

Katner’s own research has been critical of the lead-line replacement process.  The city only replaces the portions of water lines located on public property, but not connected privately owned lines, disturbing the remaining lead water lines and potentially exposing residents to higher levels of lead in the process, the subject of a 2017 report by then-Inspector General Ed Quatrevaux. Another 2017 investigation, made public in 2019, alleged multiple violations of federal regulations in how the utility was collecting samples to test for lead. 

According to Marc Edwards, a professor of environmental and civil engineering at Virginia Tech who is best known for his research exposing the Flint, Michigan water crisis, any amount of salt water in pipes can increase the risk of release of heavy metals into the water. 

“The general rule is that higher salt is worse for metallic pipes… It is both private and public pipes at risk,”  Edwards said, noting that it is difficult to predict the amount of salt that might affect pipes, especially considering age and previous corrosion. “There’s no magic threshold.” 

Gov. Edwards urged residents to stay up to date with the most recent water quality reading, releasing a centralized website for updates last Friday. “I’m going to ask the people to pray for rain,” he said. “But we’re going to do everything we can to make sure that we’re bringing every resource to bear that is reasonably necessary to help us deal with this challenge.”

The Sewerage & Water Board also provides free lead testing kits throughout the year. Water utility officials will appear before the New Orleans City Council on Wednesday (Sept. 27) to provide an update on preparations for saltwater intrusion. 

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Climate and multimedia journalist Lue Palmer is a native of Toronto, Canada, with roots in Jamaica. Before entering their career in journalism, Lue was a writer, documentarian and podcaster, covering race,...