Louisiana could see months of high salt levels in drinking water, threatening residents’ health

By Jen Christensen, CNN

(CNN) — Alisha Reed took it as a sign that times were tough in New Orleans last weekend when her local Costco store hired a brass band and Mardi Gras Indians to distract crowds of customers standing in long lines.

Bottled water was the hot seller. But it wasn’t a typical hurricane warning that prompted the purchases; it was a warning from public health officials that a lack of rain in the Midwest will bring an unwelcome ingredient to the area’s tap water: salt.

“Everyone’s panicking because it’s all over the news, and people are trying to figure out what’s going on, and everyone’s trying to stock up on water. It’s like when we have hurricane preparation,” said Reed, a pharmacist and a member of the board at the American Heart Association of Greater New Orleans. “Lots of anxiety is building up.”

The problem is saltwater intrusion, which happens when water from the Gulf of Mexico doesn’t stay there. The downstream flow of the Mississippi River is usually strong enough to keep ocean water out, but this year, its volume is extremely low due to record high temperatures and an extreme drought in several Midwest states. The river still hasn’t recovered from back-to-back low-water years.

As salt water makes its way upriver, displacing the Mississippi’s fresh water, it threatens municipal drinking water. If salt water stays in the region for too long, it can also corrode pipes, some of which are made with lead.

Most water systems in the area don’t filter out salt, although there are several ongoing engineering efforts to work around the problem.

High levels of salt – about 250 milligrams per liter (mg/L) and above – don’t just taste bad, they can make tap water unsafe to drink or cook with, according to the New Orleans Sewerage and Water Board. If salinity levels go even higher, it may also become difficult to shower or wash dishes and clothes.

When it comes to human health, the body needs a small amount of sodium to work.

“It’s not like tobacco, where we know the optimal amount is zero. Sodium is essential to your body,” said Andrew Mente, an associate professor at McMaster University in the Population Health Research Institute who has done extensive research on sodium in the diet. “Studies have shown collectively that a moderate amount of sodium is optimal, whereas high amounts are associated with harm, just like low amounts are associated with harm.”

Most Americans consume too much sodium already, according to the US Centers for Disease Control and Prevention. If the water itself has a high salt content, it could threaten people’s health.

A sodium level of 100 mg/L of water “will not substantially increase risks” for someone in good health, according to a Tulane University School of Public Health & Tropical Medicine’s website put together because of the ongoing situation. But if it gets to 250 mg/L, salty water can cause diarrhea, stomach pain and even cardiovascular problems, studies show. Some people may feel sick at lower levels, but others might not get sick at all.

Elevated salt levels in drinking water can be a bigger problem for people on low-salt diets and can make conditions worse for people who have kidney disease, heart problems or high blood pressure. They can also be a problem for people who are pregnant, infants and the elderly.

Water with high salt content can raise blood pressure, increasing the risk of heart attack and stroke. Salt makes the body hold on to water, and extra water in the blood makes the heart work harder and puts extra pressure on blood vessel walls, according to the American Heart Association.

Salty water can also exacerbate kidney disease by making the kidneys work harder than usual.

“As kidney function declines, the kidneys are less able to excrete the sodium,” said Dr. Joseph Vassalotti, chief medical officer of the National Kidney Foundation and a practicing nephrologist at Icahn School of Medicine at Mount Sinai.

Certain medicines also don’t work as well with high-sodium diets, Vassalotti said. ACE inhibitors and angiotensin receptor blockers for heart problems are less effective and lead to blood pressure that can’t be controlled well with medications.

In pregnant people, too much salt can lead to preeclampsia, a potentially deadly blood pressure condition. Infants’ kidneys can’t deal with large amounts of salt, and it can lead to high blood pressure later in life.

The city of New Orleans is encouraging parents of infants on formula to use ready-made versions or mix the powder with bottled water. The state’s WIC program will have both available for members.

The elderly may also be more sensitive to high sodium levels, according to the EPA, largely because they have a higher incidence of cardiovascular disease. They also have a higher taste threshold for salt, meaning they may be consuming a high-sodium already.

Pets can also get sick from drinking salty water, so the city is encouraging people to give their animals bottled water, too.

Reed became a pharmacist to help people, she said, but it’s frustrating that there’s so little she can offer customers other than to raise their awareness. She can’t tell residents to boil water like they do for other contaminants, because that won’t get rid of the salt. A fancy filter won’t take out salt, either.

“There’s a lot of different patient populations that can be affected or will be affected by this,” she said. And there are a lot of people in the area who must be especially careful.

Reed said that about 1 in 3 adults in New Orleans – more than half a million adults – have high blood pressure. Two-thirds are in under-resourced communities and may not be able to afford bottled water.

To add to the problem, it’s still hot outside and will probably stay that way through November. Reed often counsels people to drink a lot of water, but it’s tricky now.

“It’s scary,” she said.

Without significant rainfall, water could be undrinkable in parts of Louisiana for several months, experts say. Some residents in Plaquemines Parish, in the southeast corner of Louisiana, have been drinking and cooking with bottled water since June, although a reverse osmosis unit has been installed at the Pointe a la Hache Water Treatment Plant to filter out the salt.

For now, the water is safe to drink in New Orleans, but residents are encouraged to watch for any warnings that the situation may change. Local water systems as well as the US Environmental Protection Agency are monitoring the situation closely.

The Army Corps of Engineers expects salt water to reach New Orleans drinking water in mid to late October. Louisiana Gov. John Bel Edwards signed a state of emergency in August because of it, and in September, President Joe Biden announced that federal disaster assistance would be available.

Vassalotti said that when he was thinking about the potential health problems facing Louisiana, he noted that much of the research on the health effects of saltwater intrusion into drinking water is done in other countries, mostly developing nations.

“It’s kind of strange that we’re facing this now,” he said. “But with global warming and the sea level rising, we may be seeing more of this.”

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