Protect yourself: Floodwaters teem with bacteria from human and animal waste, carcasses

The public health risks from Hurricane Florence rise with every inch of floodwater.

Floods are notorious conduits for filth, indiscriminately sweeping away the flotsam and jetsam of civilization: raw sewage and “solids” from municipal water treatment plants, industrial solvents and potent chemicals, garbage and debris, and the carcasses of wild animals trapped by rising floodwaters.

But it could take weeks, if not months, to know how bad the contamination is. So far, neither the N.C. Department of Environmental Quality or any other public health agencies are known to have tested the floodwaters for contamination levels, largely because these agencies are focused on the immediate response to Hurricane Florence. Toxicologists and scientists at UNC Chapel Hill and N.C. State University are planning to take water samples in flooded regions, but the analysis of the results will take time.

In the meantime, North Carolina’s public health director is urging residents to avoid exposure to floodwaters.

Betsey Tilson, the state health director and medical director of the N.C. Department of Health and Human Services, urges frequent washing, tetanus shots and verification that tap water and well water are safe to drink.

“People should always assume that floodwater is always contaminated,” Tilson said. “There is potential from pesticide runoff from agriculture. There is potential human sewage from septic tanks. There is potential animal sewage as well.”

Past lab tests of floods, including Hurricane Matthew in 2016, found extensive contamination, including from pathogens that can cause food poisoning and skin infections, said Rachel Noble, an environmental microbiologist at UNC Chapel Hill. An analysis by the Department of Environmental Quality issued last year found elevated fecal coliform bacteria four months after the October 2016 hurricane.

“Most people don’t realize that when a large amount of sewage contamination gets into a water body, or a hog lagoon breaches, these things do not die immediately,” Noble said. “They have a life of their own and some of these things can survive quite nicely in a water environment, for days or weeks.”

Legions of residents will be exposed to contaminated waters, risking infection through an open sore, cut or through a splash into the mouth. Children and the elderly, as well as people who have compromised immune systems, may be at greater risk of infection.

It is nearly impossible to avoid getting wet during record flooding, as evacuees and displaced residents cross infested waters by foot, car and boat, slosh through puddles and tread on waterlogged ground. Some will spend days on end cleaning out flooded homes and cars.

“All of these waste products sitting around the landscape are now getting mixed together,” said Ryan Emanuel, an N.C. State professor of environmental sciences who plans to take lab samples from the Lumber River in Robeson County. “We focus on the drama on how high the water is. But there is a complete other dimension, too — what the water contains.”

What can kill you

Salmonella, E. coli and fecal coliform are among the common micro-predators traveling in flood currents. Another concern is “vibrio,” a catch-all term for a variety of bacteria, including the one that causes cholera, contained in sewage that can build up in shellfish and cause lethal food illness. Nearly every year, Vibrio vulnificus kills people in Florida. An outbreak occurred in New Orleans after Hurricane Katrina struck in 2005, with multiple deaths.

Following Hurricane Matthew in 2016, Noble’s teams sampled waters in the Neuse River and, in a published study, reported finding 21 different species of vibrio, including those posing the most threat to human health.

Also contributing to the contamination are farm animals who were trapped in cages or buildings when Florence struck. As of Tuesday, North Carolina had lost 5,500 hogs and 3.4 million chickens and turkeys. The animals died by drowning, were crushed in collapsing buildings, and also perished from heat exposure when farms lost electricity and ventilation systems stopped working.

The total death count for poultry could potentially double, said Doug Meckes, the state veterinarian within the N.C. Department of Agriculture.

It’s unclear how many animal corpses are decomposing in high waters.

“We still have farms that no one’s been able to get to,” Meckes said.

The livestock corpses will be disposed of in several ways. Hog carcases will be dumped in landfills, but those in salvageable condition could be “rendered” for cosmetics, animal feed and other products. The birds that perished will be composted in a mixture of sawdust and wood shavings, a decomposition process that takes 28 days, Meckes said.

State officials, hampered by flooding, have not been able to make site visits to inspect the damage and are relying on self-reporting by farmers and companies that contract with the farmers to supply animals for large meat processing plants.

The Department of Environmental Quality is still tallying total breaches, malfunctions and failures in state water systems, and the provisional numbers rise daily.

The agency said Wednesday five hog lagoons, the retention pods where swine feces and urine are broken down by microbes, have structural damage. One in Duplin County has drained 369,230 cubic feet of fluid, and two others are awaiting estimates of spill volumes. The agency also said 21 hog lagoons are “overtopping,” or overflowing, and 67 are within 3 inches of flowing over the brim. The state has 3,300 hog waste pits, many exposed to the open air, and the vast majority remain intact.

Dangers from septic systems

Municipal water treatment systems are not faring as well. So far, 15 systems are on a Department of Environmental Quality watch list for “the highest level of concern.” Overwhelmed by power outages or inundation, they are swamped with flood waters and expelling what they can’t handle, including “solids.” Some are simply diverting excessive quantities of untreated waste directly into nearby waterways.

On Thursday, the city of Greensboro reported a discharge of about 1.3 million gallons of untreated wastewater over a period of 23 hours. The city said that rainfall from Hurricane Florence flooded a treatment station, shutting it down and resulting in the overflow. The city said the untreated waste flowed into Middle Reedy Fork Creek, but “the downstream area was thoroughly inspected with no impact being found.”

Septic systems are the most numerous sources of pathogens, because nearly half the state’s residents are on private septic systems. These small-scale waste treatment processors capture solids in a household tank and release fluids to an outdoor leaching area to decompose. The exposed leach pits are vulnerable to flooding and heavy rains.

“Those septic systems immediately go into failure mode,” said Mark Sobsey, a retired UNC professor of environmental sciences and engineering. “All that waste becomes commingled with the floodwater and can go wherever it wants.”

Bob Rubin, an emeritus professor at N.C. State of water and waste management, said when partially treated human waste is flushed out of a septic system leach field, it travels underground through saturated soil. It can take several days to reach a nearby creek and more than a week to get into the nearest river.

“This process is going to take awhile,” Rubin said. “In the eastern part of North Carolina, outside any municipal boundary, you’re on a septic system, and you got flooded.”

Advice for people exposed to floodwaters

EXPOSURE: State health officials advise that people avoid exposure to floodwaters — including wading in and touching the water — and wash immediately if exposed. This is especially true for people who have cuts or open wounds. “You want to make sure you are doing really good wound care. Wash with soap and water,” said Betsey Tilson, the state health director. She also emphasized the need to keep up with their tetanus vaccinations.

DRINKING: Numerous public water systems issued “boil-water notices” because of Hurricane Fran. Some lost power or shut down operations, allowing dirty floodwaters to enter their systems because of low water pressure. Those boil-water notices are expected to end once tests show the water is safe. “People need to check with their water provider and make sure the water hasn’t been compromised,” Tilson said.

WELLS: Private wells that were inundated by Hurricane Florence’s floodwaters or rainfall need to get their wells tested, in part because of potential contamination by nearby septic tanks. “We have well water testing kits available through our local health departments,” Tilson said. Information about that testing can be found on the website of the state Department of Health and Human Services.

John Murawski: 919-829-8932; @johnmurawski
Stuart Leavenworth: 202-383-6070; @sleavenworth
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