It was one of the more alarming phrases repeated by newscasters in the days after Hurricane Katrina: the floodwaters had turned into a "toxic gumbo," they said, a swirling pool of chemicals and bacteria. Those New Orleanians who were forced to wade or swim through the water wondered what effect the exposure would have on their health, but they had no immediate answer. Now, two months after the water rushed through the breached levees, state and city officials have answers they hope will put some minds at ease.
More than 500 water samples were taken from the floodwaters, the pumping system and Lake Pontchartrain in the days and weeks following the flood, says Chris Piehler of the Louisiana Department of Environmental Quality (DEQ). Most of those samples were tested for 200 factors, including chemicals like arsenic and lead, and bacteria like E. coli and fecal coliform. DEQ staffers are still combing through the data generated, looking for "hotspots" where the level of a certain chemical was unacceptably high. While that work continues, Piehler says the team has analyzed enough samples to make a few generalizations.
"Thankfully, except for bacteria counts, we haven't found any levels to warrant concern or any special considerations," he says in reference to floodwater that has been pumped back into Lake Pontchartrain. In fact, tests show that the lake is well within the water-quality standard set for swimming.
Original alarmist reports that the floodwaters were a blend of toxins largely were due to ignorance of the city's layout, says Piehler. "Yes, we have a lot of petrochemical facilities in Louisiana, but not in the parts of New Orleans that were flooded." In the city, the most frequent chemicals found in the floodwaters were gasoline from flooded vehicles and some household chemicals like pesticides and cleaning products, but Piehler says neither were present at dangerous levels.
The DEQ, in cooperation with the U.S. Environmental Protection Agency, also has taken more than 400 samples of the sediment that was left on sidewalks and streets when the waters drained away. In New Orleans, the sediment is mostly mud from the lake, in some areas oil and diesel components also were found. Because long-term skin contact with these chemicals can cause rashes, Piehler recommends taking common-sense precautions. Residents should avoid unnecessary trips to the most damaged neighborhoods that have the most sediment. If they do drive through them, they should roll up their windows, and they should avoid direct skin contact with the sediment.
St. Bernard Parish is a somewhat different story. The Murphy Oil Refinery spilled more than 1 million gallons of oil into its Chalmette neighborhood, and large amounts of the oil components and chemicals are still present on structures and in the sediment. "There will be some places where the sediment has enough oil that it will have to be removed," says Piehler. The state's debris-management plan includes removal of the sediment, but the project is so enormous that Piehler estimates it will take a couple of years to complete.
In the meantime, however, Piehler says the scope of the devastation in St. Bernard Parish means that residents have more pressing concerns. "There are plenty of things to be concerned about in the parish, but environmental concerns are not very high on the list." Many neighborhoods have no drinking water, power or working sewerage systems, rendering them largely uninhabitable. Because residents can't return to live in those areas, they won't be exposed to the potential health threats.
Some locals say the DEQ needs to do a better job of informing citizens of its work in the most damaged areas like St. Bernard Parish. "If you talk to the average person on the sidewalk in Chalmette, they have never heard word one about any sampling that the DEQ or EPA are doing," says Anne Rolfes of the Louisiana Bucket Brigade, an environmental group that has worked in Chalmette for several years. The parish needs to do a full-scale environmental assessment and disseminate the findings widely so residents aren't tempted to move back into an unsafe environment, she says.
The DEQ encourages residents to peruse the "enviromapper" found on the EPA's website at http://www.epa.gov/enviro/katrina/. The interactive map shows sites throughout Orleans, Jefferson, St. Tammany, St. Bernard and Plaquemines parishes where water or sediment samples have been taken and also shows the chemical and biological results of the tests.
In New Orleans, the biggest source of floodwater contamination by far was sewer lines that run under the city streets, says Piehler. "We found a high bacteria count just about anywhere we looked because of the commingling of floodwater with sewage," he says. The good news is that the bacteria needs warmth and moisture to survive, and bacteria left in sediment died off when floodwaters were pumped out of the city.
The DEQ's tests of the water in Lake Pontchartrain have found low levels of bacteria there as well. Piehler attributes this to the brackish, salty nature of the lake water, in which most bacteria can't survive. Bacteria levels were low enough that on Sept. 29 the DEQ announced that it was safe to eat seafood from the lake, because thoroughly cooking fish, crabs or shrimp will kill any remaining bacteria. Raw oysters, however, are still off the menu.
Another myth repeated on newscasts following Katrina was that the storm surge would be followed by a wave of disease, with contagious illnesses like cholera and typhoid spreading through the city. Clearly, nothing of the sort occurred. Kristen Meyer, a spokesperson for the Louisiana Department of Health and Hospitals, says it was never even a threat.
"Cholera is a particular kind of bacteria not found in New Orleans," she says. "Since it wasn't found there before the hurricane, there's no scientific basis to believe it would occur after a hurricane. The hurricane didn't bring in foreign bacteria."
The department set up triage stations around New Orleans and has been tracking incidents of illness through those centers; so far, the statistics are promising. "In terms of illnesses, we fared much better than some expected," Meyer says, but there have been numerous injuries sustained from vehicle mishaps and accidents that have occurred as homeowners climbed ladders, scaled roofs and revved up chainsaws to repair their properties. In fact, 26 percent of the people who went to a triage center sought treatment for an injury, she says.
The 1,678 people who sought treatment for respiratory infections made up 7.5 percent of patient visits. Meyer says some suffered allergies or chronic respiratory problems that were aggravated by the mold and dust, but others had just picked up a seasonal cold or cough. About 2 percent of patients, or 433 people, sought treatment for diarrhea illnesses that were probably related to high bacteria levels in floodwaters. The best safeguard against the respiratory and diarrhea ailments is good hygiene, says Meyer. "It may sound simple, but it's the most effective way to prevent illnesses. Respiratory illnesses and diarrhea illnesses, those are the kinds of things that spread real easy from person to person."
Several weeks ago, the Department of Health and Hospitals announced that tap water was safe to consume in all areas of New Orleans west of the Industrial Canal. "I think people should feel fairly confident," says Karen Irion, department administrator for the safe drinking-water program. "They're taking over 100 bacterial tests a day, and they treat the hell out of the water in the plant." In New Orleans, the Sewerage and Water Board has increased chlorine levels in the water and raised the pressure in the water mains so that if there are small breaks and holes in the pipes, the water will go out and contamination won't come in.
Finding all the breaks is an ongoing process, and the public can help. "If people lose water pressure in the house, or if they see water or sewage bubbling up in the streets, they should call [the Sewerage and Water Board] right away," Irion says. "It's a big city, and finding all the line breaks is like finding a needle in a haystack."
The so-called boil advisory, which indicates that drinking water is not safe, has not yet been lifted for the areas east of the Industrial Canal, and Irion says she has no idea when it will be. The large water mains that cross the industrial canal still need repairs, and the power and sewerage systems that work in tandem with the water supply system aren't yet functional. "The eastern part of the city is going to be a longer-term endeavor," says Irion. "I know people are impatient to get back in their neighborhoods, but we think about safety first. We don't really care how much people yell at us, we care about public health."