Contaminated sediments and water continue to pose a threat to residents of hurricane-affected areas.
The biggest threat is sediment that collected in houses after the storm, Mississippi State University associate professor of chemical engineering Mark Bricka said.
“The sediment deposits in homes contain a fecal bacterium that comes from human waste,” he said.
The mud caking many homes has absorbed such hazardous materials, and any ingestion could cause a lot of problems, Bricka added.
“I talked to a person at Louisiana Department of Environmental Quality, and the tests that they were running indicated that it was six to eight times more toxic than regular mud,” Bricka said.
Another hazard is contaminated water. Stagnant water stewed in the streets of New Orleans and the Mississippi Coast, which leads experts to believe the integrity of the water system may have been breeched, MSU professor of food science, nutrition and health promotion Douglas L. Marshal said.
In normal circumstances, a leak in the water line will cause water from inside the system to leak into the environment, Marshall said. When power goes out, the reverse occurs. The pressure that holds the water in the pipe is lost.
“When you lose pressure there is a possibility the water from the environment, such as contaminated water from the flood surge, could leak into the system,” he said.
The water from the outside environment is highly dangerous, Bricka said. “The water has been sitting there, collecting oil slicks moving off from cars, break fluid, gas and other carcinogenic chemicals,” he said.
Water analysis also showed elevated metal levels, such as lead and mercury contamination, he said.
Mold causes problems for some. While mold plagues those with asthma, allergies and weakened immune systems, the average person can handle the fungus in small doses.
“Reaction to mold is individual specific. Some people can suffer very intense allergic type reactions to mold, and then there are those who don’t,” Marshall said. “It is very difficult to generalize.”
However, some molds produce toxins that, if consumed, can cause an acute or chronic toxic response, he said.
“Spores are easily airborne and can be inhaled, causing lung infection, skin infections like ringworm and allergic reactions,” he said.
While mold may not pose a serious health threat to most, there are economic implications that the infestations carry. “The mold is going to cause structural damage to the content of home and the structural integrity of home,” Marshall said.
The mold will eat away at plaster, wood, carpet and other such substances, creating an economic hazard rather than a health problem, he said. “Most people who have mold contamination in their homes will have to have very extensive renovation or complete restructuring,” he added.
“Mold is going to present a short-term health hazard rather than a long-term health hazard,” Bricka said.
In light of all these problems, residents returning home must take many safety precautions. Marshall and Bricka suggest wearing protective clothing like gloves and masks.
“People need to remove contaminated items from their homes and destroy them,” Marshall said. “They must also be very careful of open wounds, because microorganisms in that environment can cause infection, if exposed.”
Those returning must also sterilize the belongings that can be salvaged. “Bleach will help with mold problems. It will destroy anything organic like mold or fecal matter, but it won’t do anything for lead contamination,” Bricka said.
In fact, bleach can cause dangerous reactions with metals like lead or mercury. “Bleach can be a potential problem for long-term cancerous risks,” Bricka said. The chlorine reacts with certain chemicals like spilled gas, and can form carcinogenic chemicals, Bricka said.
Perhaps the more shocking implications are for environmental rather than health risks.
“All of the waste that we have generated could fill up to 1,000 football fields. And we haven’t even considered the trees that have been downed,” Bricka said.
If this wood is not used soon, it will rot, he added.
In addition, the pressure treated wood that covered the coastal region in the form of decks, boardwalks, docks and boathouses contains toxic chemicals such as arsenic, chromium and copper, Bricka said. “If we incinerate the waste, then that spreads all those contaminates through the air.”
Another environmental consequence of storms like Katrina is the affect on outlying wetlands. “Herbaceous and brackish marshes can be damaged to some extent by the wind,” Gary Ervin, assistant professor of biological sciences and University expert on wetlands, said. The intrusion of salt water from the storm surge is also a hazard to the plants of the brackish marshes off the coast of Louisiana, Ervin said.
The importance of the destruction of marshes became most evident as Katrina approached. Wetlands typically act as a buffer, absorbing some of the water from the storm surge. “If you have two or three miles of marsh, the plants slow down the water from the storm surge which can decrease the accumulation of water moving inland,” Ervin said.
Although the health hazards and long-term effects of Hurricane Katrina are still under scrutiny, all professors concurred that it will be a long time until things in affected areas are back to normal.