Dealing With the Molds of Katrina
Photo by Garth Schaefer, Volunteer Hands On Network
By Professor Joan W. Bennet
Excerpt from New York Academy of Science Update January/February 2006
New Orleans, with its’ hot and humid weather, has always been a great habitat for mold. With 80% of the buildings in New Orleans victim to flooding from Katrina and the failure of the levee protection system, many of us are now faced with houses and offices where mold growth has infiltrated floors, walls, ceiling, insulation, air-conditioning ducts, and furniture. The media following Katrina focused on the environmental health impact of the floodwaters that covered the city. These waters were often described as “toxic gumbo,” but analysis has indicated that these concerns in some cases were exaggerated. The chemical make up of the flood waters were much the same as storm water runoff with the most notable exception being areas where oil spills occurred. On the other hand, the potential health effects related to the rampant mold growth caused by the flood waters received limited press.
THE BASICS
Molds are fungi. To most of us, the most visible and recognizable fungi are mushrooms and truffles. Fungi are often referred to as the “Fifth Kingdom”, distinct from plants and animals and other living organisms in a number of ways. Unlike animals, fungi have cell walls made of chitin and glucan and unlike plants, fungi cannot produce their own nutrients through photosynthesis. Through cell walls, fungi secrete enzymes and acids that digest “foods” and these nutrients are then reabsorbed. Through this metabolic process, mold too small to be seen with a naked eye continue to grow and become the colonies that are visible to us (usually fluffy white or gray patches.) This visible growth phase of molds consists of groups of long filamentous cells called hyphae. These hyphae when grouped together are called a mycelium.
When food and water become limited, the mycelium begins producing mold spores – functionally the equivalent of seeds in plants. These spores, which may cover our belongings, may be black, green, gray, or a number of other colors. Water is the most important environmental parameter for fungi. For this reason, many of our homes and office were ideal situations for mold growth following Katrina. Once the standing water was drained, fungi were no longer limited by the lack of oxygen found underwater. Instead, homes were filled with water-logged rugs, furniture, books, and wallboard, all surrounded by air allowing rampant mold growth to occur.
HEALTH CONCERNS
There are three major health effects associated with fungi: infection, allergies, and toxins.
Only approximately 100 fungi species of the 100,000 that exist can grow on (infect) humans. All of the diseases caused by this growth are called “mycoses.” One of the most common of these is athlete’s foot. Most fungi that cause life-threatening mycoses are opportunistic pathogens and they gain a foothold in individuals who are already immuno-compromised or have a weakened immune system.
Often the most common health effect associated with fungi is development or worsening of allergies. Hay fever and asthma symptoms are often exacerbated by exposure to high concentrations of mold spores. Research which identifies specific species of molds and their propensity to cause allergy is limited, but the National Academy of Science has concluded that there is sufficient evidence for a causal link between exposure to indoor mold and coughing, wheezing, nose and throat symptoms in the general population.
The least understood health effect related to fungi is exposure to mycotoxins, or the poisonous natural products produced by molds. Exposure is often through ingestion. People eat moldy food inadvertently or because they have no choice. Skin exposure also occurs and certain mycotoxins cause burning and blistering. Within the study of mycotoxin exposure, inhalation is the least understood. Here the “sick-building syndrome” associated with a black mold called Strachbotrys comes into play. Through the 1990’s much publicity was given to high profile cases involving water damaged, Strachbotrys infested homes. The CDC in one study concluded that cause and effect relationship could not be proven and it is still a matter of speculation whether spores contain enough toxins to induce pulmonary toxicosis or other neurological symptoms that are attributed to sick-building syndrome.
WHAT DOES THIS MEAN FOR US?
Throughout the city, homes are filled with mold. In individual homes, we don’t know what types of mold are growing, how many (if any) of the molds are making toxins, or how many of these toxins get into spores. The scientific community is also only beginning to understand how high concentrations of inhaled mold spores affect human health. In part because of these unknowns, there are also no existing U.S. regulatory standards for either indoor or outdoor mold concentrations.
What we do know is that all molds are potentially allergenic. New Orleans residents who have pre-existing allergies and respiratory problems should, if possible, avoid mold clean-up. All those involved in clean-up should wear protective clothing and respiratory devices (N-95 mask) and gloves. People who are immuno-compromised should stay away from New Orleans entirely. We also know prolonged exposure to high levels of mold (and some bacterial species) can produce an immune-mediated disease known as hypersensitivity pneumonitis, (a pneumonia-like
illness with symptoms including difficulty breathing and fevers). This is commonly known as farmer's lung, woodworker's lung, and malt worker's lung.
When assessing and cleaning our homes, we must recognize that even when mold is no longer visible, it may still be present. Homes that did not have standing flood water, may have increased mold growth as a result of leaking roofs, pipes, air conditioning units. The CDC recommends these steps:
- Remove all porous items that have been wet for more than 48 hours and that cannot be thoroughly cleaned and dried. These items can remain a source of mold growth and should be removed from the home or building. Porous, noncleanable items include carpeting and carpet padding, upholstery, wallpaper, drywall, ceiling tiles, insulation material, some clothing, leather, paper, some wood and wood products, and food.
NEED MORE INFORMATION
Center for Disease Control
This page provides recommendations for protecting yourself from mold. Please note that the page recommends that if the area covered by mold is greater than 10 sq. feet you should use the recommendations found in the EPA’s publication on mold remediation in schools and commercial building.
http://www.bt.cdc.gov/disasters/mold/protect.asp
http://www.epa.gov/mold/mold_remediation.html
How To Get Rid of Mold (flyer)
http://www.bt.cdc.gov/disasters/pdf/flyer-get-rid-of-mold.pdf
LSU Ag Center Resources
Avoiding Mold Hazards in Your Home LSU Ag Center
http://www.lsuagcenter.com/en/family_home/hazards_and_threats/recovery_assistance/cleaning_up/mold_decay/Avoiding+Mold+Hazards+in+Your+Flooded+Home.htm
Mold Removal Guidelines for your Home
http://www.lsuagcenter.com/NR/rdonlyres/E06C62CC-C93D-4E16-8BEA-0164790F9FA2/19688/MoldRemovalGuidelinesfactsheet.pdf
Natural Resources Defense Council’s guidelines on Mold Removal
http://www.nrdc.org/health/effects/katrinadata/moldremoval.asp
NIOSH recommendations for the Cleaning and Remediation of Flood Contaminated HVAC systems.
http://www.cdc.gov/niosh/topics/flood/Cleaning-Flood-HVAC.html