News Briefs
Despite a wealth of anecdotal evidence indicating that healthy people can become chronically ill following exposure to indoor molds, a federal science panel could not draw a conclusive cause and effect link between the two. This finding will make ongoing state and federal legislative efforts to craft safe exposure thresholds in response to growing public concern and litigation over mold more difficult, policy analysts say. In a report released at the end of May, the Institute of Medicine (IOM), an arm of the U.S. National Academy of Sciences, concluded that damp conditions in homes and buildings could exacerbate respiratory problems, such as asthma, in sensitive individuals. Likewise, these conditions, which are linked to “sick building syndrome”, are associated with coughing and wheezing in otherwise healthy people. A dearth of scientific data, however, made it impossible for the panel to establish a clear causal relationship between mold exposure and these illnesses, as well as a wide range of other health complaints that have been attributed to sick buildings, such as brain or neurological damage, reproductive problems, and cancer. “There’s a lot of information missing, and that’s why we said we weren’t able to find these associations, but we weren’t able to rule them out either,” notes Harriet Ammann, a senior toxicologist for Washington state’s Department of Ecology and a member of the IOM panel. Part of the problem may be because scientists were measuring the wrong components of the molds (see related story on next page). Other big shortcomings stem from the lack of good methods for measuring exposure to bioaerosols, as well as the exposure levels nec-
essary to cause an adverse health impact. Without such exposure– response data, “This issue will defy setting safe exposure thresholds,” notes Bert Brunekreef, an environmental epidemiologist at the University of Utrecht in The Netherlands and a panel member. Moreover, other biological or chemical agents could be producing the health effects currently being attributed to mold. The report points out that damp indoor environments also favor the spread of dust mites and cockroaches, for example, which can produce significant allergens and have been implicated in asthma symptoms. Excessive dampness can also damage building materials and furnishings, initiating the release of chemical emissions and nonbiologic particles. Panel members are hopeful, however, that the tools of toxicogenomics will improve scientists’ ability to make the relevant measures of concentrations and exposures that cause adverse health effects. Meanwhile, Congress and especially state legislators will be hard-pressed to make decisions on regulations, predicts Aaron Trippler, government affairs director for the American Industrial Hygiene Assoc., noting that a Congressional bill (H.R. 5040) introduced in 2002 to address growing mold concerns has gone nowhere. Neither has legislation enacted in California two years ago putting together a task force to advise the state on establishing permissible mold exposure limits (Environ. Sci. Technol. 2002, 36 (1), 11A). Other complications include the existence of thousands of different mold species. “You’d have to set a threshold for each one,” explains Glenn Fellman, executive director of the Indoor Air Quality Association. Additionally, people’s re-
Adapting to climate change Because the world has already passed the point where climate change can be prevented entirely, the U.S. government and economic sectors must take steps now to adapt to the impacts of a projected increase in global temperatures of 2.5–10.4 °F by 2100, according to a report from the Pew Center on Global Climate Change. Coping with Global Climate Change: The Role of Adaptation in the United States concludes that proactive adaptation can reduce the severity and cost of adverse impacts if warming occurs at the lower end of the projected range of magnitude. Strategies include removing subsidies that pay farmers to plant specific crops in specific areas and promoting free-market water purchases. To download the report, go to www.pewclimate.org/docUploads/ Adaptation%2Epdf.
Just locks and fences? Although an accidental release or terrorist attack at any of more than 100 chemical facilities across the United States could injure or kill at least 1 million surrounding residents, the industry continues to use and store large amounts of toxic chemicals, according to a report from the U.S. Public Interest Research Group, a national advocacy group. The Dangerous Dozen: A Look at How Chemical Companies Jeopardize Millions of Americans is based on required risk-management plans submitted to the U.S. EPA from 12 large companies that have thousands of facilities across the country. The chemical industry and the Bush Administration emphasize physical security programs, according to the report. The report is available at http://uspirg.org/uspirg. asp?id2=13532&id3=USPIRG&.
AUGUST 1, 2004 / ENVIRONMENTAL SCIENCE & TECHNOLOGY ■ 281A
PHOTODISC/CINEMA 4D
Indoor mold standard could prove elusive
Environmental▼News actions to mold range from one extreme to the other, and levels of mold are constantly fluctuating. “You can’t turn them off and on like you can with a chemical substance,” Fellman notes, so “maintaining a consistent exposure rate of so many parts-permillion of some species of mold spore in the air would be hard to do.”
Instead of establishing safe exposure thresholds, panel members say the focus might be better placed on preventing or quickly remediating the moisture problems that lead to microbial growth in the first place. Key to this effort is public education on proper building maintenance, as well as national guidelines for the
construction industry, where energyefficient designs have been linked to a higher rate of indoor mold infestations (Environ. Sci. Technol. 2002, 36 (5), 95A–96A). For more information, the IOM report, Damp Indoor Spaces and Health, can be accessed at www. nap.edu. —KRIS CHRISTEN
significantly lower in environments that lacked mold growth. Even in buildings that did not For the first time, researchers have mold standards on previous page). have mold problems, the analysis measured airborne mycotoxins in In the new study, Brasel placed a detected the toxins, but at signifimoldy buildings, providing a possibioaerosol sampler in mold-contamcantly lower levels. “We got more ble link between “sick building syninated buildings to measure pollubackground noise than we would drome” and human health. tants. The sampler was originally have liked, but when you go into a “We believe that we are pioneers, designed to detect biowarfare agents, Stachybotrys environment, you can the first to find these toxins in naand similar models are now located definitely see a significant differtive, mold-contaminated buildings,” in U.S. post offices to protect workence,” adds Brasel. says Trevor Brasel, a graduate stuers against contamination during He attributes the background dent in the lab of David Straus, promail sorting. to false positives and nonspecific fessor of microbiology and binding. “The air sampler is immunology at Texas Tech collecting at a rate of 450 liters University’s Health Sciences per minute,” says Brasel. “So Center. “I think it opens up you’re collecting all types of the door to new research.” compounds, and you can imagThe study was presented this ine that some of them might May at the American Society have cross-reactivity to the of Microbiology meeting in antibody.” New Orleans. Mold toxins may be only “Previous studies looked part of the sick building synat agents that carried toxins drome, say experts. Besides [such as spores], but not the favoring mold growth, moistoxins themselves. So, this ture increases levels of bacteAmerican insurance companies have spent billions of might be a good step in the ria and dust mites, as well as dollars dealing with the thousands of cases filed every right direction,” says Harriet the release of chemicals such year in mold-related lawsuits. The majority of these Amman, a senior toxicologist as formaldehyde from plycases occur in states with high humidity such as Texas with the Washington state dewood. “The problem is that and Florida. partment of ecology. According there are so many things in to Amman, very little scientific eviThe collected samples were tested the air that interfere with any type dence exists to link mold with health against antibodies (using an ELISA) of analysis,” says Bruce Jarvis, proproblems often lumped together as for macrocyclic trichothecenes, which fessor of chemistry at the University sick building syndrome. Symptoms are the most toxic substances proof Maryland. “You would like to of sick building syndrome include duced by the common indoor mold have some idea of exposure to myheadache, dizziness, and fatigue. Stachybotrys chartarum. At low levcotoxins, which this work addressNevertheless, hundreds of lawsuits els, trichothecenes can cause skin ires. The second and more valuable have been filed and billions of dolritations, but the toxin can be lethal thing would be to have biomarkers lars have been paid by insurance if ingested in the range of milligrams in people that would be a measure companies to fix buildings with per kilograms of body weight. of their exposure to these toxins.” mold problems. In the six environments with S. Brasel says others in his lab are Last May, an Institute of Medichartarum, the toxin levels varied now looking for this additional evicine panel found evidence that from 12 to more than 1200 picodence. One group is testing houses mold and indoor dampness corregrams per cubic meter of sampled for airborne mycotoxins and then late with asthma and other respiraair. The effects of such airborne levsurveying the residents for health distory problems but was unable to els are not known because inhalaorders. Another project is examining show a correlation with sick buildtion studies with the toxin have not human serum to locate biomarkers ing syndrome (see story on elusive been conducted. Toxin levels were of exposure. —PAUL D. THACKER TREVOR BRASEL
Airborne mycotoxins discovered in moldy buildings
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