R. Kopp, R. Fillhart, Galson Laboratories, East Syracuse, NY.
Indoor air quality investigations for mold present unique challenges to investigators because standardized methods for measuring risks due to mold spores have not been developed, and every situation is unique. Airborne spore enumeration is commonly used to estimate health risks associated with indoor mold growth, and the problem facing investigators is to obtain data that permits unambiguous conclusions to be drawn. A carefully designed sampling strategy is an essential component of an effective, efficient, and successful mold investigation. Prior to collecting samples, the investigator must clearly define relevant questions to be answered, formulate and state appropriate hypotheses, and test them with statistically valid replicated experiments. Data from a single sample of any type is generally insufficient to draw conclusions about mold populations because of the large inherent variability in indoor air and many other sources of variation that are part of any sampling event. Replication is a requirement for statistical analysis and must not be confused with duplication. Using an appropriate experimental design offers advantages to the investigator that include focusing field efforts, clear resolution of questions that were asked, and the ability to unequivocally define what was accomplished in the project.
R. Spicer, Centrenel Inc., Haddonfield, NJ; H. Gangloff, Hudson International, Wayne, PA.
Because there are no set numerical standards for airborne fungi, air sampling data is often interpreted by a comparison of the indoor environment to the outdoors. Culturable airborne fungal spore sampling at four building sites during 2002–2003 provided a bank of outdoor data (91 samples total) to evaluate differences in levels of individual species of airborne fungi during the morning and afternoon hours. A minimum of 15 (outdoor) air samples was collected at each site, and data segregated into morning (before noon) and afternoon subsets. Significant differences in airborne levels (p = 0.95) were defined as differences in frequency of detection above the combined median for each fungal species between the morning and afternoon subsets (at each site), using a direct calculation of probability.
The levels of fungi in the outdoor air varied significantly between morning and afternoon data sets at all four sites, with no pattern by species, time of day, or location. For example, the common environmental species Cladosporium cladosporioides and Alternaria alternata were detected at higher levels in the afternoon at one site, but more frequently in the morning hours at another. More important, the presence of potential mycotoxin producing fungi and/or other “marker” species are often used in building evaluation as indicators of water damage or to suggest possible health effects to occupants. However, several marker species of Aspergillus and Penicillium, as well as Paeciloymces variotti, exhibited significant differences in airborne levels between the morning and afternoon at the same site.
The significant differences in levels of airborne fungal species in the outdoor air in this study indicate the necessity of collecting a sufficient number of samples in the outdoor air in both the morning and afternoon to prevent bias and to make an adequate comparison to a suspect indoor environment.
M. Barclay, BAS, LLC, Mandeville, LA.
The HVAC system can be your best friend when working properly, or your worst enemy when mold and mold conducive conditions are present within. Assessing the HVAC system for mold can be very problematic because of its design, location, and size. This paper describes a sampling strategy and techniques that can be easily and noninvasively applied to assess mold contamination in the HVAC system. The sampling strategy will discuss the use and application of air and source sampling methods to determine if fungal contamination is present, as well as measurement of climatic conditions to determine if conditions conducive to mold growth are present.
A summary of results representing a mixture of residential and commercial settings indicate that a proper sampling strategy combined with other appropriate climatic measurements can be used to diagnose mold and mold conducive conditions in HVAC systems.
R. Brounstein, Bechtel-SAICComp, LLC, Las Vegas, NV.
The Yucca Mountain Project is an underground facility, located approximately 100 miles north of Las Vegas, Nev., and has been approved by the President of the United States as the national repository for spent nuclear fuel. The Yucca Mountain Facility is expected to safely store spent nuclear materials for 10,000 years—well after the nuclear by-products’ radioactivity has been reduced to less than 1% of it’s original nuclear activity.
As part of the current program, scientific studies have been continuously performed at the site to verify that the geology of Yucca Mountain can support such a facility. Therefore, special horizontal pathways referred to as drifts have been constructed and designed to simulate such conditions as temperature, pressure, humidity, and other factors which may influence the integrity of the containers that will store the radioactive material. These drifts are closed and periodically opened for experimental data collection.
Upon the initial reentry, it was discovered that mold/fungal growth was evident. Many questions were asked in response to this unexpected finding. One of the critical points brought up was, are our employees properly protected? Industrial hygienists began conducting airborne sampling for both mold spore counts and speciation. The main questions were: What is healthful? Should respiratory protection be used? After instituting an initial procedure for mold/fungal assessment and employee protection, operations became skeptical as airborne mold concentrations would fluctuate from one day to the next. The problem was: how are employees protected while there is such a wide fluctuation in airborne mold concentrations from day to day?
The National Allergy Bureau has compiled a list of data that classifies airborne mold concentrations. These categories are broad enough to address wide daily fluctuations, while ensuring the health of all persons who need to work in potential mold-contaminated areas.
W. Vittitow, Ireland Army Community Hospital, Fort Knox, KY.
In 1998, the number of mold complaints in installation buildings increased noticeably. The Industrial Hygiene Office had received many indoor air quality complaints that turned out to be related to mold. At the time it was theorized that it might be possible to find out what mold species were most common on the installation and these species could be linked to the complaint symptoms. The advantages of having this knowledge would be the ability to diagnose the mold problem quicker and offer better solutions to remove the problem or prevent the mold problem from occurring. The challenge of this type of exposure assessment is linking specie with symptoms. Generating a mold database for the installation began the study. In addition, permanent mount microscope slides of the samples collected were made. These samples consisted of air samples, surface tape lifts, swabs, bulks, and liquids. Sample analysis was performed by optical microscopy. A selected group of 250 mold samples were evaluated that had been collected from more than 50 buildings on the installation. In these samples 25 separate species have been identified including such harmful species as Stachybotrys chartarum. The most common mold in the samples was Aspergillus specie followed closely by Cladosporium specie. A comparison of species to reported complaints and symptoms revealed the following. A wide range of symptoms was associated with these samples. They included high incidence of bronchitis, asthma, headache, lacrimation, colds, pneumonia, runny nose, sneezing, and shortness of breath. In addition, in some cases dermatitis was reported. Other possible causes for these symptoms were evaluated such as chemicals, and allergens such as mites, animal dander and cigarette smoke. The temperature and humidity were also evaluated. This was done to strengthen the link between mold and symptom and eliminate other potential causes.
F. Grimsley, B. Levingston, Y. Henderson, Tulane University, New Orleans, LA.
The potential for high levels of mold spores during large scale remediation activities is well documented and recognized as a significant health hazard. However, less is known and published about dispersal and potential exposures to mold spores during small scale remediation activities such as short-term and routine maintenance tasks in the indoor environment. The purpose of this survey was to assess the potential for exposure to mold spores during short-term and routine building maintenance activities. Maintenance activities included repairing minor water leaks and removal and replacement of water-damaged ceiling tiles. Ceiling tile damage ranged from small areas of water stain to moderate visible mold contamination. The assessment included walkthroughs, interviewing maintenance employees, and conducting a quantitative assessment for mold exposures. The sampling strategy included collecting background samples and sampling during the identified routine maintenance tasks. The results from the quantitative mold survey ranged from 130 to 54,205 spores/m3 with a mean of 7890 spores/m3. The primary genera of fungi identified included Aspergillus, Penicillium, Cladosporium, Stachybotrys, Alternaria, Curvularia, Basidiospores, and Chaetomium. In conclusion, there is a potential for dispersal and exposure to mold spores during small scale remediation activities and a need to educate and train maintenance workers on how to prevent dissemination of mold spores during these activities.
M. Lumpkin, D. Dahlstrom, Clayton Group Services Inc., Kennesaw, GA.
Methods for associating mold presence in the non-occupational indoor environment with various adverse health effects are as varied as the practitioners who participate in the field. The application of risk assessment principles to mold-related indoor air quality (IAQ) issues remains very much in its infancy due to the paucity of quality epidemiological, exposure, or dose response data. However, the subject of IAQ-related mycotoxicosis presents the best opportunity to define and fill data gaps allowing rigorous risk assessment methodologies to be implemented. In an effort to aid IAQ professionals in effectively communicating what is known about issues of mycotoxin exposure and health risks, a meta-analysis was designed and applied to existing published scientific literature pertaining to mycotoxin-related IAQ health effects. The literature was reviewed and each work categorized according to its contribution to the four requisite components of risk assessment (hazard identification, exposure assessment, dose-response assessment, and risk characterization). The literature for each component was examined for completeness, harmonization, and utility for quantitatively assessing risk. From this analysis, the relative strengths and weaknesses for each component’s database were determined. This information enabled the identification of valid uses and likely misuses of current data. The results show that discrete gaps can be defined and used as a guide for directing future research in terms of laboratory studies and data collection from the field. They also show that, while little is known about actual human exposures, a substantial number of publications are being used to validate perceived exposures. Our work suggests that the present literature regarding IAQ-related mycotoxicosis can be used to make limited conclusions about health risks. Taken as a whole, it can be a useful communication tool for dispelling widely held, but scientifically insolvent, associations of the presence of indoor mold and mycotoxicosis.
Posted May 30, 2004