C. Jenkins, MACTEC Inc., Peoria, IL.
Exposure to lead in indoor firing ranges has been documented as a significant source of lead exposure. Lead exposure exists from airborne lead resulting from the firing of lead bullets, deposits of lead dust on surfaces and exposure to lead during maintenance of equipment. Concerns of exposure to participants at a local shooting club resulted in an assessment of lead exposures and an evaluation of the local exhaust ventilation system at an indoor shooting range during different shooting discipline events. The assessment included monitoring of airborne lead during live firing and range maintenance activities, efficacy of engineering controls, and application of recommended indoor shooting range designs as outlined by the ACGIH and the NRA. Monitoring was performed during bulls-eye and action pistol, and smallbore rifle shooting events and range maintenance, including range cleanup. Wipe sampling was also performed to evaluate the rate of lead deposition and used to create a clean-up schedule to maintain lead dust levels at acceptable levels and to evaluate the efficacy of clean-up procedures used to remove deposited lead. Results of the study, including monitoring data and the efficacy of the procedures implemented to control lead exposure during range activities, will provide a baseline for further multi-use indoor shooting range design and lead control projects.
V. Belfit, U.S. Army CHPPM, Bel Air, MD.
The U.S. Army Center for Health Promotion and Preventive Medicine (USACHPPM) is working with Department of Defense (DOD) components to address the issue of high levels of lead in active, inactive, and converted DOD indoor firing ranges, and the potential for occupational and casual exposures to range-generated lead. USACHPPM has proposed lead surface wipe decontamination standards for these facilities, in the absence of existing federal standards. DOD components are also currently revising guidance for cleaning active ranges and for decontaminating closed, inactive, and converted ranges. An internal DOD audit identified the need to improve management of lead hazards in indoor small arms ranges. Safety and occupational health personnel sampled thousands of active, inactive, closed, converted, and previously decontaminated ranges and designated some ranges as unsafe because of lead contamination. Lead levels from samples collected significantly exceeded the USACHPPM recommended limits for lead in dust in indoor firing ranges. Lead in dust is being tracked by personnel from firing ranges into other parts of the facilities in which they are located. This presentation will discuss USACHPPM proposed levels of concern and action levels for decontamination of these facilities. Recommended interim actions will also be discussed, and will be based on the age, status of range use, and use of the facilities that house the ranges until the ranges can be further evaluated and corrective actions implemented.
W. Townsend, Clark County Health District, Las Vegas, NV.
Lead enters the body of small children primarily through two exposure pathways. Ingestion is the predominant route of exposure in small children, but inhalation may play more of a significant role than what is generally believed. The scientific literature documents a mathematical model describing the relationship between lead exposure via inhalation (i.e., airborne lead) and the blood lead levels (BLLs) in children aged 6 months to 5 years. Based on this model [ln(BLL) = 0.24*ln(Air lead level) + 3.17], a minimum airborne lead concentration of 27 nanograms per cubic meter is necessary to elevate a child’s BLL to the critical level of 10 micrograms per deciliter (10 µg/dL). Lead particles tracked into homes from contaminated soil or other sources that end up in the floor covering may become airborne. Particles having an aerodynamic diameter that is < 1 µ remain suspended indefinitely in air, and more than 90% of such particles entering the deep lung are absorbed into the blood. We determined the minimum airborne lead concentration needed to yield a BLL of 10 µg/dL in children from room dimensions (15 ft. × 20 ft. × 10 ft.) and the lead loading of floor coverings. The lead loading of floor coverings necessary to yield the critical airborne concentration could be beyond the limit of detection of field equipment (e.g., X-ray fluorescent devices) utilized to determine lead contamination. In practice, some environmental investigations of homes of children with elevated BLLs did not identify a positive source of lead exposure. These investigations, however, did not include monitoring for airborne lead. This study investigates the airborne lead concentration in homes of children diagnosed with elevated BLLs using cascade impactors and atomic absorption spectroscopy for sample collection and analysis, respectively. It offers a recommendation regarding the use of air monitoring during future environmental investigations of elevated BLL cases.
M. Van Dyke, J. Martyny, S. Arbuckle, J. Westcott, E. Barker, K. Pacheco, L. Newman, National Jewish Medical and Research Center, Denver, CO.
Several currently marketed consumer cleaning products advertise the ability to reduce household allergens. To date, there have been no studies reported in the literature corroborating or refuting these claims for airborne allergens. In addition, there are no reports describing a standardized testing protocol. The study describes a testing protocol that can be used to evaluate products with claims of airborne allergen reduction by spray application of a liquid, as well as testing results for spray application of both water and a bleach solution (3,750 ppm). The general testing method involved dispersion of a prepared sample of household dust into a one cubic meter chamber, treatment of the aerosolized dust by spray application, and sampling of the environment with high volume sampling pumps. The collected samples were analyzed for pet allergens, Fel-d1 and Can-f1, using ELISA methods. Household dust containing pet allergens was collected using vacuum cleaners and dry sieved to < 32 µm. The dust was dispersed into the sampling chamber using a fluidized bed dust generator. The chamber was sampled at a flow rate of 15 liters per minute using 37 mm PVC filters. Results from these experiments show that spray application of water reduces airborne allergen concentrations by an average of 56% for Fel-d1 (p =0.002) and 58% for Can-f1 (p = 0.002) as compared to no treatment. The bleach solution reduces the levels of both allergens to below the limit of detection for the ELISA method, which translates to at least a 95% reduction for Fel-d1 (p < 0.0001) and at least a 91% reduction for Can-f1 (p < 0.0001) as compared to water alone. These data suggest it is possible to generate a reproducible allergen test aerosol, treat the aerosol with a liquid spray, and measure the resulting decrease in allergen levels.
J. Dobranic, EMSL Analytical, Inc., Westmont, NJ; G. Saenz, K. Ralutin, M. Morgan, K. Ludwig, R. Norman, J. Steedman-Lyde, LA Testing/ EMSL Analytical Inc., South Pasadena, CA.
Gram-negative bacteria in the indoor environment are associated with the presence of moisture and can typically be found in water cooling systems, humidifiers, and even water-related building damage. Gram-negative bacteria are the source of endotoxins, a liposaccharide component of the cell wall. Recent studies have implicated endotoxins as a major irritant for aggravating asthma-related symptoms. However, most indoor environmental surveys focus on fungi and tend to ignore bacteria and associated endotoxins, and therefore may miss the target irritant. A survey of residences and businesses is being conducted focusing on the presence of endotoxins in the air and in settled dust. We are analyzing air and settled dust from various buildings for endotoxins. We are also analyzing traditional sample types for fungi and bacteria. A discussion of sampling media, procedure, and each sampling environment will accompany the presentation of the resulting data to inform what type of results can be anticipated from such sampling events.
R. Moore, Boelter & Yates Inc., Park Ridge, IL.
Indoor environmental quality complaints (odors, eye irritation, stale air, sinus problems, etc.) can be directly related to insufficient amounts of outside air or inefficient distribution of outside air to an occupied space. Failure to provide adequate amounts of outside air into an office building can result in a build-up of odors and chemicals (emitted from building materials) to levels that can be offensive or irritating to occupants. Traditional means of assessing these issues (volumetric flow measurements, smoke tubes, and outside air louver settings, etc.) may be inaccurate and subjective. There is an ASTM Standard Test Method for Determining Air Change in a Single Zone by Means of Tracer Gas Dilution Designated as E 741-00. This method specifies several test methods utilizing sulfur hexafluoride and other tracer gases to determine how much outside air is being delivered into a building by a HVAC system. There is an ANSI/ASHRAE Standard for Measuring Air Change Effectiveness designated 129-1997 (RA 2002). This standard specifies methods using sulfur hexafluoride and other tracer gases to determine how effectively the supply air system of a HVAC unit is distributing outside air to the breathing zone of building occupants. This presentation will address how these test methods can be used successfully to diagnose indoor environmental quality problems related to ventilation issues. There will be discussion on the pros and cons of the various equipment (portability, limits of detection, accuracy, etc.) and instrumentation options available for industrial hygienists to use in using these test methods as well as potential problems encountered (plumbing leaks, re-entrainment, etc.) and precautions to take.
E. Iyiegbuniwe, Western Kentucky University, Bowling Green, KY.
Children are particularly sensitive and increasingly vulnerable to indoor environmental pollutants and diseases since they spend most of their time indoors and have limited abilities to communicate concerns. A few studies have reported significant indoor sources and health effects of environmental pollutants at child care facilities. This study was conducted to assess airborne levels of indoor environmental quality parameters in a childcare facility located within a university in South Central Kentucky. Temperature, relative humidity, dew point, carbon dioxide (CO2), and carbon monoxide were recorded for six hours a day throughout a period of five days. Air samples were collected at randomly selected locations for specific pollutants, including bacteria, fungi, and respirable particulate matter. Comfort parameters showed noticeable swings but generally within guidelines recommended by the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE). Daily CO2 concentration differentials (indoor minus outdoor) were higher than the ASHRAE’s guideline of 700 ppm and the OSHA standard of 800 ppm. Higher than acceptable CO2 concentrations suggest the facility lacked adequate ventilation. Indoor concentrations of particulate matter, bacteria, and fungi were below outdoor levels. However, based on the frequency of detection, more distinct bacteria and fungal genera or groups were isolated indoors than outdoors, and some of the fungi are reported toxin-producing species. Additionally, higher concentrations of environmental parameters occurred in the child care rooms than in faculty and staff offices in the same facility and a comparison building. Preliminary statistical analysis also showed a positive relationship between airborne levels of environmental pollutants. The presence of potentially toxigenic fungi, respirable particulate matter, and higher than acceptable CO2 levels raises questions about potential exposures of children to indoor pollutants. The study recommends preventive measures and strategies for reducing exposure risks, potential health problems, and effectively managing indoor environmental pollutants in child care settings.
Posted May 30, 2006