Airborne Endotoxin Concentrations Research Articles

Beyond the Bench: COEPs Contribute to Hurricane Relief

The conditions in Louisiana and Mississippi following Hurricanes Katrina and Rita reminded us all of our commonality in the human experience and moved many to help. Among those moved to help were the staff at the Community Outreach and Education Programs (COEPs) of NIEHS Centers across the country. Responding to communities in need is one of the primary functions of the COEPs, so providing outreach to those areas on the Gulf Coast impacted by the hurricanes seemed a natural step to take. “When our director volunteered our COEP [to lead efforts], we remarked that if COEPs had never existed, they would have had to be invented on August 28,” says Pamela Diamond, director of the NIEHS Center COEP at University of Texas Medical Branch (UTMB) in Galveston. Adds Robin Fuchs-Young, director of the COEP of the Center for Research on Environmental Disease at the University of Texas, M.D. Anderson Cancer Center (UTMDACC), “All of us saw what was happening on television and felt compelled on a human level to help in whatever way we could.”

Respiratory effect of acute and subacute exposure to endotoxin-contaminated metal working fluid (MWF) aerosols on Sprague-Dawley rats

Male Sprague-Dawley rats were exposed to a water-soluble metal working fluid (MWF) (5% v/v) contaminated with endotoxins (10,000 eu/ml or 100,000 eu/ml) at 10 mg/m3 for six hours per day for three days (acute exposure) or two weeks (subacute exposure). The geometric mean diameter of the MWF aerosols was 1.56 microm, and the airborne endotoxin concentrations ranged from 1,231 to 2,173 eu/m3 (10,000 eu/ml in the bulk MWF) for the low dose and 19,263-27,386 eu/m3 (100,000 eu/ml in the bulk MWF) for the high dose. Minimal effects were observed after exposure to 10 mg/m3 of the MWF without endotoxins for three days or two weeks. However, an increase in the number of polymorphonuclear cells (PMNs) and the level of protein was noted in the bronchoalveolar lavage (BAL) fluid from the rats acutely exposed to the MWF with endotoxins. The acute exposure produced a greater increase in the number of PMNs and total cell number in the BAL fluid than the subacute exposure. The number of white blood cells in the peripheral blood and the weight of the lungs both increased after the subacute exposure to the MWF aerosol with endotoxins, indicating increased vascular permeability in response to the endotoxin exposure. The levels of cyotokines such as IL-4, INF-gamma, and IL-1beta in the BAL fluid from the rats exposed to the MWF with or without endotoxins remained unchanged. Although the level of nitric oxide (NO(x)) in the BAL supernatant did not show any change, the induction of NO(x) from the alveolar macrophages increased in the rats acutely or subacutely exposed to the MWF contaminated with endotoxins. The ConA-induced proliferation response showed no change, yet the LPS-induced proliferation response was significantly increased in the splenocytes from the rats subacutely exposed to the MWF with and without endotoxins. The level of TNF-alpha in the spleen cell culture obtained from the rats exposed to the MWF with or without endotoxins increased without changing the levels of IL-1beta, IL-4, and INF-gamma. The level of endotoxin-specific IgE in the serum obtained from the rats exposed to the MWF with endotoxins increased dose-dependently, while the levels of total immunoglobulins (IgG(1), IgG(2a) and IgE) and endotoxin-specific IgG(1) and IgG(2a) remained unchanged. Accordingly, the current results indicate that lung inflammation can be immediately induced by acute or subacute exposure to an MWF contaminated with endotoxins, and macrophages would appear to play a role in the induction of inflammation along with B-cell functions rather than T-cell functions, after subacute exposure to an MWF with endotoxins. In addition, endotoxin-specific IgE is an early marker for endotoxin exposure in the workplace.

Effects of Ceiling-Mounted HEPA-UV Air Filters on Airborne Bacteria Concentrations in an Indoor Therapy Pool Building

The purpose of this study was to assess the effectiveness of a new generation of high-volume, ceiling-mounted high-efficiency particulate air (HEPA)-ultraviolet (UV) air filters (HUVAFs) for their ability to remove or inactivate bacterial aerosol. In an environmentally controlled full-scale laboratory chamber (87 m3), and an indoor therapy pool building, the mitigation ability of air filters was assessed by comparing concentrations of total bacteria, culturable bacteria, and airborne endotoxin with and without the air filters operating under otherwise similar conditions. Controlled chamber tests with pure cultures of aerosolized Mycobacterium parafortuitum cells showed that the HUVAF unit tested provided an equivalent air-exchange rate of 11 hr−1. Using this equivalent air-exchange rate as a design basis, three HUVAFs were installed in an indoor therapy pool building for bioaerosol mitigation, and their effectiveness was studied over a 2-year period. The HUVAFs reduced concentrations of culturable bacteria by 69 and 80% during monitoring periods executed in respective years. The HUVAFs reduced concentrations of total bacteria by 12 and 76% during the same monitoring period, respectively. Airborne endotoxin concentrations were not affected by the HUVAF operation.

Occupational hygiene in a Finnish drum composting plant

Bioaerosols (microbes, dust and endotoxins) and volatile organic compounds (VOCs) were determined in the working air of a drum composting plant treating source-separated catering waste. Different composting activities at the Oulu drum composting plant take place in their own units separated by modular design and constructions. Important implication of this is that the control room is a relatively clean working environment and the risk of exposure to harmful factors is low. However, the number of viable airborne microbes was high both in the biowaste receiving hall and in the drum composting hall. The concentration (geometric average) of total microbes was 21.8 million pcs/m 3 in the biowaste receiving hall, 13.9 million pcs/m 3 in the drum composting hall, and just 1.4 million pcs/m 3 in the control room. Endotoxin concentrations were high in the biowaste receiving hall and in the drum composting hall. The average (arithmetic) endotoxin concentration was over the threshold value of 200 EU/m 3 in both measurement locations. In all working areas, the average (arithmetic) dust concentrations were in a low range of 0.6–0.7 mg/m 3, being below the Finnish threshold value of 5 mg/m 3. In the receiving hall and drum composting hall, the concentrations of airborne microbes and endotoxins may rise to levels hazardous to health during prolonged exposure. It is advisable to use a respirator mask (class P3) in these areas. Detected volatile organic compounds were typical compounds of composting plants: carboxylic acids and their esters, alcohols, ketones, aldehydes, and terpenes. Concentrations of VOCs were much lower than the Finnish threshold limit values (Finnish TLVs), many of the quantified compounds exceeded their threshold odour concentrations (TOCs). Primary health effects due VOCs were not presumable at these concentrations but unpleasant odours may cause secondary symptoms such as nausea and hypersensitivity reactions. This situation is typical of composting plants where the workers are exposed to dozens of VOCs simultaneously. The odour units (OU/m 3) were measured using olfactometer. The numbers were 23,000 OU/m 3 at the output end of the composting drum and 6300 OU/m 3 in the exhaust pipe. Inside the composting hall, the number of odour units was 500 and 560 OU/m 3.

Airborne Endotoxins and Airborne Gram-Negative Bacteria in a Residential Neighborhood

Ambient outdoor concentrations of airborne endotoxins and airborne gram-negative bacteria were measured in a residential area. Further, the species composition of the airborne gram-negative bacterial flora was investigated. The results demonstrated that humans and other mammals are exposed to airborne endotoxins in the outdoor air, but at levels where a development of adverse health effects is unlikely. The total amount of inhalable endotoxins ranged from <3.0 EU/m3 to 27.8 EU/m3. Airborne gram-negative bacteria were detected only at low concentrations (maximum 7.9 cfu/m3). Most gram-negative bacterial isolates belonged to the family Enterobacteriaceae and Pseudomonadaceae. Furthermore, the results of this study suggest that soil and vegetation are potential sources of airborne endotoxins and airborne gram-negative bacteria in the outdoor air of this environment.

Endotoxin in fine (PM2.5) and coarse (PM2.5–10) particle mass of ambient aerosols. A temporo-spatial analysis

Abstract Objectives : We collected fine (PM 2.5 ) and coarse (PM 2.5−10 ) particulate matter fractions in two areas ∼80 km apart and measured soluble endotoxin concentrations in both particle fractions. Here we report on temporo-spatial variation of endotoxin content in the collected particles. Methods : Dichotomous Anderson samplers were used to collect 21 weekly samples of PM 2.5 and PM 2.5−10 in both towns from January to June 2002. Each Teflon filter was water extracted and endotoxin was measured by a chromogenic Limulus Amoebocyte Lysate method. Endotoxin concentrations were expressed per mg of fine or mg of coarse mass and per sampled air volume (m 3 ). Results : For both cities, the mean endotoxin content in PM 2.5 was 1.2 EU mg −1 ; however the endotoxin content in the coarse fraction was ∼10 times higher compared to the fine mass fractions. Although endotoxin content is highly variable over time, a good correlation was observed between the two town sites for both fine ( r =0.85) and coarse PM ( r =0.88). The fluctuations of weekly endotoxin means were high in both areas suggesting a strong temporal dependence on particle source and composition. The endotoxin content in particles collected during May and June were two to four times higher than concentrations measured during the winter and early spring weeks. Conclusions : Ambient airborne endotoxin concentrations were detected in coarse and fine particle fraction, but 10-fold higher in the coarse PM. The strong seasonality and the week to week fluctuation of endotoxin content in PM indicate different biologic PM properties which might affect results of time series studies on short-term effects as well as in vitro studies and human exposure studies.

Inhaled endotoxin and organic dust particulates have synergistic proinflammatory effects in equine heaves (organic dust-induced asthma).

Equine heaves is a naturally occurring organic dust-induced asthma characterized by airway neutrophilia, mucus hypersecretion and obstructive lung dysfunction. However, the relative role of different dust components in disease severity remains unclear. This study investigated the relative contribution of inhaled endotoxin and organic dust particulates (mainly mould spores) in inducing heaves in heaves-susceptible horses. Control and heaves-susceptible horses received inhalation challenges with hay dust suspension (HDS) before and after lipopolysaccharide (LPS) depletion. Heaves-susceptible horses also received inhalation challenge with HDS particulates with and without the addition of LPS and were housed in two separate dusty environments during which mould and endotoxin exposure was measured. The airway inflammatory and functional response to each challenge was measured. Depletion of endotoxin from HDS attenuated the airway neutrophilia and abrogated the airway dysfunction induced in heaves horses by inhaled HDS. The airway response was re-established by adding back LPS to the depleted HDS, confirming that the attenuation in airway response was due specifically to endotoxin depletion. Interestingly, the magnitude of alteration in airway response following endotoxin depletion and add-back was greater than that which could be attributed solely to endotoxin per se, indicating that the LPS activity was enhanced by the other dust components. Consistent with this possibility, washed particulates harvested from HDS enhanced the airway response to inhaled LPS in heaves horses. Heaves horses given two different hay/straw challenges had a significantly different severity of airway inflammation and dysfunction, despite airborne dust and endotoxin concentrations in the horses' breathing zones being similar. Although inhaled endotoxin appears not to be the only determinant of disease severity in heaves, it does contribute significantly to the induction of airway inflammation and dysfunction. This contribution is largely via the synergistic action of inhaled endotoxin and organic dust particulates, although other soluble dust components also contribute to a lesser degree.

Airborne Fungi and Endotoxin Concentrations in Different Areas within Textile Plants in Taiwan: A 3-Year Study

Bioaerosols have been found in many occupational environments, including animal feeding houses, poultry slaughter houses, and cotton textile plants. This study was undertaken to examine a group of bioaerosols, the endotoxins, fungi, and bacteria, inside two textile factories over 3 years in Taiwan, where temperature and humidity are usually high year-round. Airborne dust was collected with filter cassettes attached to personal pumps and analyzed by the Kinetic Limulus Assay with Resistant-parallel-line Estimation. For fungi and bacteria determination, samples were collected using duplicated single-stage impactors, and organisms were counted after incubation. Endotoxin was the ajor contamination inside textile plants. Indoor levels were substantially higher than outdoor concentrations by 63- to 278-fold. The average values of fungi inside and outside the plants were not significantly different. Airborne bacteria levels were higher inside the plants as compared to outside. The carding sites, using only cotton, had extremely high endotoxin levels, greater than those at sites using synthetic fibers. Cotton, may be a major source of endotoxin contamination. In conclusion, the early stage of textile processing seems to generate high endotoxin and bacteria contamination. Priorities should be given to occupational hygiene programs for workers at various sites in textile plants.

A new and simple method used as cleaning system for measuring mite and cat allergens in homes

A new and simple method used as cleaning system for measuring mite and cat allergens in homes

Airborne endotoxin concentrations in domestic environment

Airborne endotoxin concentrations in domestic environment

Airborne contaminants in conventional laboratory rabbit rooms.

Besides the well known allergens, several other risk factors may exist for health in a laboratory animal unit. The exposure to these factors may be significant in animal units with poor general or local ventilation systems. Moreover, means to prevent the distribution of airborne contaminants may be limited in animal units housing rabbits or other bigger laboratory animals. Airborne contaminants in conventional laboratory rabbit rooms were sought to evaluate the occupational exposure of animal care personnel. Concentrations of airborne dust, bacteria, fungi, ammonia and endotoxins were measured during 2 days in three phases: before working activities began, during them and afterwards. Both stationary and some personal samples were taken. All of the contaminants sought were found in the rabbit room air. When compared to reported levels in farm animal production areas, the concentrations measured were generally low. However, moderate or high levels of airborne bacteria and fungi were found occasionally during work routines. Airborne contaminants should be considered as a potential occupational health risk for persons working with laboratory animals.

Pulmonary and systemic effects of inhaled endotoxin in control and heaves horses

To investigate whether inhaled endotoxin contributes to airway inflammation and dysfunction in stabled horses, control (n = 6) and asymptomatic heaves (previously termed chronic obstructive pulmonary disease)-susceptible (n = 7) horses were given inhalation challenges with 20, 200 and 2,000 microg of soluble Salmonella typhimurium Ra60 lipopolysaccharide (LPS). LPS inhalation induced a dose-dependent neutrophilic airway inflammatory response in both groups. Inhalation with 2,000 microg of LPS also induced detectable lung dysfunction in the heaves group. LPS inhalation did not alter clinical score, tracheal secretion volume or airway reactivity in either group. The no-response thresholds were lower for the heaves group (<20 microg for airway inflammation; 200 to 2,000 microg for lung dysfunction) than for the control group (20 to 200 microg for airway inflammation; >2,000 microg for lung dysfunction). To enable comparison of these threshold levels with airborne endotoxin concentrations in stables, horses also received a 5 h duration hay/straw challenge, during which the total and respirable airborne endotoxin concentrations were determined. Comparison of the effects of acute LPS inhalation and hay/straw challenges suggest that inhaled endotoxin is not the sole cause of heaves. However, it is likely that it contributes to airway inflammation, both in heaves horses in concert with other inhalants, and in normal horses when they are exposed to high levels in poor stable environments.

Exposure to microbes, endotoxins and total dust in cigarette and cigar manufacturing: an evaluation of health hazards

The concentrations of airborne microbes, endotoxins and total dust were measured in one cigar and two cigarette factories in order to evaluate the risk of respiratory symptoms. The role of humidifiers as a source of microbes was investigated. Air samples for the analyses were collected near workers' breathing zones during different phases of production. Gram-negative bacteria, mesophilic fungi, thermotolerant fungi and thermophilic actinomycetes, but not Aspergillus glaucus fungi, were found in higher concentrations in the cigar factory than in the cigarette factories. High microbe concentrations (10 4 –10 5 cfu m −3 ) occurred throughout the production line in the cigar factory. The highest dust and endotoxin concentrations were found in the wick-making department in the cigar factory (3.3 mg dust per m 3 and 38 ng endotoxin per m 3 ) and during the weighing or handling of raw tobacco in the cigarette factories (4.5 mg dust per m 3 and 106 ng endotoxin per m 3 ). The spray humidifiers in the cigar factory were a more important source of microbes than was raw tobacco. In the cigarette factories, steam humidifiers were used; the humidified air was free of microbes. The microbe concentrations in the tobacco factories were lower than in environments known to have caused allergic alveolitis.

Exposure to Microbes, Endotoxins and Total Dust in Cigarette and Cigar Manufacturing: an Evaluation of Health Hazards

The concentrations of airborne microbes, endotoxins and total dust were measured in one cigar and two cigarette factories in order to evaluate the risk of respiratory symptoms. The role of humidifiers as a source of microbes was investigated. Air samples for the analyses were collected near workers' breathing zones during different phases of production. Gram-negative bacteria, mesophilic fungi, thermotolerant fungi and thermophilic actinomycetes, but not Aspergillus glaucus fungi, were found in higher concentrations in the cigar factory than in the cigarette factories. High microbe concentrations (10(4)-10(5)cfu m(-3)) occurred throughout the production line in the cigar factory. The highest dust and endotoxin concentrations were found in the wick-making department in the cigar factory (3.3mg dust per m(3) and 38ng endotoxin per m(3)) and during the weighing or handling of raw tobacco in the cigarette factories (4.5 mg dust per m(3) and 106ng endotoxin per m(3)). The spray humidifiers in the cigar factory were a more important source of microbes than was raw tobacco. In the cigarette factories, steam humidifiers were used; the humidified air was free of microbes. The microbe concentrations in the tobacco factories were lower than in environments known to have caused allergic alveolitis.

COMPARISON OF FILTRATION AND IMPINGEMENT FOR SAMPLING AIRBORNE ENDOTOXIN

AGI-30 impingers and the PGP dust-sampling system were used to collect airborne endotoxin in animal houses. Both sampling methods correlated well with each other ( r 2=0.75). The collection efficiency of the impinger was higher than the efficiency of the PGP dust-sampling system, especially in animal houses with high concentrations of airborne endotoxin. The use of AGI-30 impingers for sampling airborne endotoxin is limited to short-term investigations, due to continuous loss of sampling fluid during operation. AGI-30 impingers offers the possibility for simultaneous measurement of airborne bacteria and endotoxin.

Occupational hygiene in biowaste composting

Source-separated biowastes from the Helsinki Metropolitan Area have been composted in open air windrows at Ammas suo, the Helsinki regional landfill in Espoo (Finland). The most significant problem encountered in the early stages of the process has been the formation of rancid odor causing human discomfort. The offensive odor was mainly due to car boxylic acids. A total of 110 organic compounds were detected in volatile emissions from windrow composts with an integrated sensory and instrumental method. Occasionally the temperatures in the windrows exceeded 80°C. Bacterial measurements also revealed substantial populations of bacte ria at 75°C. The concentrations of airborne microbes and endotoxins were highest during the crushing of fresh biowaste and the turning of compost, and were relatively high in sum mer and when windrows were dry. The most common fungi in the air were Aspergillus and Penicillium. Dust concentrations were consistently low. The concentrations of microbes were never so high as to constitute an acute health hazard from the occasional exposure. Continuous exposure to such concen trations nevertheless increases the risk of illness. The time, neccessary for the compost to become hygienic improved from four months to four weeks during the project. Drum composting was also tested and was found to be an alternative approach to treating organic wastes. Emissions from the drum composting were low compared to open air composting.

Total and respirable airborne dust endotoxin concentrations in three equine management systems.

The concentrations of total and respirable airborne endotoxin in the breathing zone of a pony in 3 different management systems, on 8 occasions, are reported. Airborne endotoxin concentrations in all 3 systems were lower than those reported for many other agricultural environments. However, total airborne endotoxin concentrations in many of the conventional stables exceeded those which can induce pulmonary inflammation and bronchial hyper-responsiveness in normal human subjects, and exceeded those which can induce bronchoconstriction in humans with pre-existing pulmonary inflammation. Therefore, airborne endotoxin may contribute to the development of airway inflammation and dysfunction in conventionally stabled horses. Potentially detrimental effects of airborne endotoxins on the welfare and exercise performance of stabled horses can be reduced by maintaining horses in 'low dust' stables or at pasture, since these environments had significantly lower airborne dust and endotoxin concentrations.

In living rooms occupied by cigarette smokers and non-smokers in Sosnowiec, Upper Silesia, Poland

In 12 selected flats in Sosnowiec, Upper Silesia, the concentrations of particulate aerosol, bioaerosol and bacterial endotoxin were examined. Concentrations of particulate aerosol, bacteria, fungi and endotoxin were in the order of 101–102 μg/m3, 101–103 cfu/m3, 100–102 cfu/m3 and 10−2–10−1 ng/m3, respectively. The most numerous group of microorganisms in indoor air during the winter season were Gram positive mesophilic bacteria. They were more common in flats polluted with tobacco smoke. The concentrations of airborne endotoxins were higher in flats polluted with tobacco smoke in all size ranges. The highest level of endotoxins was found in the fraction of fine particles below 5μm.

Concentrations and Emissions of Airborne Endotoxins and Microorganisms in Livestock Buildings in Northern Europe

Abstract The concentration of airborne endotoxins and microorganisms in livestock buildings (cattle, pig, poultry) was surveyed in four European countries (England, The Netherlands, Denmark and Germany). Measurements were made during the day and night. The endotoxin concentrations were determined from dust samples separated into inhalable and respirable fractions. Airborne microorganisms were classified as total bacteria,Enterobacteriaceaeand total fungi. The lowest endotoxin concentrations were found in cattle houses. The highest concentrations of endotoxin were measured in poultry houses, especially percheries, with an overall mean of 692 and 49 ng/m3for inhalable and respirable fractions, respectively. Endotoxin concentration was usually higher in the day than at night. These concentrations give cause for concern for the health of stockmen working in such buildings. The corresponding mean emission rates from poultry houses were 678 and 43 μg/h (500kg) liveweight, respectively, 51 and 6 μg/h (500kg) liveweight from pig buildings and 9 and 1 μg/h (500kg) liveweight from cattle houses. A new automated bioaerosol sampler was developed, which allows remote, independent sampling of airborne microorganisms. Its principle of operation is similar to a slit sampler: airborne microbes are collected by impaction on an agar surface. Most measurements of airborne microorganisms were made in Germany. The indoor concentration of total bacteria was 6·43 log colony-forming units (cfu)/m3in broiler houses, 5·1 log cfu/m3in pig buildings and 4·3 log cfu/m3in cattle buildings. During the day, the overall concentration ofEnterobacteriaceaeranged between 3 and 4 log cfu/m3. The mean fungi concentration for cattle was 3·8, for pigs 3·7 and for poultry 4·0 log cfu/m3during the day. Slightly lower concentrations were measured at night. No significant correlation was found between the concentrations of endotoxin andEnterobacteriaceae. The highest emission rate of total bacteria and fungi was measured for broilers, i.e. 9·5 and 4·7 log cfu/h (500 kg) liveweight, respectively. Buildings for laying hens had the highest mean emission rate of 7·1 log cfu/h (500 kg) liveweight forEnterobacteriaceae.

Longitudinal changes in inflammatory markers in nasal lavage of cotton workers. Relation to endotoxin exposure and lung function changes.

The aim of this study was to evaluate time-related changes in inflammatory markers in nasal lavage (NAL) in relation to endotoxin exposure and lung function changes. Endotoxin in cotton dust is well known to elicit proinflammatory mediators involved in acute or chronic respiratory inflammation due to cotton dust. We applied nasal lavage as well as lung function and exposure measurements in a small group (n = 11) of cotton workers during 6 weeks of observation (after 2 weeks free of exposure). Several inflammatory markers in NAL, such as interleukin 8 (IL-8), IL-6, and down-stream mediators, including soluble tumor necrosis factor receptor 75 (sTNF-R75) and soluble intercellular adhesion molecule 1 (ICAM-1), cell counts, marker of epithelial response (uric acid), and marker of plasma exudation (albumin) were measured. At the exposure levels examined in this study [cotton dust, geometric mean (GM) = 1.10 mg/m3; endotoxin, GM = 2,869 EU/m3], several inflammatory markers in NAL such as IL-8, sTNF-R75, and albumin tended to increase through the measurement period with increasing airborne endotoxin concentration (in six workers who had paired measurements in weeks 1 and 6). Although no statistical significance was reached, airborne endotoxin exposure and all inflammatory markers in NAL were relatively higher in cotton workers with a 6-week lung function decrease. The data suggest that inflammatory markers in NAL are associated with repeated airborne endotoxin exposure.