Environmental Dust Samples Research Articles

Allergens in School Settings: Results of Environmental Assessments in 3 City School Systems

Environmental allergens are major triggers for pediatric asthma. While children's greatest exposure to indoor allergens is in the home, other public places where children spend a large amount of time, such as school and day care centers, may also be sources of significant allergen encounters. The purpose of this article is to describe schoolroom allergen levels from 3 different geographic sites obtained from dust samples collected in the fall and in spring. Environmental dust samples were collected from elementary schools in Birmingham (AL), Detroit (MI), and Houston (TX), from 4 room locations, including the cafeteria, library, upper grades, and lower grades. Samples were assayed for dust mite (Dermatophagoides pteronyssinus and Dermatophagoides farinae), cat (Felis domesticus), and cockroach (Blatella germanica 2) allergen levels. Allergen levels varied by geographic location and type of schoolroom. Schoolroom settings differed by the type of flooring (hard and carpet), room characteristics and use (food service, library shelves with books, and general classroom with multiple types of materials [individual desks and different types of furniture]), and the average age of the schoolroom dwellers (younger vs. older children). Dust mite, cat, and cockroach allergens were present in all schoolrooms and all sites at varying levels by season and by type of room. Schools may be important sources of direct allergen exposure and reservoirs that could potentially contribute to allergic sensitization and disease exacerbation in children. Further studies are needed to carefully examine the environmental allergen load in schools and its effect on children.

Reduction in asthma morbidity in children as a result of home remediation aimed at moisture sources.

ObjectiveHome dampness and the presence of mold and allergens have been associated with asthma morbidity. We examined changes in asthma morbidity in children as a result of home remediation aimed at moisture sources.DesignIn this prospective, randomized controlled trial, symptomatic, asthmatic children (n = 62), 2–17 years of age, living in a home with indoor mold, received an asthma intervention including an action plan, education, and individualized problem solving. The remediation group also received household repairs, including reduction of water infiltration, removal of water-damaged building materials, and heating/ventilation/air-conditioning alterations. The control group received only home cleaning information. We measured children’s total and allergen-specific serum immuno-globulin E, peripheral blood eosinophil counts, and urinary cotinine. Environmental dust samples were analyzed for dust mite, cockroach, rodent urinary protein, endotoxin, and fungi. The follow-up period was 1 year.ResultsChildren in both groups showed improvement in asthma symptomatic days during the preremediation portion of the study. The remediation group had a significant decrease in symptom days (p = 0.003, as randomized; p = 0.004, intent to treat) after remodeling, whereas these parameters in the control group did not significantly change. In the postremediation period, the remediation group had a lower rate of exacerbations compared with control asthmatics (as treated: 1 of 29 vs. 11 of 33, respectively, p = 0. 003; intent to treat: 28.1% and 10.0%, respectively, p = 0.11).ConclusionConstruction remediation aimed at the root cause of moisture sources and combined with a medical/behavioral intervention significantly reduces symptom days and health care use for asthmatic children who live in homes with a documented mold problem.

Elimination of interferences in determination of platinum and palladium in environmental samples by inductively coupled plasma mass spectrometry

Various approaches were evaluated in order to eliminate the spectral interferences noted when Pt and Pd has to be determined in environmental dust samples by ICP-MS. The chemical separation of Pt and Pd from the matrix components on ion-exchange resins was applied. The performance of cation-exchange resins (Dowex 50 WX-8, Dowex 50 WX-2, Dowex HCR-S, Varion KS, Cellex-P) for the separation of interfering ions was then examined. It was found that Dowex 50 WX-8 shows best performance. The effects of mass, mesh number of resin and concentration of Cl − ions on matrix separation were also studied. Another approach was to use the anion-exchange sorbent Cellex-T, which allows almost total retention of both analytes followed by their elution with 0.1 mol L −1 thiourea in 1 mol L −1 HCl. This procedure however can be used only for platinum determination by ICP-MS. The accuracy of proposed procedures was confirmed by the analysis of certified material BCR-723, and then it was used for determination Pt and Pd in samples of road dust.

Organophosphate Pesticide Exposure and Neurobehavioral Performance in Agricultural and Nonagricultural Hispanic Workers

Our understanding of the health risks of farmworkers exposed to pesticides in their work and home environments is rapidly increasing, although studies designed to examine the possible neurobehavioral effects of low-level chronic pesticide exposure are limited. We measured dialkyl phosphate urinary metabolite levels, collected environmental dust samples from a subset of homes, obtained information on work practices, and conducted neurobehavioral tests on a sample of farmworkers in Oregon. Significant correlations between urinary methyl metabolite levels and total methyl organophosphate (azinphos-methyl, phosmet, malathion) house dust levels were observed. We found the neurobehavioral performance of Hispanic immigrant farmworkers to be lower than that observed in a nonagricultural Hispanic immigrant population, and within the sample of agricultural workers there was a positive correlation between urinary organophosphate metabolite levels and poorer performance on some neurobehavioral tests. These findings add to an increasing body of evidence of the association between low levels of pesticide exposure and deficits in neurobehavioral performance.

Evaluation of interference to conventional and real-time PCR for detection and quantification of fungi in dust

Advances in polymerase chain reaction (PCR) have permitted accurate, rapid and quantitative identification of microorganisms in pure cultures regardless of viability or culturability. In this study, a simple sample processing method was investigated for rapid identification and quantification of fungal spores from dust samples using both conventional and real-time PCR. The proposed method was evaluated for susceptibility to interference from environmental dust samples. Stachybotrys chartarum and Aspergillus fumigatus were used as test organisms. The sensitivity of detection in pure culture was 0.1 spore DNA equivalents per PCR reaction corresponding to 20 spores ml(-1) in the sample. However, 1 spore DNA equivalent per PCR reaction corresponding to 200 spores ml(-1) in the sample was the lowest amount of spores tested without interference in dust samples spiked with spores of either fungal species. The extent of inhibition was calculated using conventional and real-time PCR reactions containing fungal spores, specific primers, specific probes (for real-time PCR) and various amounts of dust. The results indicate that the extent of inhibition by dust on PCR varies with the type and amount of dust, and number of spores. No interference in the analysis of spiked samples was detected from 0.2 mg ml(-1) of four real-life dust samples at p-value >0.05 using 2 x 10(4) spores for conventional PCR and 2 x 10(5) spores for real-time PCR. However, samples containing >0.2 mg ml(-1) real-life dust compromised the PCR assay. These results suggest the potential usefulness of a simple sample processing method in conjunction with PCR for monitoring the fungal content of aerosols collected from indoor environments.

Indirect lead exposure among children of radiator repair workers.

Secondary exposure to lead has been identified as a public health problem since the late 1940s; we investigate the risk of lead exposure among families of radiator repair workers. A sample of the wives and children, aged 6 months to 6 years (exposed children) (n = 19), of radiator repair workers and a sample of children whose parents were not occupationally exposed to lead (non-exposed children) (n = 29) were matched for age and residence; their geometric mean blood lead levels are compared. Blood samples were obtained by the finger stick method and environmental dust samples by the wipe method; both were analyzed using a portable anodic stripping voltameter. Dust lead levels were significantly higher in the houses of exposed children (143.8 vs. 3.9 microg/g; P < 0.01). In crude analyses, the highest lead levels were observed among children whose fathers worked in home-based workshops (22.4 microg/dl)(n = 6). Children whose fathers worked in an external workshop (n = 13) also had high levels (14.2 microg/dl) (P < 0.01), while blood lead levels in non-exposed children were significantly lower (5.6 microg/dl)(P < 0.01). The observed differences remained significant after adjustment for age and gender. This study confirms that children of radiator repair workers are at increased risk of lead exposure and public health interventions are needed to protect them.

Evaluation of rapid DNA extraction methods for the quantitative detection of fungi using real-time PCR analysis

Three comparatively rapid methods for the extraction of DNA from fungal conidia and yeast cells in environmental (air, water and dust) samples were evaluated for use in real-time PCR (TaqMan™) analyses. A simple bead milling method was developed to provide sensitive, accurate and precise quantification of target organisms in air and water (tap and surface) samples. However, quantitative analysis of dust samples required further purification of the extracted DNA by a streamlined silica adsorption procedure.

Rapid screening of possible cytotoxic effects of particulate air pollutants by measurement of changes in cytoplasmic free calcium, cytosolic pH, and plasma membrane potential in alveolar macrophages by flow cytometry.

Inhalable particulate dusts are involved in the genesis of several lung diseases. Besides the well-known toxic dusts, i.e., asbestos and quartz, heavy metal-containing pollutants are considered as possible harmful substances. In the present study, we compared the effect of silica chemically coated with certain metal oxides and dusts from industrial productions on cell physiological parameters of bovine alveolar macrophages (BAM). The cytosolic free calcium concentration, [Ca2+](i), the intracellular pH (pH(i)), and the plasma membrane potential (MP) of BAM were measured by flow cytometry. The dust-induced secretion of reactive oxygen species (ROS) was measured enzymatically. Compared with control incubations with pure silica, the dust-induced secretion of ROS by BAM was not affected when the particles were coated with Cr(2)O(3), NiO, and Fe(3)O(4), whereas VO(2)-coated dust induced a marked increase in ROS release. This effect was not correlated to changes in [Ca2+](i), pH(i), or MP. On the other hand, Cr(2)O(3)-coated silica caused alterations in all of the three latter parameters. The same pattern of changes has been reported previously for quartz dusts (Tárnok et al.: Anal Cell Pathol 15:61-72, 1997). We conclude that cell physiological measurements by flow cytometry could extend the palette of tools to evaluate possible toxic effects of environmental dust samples.

A survey of toxocara infections in cat breeding colonies in the Netherlands

Summary Faecal samples from 225 adults cats and 112 kittens and dust and soil samples from 25 catteries in the Netherlands were examined for Toxocara eggs. The results of this survey showed a low nematode infection rate in the investigated Dutch catteries since only four adult cats (2%) from two catteries (8%) were found to shed Toxocara cati eggs. No other helminth eggs were seen in the faecal samples. Nematode eggs were not present in the environmental dust and soil samples from houses and kennels; only Dipylidium caninum eggs were found in only two samples of household dust.

Trace Detection of Underivatized Muramic Acid in Environmental Dust Samples by Microcolumn Liquid Chromatography−Electrospray Tandem Mass Spectrometry

Muramic acid (MA) is a universal chemical marker for bacterial cell wall polymers (peptidoglycan) present in complex environmental, industrial, and clinical matrices. Trace analysis of MA has been limited to a handful of laboratories because of the lengthy nature of derivatization procedures necessary for GC/MS and GC/MS/MS. The focus of the current report concerns environmental analysis (organic dust) using LC/MS/MS of native MA. Dust was heated in sulfuric acid to release MA from cell wall polymers. Acid was removed by extraction with an organic base. The samples were passed through a hydrophobic C-18 extraction column to remove nonpolar contaminants. This was followed by binding of MA to a strong cation-exchange extraction column to eliminate neutral and anionic components of the sample. MA was then eluted with hydrochloric acid, which was removed by evaporation. Analysis was done by microscale LC ES/MS/MS using a custom-made Lichrosphere-diol capillary column. 13C-Labeled MA was used as an internal standard. Total sample preparation takes approximately 12 h. The simplicity of the sample preparation may eventually allow MA analysis to be used in a host of applications, including air monitoring for biocontamination. This is the first report, to our knowledge, of microscale LC ES/MS/MS analysis for MA (or, indeed, any other sugar monomer) in a complex matrix.

The Relationship Between the Dust Lead Concentration and the Particle Sizes of Household Dusts Collected in Jersey City Residences

Abstract Lead concentrations measured in total dust samples collected from various environmental surfaces have been used as a surrogate for the lead concentration found in hand dust and subsequently in calculations of lead exposure due to ingestion. However, since the relationship between the characteristics of environmental dust samples and hand dusts is not yet well established, conclusions derived from lead measurements in contaminated household dusts may provide misleading information about childhood exposure. Household dusts collected from seven different residences by a high efficiency particulate air vacuum cleaner were sieved into eight different size fractions (>500, 500 to 355, 355 to 250, 250 to 180,180 to 125, 125 to 90, 90 to 63, and <63 μm) and analyzed for lead in dust (PbD) concentrations using both flame atomic absorption and laboratory X-ray fluorescence. In contrast to results found for street dust, where the PbD concentration increased as the particle size decreased, the reported results indicate that PbD concentration in household dust for six of the seven residences increased as particle size increased. The PbD concentrations in the fractionated dusts ranged between 700 ppm (dust <63 μm in diameter) and 35,300 ppm (dust >500 μm in diameter). Analyses suggested that the dust samples collected from residential environments will have a location-specific distribution of lead concentration that is a function of particle size. The results show that the lead mass and dust mass distributions differed substantially among the seven households as a function of particle size, possibly reflecting different local lead sources, different weathering processes, and different household activities which determine the particle size distribution. For each of these seven Jersey City, New Jersey, household dusts, total PbD concentrations (ppm) were higher than the PbD concentrations (ppm) for particles <125 μm. Leaded paint was the main source of lead-rich particles in the household dusts analyzed in this study. Strong correlations were observed between particle size and concentrations of the elements lead, titanium, and barium in fractionated dust samples known to be rich in leaded paint dust. With the current knowledge suggesting that dust particles which adhere to dry hand surfaces are primarily smaller than 10 μm, this study suggests that there is a potential for overestimating children's blood lead levels by using total PbD concentration as the surrogate for hand dust PbD concentration.

Measurement of environmental formylmethionyl-peptides.

Formylmethionyl-peptides are naturally occurring, biologically active ligands produced by bacteria. They produce a variety of biological effects including neutrophil chemotaxis, cellular degranulation, oxygen-free radical production, and smooth muscle contraction. Our studies have demonstrated that oxidized and reduced forms of formylmethionyl-leucyl-phenylalanine (fMLP) can be detected in bulk environmental organic dust samples. Organic dust fMLP content may not reflect total formylmethionyl-peptide content and pathological sequelae. Attempts to develop a total formylmethionyl-peptide assay that would reflect its pathological potential have thus far been unsuccessful. Information has been derived concerning the biology of formylmethionyl-peptides from these studies. Chromatographic, radioenzymatic, and radioreceptor-ligand binding studies were performed. High-performance liquid chromatography (HPLC) analysis of synthetic and environmental fMLP demonstrated that fMLP is labile, forming three oxidation products. HPLC is limited by inadequate sensitivity for air sample analysis and the probability of the presence of multiple formylmethionyl-peptides. Deformylases were isolated from Escherichia coli, but their usefulness in a competitive assay to detect formylmethionyl-peptides was limited by specificity differences from that for biological receptors. Receptor binding studies were conducted in an attempt to replace the deformylase with a biological receptor. The receptor binding patterns noted were consistent with the existence of three distinct formylmethionyl-peptide receptor subsets in neutrophils and alveolar macrophages. The plurality of fMLP receptor subtypes interfered with formylmethionyl-peptide measurement in a competitive assay. Formylmethionyl-peptides may contribute to organic dust-induced disease, but better techniques for the assessment of exposure to these agents are needed to properly assess their health impact.

Ion-exchange separation of nanogram platinum in environmental dust samples for isotope dilution ICP-MS.

Ion-exchange separation of nanogram platinum in environmental dust samples for isotope dilution ICP-MS.

Estimation of the allergen content of house dust samples by enzymatic assay

House dust extracts contain protease and acid phosphatase activities which can be shown to be related to the content of major allergens for humans. A study of the quantitative association between measured enzyme activities and the potency of the extracts to bind IgE antibodies from the serum of house-dust-allergic patients is presented. Since major allergens from mites and other insects contributing to the allergenic potential of household dust on chemical isolation coincide with proteolytic enzymes, and since the bulk of pollen allergenic activity is related to acid phosphatase, the method presented here allows the quantitative appraisal of the contribution of the biomass of animal and plant origin to the allergenic potency of environmental dust samples without the use of human blood samples as sources of specific antibodies.

Blood lead levels in South African inner-city children.

Little is known about childhood lead absorption in South Africa. In this study a cross-sectional analytic survey was carried out to determine the blood lead levels and associated risk factors for inner-city, first-grade schoolchildren. Blood lead analyses, hematological and anthropometric measurements were conducted, and a pretested questionnaire was administered to parents to identify risk factors for lead exposure. In a detailed environmental study, daily air and dust samples were collected over a period of 1 year from several sites in the study area, contemporaneously with the blood and questionnaire surveys. Spatial and temporal variations in atmospheric lead were determined. It was found that 13% of mixed race children, but no white children, had blood lead levels greater than or equal to 25 micrograms/dL, the U.S. action level. Air lead levels averaged around 1 microgram/m3, and dust lead levels ranged from 410 to 3620 ppm. Environmental lead levels were significantly elevated near heavy traffic, where Environmental Protection Agency standards were exceeded mainly during winter months. Baseline exposure was of significance in influencing blood lead levels of children attending schools in direct proximity to heavy traffic, where blood lead levels were elevated irrespective of other influencing factors. Primary and secondary preventive measures are urgently needed in South Africa to reduce environmental lead exposure. At the time of the study, South Africa had one of the highest levels of lead in gasoline in the Western World, namely, 0.836 g/L. Although levels have subsequently been reduced, this is typical of the situation in many African countries today.

Blood Lead Levels in South African Inner-City Children

Little is known about childhood lead absorption in South Africa. In this study a cross-sectional analytic survey was carried out to determine the blood lead levels and associated risk factors for inner-city, first-grade schoolchildren. Blood lead analyses, hematological and anthropometric measurements were conducted, and a pretested questionnaire was administered to parents to identify risk factors for lead exposure. In a detailed environmental study, daily air and dust samples were collected over a period of 1 year from several sites in the study area, contemporaneously with the blood and questionnaire surveys. Spatial and temporal variations in atmospheric lead were determined. It was found that 13% of mixed race children, but no white children, had blood lead levels greater than or equal to 25 micrograms/dL, the U.S. action level. Air lead levels averaged around 1 microgram/m3, and dust lead levels ranged from 410 to 3620 ppm. Environmental lead levels were significantly elevated near heavy traffic, where Environmental Protection Agency standards were exceeded mainly during winter months. Baseline exposure was of significance in influencing blood lead levels of children attending schools in direct proximity to heavy traffic, where blood lead levels were elevated irrespective of other influencing factors. Primary and secondary preventive measures are urgently needed in South Africa to reduce environmental lead exposure. At the time of the study, South Africa had one of the highest levels of lead in gasoline in the Western World, namely, 0.836 g/L. Although levels have subsequently been reduced, this is typical of the situation in many African countries today.

Environmental factors responsible for the unusual corrosion of galvanized steel

AbstractA phenomenon of unusual heavy corrosion of hot dip galvanized structural steelwork in a subtropical severe marine atmosphere has been studied. Through the data optained from X‐ray diffraction analysis of corrosion products, surrounding soil samples and environmental dust samples, and from SEM observations and EDAX analysis of loose corrosion scale, as well as from the information provided by the metallographic study of galvanized steel sections with different degree of corrosion, a mechanism of attack has been proposed, which accounts for the special environmental factors prevailing on the place.

Application of inductively coupled plasma mass spectrometry to the simultaneous determination of chlorine, bromine and iodine in the National Bureau of Standards Standard Reference Material 1648 Urban Particulate

The application of inductively coupled plasma mass spectrometry (ICP-MS) to the simultaneous determination of chlorine, bromine and iodine in the National Bureau of Standards (NBS) Standard Reference Material (SRM) 1648 Urban Particulate is described. The potential of ICP-MS for simultaneous multi-element trace determinations after a conventional dissolution procedure is illustrated. Various possible methods for including the halides are considered, and various sample dissolution procedures are investigated. Data presented for the NBS SRM 1648 Urban Particulate are considered in terms of the previously published results and polyatomic ion interferences from sample fusion procedures. It has been shown that the method has great potential for the determination of total chlorine, bromine and iodine in environmental dust and other samples.

Polycyclic aromatic hydrocarbons in the environment: high-performance liquid chromatography using chemically modified columns

A simple and rapid procedure for the separation and determination of a number of polycyclic aromatic hydrocarbons (PAHs) in environmental dust samples is described. An ultrasonic extraction method was used to separate the organic compounds from the dust particles. Only small amounts of dust and solvents are needed and the extraction requires only a few minutes. Compounds that would interfere in UV detection after high-performance liquid chromatography (HPLC) are separated from the aromatic fraction by preparative thin-layer chromatography on silica gel. The chromatographic behaviour of the carcinogenic hydrocarbons on several stationary phases in HPLC was investigated. A comparison of the chromatographic data showed that silica gel chemically modified with NO 2 groups gives the best selectivity. Nanogram amounts of PAHs were easily detected by using a UV monitor.

The occupational hazards of formulating oral contraceptives--a survey of plant employees.

In May 1976 an investigation of a factory in Puerto Rico which formulates oral contraceptives revealed that during the previous 12 months five of the company's twenty-five employees (20%), and twelve of the company's thirty female employees (40%) had experienced symptoms associated with hyperestrogenism. The affected males had gynecomastia and three of them also reported a history of decreased libido or impotence. The affected females each had had at least one episode of intermenstrual bleeding during the preceding 12 months. There was an estimated relative risk of 4.3 for intermenstrual bleeding in nonclerical female employees compared with matched controls who did not work at the plant. Elevated levels of plasma ethinyl estradiol were twice as frequent in the two highest-risk job categories compared with the rest of the factory population, but the difference in prevalence of elevated levels was not statistically significant (P = 0.08). Wide variations in mestranol concentration were noted in the environmental dust samples. Prompt consideration should be given to establishing health standards for persons occupationally exposed to estrogens in view of the possible long-term sequelae of such exposure.