William Popendorf

Characterization of Dusts Collected from Swine Confinement Buildings

As part of a project to evaluate health hazards for workers in swine confinement buildings, the air in 21 different buildings was sampled with 37 mm cassette filters with and without cyclone preselectors and with cascade impactors. Filter results yielded a mean total aerosol of 6.3 mg/m3, a mean respirable aerosol of 0.5 mg/m3; the geometric mean diameter was 2.9 microns. Cascade impactor measurements revealed a mean total aerosol of 7.6 mg/m3, a respirable aerosol of 2.5 mg/m3 and a mass median diameter of 9.6 microns. The two major constituents in these aerosols were grain particles and dried fecal matter. The grain particles were larger than fecal particles and proportionately more abundant in finishing buildings where 50 kg X 100 kg animals are housed. Therefore the respirable fraction was less in finishing buildings than in farrowing and nursery buildings. Culturing of settled dusts yielded six different mold species, with the highest counts for Verticillium sp. (5 X 10(2) cfu/mg dry dust) grown at 37 degrees C. Thermophilic Actinomycetes and both gram negative and gram positive bacteria were isolated. Azocasein proteinase activity was found in most dust samples analyzed. This dust had a protein content of about 23% and a mean adsorbed ammonia content of 0.4%.

Ambient Levels of Selected Gases Inside Swine Confinement Buildings

To assess potential worker health hazards, the air in confinement structures on 21 randomly selected swine producing farms in Iowa was evaluated for selected gases. The gases measured (mean concentration) included ammonia (34 ppm), hydrogen sulfide (1.4 ppm), carbon monoxide (9.1 ppm) and carbon dioxide (1640 ppm). Ammonia (compared to other gases) most commonly exceeded the Threshold Limit Value (TLV); however, it was common to find buildings with several gases in excess of the TLV. Buildings housing younger animals were more likely to have hazardous gas levels than buildings housing older animals. This complex mixture of gases represents a potential health hazard to an estimated 400,000 individuals who work in swine confinement buildings. These data suggest that research is needed to control these exposures affecting a large number of workers.

Assessing airborne aflatoxin B1 during on-farm grain handling activities

The presence of aflatoxin in corn and corn dust during relatively normal years and the increased risk of Aspergillus flavus infestation during drought conditions suggest that airborne agricultural exposures should be of considerable concern. Liquid extraction, thin layer chromatography, and high pressure liquid chromatography were used for the analysis of aflatoxin B1 in grain dust and bulk corn samples. A total of 24 samples of airborne dust were collected from 8 farms during harvest, 22 samples from 9 farms during animal feeding, and 14 sets of Andersen samples from 11 farms during bin cleaning. A total of 14 samples of settled dust and 18 samples of bulk corn were also collected and analyzed. The airborne concentration of aflatoxin B1 found in dust collected during harvest and grain unloading ranged from 0.04 to 92 ng/m3. Higher levels of aflatoxin B1 were found in the airborne dust samples collected from enclosed animal feeding buildings (5-421 ng/m3) and during bin cleaning (124-4849 ng/m3). Aflatoxin B1 up to 5100 ng/g were detected in settled dust collected from an enclosed animal feeding building; however, no apparent correlation was found between the airborne concentration of aflatoxin B1 and its concentration in settled dust or bulk corn. The data demonstrate that farmers and farm workers may be exposed to potentially hazardous concentrations of aflatoxin B1, particularly during bin cleaning and animal feeding in enclosed buildings.

Respiratory symptoms and lung function abnormalities among machine operators in automobile production

This cross-sectional study was designed to assess differences in prevalence of respiratory symptoms and lung function between machine operators exposed to semisynthetic or soluble metal-working fluids (MWFs) and unexposed assemblers and to assess exposure-response relationships with MWF type, total aerosol, endotoxin, culturable bacteria and fungi. We evaluated 183 machine operators and 66 assemblers from one large automobile transmission plant using questionnaires, spirometry data, and cross-shift assessment of both lung function and respiratory symptoms. We found that airborne exposures to total aerosol, endotoxin, culturable bacteria and fungi were higher in machine operations than in the assembly area. There was a correlation between bulk and airborne culturable bacteria, but not between bulk and airborne culturable fungi. Machine operators had significantly more usual cough, usual phlegm, work-related chest tightness and post-shift symptoms of chest tightness, throat irritation, and cough compared with assemblers. We found exposure-response relationships between respiratory symptoms and total aerosol, as well as culturable fungi and bacteria. Associations with endotoxin were not strong or consistent, possibly because airborne levels were generally low. Cross-shift lung function decrements did not differ between machine operators and assemblers and there were no associations with MWF or specific exposures. The finding of respiratory symptoms at low levels of exposure in this study suggests the need to re-assess total aerosol thresholds. Associations between airborne fungal exposures and respiratory symptoms need further study to characterize sources of exposure other than MWF in machining operations.

Dermatitis among automobile production machine operators exposed to metal‐working fluids

This cross-sectional study was designed to assess differences in prevalence of contact dermatitis between machine operators exposed to metal-working fluids (MWFs) and unexposed assemblers, and to assess potential risk factors for contact dermatitis among these machine operators. In their work, machine operators were exposed to either semisynthetic or soluble oil MWFs. We evaluated 158 machine operators and 51 assemblers from one large automobile transmission plant using questionnaires, dermatologist examination of the skin, and dermal dosimetry to measure wetness and metal exposures. We found that machine operators had more combined (definite plus possible) dermatitis (27.2% vs. 13.7%, chi(2) = 3.9, p = 0.05, 1 df) compared with assemblers. Among machine operators, risk factors significantly associated with (combined) dermatitis were subjective assessment of wetness of the work, exposure to semisynthetic as opposed to soluble oil MWF, current cigarette smoking, and increasing worker age. These risk factors suggested preventive and control measures including control of wet work, surveillance program including early self-report of dermatitis, consideration of replacement of semisynthetic with soluble oil MWFs, and strictly limiting smoking among machine operators exposed to MWFs.

Urinary excretion of the N-acetyl cysteine conjugate of cis-1,3-dichloropropene by exposed individuals.

A gas chromatographic-mass spectrometric assay was developed to identify and measure the N-acetyl cysteine conjugate of cis-1,3-dichloropropene. The assay was used to show that individuals exposed to 1,3-dichloropropene vapor during field applications excrete this conjugate in their urine. The recoveries of the conjugate were correlated with the product of airborne concentrations and the duration of exposure (r = 0.83).

A method for monitoring dermal exposure to volatile chemicals

Absorptive pads of charcoal cloth were developed and tested for monitoring the deposition of volatile toxic materials on skin. The dosimeters can retain over 60% of volatile deposits such as toluene or dichloropropene droplets over an 8-hr workday. Evaporation from liquid deposits and vapor adsorption onto the dosimeters are factors which can complicate the interpretation of exposure data. Evaporation was inversely proportional to the log of the deposit size (volume), vapor pressure, and the air humidity. Vapor adsorption was proportional to the vapor concentration, exposure duration, and the log of air velocity. A procedure is offered for estimating the initial size of the liquid deposit from retained mass. The charcoal cloth dosimeters accuracy and precision are optimal in situations involving possible dermal exposure to toxic materials with low to moderate volatility or with low vapor concentration, i.e., those where dermal exposure may be equal to or more significant than respiratory exposure.

A synopsis of agricultural respiratory hazards.

This report summarizes the current state of both knowledge and programs concerning a wide range of respiratory hazards facing agricultural producers including cotton dust, grain dust, agricultural chemicals, organic and inorganic dusts, and microbiologic and immunologic agents. Comparisons and criticisms are made among the hazards on the basis of their epidemiology, their occurrence within the agricultural setting, and current approaches, interest, and support for evaluating and controlling the hazard. This report was prepared as both an overview of the technical issues and as a focal point of organizational concern for what appears to be a very broad and largely underrecognized spectrum of occupational health hazards affecting large segments of the agricultural industry. The difficulties confronting research and human health in these areas are at once technical, sociological, and organizational in nature, and remain a challenge to the industry, to government, and to the health profession.

Exposure While Applying Industrial Antimicrobial Pesticides

Forty-three assessments were made of dermal and/or inhalation chemical exposure while applying industrial antimicrobial pesticide products, either by manually pouring or pumping liquids or by pouring a solid (powder or flake) product. Inhalation exposure was assessed via a personal air sample but was usually below the chemical limit of detection. Dermal exposure outside work clothing and dermal deposition inside the clothing was assessed via dermal gauze dosimeters. While dosimeters at discrete body locations often received exposures below the limit of detection, one or more dosimeters on individual applicators almost always showed measurable exposure. The median measured dose was between 30% and 70% of the maximum credible summed dose calculated by assuming that each dosimeter showed either the level of measurable deposition or one-half of the detection limit at locations where the chemical was unmeasurable. Because of differences in settings and the low level of control implicit in these application processes, measurable dermal doses were highly variable. Mean measurable dose rates were near 3, 8, and 10 mg product/hr, and daily total deposited doses were 2, 3.5, and 5 mg of product for pouring and pumping liquids and for pouring solids, respectively. Although the effect of gloves cannot be directly determined, wearers of gloves had geometric mean hand total doses 155- to 290-fold less than those not wearing gloves. Similar to the statistics for agricultural pesticides, the dermal route of exposure for these industrial pesticides exceeds the inhalation route by 5X to 100X, depending on assumptions regarding nondetectable values.

Respirator Protection and Acceptability Among Agricultural Workers

Abstract Results are presented of field determinations of effectiveness (workplace protection factor; WPF) and acceptability (questionnaire responses) by respirator users in indoor swine production, poultry production, and grain handling facilities. Dust mass and endotoxin in air samples collected over 4 hours outside the mask and inside the mask were compared to yield the WPF. Disposable respirators had a mean WPF of 13; quarter-mask respirators, 22; half-mask respirators, 19; and powered air purifying helmets, 30. These values are generally less than laboratory-based measures of effectiveness but similar to other field data. Acceptability among these four classes of respirators varied among the three user groups: poultry operators preferred the powered helmet; grain handlers preferred the half-mask; and swine producers were split between the quarter-mask and half-mask respirators. Fully disposable masks were preferred by only 20 to 22 percent of the workers in each setting. Among all groups of workers, ...