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The literature has suggested that many commercially important plant species contain amorphous silica. This report provides a summary of that literature as well as the findings from a field survey in Florida of sugar-cane field workers where airborne concentrations of amorphous silica fibres were determined. In addition to the fibre analysis, concentrations of polynuclear aromatic hydrocarbons (PAHs) and total airborne dust were also determined. It was confirmed that biogenic amorphous silica fibres exist in the mature sugar-cane leaf and that these fibres become airborne during the manual harvesting of the cane after the leaf is burned. Airborne amorphous silica fibres that were found were 3.5–65 μm long (mean=12 μm) with an average diameter of 0.6 μm. Air concentrations were calculated to be as high as 300000 fibres m of air during cane cutting. Some PAH compounds were found to be present in the burnt leaf but the concentrations were below the limits of detection in the air. The health significance of these findings to sugar-cane workers as well as to other agricultural workers is discussed. [ABSTRACT FROM PUBLISHER]

Exposure during the manufacture of pesticides is of particular concern due to their toxicity and because little is known about worker exposure, since most studies have focused on end-use application within agriculture or buildings. Even though dermal exposure can be expected to dominate for pesticides, little is known about workplace dermal exposures or even appropriate methods for their assessment. The current study begins to address this gap by evaluating alternative methods for assessing dermal exposure at a chemical manufacturing plant. For this pilot study, eight workers were recruited from a U.S. plant that produced the pesticide cypermethrin. Exposure was evaluated using three approaches: (1) survey assessment (questionnaire), (2) biological monitoring, and (3) workplace environmental sampling including ancillary measurements of glove contamination (interior and exterior). In each case, cypermethrin was quantified by enzyme-linked immunosorbent assay (ELISA). Environmental measurements identified two potential pathways of cypermethrin exposure: glove and surface contamination. Workplace exposure was also indicated by urine levels (specific gravity adjusted) of the parent compound, which ranged from 35 to 253 μg/L (median of 121 μg/L) with no clear trend in levels from pre- to post-shift. An exploratory analysis intended to guide future studies revealed a positive predictive association (Spearman correlation, p ≤ 0.10) between post-shift urine concentrations and a subset of survey questions evaluating worker knowledge, attitudes, and perceptions (KAP) of workplace dermal hazards, i.e., personal protective equipment self-efficacy, and inverse associations with behavior belief and information belief scales. These findings are valuable in demonstrating a variety of dermal exposure methods (i.e., behavioral attributes, external contamination, and biomarker) showing feasibility and providing measurement ranges and preliminary associations to support future and more complete assessments. Although these pilot data are useful for supporting design and sample size considerations for larger exposure and health studies, there is a need for validation studies of the ELISA assay for quantification of cypermethrin and its metabolites in urine.

The US EPA Worker Protection Standard requires pesticide safety training for farmworkers. Combined with re-entry intervals, these regulations are designed to reduce pesticide exposure. Little research has been conducted on whether additional steps may reduce farmworker exposure and the potential for take-home exposure to their families. We conducted an intervention with 44 strawberry harvesters (15 control and 29 intervention group members) to determine whether education, encouragement of handwashing, and the use of gloves and removable coveralls reduced exposure. Post-intervention, we collected foliage and urine samples, as well as hand rinse, lower-leg skin patch, and clothing patch samples. Post-intervention loading of malathion on hands was lower among workers who wore gloves compared to those who did not (median=8.2 vs. 777.2 microg per pair, respectively (P<0.001)); similarly, median MDA levels in urine were lower among workers who wore gloves (45.3 vs. 131.2 microg/g creatinine, P<0.05). Malathion was detected on clothing (median=0.13 microg/cm(2)), but not on skin. Workers who ate strawberries had higher malathion dicarboxylic acid levels in urine (median=114.5 vs. 39.4 microg/g creatinine, P<0.01). These findings suggest that wearing gloves reduces pesticide exposure to workers contacting strawberry foliage containing dislodgeable residues. Additionally, wearing gloves and removing work clothes before returning home could reduce transport of pesticides to worker homes. Behavioral interventions are needed to reduce consumption of strawberries in the field.

This article describes the laboratory assessment of a hand and surface wipe sampling method for polycyclic aromatic hydrocarbons (PAHs). The analytical method employed extraction of the wipe samples into dimethyl sulfoxide (DMSO) and high-performance liquid chromatography (HPLC) flourometric detection of pyrene, a predominant PAH in used gasoline engine oils (UGEO). Recovery of pyrene was evaluated for two different sampling media by first contaminating the hands of a small number of volunteers with UGEO, followed by applying a small amount of corn oil to the palms, and by wiping the skin with a Whatman cellulostic filter paper or a polyester fabric wipe (i.e., Alpha wipes). In summary, using either Whatman or Alpha wipes, the mean recovery of pyrene from the UGEO that was applied to the hands and contained within three consecutive wipes was 69% and 54%, respectively. However, the relative recovery of the first to second wipe was on average 47% and 75% for the two media, respectively. These results indicate that the Alpha wipes were more efficient at recovering pyrene in the first wipe but less efficient overall when all three consecutive samples were included. Even though this sampling was performed in a controlled laboratory environment, the minimum and maximum amount of pyrene recovered in the individual composite samples using either method spanned a range of twofold. Overall, intra-and interpersonal variability, as measured by coefficient of variation, were 22% and 19%, respectively, and were not statistically different by type of media used. This method was used in a pilot field survey to sample the hands of 18 automotive repair technicians and 18 office workers. Detectable amounts of pyrene (>0.2 microg/sample) were found on the hands of 61% and 0% of these two groups, respectively, with the highest measured quantity equal to 1.06 microg. Samples from the upper surfaces of automobile motors were generally low to nondetectable (<0.027 microg/sample), while the median value of 0.047 mkcrlg/50 cm(2)(CV = 160%) and up to 0.640 microg were found on the drip pans.

Hand contamination by toxic agents such as lead presents a potentially significant health hazard to workers if the contamination is transferred to the mouth by food, smoking, or touching the mouth. One method to sample the mass of contamination on hands is to wipe the skin and analyze the wipe media for the analyte. Several commercially available, prewetted wipe media were evaluated and compared. The Palintest and Wash'n Dri media are made of cellulose fiber; the Ghost wipe is made of a nonwoven polyvinyl alcohol fiber. ASTM test method E1792 for surface lead sampling provides some specified minimum requirements and some general, nonspecific criteria that these media should meet. However, no objective determination of the performance or characteristics of these different wiping media were found in the open literature for sampling lead on hands, particularly relating to typical collection efficiency. To test the recovery of lead oxide dust collected from two hands, two different loading levels were used for each wipe medium. Four successive wipes were collected and analyzed individually. The results of this study indicate that only about 52-62% of the total lead loading is recovered with the first wipe, but that up to 75% recovery could be obtained by combining all three successive wipes. This study also describes testing several physical aspects of these wipes that included tensile strength, wetness, and drying rate, which are characteristics that are not specified by ASTM E1792. The results indicate a higher fragility among the cellulosic wipes, less moisture content, and higher drying rates than the Ghost wipe. This information should be helpful when selecting a wipe material that is best suited for an environmental or industrial hygiene surface or skin sampling task and might also be useful for improving such media in the future.

The aim of the study was to assess the use of 3M porous polymer extraction discs (3M Empore sorbent filters) for detection of chemical permeation of protective clothing. Analysis of some commonly used solvents on 3M Empore sorbent filters was performed for methanol, acetone, trichloroethylene (TriCE), and toluene by solvent desorption and gas chromatography. All solvents exhibited >98 percent adsorption on the filters at a spiking level of 1.8 microL for each solvent. Solvent recovery for the system was calculated for each solvent, ranging from 72-94 percent (RSD < or = 4.0%) for all solvents over the spiking range 0.2-1.8 microL. The modified ASTM F739 method was used to determine breakthrough times for five protective glove materials (polyvinyl chloride, natural rubber, polymerized alkene, nitrile, and nitrile butyl rubber) using the model solvents as test chemicals. Breakthrough times for each type of protective glove were determined, and found to range from 36 s to 9 min for acetone, from 142 s to 52 min for methanol, from 18 s to 12 min for TriCE, and from 32 s to 28 min for toluene. The quantitative mass of the solvents on the filters at the time of breakthrough detection ranged from 150-159, 157-166, 570-581, and 371-382 microg/cm2 for acetone, methanol, TriCE, and toluene, respectively. The sorbent filter should find utility in collecting chemical permeation samples through protective gloves in both laboratory and field studies for quantitative analysis.

Proteinaceous materials in the air can be highly allergenic and result in a range of immunologically mediated respiratory effects, including asthma. We report on the largest evaluation of exposure to date of airborne egg protein concentrations in an egg breaking and processing plant that had cases of occupational asthma. Personal air samples for egg protein were analyzed in duplicate on each PTFE filter using two analytical methods: (1) a commercial assay for non-specific total protein, and (2) indirect competitive inhibition assay using an ELISA method to quantify specific egg protein components. The highest concentrations were found in the egg washing room (mean exposure 644 microg/m3) and breaking room (255 microg/m3), which were also the areas where the risk of being sensitized was the greatest. There was excellent quantitative agreement between the airborne concentrations of total protein and sum of the specific protein antigens (ovalbumin, ovomucoid, and lysozyme). The correlation coefficient of the log-transformed data from the two methods was 0.88 (p < 0.0001). Size-selective sampling also indicated that most of the aerosol was capable of reaching the small airways. The methods described can be utilized to evaluate employee exposure to egg proteins. Exposure documentation, coupled with recommended exposure reduction strategies, could facilitate prevention of future employee sensitization and allergic respiratory responses by identifying high-exposure jobs and evaluating control measures.

Ethylene oxide (EtO) is a genotoxic carcinogen with widespread uses as an industrial chemical intermediate and sterilant. We examined the effects of glutathione S-transferase T1 (GSTT1) and M1 (GSTM1) genotypes on the levels of N-(2-hydroxyethyl)valine (HEV) adducts in the erythrocytes and sister chromatid exchange (SCE) in lymphocytes from a group of 58 operators of sterilizers that used EtO and nonexposed workers from nine hospitals in the United States and one hospital in Mexico City. Cumulative exposure to EtO was estimated during the 4-month period before the collection of blood samples. Results showed that EtO exposure was significantly associated with the levels of HEV adducts and SCE after adjusting for cigarette smoking and other potential confounders. A significantly higher HEV adduct level (0.17 +/- 0.03 versus 0.08 +/- 0.01, mean +/- SE; P = 0.02) but lower SCE frequency (5.31 +/- 0.39 versus 6.21 +/- 0.17; P = 0.04) was observed in subjects with homozygous deletion of the GSTT1 gene (null genotype) as compared with those with at least one copy of the gene (positive genotype). In multiple regression analysis, the GSTT1-null genotype was associated with an increase in HEV adduct level (beta = 1.62; P = 0.02) and a decrease in SCE frequency (beta = -1.25; P = 0.003) after adjusting for age, gender, race, education, cigarette smoking, and EtO exposure status. The inverse SCE-GSTT1 relationship remained unchanged when SCE was further examined in relation to HEV adducts as an indicator of the internal EtO dose. The GSTM1 genotype was not associated with the level of either HEV adduct or SCE. These data indicate that the GSTT1-null genotype is associated with increased formation of EtO-hemoglobin adducts in relation to occupational EtO exposure, suggesting that individuals with homozygous deletion of the GSTT1 gene may be more susceptible to the genotoxic effects of ETO: The unexpected finding of decreased SCEs, which is less clear, may be attributed to the nonchemical specificity of this end point and the lack of expression of the GSTT1 enzyme in lymphocytes.

Hand wash and skin wipes are major techniques that have been used for dermal exposure sampling. Both techniques remove chemicals either deposited on or transferred to the skin contaminant layer by a combination of chemical and mechanical actions. The paper overviews identified methods and techniques, with emphasis on sampling parameters and sampling efficiency. It is concluded that identified sampling protocols, including sampling techniques, deviate at possible key issues, which hampers comparisons of study results. It is recommended to conduct sampling efficiency studies prior to field sampling, under conditions that are quite similar to conditions of exposure regarding exposure process, levels of skin loading, and time of residence of the compound on the skin. Harmonization of sampling protocols will be a first step in creating a database for better understanding the influence of sampling parameters on the performance of removal techniques to assess dermal exposure.

This study compared four solvents (1-propanol, polyethylene glycol [avg. MW 400], 10% Ivory Liquid and water, and D-TAM) for their ability to remove selected pesticides from an in vitro porcine skin model using a solvent-moistened wipe. Wipes were performed 90 min after pesticide was applied to the skin. The four pesticides selected (glyphosate, alachlor, methyl parathion, and trifluralin) were chosen because of their differences in water solubility. This study also determined whether pretreatment of skin with a solvent prior to pesticide application would either increase or decrease recovery of the pesticide. Recovery efficiencies for all solvents and pesticides were affected by the amount of contaminant on the skin. Although pesticide recoveries from all four solvents were similar (range: 45-57%), on average 1-propanol had significantly higher recoveries, followed by soap and water. There was no significant difference between polyethylene glycol, and D-TAM. When skin was pretreated with any of the four solvents before pesticide application, the recoveries of the more water soluble compounds, glyphosate and alachlor, decreased. When pretreatment with solvent preceded application of trifluralin, the pesticide with the lowest water solubility, recoveries increased. 1-Propanol or soap and water were more effective in removing pesticides from skin than polyethylene glycol or D-TAM, but the amount of pesticide recovered from skin was affected by the chemical characteristics of the pesticide (such as water solubility) and the amount of pesticide originally on the skin. This study provides information useful to the interpretation of skin wipe sample results collected in field studies.

A comprehensive panel of immune parameters was evaluated among 145 lead-exposed workers with a median blood lead level (BLL) of 39 micrograms/dL (range: 15-55 micrograms/dL) and 84 unexposed workers. After adjusting for covariates, we found no major differences in the percentage of CD3+ cells, CD4+ T cells, CD8+ T cells, B cells, or NK cells between lead-exposed and unexposed workers, although the association between lead exposure and the number of CD4+ T cells was modified by age. We also found no differences between exposed and unexposed workers in serum immunoglobulin levels, salivary IgA, C3 complement levels, or lymphoproliferative responses. However, among exposed workers, the percentage and number of B cells were positively associated with current BLL, serum IgG was negatively associated with cumulative lead exposure, and the percentage and number of CD4+/CD45RA+ cells were positively associated with cumulative lead exposure. We found no evidence of a marked immunotoxic effect of lead at the exposure levels studied, although some subtle differences in immunologic parameters were noted.

O6-Alkylguanine-DNA alkyltransferase (AGT) activity was assessed in peripheral blood lymphocytes among 23 mortuary science students before and after 9 weeks in a laboratory course in techniques of embalming. Formaldehyde exposure was established by environmental monitoring. The average air concentration of formaldehyde during embalming was about 1.5 ppm. At the pre-exposure sampling, baseline DNA repair capacity tended to be reduced in subjects who reported a prior history of embalming (p = 0.08). From pre- to post-exposure, 17 subjects decreased in DNA repair capacity, while only 6 increased (p < 0.05). Analysis of variance, including adjustment for age, sex, and smoking status, confirmed these findings. Among the eight subjects who had no embalming experience during the 90 days before study, seven had decreased and one had increased AGT activity during the period of study (p < 0.05). For those with prior embalming experience, 10 subjects decreased in AGT activity, while 5 increased (p < 0.05). Although the major chemical exposure in embalming practice was to formaldehyde, no clear link was established between amount of formaldehyde exposure and AGT activity.

A micronucleus assay employing fluorescence in situ hybridization (FISH) with a centromeric probe was used on specimens of exfoliated buccal and nasal cells collected from mortuary science students exposed to embalming fluid containing formaldehyde. FISH labeling allowed micronuclei (MN) containing a whole chromosome (centromere-positive, MN+) to be differentiated from those containing only chromosomal fragments (centromere-negative, MN-). Each student was sampled before and after the 90 day embalming class. We determined if an increase in MN frequency could be attributed to formaldehyde exposure and was specific to either MN+ or MN-. In buccal cells, total MN frequency was significantly increased from 0.6/1000 to 2/1000 (p = 0.007) following the course, whereas in nasal cells it was not (2 and 2.5/1000, respectively, p = 0.2). Cells with multiple MN were present only in samples taken after exposure to embalming fluid. Although the baseline frequency was higher for MN+ in both buccal (0.4/1000 for MN+ and 0.1/1000 for MN-) and nasal cells (1.2/1000 for MN+ and 0.5/1000 for MN-), the increase in MN frequency was greater for MN-, (9-fold, p = 0.005 for buccal cells; 2-fold, p = 0.03 for nasal cells) than for MN+ (> 2-fold, p = 0.08 for buccal cells; no change, p = 0.31 for nasal cells) in both tissues. Thus, the primary mechanism of micronucleus formation appeared to be chromosome breakage. This finding is consistent with known clastogenic properties of formaldehyde, the component of embalming fluid most likely responsible for micronucleus induction.

Room ozonization has been in widespread use to "freshen" indoor air for more than 100 years. This use is sometimes promoted with the claim that ozone can oxidize airborne gases, and even particulates, to simple carbon dioxide and water vapor. Aside from whether ozone can improve indoor air quality, the potentially deleterious consequences to public health of overexposure to ozone are of concern. The literature on both allegations is reviewed. It indicates that ozone is not a practical and effective means of improving indoor air quality, especially in light of its potentially serious risk to health.

Women comprise the majority of workers exposed to ethylene oxide during sterilization of medical instruments and supplies. This article evaluates molecular, cytogenetic, and hematologic effects of ethylene oxide on 68 women workers employed in nine hospitals in the United States and one hospital in Mexico. Workers were classified by three exposure categories: none (0), low (> 0-32 ppm-hrs), and high (> 32 ppm-hrs). Hematologic effects were evaluated using complete blood count with differential, which has been questioned as a test for screening ethylene oxide-exposed workers. A statistically significant decrease in hematocrit (n = 0.02) and hemoglobin (P = 0.03) levels, an increase in lymphocyte percentages (P = 0.04), and a relative decrease in neutrophil percentages (P = 0.03) with exposure were observed in US workers. The absolute number of lymphocytes, however, showed no relationship with exposure. No statistically significant results were seen for Mexican workers, although hematocrit decreased with exposure. An exposure-response relationship for the percentage for lymphocytes (positive) and neutrophils (negative) in US subjects and for neutrophils (positive) in Mexican subjects was seen. No overall relation with exposure was observed for total number of white cells. Molecular and cytogenetic results are also reported for the 68 women, who constitute a subgroup from a previous report. US women workers showed a statistically significant exposure-response relationship for ethylene oxide and hemoglobin adducts (P = 0.0002) and sister chromatid exchanges (P = 0.001). For micronuclei, the difference (P = 0.02) between low and high exposure was statistically significant. In Mexican workers, an exposure-response relationship was observed (P = 0.002) for hemoglobin adducts but not for sister chromatid exchanges or micronuclei.

We conducted a cross-sectional environmental and medical survey of 355 male sugarcane workers in Hawaii to determine whether exposure to biogenic silica fibers (BSF) affected their respiratory health. Exposures to BSF ranged from nondetectable to more than 0.700 BSF/mL and varied by job and department. Respiratory symptoms, chest radiograph findings, and pulmonary function were not associated with BSF exposures. Cigarette smoking was associated with respiratory symptoms and pulmonary obstruction. Fifteen workers had pleural thickening or pleural plaques and 3 of these workers were exposed to BSF for more than 10 years. BSF exposure does not appear to influence the respiratory health of sugarcane workers; however, further study is warranted.

This paper reviews the process of elimination of creatinine (CRE), and the limitations presented when using it to express urine concentrations. This literature review leads to three conclusions: (1) CRE excretion is subject to wide fluctuations due to specific internal and external factors; (2) the use of CRE to correct chemical concentrations in urine will not necessarily improve the correlation to the exposure dose for all chemicals (it may, in fact, worsen the result); and (3) other means of expressing urine concentration may offer greater accuracy towards estimating individually absorbed dose.

The effect of low-level exposure to formaldehyde on oral, nasal, and lymphoycte biological markers was studied prospectively in a group of 29 mortician students who were about to take a course in embalming. During the 85-day study period, the subjects performed an average of 6.9 embalmings and had average cumulative formaldehyde exposures of 14.8 ppm-h, with an average air concentration of 1.4 ppm during embalming. Since the average time spent embalming was 125 min, formaldehyde exposures calculated as an 8-h time-weighted average were 0.33 ppm on days when embalmings were done, which was less than the Occupational Safety and Health Administration permissible exposure limit of 0.75 ppm. Epithelial cells from the buccal area of the mouth showed a 12-fold increase in micronucleus frequency during the study period, from 0.046 +/- 0.17/1000 cells preexposure to 0.60 +/- 1.27/1000 cells at the end of the course (P < 0.05). Nasal epithelial micronuclei increased 22%, from 0.41 +/- 0.52/1000 cells to 0.50 +/- 0.67/1000 cells (P = 0.26). In blood cells, the frequency of micronucleated lymphocytes increased 28%, from 4.95 +/- 1.72/1000 cells to 6.36 +/- 2.03/1000 cells (P < 0.05), while sister chromatid exchanges decreased 7.5% (P < 0.05). A dose-response relationship was observed between cumulative exposure to formaldehyde and increases in buccal micronuclei in the 22 male subjects but not in the 7 female subjects. We conclude that low-level exposure to formaldehyde is associated with cytogenetic changes in epithelial cells of the mouth and in blood lymphocytes. These cytogenetic effects may be useful as markers of biologically effective dose.