Solvent exposures in screen printing shops.

A comprehensive description of working conditions, exposure patterns for organic solvents, and related health symptoms among workers in ten small screen printing companies located in Seattle, Washington, is presented. Sampling methods included continuous area monitoring, grab sampling, personal sampling, and time study observation. A total of 27 workers were observed and monitored for solvent exposure. Short-term peak exposures were characterized in terms of magnitude, duration and repetition, and their contribution to time weighted average (TWA) exposures were evaluated. A health questionnaire addressing the symptoms potentially attributable to solvents was used to investigate the possible health effects from exposure. Significant differences in the prevalence of headaches, dizziness, intoxication, and dry skin (p < 0.01) were reported among workers who had some solvent exposure compared with the referent group that was not exposed. Exposed workers were also more likely to report fatigue, loss of strength in the arms and hands, difficulty concentrating, sore throat, and a low alcohol tolerance. The study documented highly variable levels of solvent exposures. Screen printing workers in different companies, while performing the same basic tasks, had time weighted average (TWA) exposures ranging from 2% to 100% of the recommended threshold limit value (TLV) for mixtures. Continuous monitoring indicated that high short-term exposures are responsible for the bulk of TWA exposures. Grab samples and continuous monitoring verified that recommended Short Term Exposure Limits (STEL) for individual solvents may be exceeded on a routine basis. Frequent skin contact with solvents was also observed. Health problems in this industry and other small industries using organic solvents may result from these complex patterns of exposure.

Triazine herbicide exposure and breast cancer incidence: an ecologic study of Kentucky counties.

The incidence of breast cancer in the United States has steadily increased for the past three decades. Exposure to excess estrogen, in both natural and synthetic forms, has been implicated as a risk factor for the development of this disease. Considerable interest has been focused on organochlorines, such as the triazine herbicides, and their possible role in the initiation or promotion of human breast cancer. To explore this relationship, an ecologic study of Kentucky counties was designed. Exposure to triazines was estimated by use of water contamination data, corn crop production, and pesticide use data. A summary index of triazine herbicide exposure was developed to classify counties into low, medium, or high exposure levels. Data on county breast cancer rates were obtained from the state registry. A Poisson regression analysis was performed, controlling for age, race, age at first live birth, income, and level of education. Results revealed a statistically significant increase in breast cancer risk with medium and high levels of triazine exposure [odds ratio (OR) = 1.14,p<0.0001 and OR = 1.2, p<0.0001, respectively]. The results suggest a relationship between exposure to triazine herbicides and increased breast cancer risk, but conclusions concerning causality cannot be drawn, due to the limitations inherent in ecologic study design.

Arsenic poisoning in central Kentucky: a case report.

A recent case of chronic arsenic intoxication due to prolonged accidental ingestion of a commercially available crabgrass killer illustrates one of the more common etiologies of present day arsenic poisoning. A review of 20 years of arsenic poisoning at the University of Kentucky (21 cases) revealed no cases attributable to an industrial source. A tabulation of the 21 most recent cases is included.

Environmental equity and pesticide exposure.

Although people of color and low-income groups bear a disproportionate share of the health risks from exposure to pesticides, research attention has been meager, and data on acute and chronic health effects related to their toxic exposures are generally lacking. Increased resources are needed both to study this issue and to mitigate problems already identified. People of color should be a major research focus, with priority on long-term effects, particularly cancer, neurodevelopmental and neurobehavioral effects, long-term neurological dysfunction, and reproductive outcome. Suitable populations at high risk that have not been studied include noncertified pesticide applicators and seasonal and migrant farm workers, including children.

Neuropsychological performance and solvent exposure among car body repair shop workers.

A cross sectional study to evaluate symptom reporting and neuropsychological test performance among a cohort of car body repair workers (n = 124) was performed using a computer-administered test system. Subjects with high and medium current exposures to solvent and paint (n = 39 and 32), and low exposure subjects who formerly painted (n = 29) reported significantly more acute and chronic neurological symptoms than did low exposure subjects with no history of painting (n = 24). Subjects with higher current exposure performed significantly less well on selected tests of visual perception and memory, but there were no significant exposure related differences in mood state, motor speed, or visuomotor performance. The exposure related effects were most noticeable among subjects 35 years or older. The findings are consistent with age interactive central neurotoxic effects of current exposure to solvents or of cumulative past exposure, although the study is unable to distinguish between these possibilities. The computer administered test system was effective in this field based investigation involving multiple, geographically dispersed worksites.

Organophosphate pesticide exposure in a group of Washington State orchard applicators.

As part of a study to investigate the potential for organophosphates to cause chronic neurologic sequelae, we assessed the pesticide exposure experience of a group of Washington State apple orchard applicators. Seasonal monitoring of cholinesterase activity for 48 regular organophosphate applicators and a control group of 40 slaughterhouse workers was performed. A subset of the pesticide applicators participated in an in-depth exposure assessment. This involved observation of spraying activities during 1 spray day, as well as cholinesterase monitoring and dermal exposure assessment using a fluorescent tracer in the pesticide formulation. Comparison of seasonal red blood cell cholinesterase change in pesticide workers according to exposure level, characterized by frequency of pesticide spraying and protective equipment use, showed lower cholinesterase levels among higher exposed groups compared to lesser exposed groups. In-depth exposure assessment revealed exposure primarily on the head and hand regions. Subclinical changes (less than 15% inhibition) in red cell cholinesterase correlated well with dermal exposure calculations. This study suggests that cholinesterase monitoring may be a useful biological marker for even subclinical organophosphate pesticide effects.

Cobalt exposure in a carbide tip grinding process.

Reports relating hard metal disease or nonspecific respiratory symptoms to tungsten or cobalt exposure have been published in the past 20 yr. This report discusses a work site investigation of a small company, employing approximately 50 workers, producing carbide tip saw blades for the woodworking industry. Cobalt exposure was characterized by ambient air monitoring (area and personnel), particle size determination, and biological monitoring. Area sampling for cadmium, cobalt, and tungsten indicated low ambient air levels in all manufacturing areas except the grinding department, which had cobalt air levels approaching the threshold limit value of 0.05 mg/m3. Area airborne cobalt exposure levels measured over six shifts in the grinding department ranged from 0.017 to 0.12 mg/m3 for the total collection method and 0.002 to 0.028 mg/m3 for the method collecting respirable particles. Cobalt content in the total and respirable fractions was similar. Urine monitoring indicated production workers have elevated cobalt levels, and the grinders' levels were higher than other production workers. The grinding coolant was found to have elevated cobalt concentrations. A survey of coolants from nine carbide grinding shops indicated the elevated cobalt concentrations may be common.

The contributions to solvent uptake by skin and inhalation exposure.

Solvent exposures were assessed among 97 auto body repair workers in order to determine whether skin contact represented a significant route of exposure. Each subject's cumulative skin exposure was ranked categorically based on simple observation: 49 none, 33 incidental or low, and 15 moderate or high. The median time-weighted average air exposure to solvents was 8.4% of the American Conference of Governmental Industrial Hygienists (ACGIH) combined solvent threshold limit value (TLV) with a range of 0-62% TLV, including toluene (median 4 ppm) and xylenes (median 0.9 ppm). Urine methyl hippuric acids (MHAs, metabolites of xylenes) were low compared to the ACGIH biological exposure index (BEI) with a median of 2% and a range of 0-12% BEI but were strongly correlated with both the level of airborne xylenes and skin exposure when considered simultaneously by using analysis of covariance (R = 0.91, p less than 0.0001). MHA excretion attributable to skin exposure for 15 min or more generally was comparable to or greater than that from associated air exposure over the full work shift. This study had limited ability to assess quantitatively the contributions of toluene exposures, but there was evidence that skin exposures also contributed significantly to toluene absorption. Air sampling will substantially underestimate a worker's total solvent dose in the setting of moderate or high skin exposure. Simple observation was effective in identifying workers in this sample who appeared to have sufficient skin exposure to produce a measurable increase in solvent uptake.

Industrial hygiene, chemical and biological assessments of exposures to a chlorinated phenolic sapstain control agent.

A two-year study of the occupational exposure of workers in a lumber mill to a wood preservative containing chlorophenol has been conducted. The methods were biological (urine) monitoring, industrial hygiene assessment and a questionnaire related to worker-perceived health effects. Approximately 40 workers exposed to the wood preservative and 40 unexposed controls working in other locations of the plant participated in the study. Evaluation of work conditions, assessment of urinary levels of tetra- and pentachlorophenol, and administration of a medical questionnaire were performed at a six-month intervals over a two-year period. Industrial hygiene ratings of exposures and adequacy of protection were evaluated in relation to the results of biological monitoring. Workers who came into contact with freshly treated and still wet wood had consistently higher urinary levels of tetrachlorophenol. Workers stationed adjacent to the spray applicator also had higher tetrachlorophenol levels. There was no statistically significant relationship between the subjective ratings by the industrial hygienist of exposure and adequacy of worker protection with the urinary levels of tetrachlorophenol. Nor was there a consistent pattern linking exposure ratings with adequacy of protection. The short half-life of tetrachlorophenol in the urine makes this a good indicator of only the most recent exposure. The differences in urinary levels between controls and exposed workers were large, with averages of 240.4 ppb for exposed workers and 14.6 for controls. Traditional industrial hygiene evaluation techniques, in conjunction with biological monitoring, proved to be the most effective method of assessing both exposure and work practices. Exposed workers reported a statistically significant increase of positive answers to known signs and symptoms of chlorophenol exposure compared with the controls. There was no statistically significant relationship between the number of these health problems reported and the mean urinary levels of tetra- or pentachlorophenol for the exposed group; however, for certain variables (heavy vs. light exposure, inadequate vs. adequate protection, greater than 100 ppb urinary tetrachlorophenol vs. less than 100 ppb), those with heavier exposure, inadequate protection or higher urinary tetrachlorophenol reported on the average more health problems over the two-year period. Firm statistical conclusions could not be drawn because of the small size of the study population.

Permeation through five commercially available glove materials by two pentachlorophenol formulations.

Five glove materials were tested for permeation by two commonly used formulations of pentachlorophenol (PCP). Permeation was conducted using the method used in two prior studies by NIOSH. The lower limit of PCP quantitation in the receiving side of the permeation cell was 70 parts per billion (ppb). When challenged with a 4.3% PCP in diesel oil solution, both the Dayton Flexible Products Triflex (PVC) and the Best 64 NFW (natural rubber) gloves exhibited breakthrough times thirty seconds after exposure. The Playtex #835 (latex/neoprene) glove exhibited breakthrough after sixty minutes, but showed a five fold greater rate of permeation than the Dayton and the Best glove. Neither the Edmont Sol-Vex (nitrile rubber) nor the Granet Glo-Gluv (PVC) gloves had been permeated after testing for 8 and 16 hours respectively. Following challenge with a 4.2% sodium pentachlorophenate solution, only the Best (natural rubber) glove allowed breakthrough; this only thirty seconds after exposure. Neither the Dayton (5 hours), Playtex (7.5 hours), Edmont (15.5 hours), nor Granet (15.5 hours) gloves had been permeated following completion of testing after the listed duration. This study has shown that different gloves offer differing resistance to permeation by PCP based upon the composition of the glove and the PCP formulation tested.

Persistence of tetrachlorophenol and pentachlorophenol in exposed woodworkers.

The decline in urinary concentrations of pentachlorophenol (PCP) and 2,3,4,6-tetrachlorophenol (TCP) were observed for a group of woodworkers chronically exposed to Permatox 100 (3% PCP, 21% TCP) during a 16 day vacation and plant shutdown. The group was monitored annually for two years, with sampling occurring on the last working day prior to shutdown and on the first day after the shutdown. Among those workers with the highest pre-shutdown levels, uniform TCP reductions of 90 +/- 6% were observed, indicating elimination rates similar to those reported for PCP in a single dose human exposure study. Four workers were sampled on alternate days during the shutdown in the second year. Of these, two workers had significant pre-shutdown levels, and showed declines in urine TCP levels over this period consistent with simple one-compartment first order decay. The possible effect of environmental PCP exposure on observed biological decay rates when occupational PCP exposures are low was indicated by the wide variation in urinary PCP reduction and slight decreases or actual increases observed over the shutdown period.

Health complaints attributed to the use of carbonless copy paper (a preliminary report).

Persistent health complaints attributed to the use of carbonless copy paper by office workers on the campus of the University of Washington led to this preliminary study. The goals were to estimate the extent of the problem in a population of known carbonless copy paper users; to describe those health problems which the users attribute to the use of carbonless copy paper; and to make a preliminary determination of the chemical constituents of the paper. Participants were asked to complete a health questionnaire and to attach to it copies of the forms they used. A minimum estimate of 10.7 health complainants per 100 users was similar to that found by investigators in Denmark, but lower than that reported by other investigators and of anecdotal material reported to the study group. There was a statistically significant association between complainants and the amount of paper used. Reports of headaches and irritation of the skin, eye and respiratory tract were similar to those reported elsewhere. Concurrent factors such as poor ventilation, high temperature and/or low humidity need to be investigated for possible synergistic or additive effects.

Investigation of a dual filter sampling method for gaseous and particulate fluoride.

A two stage filter method designed to separate gaseous and particulate fluoride utilizing an alkaline treated filter to trap gaseous fluoride and post sampling heat treatment of the filters to promote desorption of gaseous fluoride from particulate phase was compared to standard impinger methods for the collection of hydrogen fluoride. Results indicate a high degree of comparability between the two methods. Initial studies involving the recovery of HF from dusted filters by heat treatment suggest recovery rates may vary directly with the amount of HF sampled for a given dust load.

Biomonitoring of industrial styrene exposures.

Worker exposure to styrene in two fiberglass boat plants was evaluated using conventional sampling techniques. The use of expired air and urine metabolite concentrations as indicators of styrene exposure is evaluated. The concentration of mandelic acid, a styrene metabolite in urine, is quantitated for workers without and with intermittent personal respiratory protection. A urinary Biological Limit Value is determined for exposures to the Threshold Limit Value of styrene.

A field study of near ultraviolet welding irradiance.

Spectral irradiance in the near U.V. was measured for several welding operations at a large steel fabrication shop. The variations of spectral irradiance with time were measured and a brief study of the effects of amperage welding rod, and distance was performed. At the measurement distance used in this study the proposed standard for near U.V. was not exceeded.

A comparison of two impact noise measurement techniques.

An impact noise analyzer has been tested to determine its accuracy and precision. Results showed that peak estimation when corrected by a suitable correction factor were good and the confidence limits on the corrected peak determination were less than +/- 1.0 dB. Determination of pulse duration with the meter proved to be poor. At present it is useful for making only general estimations of duration. For exact pulse duration measurements, it appears that development of a small, portable oscilloscope holds the most promise for a field instrument with the necessary accuracy and precision.

An acoustical trigger for impact noise studies.

In making oscilloscopic studies of impact noise there is often a problem of coordinating the oscilloscope with the noise event. This paper describes a simple noise trigger that has been used successfully in a number of studies.