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PubMed2004

Simultaneous sampling of peroxyacetic acid and hydrogen peroxide in workplace atmospheres.

The use of peroxyacetic acid (PAA) in the disinfection processes in the food industry or for medical purposes is increasing. As it is the product of the reaction of acetic acid (AA) and hydrogen peroxide (HP) and coexists with them, and given the fact that the chemical properties of these two substances are not very different from PAA, the sampling and analysis of this substance in working atmospheres is difficult. A specific sampling device was developed. It is composed of: (i) a cassette with quartz fibre filters impregnated with titanium oxysulfate hydrate for the sampling of HP followed by; (ii) a tube filled with silica gel soaked with methyl p-tolylsulfoxide for the sampling of PAA. The analysis of this silica gel was performed by liquid chromatography with UV detection of the methyl p-sulfone generated by the sampling of PAA. The conservation of the sampling media (before and after sampling) and its efficiency were also checked. From the results of sampling campaigns performed in various workplaces, the relative contributions of PAA, AA and HP to an exposure index, taking into account the atmospheric concentrations and the threshold limit values, were established. This calculation shows that the simultaneous determination of PAA and HP, which the method presented in this paper allows, provides a fairly good estimation of the exposure.

Air Pollutants, Occupational↗
PubMed1976

Degeneration in central and peripheral nervous systems produced by pure n-hexane: an experimental study.

Rats intoxicated with pure n-hexane, either by repetitive subcutaneous injection or by continuous inhalation, developed clinical and/or pathological evidence of peripheral neuropathy. Animals intoxicated by inhalation (400-600 ppm) developed clinical signs after forty-five days and displayed giant axonal swellings and fibre degeneration both in the central and peripheral nervous systems. The changes were most strking in tibial nerves supplying calf muscles and in selected areas of the cerebellum, medulla and spinal cord. In contrast to the usual picture associated with dying-back disease, the distal regions of proximal nerve fibres supplying calf muscles degenerated before equivalent regions of longer fibres supplying the hindfeet. The relevance of the central nervous changes to individuals recovering from toxic neuropathies and the need for a reduction of the present Threshold Limit Value (500 ppm) for human exposure are discussed.

Alkanes↗
PubMed1992

Investigations of the frequency of DNA strand breakage and cross-linking and of sister chromatid exchange frequency in the lymphocytes of female workers exposed to benzene and toluene.

Peripheral lymphocyte DNA damage as measured by the method of alkaline filter elution and the frequency of sister chromatid exchange (SCE) in lymphocytes was investigated for a group of 20 female workers of a shoemaking plant who were exposed to benzene and toluene, primarily below the German threshold limit value of 5 and 100 p.p.m. respectively; the results were compared with those from a control group. In the female workers significantly raised (P less than 0.05) SCE values were found. The relative DNA elution rate through polycarbonate filters was significantly increased (P less than 0.001). The elution rate through polyvinylidene fluoride (HVLP) filters showed a tendency to increase (P = 0.052), which must be interpreted as indicating increased DNA strand breakage. The SCE rates of the female workers were significantly correlated (P less than 0.01) with the relative DNA elution rate through HVLP filters. There was no correlation with the actual benzene and toluene uptake measured by personal air monitoring. Four months after cessation of work, DNA strand breakage decreased significantly (P less than 0.05) in blood samples of six reinvestigated female workers.

Adult↗
PubMed1984

A cytogenetic study on workers exposed to low concentrations of benzene.

A cytogenetic study was performed on 22 healthy workers engaged in benzene production and exposed to low concentrations of benzene, ranging from 0.2 to 12.4 p.p.m. (threshold limit value 10 p.p.m.). Workers were divided into two groups according to the different levels of exposure, inferrable also from the concentration of benzene in the alveolar air and the levels of urinary phenols. Each exposed subject was paired with a suitable control, living in the same area and of similar smoking habits and age. No statistically significant increase of sister chromatid exchange (SCE) frequency was observed in the exposed groups. In controls, SCE frequency was positively correlated with age and smoking habits. Among structural chromosomal aberrations, only the chromosome-type ones were significantly higher in exposed than in control subjects, and their increase was still significant when gaps were discarded.

Adult↗
PubMed2000

Ovarian antibodies, FSH and inhibin B: independent markers associated with unexplained infertility.

Premature menopause and unexplained infertility are associated with ovarian antibodies, a marker of ovarian autoimmunity. In premature menopause, FSH is also elevated while in unexplained infertility FSH concentrations are often normal. The relationship of ovarian antibodies and FSH and inhibin B, as markers of follicle function, was investigated in unexplained infertility. Ovarian antibodies were determined by immunoassay in comparison to normal controls (n = 12); 51.9% were positive at two SD (P < 0.05) and 38.5% were positive at three SD above the control mean (P < 0.01). In this study three SD above the control mean was considered positive. In unexplained infertility, three out of 10 (30%) had elevated day 3 FSH (>10 mIU/ml) and ovarian antibodies, while 17/42 (40%) had normal FSH (<10 mIU/ml) and ovarian antibodies. In women with normal FSH, two out of seven (29%) had low inhibin B concentrations (<33 pg/ml) and ovarian antibodies, and 15/35 (43%) had normal inhibin B concentrations (> 33 pg/ml) and ovarian antibodies. Similarly, when women with and without ovarian antibodies were compared there was no difference in mean FSH or mean inhibin B concentrations. Thus, unlike other endocrine autoimmune disorders, hormone concentrations are not predictors of potential ovarian autoimmunity. This suggests that in unexplained infertility ovarian antibodies are an independent marker of potential ovarian failure, and may precede changes in regulatory hormones.

Adult↗
PubMed1991

Environmental and biological monitoring of workers exposed to inorganic lead.

A total of 20 workers who were exposed to inorganic lead in two local firms (M and N) were studied. Lead concentrations in the air (PbA) at firm M exceeded the threshold limit value (TLV) of 0.150 mg/m3 established by Spanish and EC legislation, while atmospheric lead at firm N exceeded the action level of 0.075 mg/m3. In the same population, biological exposure indices (BEI) were also determined; these included lead in whole blood (PbB), erythrocyte activity of aminolevulinic acid (ALA-D), urinary excretion of aminolevulinic acid (ALA-U) and zinc protoporphyrin (ZPP). The relationship between the exposure parameters (PbA, PbB) and the biological activity indices (ALA-D, ALA-U, ZPP) were analysed statistically in order to obtain levels of significance, coefficients of correlation and regression equations. The high coefficients of correlation found confirm the usefulness of BEI in evaluating exposure to lead fumes and lead dust.

Adult↗
PubMed1992

Causes of hypersensitivity reactions in flour mill workers in Sudan.

A study of 237 male workers at two flour mills and 71 controls was carried out in Sudan in order to investigate the main possible causes of hypersensitivity reactions to flour dust. Statistical analysis was carried out for the skin test results of wheat, mixed moulds (A13), grain dust, and mixed moulds (group MH) allergen extracts. The results showed that there was no statistical significance between the two exposed groups namely allergy complaining vs. allergy non-complaining except for wheat results in one of the two flour mills which was very slightly significant. But there were highly significant differences between the exposed compared with the control group in all allergens tested. There was no significant correlation, between allergic symptoms and precipitins to wheat or grain dust, nor between precipitins and positive skin tests. The results of respirable flour dust concentrations at different work locations had exceeded the threshold limit values which were taken as 10 mg/m3. Aspergillus supp. and Rhizopus niger were the predominant fungi in the wheat grains and products which were collected from the two mills.

Adult↗
PubMed1999

Absence of prenatal developmental toxicity from inhaled arsenic trioxide in rats.

A review of the literature revealed no published inhalational developmental toxicity studies of arsenic performed according to modern regulatory guidelines and with exposure throughout gestation. In the present study, inorganic arsenic, as arsenic trioxide (As(+3), As2O3), was administered via whole-body inhalational exposure to groups of twenty-five Crl:CD(SD)BR female rats for six h per day every day, beginning fourteen days prior to mating and continuing throughout mating and gestation. Exposures were begun prior to mating in order to achieve a biological steady state of As(+3) in the dams prior to embryonal-fetal development. In a preliminary exposure range-finding study, half of the females that had been exposed to arsenic trioxide at 25 mg/m3 died or were euthanized in extremis. In the definitive study, target exposure levels were 0.3, 3.0, and 10.0 mg/m3. Maternal toxicity, which was determined by the occurrence of rales, a decrease in net body weight gain, and a decrease in food intake during pre-mating and gestational exposure, was observed only at the 10 mg/m3 exposure level. Intrauterine parameters (mean numbers of corpora lutea, implantation sites, resorptions and viable fetuses, and mean fetal weights) were unaffected by treatment. No treatment-related malformations or developmental variations were noted at any exposure level. The no-observed-adverse-effect level (NOAEL) for maternal toxicity was 3.0 mg/m3; the NOAEL for developmental toxicity was greater than or equal to 10 mg/m3, 760 times both the time-weighted average threshold limit value (TLV) and the permissible exposure limit (PEL) for humans. Based on the results of this study, we conclude that arsenic trioxide, when administered via whole-body inhalation to pregnant rats, is not a developmental toxicant.

Abnormalities, Drug-Induced↗
PubMed1994

A preliminary study of blue light on an aircraft flight deck.

Measurements were made of blue light radiance on the flight deck of an aircraft during a flight from London to Spain. Although the levels recorded were below the threshold limit value, pilots were exposed to radiance levels which may be an order of magnitude higher than encountered by people outdoors at ground level.

Aircraft↗
PubMed1996

Assessment of chlorine exposure in swimmers during training.

The presence of a high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers has been recently reported. Chlorine, a strong oxidizing agent, is an important toxic gas that the swimmer can breath during swimming. Measurements of the chlorine concentration at the breathing level (< 10 cm) were obtained randomly during five nonconsecutive days in four different swimming pool enclosures. The mean level in all the swimming pools was 0.42 +/- 0.24 mg.m-3, far below the threshold limited value (TLV) of 1.45 mg.m-3 for the work places for a day of work (8 h). The TLV could be reached and even exceeded if we consider the total amount of chlorine that a swimmer inhales in a daily training session of 2 h (4-6 g) compared with a worker during 8 h at the TLV (4-7 g). Low correlation was observed with the number of swimmers in the swimming pool during the measurements (0.446) and other variables as the water surface area of the pool, volume of the enclosure, and the chlorine-addition system in the swimming pool. A low turnover rate in the air with an increase of chlorine levels through the day (P < 0.05) was observed in all pools. The concentration of chlorine in the microenvironment where the swimmer is breathing is below the TLV concentration limit, but nevertheless results in a high total volume of chlorine inhaled by the swimmers in a given practice session. The possible role of chlorine in producing respiratory symptoms in swimmers needs further investigation.

Chlorine↗
PubMed1978

Silicosis in kaolin workers and firebrick makers.

Nine patients with disabling pneumoconiosis were selected over a three-year period for study because of a work history of kaolin exposure. All had worked in the Missouri firebrick industry. Chest roentgenograms from all nine and lung tissue from two were consistent with silicosis. Worksite analysis of airborne dust at several Missouri firebrick factories revealed that some current workers are exposed to both free silica (up to 4.5%) and cristobalite (up to 8.9%) at levels exceeding the threshold limit value (TLV). Analysis of airborne dust from several kaolin processing plants in South Carolina and Georgia revealed that a few workers are exposed to about 1% free silica at levels occasionally exceeding the TVL. We conclude that silicosis is a serious risk for Missouri kaolin workers and a potential risk for workers in South Carolina and Georgia. A prevalence survey is needed in Missouri to assess the problem.

Aged↗
PubMed1989

Measurement of vibration of hand-held tools: weighted or unweighted?

The standards for hand-arm vibration have evolved from research studies in the late 1960s and were based on discomfort and tolerance levels. The lower frequencies were more intolerant and were weighted accordingly. The vascular and neurologic components of the hand-arm vibration syndrome may develop independently, and recent epidemiologic studies have shown both underestimation and overestimation in the incidence of Raynaud's phenomenon from the International Standard Organization dose-response criteria with respect to different tools. The validity of the current International Standard Organization, British Standards Institute, American National Standards Institute, and The American Conference of Governmental Industrial Hygienists Threshold Limit Values is therefore questionable. The weighted and unweighted frequency spectra of various hand-held tools are presented in this paper. It is concluded that, until such time as more dose-effect data become available, unweighted measurements should be determined. Furthermore, the frequencies measured should be extended to 5 kHz.

Arm↗
PubMed1990

Monitoring of nitrous oxide in operating rooms: identification of sources and estimation of occupational exposure.

In an academic hospital, nitrous oxide (N2O) levels were measured continuously and detailed workplace observations made in three different operating rooms for 18 days. The study was designed to determine the exposure of different categories of staff to nitrous oxide, to localize and quantify the emissions, and to predict and validate the effect of corrective measures. Nitrous oxide levels appeared to be highly time and place dependent; all staff, except for surgeons, were exposed to N2O levels (8-hour time-weighted average) above 25 parts per million. The most important contributor to total release of N2O was the ventilator (about 70%), especially during artificial respiration of the patient. A simulation model was developed and used to predict the effect of technical improvement of the ventilators and use of scavenging during anesthesia (total 58% reduction of release). The model shows that under these conditions, without altering room ventilation rates, room air circulation can be increased up to 50% without exceeding the proposed threshold limit value (25 parts per million). Measurement of N2O levels after intervention showed a reduction in the area surrounding the ventilator of about 80%, thereby reducing occupational exposure of all staff to below 18 parts per million.

Air Pollutants, Occupational↗
PubMed1995

Monitoring acrylic fiber workers for liver toxicity and exposure to dimethylacetamide. 1. Assessing exposure to dimethylacetamide by air and biological monitoring.

Worker exposure to N,N-dimethylacetamide (DMAC) in an acrylic fiber manufacturing facility was measured, over a 1-year study period, by full-shift (12 hours) personal air monitoring for DMAC and by biological monitoring for levels of DMAC, N-methylacetamide (MMAC), and acetamide in spot urine samples. Ninety-three of 127 male workers in seven job classifications in the solution preparation and spinning departments of the plant were monitored on the second consecutive workday after at least 3 days off for the first 10 months of the study and on both the first and second days during the study's final 2 months. Postshift urinary MMAC levels were significantly correlated (P < .0001, r2 = .54) with DMAC in air levels. An air level of 6.7 ppm 12-hour time-weighted average (TWA) corresponded to a urine MMAC level of 62 mg/g creatinine in a postshift spot urine sample obtained after the second consecutive workday. To minimize exposure misclassification due to variability in the regression relationship, a level of 35 mg MMAC/g creatinine in a postshift spot urine sample was recommended as a biomonitoring index. Postshift urine MMAC levels did not appear to plateau at higher air levels, nor did it appear that the DMAC demethylation metabolic mechanisms became saturated at threshold limit value (TLV)-level air-exposure levels. Urine MMAC levels in postshift samples obtained the second workday appeared to be greater than levels in postshift first-day samples, but the number of days until this postshift level would plateau could not be determined from this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetamides↗
PubMed2002

Assessing the suitability of cross-sectional and longitudinal cardiac rhythm tests with regard to identifying effects of occupational chronic lead exposure.

The aim of this study was to examine whether signs of neurotoxic influence on the autonomic nervous system, after lengthy occupational lead exposure, could be revealed by appropriate cardiac rhythm analysis. A total of 109 male lead-exposed workers and 27 controls were examined in a cross-sectional study. In addition, 17 lead-exposed participants were investigated a second time in a follow-up study 4 years later. Heart rate variability was assessed in rest, strain, and recovery phases. In the cross-sectional study, lead-exposed persons showed a delayed restoration of cardiac rhythm parameters to the initial vegetative state after the strain phase. This effect significantly increased over a period of 4 more years of exposure in the 17 workers participating in the follow-up study. We found vagal depression caused by long-term lead exposure within the current threshold limit value range, which can be interpreted as an adverse effect.

Arrhythmia, Sinus↗
PubMed2005

Effects of concurrent noise and jet fuel exposure on hearing loss.

UNLABELLED: We sought to examine the effects of occupational exposure to jet fuel on hearing in military workers. METHODS: Noise-exposed subjects, with or without jet fuel exposure, underwent hearing tests. Work histories, recreational exposures, protective equipment, medical histories, alcohol, smoking, and demographics were collected by questionnaire. Jet fuel, solvent, and noise exposure data were collected from records. Fuel exposure estimates were less than 34% of the OSHA Threshold Limit Values. RESULTS: Subjects with 3 years of jet fuel exposure had a 70% increase in adjusted odds of hearing loss (OR = 1.7; 95% CI = 1.14-2.53) and the odds increased to 2.41 (95% CI = 1.04-5.57) for 12 years of noise and fuel exposure. CONCLUSIONS: These findings suggest that jet fuel has a toxic affect on the auditory system.

Adult↗
PubMed1981

Toluene-diisocyanate induced asthma: evaluation of antibodies in the serum of affected workers against a tolyl mono-isocyanate protein conjugate.

Radioallergosorbent testing was used to look for the presence of specific IgE antibody against a para-tolyl-mono-isocyanate human serum albumin conjugate in sera from five groups of subjects. The first three groups consisted of individuals exposed to toluene diisocyanate (TDI) who had been shown by bronchial provocation testing with levels of TDI below the threshold limit value of 0.02 parts/10(6), to have immediate asthmatic reactions, late asthmatic reactions or no respiratory changes at all. The two control groups consisted of atopic and non-atopic individuals who had no respiratory symptoms and no known exposure to TDI. Although RAST showed high ct/min in some of the sera from patients with proven TDI-induced respiratory disease, these levels were not significantly different from controls and appeared to reflect the presence in these sera of high levels of total IgE (greater than 100 mu ml--1). There is no evidence from this study for the presence of specific IgE antibody against a para-tolyl mono isocyanate human serum albumin conjugate in patients with TDI-induced respiratory disease. This finding may reflect absence of antibodies, or that the techniques for their detection are not always effective even when performed by experienced persons, and there is a potential source of error in the interpretation of results when sera contain large amounts of IgE.

Antibody Formation↗