Biological and chemical monitoring of occupational exposure to ethylene oxide

Studies were carried out on two populations occupationally exposed to ethylene oxide (EtO) using different physical and biological parameters. Blood samples were collected from 9 hospital workers (EI) and 15 factory workers (EII) engaged in sterilization of medical equipment with EtO and from matched controls (CI and CII). Average exposure levels during 4 months (the lifespan of erythrocytes) prior to blood sampling were estimated from levels of N-(2-hydroxyethyl)valine adducts in hemoglobin. They were significantly enhanced in EI and EII and corresponded to a 40-h time-weighted average of 0.025 ppm in EI and 5 ppm in EII. Exposures were usually received in bursts with EtO concentrations in air ranging from 22 to 72 ppm in EI and 14 to 400 ppm in EII. All samples were analyzed for HPRT mutants (MFs), chromosomal aberrations (CAs), micronuclei (MN) and SCEs. MFs were significantly enhanced by 60% in EII but not in EI. These results are the first demonstration of mutation induction in man by ethylene oxide. CAs were significantly enhanced in EI and EII by 130% and 260% respectively. MN were not enhanced in EI but significantly in EII(217%). The mean frequency of SCEs was significantly elevated by 20% in EI and by almost 100% in EII. SCE was the only parameter that allowed distinction between daily and occasionally exposed workers in EII. An interesting finding in exposed workers was the large increase of the percentage of cells with high frequencies of SCE (3–4 times in EI and 17-fold in EII).

The relative sensitivity of endpoints for detection of EtO exposure in the present investigation was in the following order: HOEtVal adducts > SCEs > chromosomal aberrations > micronuclei > HPRT mutants.     

Biological monitoring of environmental pollution and human exposure to some trace elements

The extent of environmental pollution and resulting human exposure to hazardous toxic chemicals in the environment is often difficult to assess. One of the possible alternative approaches to this problem is the use of the biological indicators to demonstrate environmental pollution. This approach appears to be particularly suitable for demonstrating exposure to potentially toxic trace elements. In addition to analyses of plant and animal specimens the element content of human hair as an indicator of exposures to arsenic, mercury, cadmium, lead, antimony, manganese, nickel and cobalt has been repeatedly confirmed as reliable, provided the analyses were carried out and evaluated on group diagnostic basis and were done in groups of individuals occupationally not exposed to these metals. Preferably groups of 10-year-old children are to be used when only environmental pollution is to be taken into account. Hair samples are incomparably easier to collect, transport and store than the alternative biological material such as blood and urine used commonly to demonstrate exposure to various toxic agents. Biological monitoring of environmental pollution cannot replace the standard procedures of measuring air, water and soil pollution; however, the technique appears to have the potential of being an effective tool search for the extent of environmental pollution and for delimitation of territorial boundaries of areas affected most by hazardous emissions containing potentially toxic trace elements.     

Biological monitoring of bidi rollers with respect to genotoxic hazards of occupational tobacco exposure

Smokeless tobacco habits are associated with a high incidence of oropharyngeal cancer in India. Hence, the biological effects of occupational exposure to smokeless tobacco used for making bidis (the Indian version of cigarettes) were studied in 2 groups of bidi rollers designated BR-K and BR-S and in control subjects with no tobacco habits. Specific tobacco exposure and the electrophilic burden were determined by estimating urinary cotinine and thioethers respectively. Urine mutagenicity was tested with the Ames assay using Salmonella typhimurium strains TA98 and TA100. While cotinine was not detected in control samples, the mean cotinine levels (mmole/mole creatinine) in the BR-K and BR-S groups were 0.79 +/- 0.30 and 0.09 +/- 0.03 respectively. Urinary thioether excretion (mmole/mole creatinine) was significantly elevated in the BR-S group 4.59 +/- 0.52; p less than 0.001) but it was lower in the BR-K group (0.54 +/- 0.08; p less than 0.001) compared to the control (1.83 +/- 0.34). Furthermore, beta-glucuronidase-treated samples from both groups of bidi rollers exhibited increased mutagenicity to TA98 compared to the control group; in addition, BR-S samples exhibited direct mutagenicity to TA98. The results show that occupational tobacco exposure modulates the glutathione conjugation pathway and increases the mutagenic burden of bidi rollers.     

Biological monitoring of human exposure to metals

Biological monitoring of exposure to metals and metalloids involves not only determination of these elements in selected body fluids and tissues but, in some cases, also determination of a certain biochemical indicator which signalises the presence of the monitored element in the organism. Biological monitoring of occupational exposure to metals has a long tradition whereas biological monitoring of exposure in general environment has developed more intensively only in the past two decades. New information about the toxic effect of some metals and metalloids and about their kinetics of absorption, distribution and excretion in experimental animals, and particularly in man, is necessary for elaborating suitable biological exposure tests. Of current interest is also the movement of persistent noxae in the environment, seen from the ecologic view point. This report outlines the present state of the problem in Czechoslovakia.     

Evaluation of environmental and biological monitoring methods for toluene exposure assessment in paint industry

The aim of this study was to assess the exposure to Toluene in paint industry and to evaluate the environmental and biological monitoring techniques for the assessment of occupational exposure to this aromatic hydrocarbon. In this study, personal active and passive air sampling for toluene measurements, blood and urine sampling respectively for B-Tol and HA or U-Tol analyses for eight workers from two paint and thinner production factories were collected during four successive working days. Correlations were analyzed between biological indicators and environmental toluene exposure levels.The concentration of Toluene measured in air samples ranged from 0.2 to 414.0 ppm (mean = 59.8 ppm), with high variability of atmospheric levels between activities and between days. No significant difference was found between airborne toluene concentrations measured by the two sampling methods. The correlation between air concentrations sampled by the diffusive sampling method and the biomarkers was the best for HA (r = 0.902, p < 0.01), followed by B-Tol (r = 0.820; p < 0.01), o-Cr (r = 0.691; p < 0.01) and U-Tol (r = 0.607; p < 0.05). The correlation was better between air concentrations and urinary metabolites HA and o-Cr for exposure levels higher than 50 ppm (r = 0.931; p < 0.01), and lower than 300 ppm (r = 0.827; p < 0.01), respectively.According to our results, workers in the studied industries are highly exposed to Toluene. Given the high correlation found between toluene concentrations in samples taken on dosimeters and those actively sampled on charcoal tubes, it may be assumed that both sampling methods are valuable. Despite the influencing factors, HA was found to be a reliable biological indicator for the monitoring of occupational exposure to toluene for high exposure levels. However, B-Tol seems to be an interesting alternative, since it is more specific and showed the best correlations with airborne toluene levels.     

Biological monitoring of occupational exposure to 1-bromopropane by means of urinalysis for 1-bromopropane and bromide ion

The purposes of the present study are (1) to develop a sensitive analytical method to measure 1-bromopropane (1-BP) in urine, (2) to examine if 1-BP or bromide ion (Br) in urine is a useful biomarker of exposure to 1-BP, and (3) to identify the lowest 1-BP exposure concentration the method thus established can biomonitor. A factory survey was carried out on Friday, and 33 workers (all men) in cleaning and painting workshops participated; each worker was equipped with a diffusive sampler (carbon cloth KF-1500 as an adsorbent) to monitor 1-BP vapour for an 8-h shift, and offered a urine sample at the end of the shift for measurement of 1-BP and Br in urine. In addition, 10 non-exposed men offered urine samples as controls. The performance of the carbon cloth diffusive sampler was examined to confirm that the sampler is suitable for monitoring time-weighted average 1-BP vapour exposure. A head-space GC technique was employed for analysis of 1-BP in urine, whereas Br in urine was analysed by ECD-GC after derivatization to methyl bromide. The workers were exposed to vapours of seven other solvents (i.e. toluene, xylenes, ethylbenzene, acetone, etc.) in addition to 1-BP vapour; the 1-BP vapour concentration was 1.4 ppm as GM and 28 ppm as the maximum. Multiple regression analysis however showed that 1-BP was the only variable that influenced urinary 1-BP significantly. There was a close correlation between 1-BP in urine and 1-BP in air; the correlation coefficient (r) was >0.9 with a narrow variation range, and the regression line passed very close to the origin so that 2 ppm 1-BP exposure can be readily biomonitored. The correlation of Br in urine with 1-BP in air was also significant, but the r (about 0.7) was smaller than that for 1-BP, and the background Br level was also substantial (about 8 mg l^-1). Thus, it was concluded that 1-BP in end-of-shift urine is a reliable biomarker of occupational exposure to 1-BP vapour, and that Br in urine is less reliable.     

Biological monitoring,by in vivo XRF measurements,of occupational exposure to lead,cadmium, and mercury

In vivo X-ray fluorescence (XRF) techniques were used for biological monitoring of lead, cadmium, and mercury. Lead accumulates in bone, the level of which may thus be used for monitoring of exposure. However, there was no close association between lead levels in bone and exposure time, partly because of differences in exposure patterns and partly, probably, because of variations in the toxicokinetics of lead. There are at least two separate bone lead compartments. The average over-all half-time is probably 5–10 yr. The finger bone level may be an index of the lead status of the total skeleton. In lead workers, the mobilization of bone lead causes an “internal” lead exposure and affects the blood lead level considerably. In cadmium workers, in vivo XRF is a sensitive and risk-free method for assessment of accumulation in kidney cortex, the critical tissue as to toxic effects; workers displayed increased levels. However, there was no clear association with duration and intensity of exposure, cadmium levels in urine, or microglobulinuria. Determinations of kidney cadmium may add important information on the state of accumulation and, thus, risk of kidney damage. Workers exposed to elemental mercury vapor, as well as fishermen exposed to methyl mercury, had mercury levels in bone below the detection limit of the XRF method.     

Hygienic and toxicological aspects of occupational and environmental exposure to beryllium

As the production of missile, nuclear devices and electronics grew and modern industrial technologies emerged the risk of the occupational exposure to beryllium has become increasingly common and widespread. The environmental burden of beryllium is also on the increase, not only as a result of emissions from plants producing and processing beryllium, or its alloys and compounds, but also from burning coal of higher beryllium content in some localities. This article discusses primarily the hygienic and toxicologic aspects of beryllium and its threat to human health. The following topics are included in this review: occurrence, production and uses of beryllium; its metabolism and experimental toxicology; clinical toxicology and pathogenesis of berylliosis; hygienic and epidemiologic aspects of berylliosis; berylliosis treatment and prevention. Berylliosis is here characterized as a disease combining clinical manifestations of pneumosclerosis, allergy to beryllium and, in its granulomatous form, autoimmune reactions. Importantly, the available technical means and measures can ensure that the both occupational and environmental exposure to beryllium can be kept below the established MAC values. If occasionally impossible, special preventive measures should be adopted. It is essential that all persons with allergy be prophylactically excluded from work at risk of exposure to beryllium.     

Breath air analysis and its use as a biomarker in biological monitoring of occupational and environmental exposure to chemical agents

The analysis of exhaled air has several advantages since it is a noninvasive method applicable to a large number of toxic agents, in addition to being a simpler matrix than those of other biological samples such as urine and blood. However, it presents some challenges, such as the necessity of a more sensitive sampling procedure, since the chemical substances eliminated through exhaled air are unchanged in form, not being metabolized, and exhaled compounds are present at extremely low concentrations, i.e. in the nanomolar range. To improve the sensitivity and precision of measurement of the concentration of these substances in exhaled air, the sample usually has to be concentrated before assay by gas chromatography. To this end, the use of the solid-phase microextraction (SPME) technique has been proposed as an efficient sampling method. This paper presents a revision of breath analysis as a biomarker for occupational and environmental exposure to chemicals. The sampling methods and the potential use of SPME for determining chemical substances in exhaled air are discussed.     

Quality assurance of biological monitoring in occupational and environmental medicine

Biological monitoring of chemical exposure in the workplace has become increasingly important in the assessment of health risk as an integral part of the overall occupational health and safety strategy. In environmental medicine biological monitoring plays also an important role in the assessment of excessive, acute or chronic exposure to chemical agents. To guarantee that the results obtained in biological monitoring are comparable with threshold limit values and results from other laboratories, the analysis must be carried out with tested and reliable analytical methods and accompanied by a quality assurance scheme. Confounding influences and interferences during the pre-analytical phase can be minimised by recommendations from experienced laboratories. For internal quality control commercially available control samples with an assigned concentration are used. External quality control programs for biological monitoring are offered by several institutions. The external quality control program of the German Society of Occupational and Environmental Medicine has been organised since 1982. In the meantime the 27th program has been carried out offering 96 analytes in urine, blood and plasma for 47 substances. This program covers most of the parameters relevant to occupational and environmental medicine. About 350 laboratories take part in these intercomparison programs. At present, ten German and 14 international laboratories are commissioned to determine the assigned values. The data evaluated from the results of the intercomparison programs give a good overview of the current quality of the determination of analytes assessed in occupational and environmental toxicological laboratories. For the analysis of inorganic substances in blood and urine the tolerable variation ranges from 7.5 to 43.5%. For organic substances in urine the tolerable variation ranges from 12 to 48%. The highest variations (36-60%) were found for the analysis of organochlorine compounds in plasma. The tolerable variations for the determination of solvents in blood by head space gas chromatography range from 26 to 57%. If the recommendations for the pre-analytical phase, the selection of reliable analytical methods by the laboratory and the carrying out of adequate quality control are observed, the pre-requisites for reliable findings during biological monitoring are fulfilled     

Decrease in environmental pollution and changes in biological indicators in occupational exposure to lead

The Authors examine the variations of the levels of PbB and EPP in 39 workers at known lead exposure and evaluate the capacity of these parameters to follow the measured decreases of the environmental pollution. They conclude that the variations of the mean PbB values are well related to environmental pollution and that the diagram on the probability paper of median values and their corresponding standard deviations allows to calculate the number of exposed workers with biological values above a fixed limit.     

Biological consequences of occupational exposure to elementary mercury in light of hematologic tests

Principal haematological tests in peripheral blood, non-specific phosphatases and myeloperoxidase in granulocytes were determined in a group of 89 males occupationally exposed to the elementary mercury during manufacture of chlorine. Examined males were employed for 2-26 years. Blood mercury levels did not exceed 50 micrograms per l-1. The obtained results indicate that low concentrations of the elementary mercury in the environment do not produce significant abnormalities in both quantitative and qualitative picture of peripheral blood but markedly inhibit neutrophil non-specific phosphatases activity.     

Biological monitoring of n-hexane exposure in shoe workers

To analyse working conditions and to provide information about the degree to which shoe workers are exposed to n-hexane, the urinary excretion of total 2,5-hexanedione (2,5-HD) was determined in 81 employees in 12 shoe factories. Twenty-five individuals who had experienced no exposure to solvents were used as controls. 2,5-HD was measured in spot urine samples collected from workers at the end of shift. In the urine of shoe workers, the 2,5-HD presented a mean value of 2.33 mg g^-1 creatinine, a median of 1.96 mg g^-1 creatinine. The mean 2,5-HD concentration in the urine samples from non-exposed subjects was 0.28 mg g^-1 creatinine, the median value was 0.18 mg g^-1 creatinine. The mean time-weighted average (TWA) concentration of n-hexane in 12 shoe workshops was 126.1 ppm, ranging from 23 to 215 ppm. We found a significant, but low, correlation (r = 0.40; p < 0.001) between TWA intensity of environmental exposure to n-hexane and the concentration of 2,5-HD in urine. The probable effect of toluene on the concentration of 2,5-HD was also discussed in the present study.     

Biological monitoring of exposure to pesticide residues among Belgian florists

Abstract

Many pesticides applied in cut flowers can be readily absorbed through the skin of florists during preparing bouquets and handling contaminated flowers. A study was conducted among volunteer Belgian florists in order to assess their total exposure by measuring concentrations of pesticides (parent compounds and metabolites) in their urines. A total of 42 urine samples (24-h urines) were collected from florists during their professional activities, on the three most important commercial periods. The concentrations of pesticide residues and metabolites in urine samples were analyzed with a multiresidue liquid chromatography tandem mass spectrometry method, after an ethyl acetate extraction. The results are compared with those of a control group of 42 subjects not occupationally exposed to pesticides, collected in the same periods. A total of 70 residues (56 pesticides and 14 metabolites) were identified, with an average of about eight pesticide residues and metabolites per florist’s urine sample and an average total concentration per sample of 4.3 µg/g creatinine, ranging from 0.2 to 67 µg/g creatinine. Significantly higher urinary excretion of metabolites (t-test) was found in florists than in control group. These results demonstrate that Belgian florists are exposed daily to pesticide residues with a potential effect on their health.     

High-performance liquid chromatography of methotrexate for environmental monitoring of surface contamination in hospital departments and assessment of occupational exposure

In the frame of applicative research in occupational hygiene of hospital workplaces, we investigate hospital indoor contamination as a consequence of the use of antineoplastic drugs (ANDs), with the purpose of assessing exposure of medical and nursing personnel to potentially harmful doses of ANDs, and ultimately of yielding advice on safe operating procedures for manipulation of ANDs in hospitals and in house-care of cancer patients. Among the large number of currently employed ANDs, methotrexate (MTX) has been selected as a tracer of surface contamination, on the basis of its wide use in therapy, its ease of measurement and of its chemical properties relevant to persistence and transport in the indoor environment. MTX is a polyelectrolyte, with a high water, but lower organic solvent solubility, a negligible vapour pressure and a high chemical robustness to environmental stress, thus allowing to measure surface-to-surface carryover (e.g. from spillage or glove fingerprint) and indoor contamination due to aerosol transport (e.g. from syringe manipulation procedures). Monitoring of MTX in environmental samples such as swab washings of surfaces and objects requires an analytical method with characteristics of sensitivity, reproducibility, precision, analytical speed, ease of automation and robustness. We have therefore developed an analytical procedure which employs simple short-column RP-HPLC with UV detection, automated sample injection and a close analogue internal standard for improved precision and solid-phase extraction (SPE) for sample concentration. Our method has proven suitable for detecting traces of MTX on a wide variety of surfaces and objects, with a limit of quantification in the range of 50 μg/dm³ for direct injection of unconcentrated washings, corresponding to the possible detection of surface contamination as low as 1 μg/m³ and a limit of detection in the range of 10 ng/m² for samples as large as 100 dm³ concentrated by SPE. We present preliminary results from a recent hospital case-study, assessing the contamination level of furniture and equipment in drug preparation areas. Spillage fractions as high as 5% of the employed mass (70–260 mg/day) are measured on the polythene-backed paper disposable hood cover sheet; traces of MTX in the microgram range can also be measured on floor surfaces, furniture and handles, even at a distance from the preparation hoods.