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PubMedDate not supplied

[The role of biological monitoring in health and epidemiological surveillance: the epidemiological approach].

A fundamental pre-requisite for the realization of biological monitoring programs for health surveillance is the availability of sufficiently accurate tests and adequate knowledge of the relationship between biomarkers and health effects. In this respect, epidemiology plays an essential role: in conjunction with other disciplines (industrial hygiene, toxicology, occupational medicine), it provides a conceptual and methodological framework for many biological monitoring activities. Compared to biomarkers of dose and effect, susceptibility markers (for example, metabolic polymorphisms), for which we have seen an explosion of research in recent years, need a specific consideration in that they pose (or may pose in a non-remote future) special problems. For different reasons, the use of genetic tests for predictive aims at the individual level should now be avoided; their use should be restricted to the research field for a better understanding of etiopathogenetic mechanisms.

Biomarkers↗

PubMed2000

Personal air sampling and biological monitoring of occupational exposure to the soil fumigant cis-1,3-dichloropropene.

OBJECTIVES: To assess exposure of commercial application workers to the nematocide cis-1,3-dichloropropene (cis-DCP). METHODS: The study was conducted during the annual application season, August to 15 November, in the starch potato growing region in The Netherlands. 14 Application workers collected end of shift urine samples on each fumigation day (n=119). The mercapturic acid metabolite N-acetyl-S-(cis-3-chloro-2-propenyl)-L-cysteine (cis-DCP-MA) in urine was used for biological monitoring of the cis-DCP uptake. Inhalatory exposure was assessed by personal air sampling during a representative sample (n=37) of the fumigation days. Extensive information was collected on factors of possible relevance to the exposure and the application workers were observed for compliance with the statutory directions for use. The inhalatory exposure during all fumigation days was estimated from the relation between the personal air sampling data and the biological monitoring data. Exposure levels were correlated with the general work practice. The fumigation equipment and procedures were in accordance with the statutory directions of use, with the exception of the antidrip systems. Two antidrip systems were used: antidrip nozzles or a compressed air system. RESULTS: The geometric mean exposure of the application workers was 2.7 mg/m(3) (8 hour time weighted average); range 0.1-9.5 mg/m(3). On 25 days (21%) the exposure exceeded the Dutch occupational exposure limit (OEL) of 5 mg/m(3). This could mainly be explained by prolonged working days of more than 8 hours. The general work practice of the application workers was rated by the observers as good or poor. No difference in exposure to cis-DCP was found in the use of none, one, or two antidrip systems. Malfunctioning of the antidrip systems and lack of experience with the compressed air system were identified as possible causes for the lack of effectiveness of these antidrip systems. The use of personal protection was not always in accordance with the statutory directions of use. Dermal exposure to liquid cis-DCP was found four times during repair and maintenance, but the biological monitoring data did not suggest a significant increase in cis-DCP uptake. CONCLUSIONS: The application of cis-DCP in the potato growing industry can be performed at exposure concentrations below the Dutch OEL of 5 mg/m(3) if the working days are limited to 8 hours. An injector equipped with either kind of antidrip system which is in good working order, as well as the consistent use of personal protection in accordance with the statutory directions of use, may ensure exposure concentrations below the Dutch OEL.

Adult↗

PubMed1992

[Biological monitoring in chromium-plating industry].

The purpose of the present investigation was to evaluate the role of biological monitoring as a means of surveillance of exposure in the Danish chromium-plating industry. We collected spot urine samples from 47 employees in five electro-plating plants near Aarhus and compared the results wide 40 non-exposed workers. We found no increase of chromium in urine during a work shift (mean = 0.11 nmol chromium/mmol creatinine, p = .46). The mean urine chromium value among the chromium workers was twice the mean value of the referent population (p = 0.001). There was, however, a considerable overlap between the two populations. All of the urine chromium values were much lower than the proposed American biological exposure indices. The results do not indicate any need for implementation of biological monitoring in the Danish chromium-plating industry, but longitudinal studies concerning possible accumulation of chromium at present occupational exposure levels should be carried out.

Adult↗

PubMed1983

Human styrene exposure. V. Development of a model for biological monitoring.

The use of biological indicators to monitor workers' exposure to styrene requires a good understanding of the kinetics of the solvent in the organism. The absorption, distribution and elimination of styrene (STY), as well as the kinetics of formation and excretion of its metabolites (mandelic [MA] and phenylglyoxylic [PGA] acids) are simulated using a mathematical model. The results obtained compare well with experimental data for pulmonary (STY) and urinary (MA and PGA) excretion obtained during controlled human exposures. The model is then used to predict the behaviour of STY, MA and PGA during repeated occupational exposure. It is shown that the results are comparable to the data collected during field surveys in the polyester industry, if the level of physical activity of the workers is taken into account. This latter parameter appears to have a great influence on the urinary excretion of the metabolites. Based on the results obtained, biological limits of exposure are proposed (referenced to a TLV [threshold limit value] of 50 ppm) for MA and MA + PGA excretions in urine collected at the end of the shift (800 and 1000 mg/g creat.) and the next morning (150 and 300 mg/g creat.). Their validity is tested against experimental data obtained under field conditions.

Environmental Exposure↗

PubMedDate not supplied

Biological monitoring.

It is important to distinguish biological from medical or health monitoring because the submission of a biological specimen often leads to the assumption of the part of workers and also health professionals that health effects are being measured, and that measurement exceeding a reference value indicates disease rather than exposure or health risk. This chapter briefly reviews the basic principles of biological monitoring, focusing primarily on its role within medical surveillance.

Environmental Monitoring↗

PubMed1996

[Biological monitoring and prevention of complications from antithrombotic agents].

Antithrombotic agents are widely prescribed in cardiovascular diseases. It is essential to understand the conditions of biological monitoring and the potential complications of these drugs. Treatment with unfractionated heparin and vitamin-K antagonists requires strict biological follow-up, the rules of which must be respected to avoid therapeutic failure or bleeding complications. Biological monitoring of low molecular weight heparins is extremely simple and that of antiplatelet agents is unnecessary. Regular patient follow-up, both clinical and biological, the respecting of contra-indications and recommendations of usage, and special attention to the problem of drug interaction, should result in better efficacy and tolerance of antithrombotic therapy.

Adult↗

PubMed1993

Biological monitoring of occupational exposure to n-hexane by exhaled air analysis and urinalysis.

To compare two methods of biological monitoring for the evaluation of risk of occupational exposure to n-hexane, we analyze the relationship between environmental exposure to this solvent and urinary excretion of 2,5-hexanedione and n-hexane in exhaled air in 69 workers employed in the shoe industry. Environmental exposure to the solvent was monitored with personal diffusive samplers, which were desorbed with carbon sulfide and analyzed by gas chromatography. To measure 2,5-hexanedione, urine was subjected to acid hydrolysis, separation in octadecyl silane columns, elution with 5% aqueous acetonitrile solution and extraction with dichloromethane, followed by gas chromatography. In exhaled air, n-hexane was measured with a sampling system that permitted concentration of aliquots of end-exhaled air (alveolar air) from one or more exhalations in a tube packed with activated charcoal, which was then desorbed with carbon sulfide and analyzed by gas chromatography. Concentrations of n-hexane in breathing zone air were significantly correlated with urinary concentrations of 2,5-hexanedione (r = 0.88) and with exhaled air n-hexane (r = 0.86); in addition, the two biological indicators correlated significantly (r = 0.70). Analyses in both exhaled air and urine were thus considered useful for biological monitoring of the risk of exposure to n-hexane.

Adhesives↗

PubMed2002

[Evaluation of urinary ortho-cresol as biological monitoring indicator of occupational exposure to toluene].

OBJECTIVE: To investigate the feasibility of urinary ortho-cresol levels as a biological monitoring indicator for toluene exposure. METHODS: Establish pre-column derivation HPLC method to detect ortho-cresol levels in urine of human body. Ortho-cresol levels in urine of workers non-exposed and exposed to toluene was examined using this pre-column derivation HPLC method, and exposure assessment was conducted. RESULTS: It was shown that urinary ortho-cresol level in exposed workers was (2.61 +/- 1.94) mg/L, higher than those of control group [(0.32 +/- 0.23) mg/L, P < 0.001]. Urinary ortho-cresol level in exposed workers at the end of a workshift was higher than those before exposure to toluene, and also was correlated with the concentration of toluene to which individual exposed(r = 0.6295, P < 0.01). CONCLUSION: Urinary ortho-cresol as a biological monitoring indicator for toluene exposure is feasible.

Chromatography, High Pressure Liquid↗

PubMed1994

A biological monitoring assessment of exposure to methylene dianiline in manufacturers and users.

This paper describes a cross sectional study in which biological monitoring was used to assess exposure to methylene dianiline (MDA) in a selection of United Kingdom industries that manufacture or use MDA. Samples of urine were collected from 411 workers, representing 45 factories engaged in various activities. All urine samples were analysed for MDA and its acetyl metabolites and results are reported as total MDA. In this study, 91% of postshift urine samples and 88% of preshift samples had less than 50 nmol MDA/mmol creatinine. Some evidence was obtained which showed that when exposure to MDA was through inhalation (as solid material or contaminated dust), postshift urine samples had higher MDA concentrations than samples taken preshift the next day. When exposure was most likely to be through the dermal route, urine samples taken preshift next day tended to have higher MDA concentrations than urine samples collected immediately postshift on the day of exposure. Therefore a biological monitoring sampling strategy for MDA must take account of the route of entry into the body. If exposure is likely to be via inhalation, postshift samples should be collected and if exposure is likely via the skin, preshift samples next day are more appropriate. The results show that in most factories, regardless of the route of exposure, it is possible to keep urinary MDA concentrations below 50 nmol/mmol creatinine. In the absence of a health based or hygiene based standard, the use of a "yardstick" as a target to aim for, which has been derived from good working practice across the industry, may be a useful way of helping to control exposure.

Administration, Cutaneous↗

PubMed1986

Biological monitoring of chlorinated hydrocarbon solvents.

The possibility of biological monitoring of exposure to some volatile, halogenated hydrocarbons will be discussed. Most of these agents are widely used as solvents. All agents act on the nervous system as narcotics and differ widely in toxicity. Most of the solvents undergo biotransformation to metabolites. This allows biological assessment of exposure by measurement of the solvent and/or metabolites in exhaled air, blood, and/or urine. However, the same metabolites may occur with exposure to different chlorinated hydrocarbons, eg, trichloroethanol and trichloroacetic acid from exposure to trichloroethene, tetrachloroethene, and 1,1,1-trichloroethane. On the other hand, these agents differ widely in the percentage that is metabolized. There are large gaps in our knowledge, however, and much research will have to be carried out before even tentative data can be established for most of the solvents.

Environmental Exposure↗

PubMed2002

Interest of genotyping and phenotyping of drug-metabolizing enzymes for the interpretation of biological monitoring of exposure to styrene.

In the field of occupational and/or environmental toxicology, the measurement of specific metabolites in urine may serve to assess exposure to the parent compounds (biological monitoring of exposure). Styrene is one of the chemicals for which biological monitoring programs have been validated and implemented in environmental and occupational medicine. However, inter-individual differences in the urinary excretion exist both for the main end-products (mandelic acid and phenylglyoxylic acid) and for its specific mercapturic acids (phenylhydroxyethylmercapturic acids, PHEMA). This limits to a certain extent the use of these metabolites for an accurate assessment of styrene exposure. In a group of 26 volunteers selected with relevant genotypes, and exposed to styrene vapours (50 mg/m3, 8 h) in an inhalation chamber, we evaluated whether genotyping or phenotyping relevant drug-metabolizing enzymes (CYP2E1, EPHX1, GSTM1, GSTT1 and GSTP1) may help to explain the observed inter-individual variability in the urinary metabolite excretion. Peripheral blood lymphocytes were used for genotyping and as reporter cells for the phenotyping of CYP2E1 and EPHX1. The GSTM1 genotype was clearly the most significant parameter explaining the variance in urinary PHEMA excretion (6-fold lower in GSTM1 null subjects; P < 0.0001) so that systematic GSTM1 genotyping should be recommended routinely for a correct interpretation of PHEMA urinary levels. Variant alleles CYP2E1*6 (7632T>A) and His113EPHX1 were associated with a significant reduction of, respectively, the expression (P = 0.047) and activity (P = 0.022) of the enzyme in peripheral blood lymphocytes. In combination with GSTM1 genotyping, the phenotyping approach also contributed to improve the interpretation of urinary results, as illustrated by the combined effect of CYP2E1 expression and GSTM1 allelic status that explained 77% of the variance in PHEMA excretion and allows the recommendation of mercapturates as specific and reliable biomarkers of exposure to styrene.

Acetylcysteine↗

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↗

PubMed2006

External and internal exposure to polycyclic aromatic hydrocarbons (PAH) among workers in the production of fire-proof materials - proposal of a biological monitoring guidance value.

In 1999, we introduced the German polycyclic aromatic hydrocarbons (PAH) study. The study was designed as a nation-wide investigation on workers exposed to PAH. One aim of the study was to establish biological monitoring guidance values (BMGVs) for different branches. Here, we report on the production of fire-proof materials. This branch of industry is typically confronted with high exposure to PAH and with PAH-induced occupational (cancer) diseases. One hundred and thirty-five employees participated in the course of seven sampling dates in four different plants in Germany. External exposure was determined by personal air monitoring of the 16 EPA-PAH. Human biological monitoring was accomplished by the determination of 1-hydroxypyrene and monohydroxyphenanthrenes in post-shift spot urine samples. Concentrations of PAH in the air of the workplaces ranged up to 1102.6microg/m(3). Maximum benzo[a]pyrene concentration was 38.2microg/m(3). The internal PAH exposure of workers was much higher compared with that of the general population. Median concentration for 1-hydroxypyrene was 6.4microg/g creatinine (maximum 279.6, 90th percentile 23.9microg/g creatinine) and for the sum of monohydroxyphenanthrene metabolites 13.3microg/g creatinine (maximum 313.4, 90th percentile 70.8microg/g creatinine). The following BMGVs for the non-smokers of this branch of industry are proposed: for 1-hydroxypyrene 18microg/g creatinine and for the sum of hydroxyphenanthrenes 77microg/g creatinine in urine measured at the end of the shift.

Adult↗

PubMed2001

[Biologic monitoring of occupational and non-occupational exposure to pesticides].

Occupationally or otherwise, much of the population is exposed to pesticides. To obtain information on exposure levels, biological monitoring is often the best choice because it provides data that reflects total exposure by all routes. Biological monitoring has been used to evaluate exposure in agricultural and industrial environments, in subjects poisoned by accidental or voluntary contact, in volunteers for pharmacokinetic studies and in the general population. This paper is based on 100 studies published on this topic and reviews exposure indices for the main classes of pesticides. Methods of sampling and conservation of samples are outlined, together with the analytical procedures used. For compounds such as organophosphate and pyrethroid insecticides, ethylenebisdithiocarbamate fungicides, and phenoxyacetic herbicides, the results of studies on the general population and groups of occupationally exposed workers are reported.

Environmental Monitoring↗

PubMed1991

Biological monitoring of environmental and occupational exposure to mercury.

Biological monitoring was used to assess mercury exposure from occupational and environmental sources in a group of chloralkali workers (n = 89) and in a control group (n = 75). In the control group, the median value for blood mercury (B-Hg) was 15 nmol/l, that for serum mercury (S-Hg) was 4 nmol/l and that for urinary mercury (U-Hg) was 1.1 nmol/mmol creatinine. Corresponding levels in the chloralkali group were 55 nmol/l, 45 nmol/l and 14.3 nmol/mmol creatinine, respectively. In the control group, there were statistically significant relationships between fish consumption and both B-Hg and S-Hg values (P less than 0.001), whereas U-Hg correlated best with the individual amalgam burden (P less than 0.01). In the chloralkali group, the mercury levels in blood and urine were significantly related to the type of work (P less than 0.001) but not to the length of employment, to fish consumption or to the quantity of dental amalgam fillings. In both groups there were poor correlations between smoking or alcohol intake and the mercury levels in blood and urine. The results strongly suggest that fish is an important source of methylmercury exposure and that amalgam fillings are probably the most important source of inorganic mercury exposure among occupationally unexposed individuals. In the chloralkali group, mercury exposure from fish and amalgam was overshadowed by occupational exposure to inorganic mercury.

Adult↗

PubMed1988

Nonselective and selective methods for biological monitoring of exposure to coal-tar products.

Biological monitoring of exposure to coal-tar products has been carried out using the nonselective urinary mutagenicity and thioether assays and a selective method for the detection of 1-hydroxypyrene in urine. The sensitivities of the three methods have been compared. In several work environments, no increase that could be related to exposure to coal-tar products was found with the nonselective methods, whereas the levels of 1-hydroxypyrene in urine were enhanced. The applicability of the method for the detection of 1-hydroxypyrene in urine is further demonstrated.

Coal Tar↗

PubMed1978

Trichloroethylene exposure. Biological monitoring by breath and urine analyses.

A mathematical model developed previously has been used to study some aspects of biological monitoring of exposure to trichloroethylene (TRI) by the analysis of this solvent in alveolar air or of its metabolites, trichloroethanol (TCE) and trichloroacetic acid (TCA), in urine. Assuming that a biological control must be representative of the time-weighted average concentration (TWA), it was found that sampling for TRI and TCE analyses must be carried out the morning after the exposure being considered. On the other hand, for a TCA analysis, the timing of urine sampling is not a determinant factor. Theortical limit concentrations have been set up for these biological indicators, but it is shown that their application must be restricted to exposures which are quantitatively reproducible from one day to the next. In all other cases, it appears that this monitoring method can lead to errors in the estimated exposure concentrations. A tentative method of biological monitoring is therefore proposed. It is based on the analysis of TCE in the urine or TRI in the alveolar air before and after the exposure being monitored. TCA is not considered to be sensitive enough to variations in the inspired concentration to be used as an indicator of a single exposure risk.

Environmental Exposure↗

PubMed2001

Biological monitoring of workers exposed to ethylbenzene and co-exposed to xylene.

OBJECTIVE: Ethylbenzene is an important constituent of widely used solvent mixtures in industry. The objective of the present study was to provide information about biological monitoring of occupational exposure to ethylbenzene, and to review the biological limit values corresponding to the threshold limit value of ethylbenzene. METHODS: A total of 20 male workers who had been exposed to a mixture of ethylbenzene and xylene, through painting and solvent mixing with commercial xylene in a metal industry, were recruited into this study. Environmental and biological monitoring were performed during an entire week. The urinary metabolites monitored were mandelic acid for ethylbenzene and methylhippuric acid for xylene. Correlations were analyzed between urinary metabolites and environmental exposure for ethylbenzene and xylene. The interaction effects of a binary exposure to ethylbenzene and xylene were also investigated using a physiologically based pharmacokinetic (PBPK) model. RESULTS: The average environmental concentration of organic solvents was 12.77 ppm for xylene, and 3.42 ppm for ethylbenzene. A significant correlation (R2 = 0.503) was found between environmental xylene and urinary methylhippuric acid. Urinary level of methylhippuric acid corresponding to 100 ppm of xylene was 1.96 g/g creatinine in the worker study, whereas it was calculated as 1.55 g/g creatinine by the PBPK model. Urinary level of mandelic acid corresponding to 100 ppm of ethylbenzene was found to be 0.7 g/g creatinine. PBPK results showed that the metabolism of ethylbenzene was highly depressed by co-exposure to high concentrations of xylene leading to a non-linear behavior. CONCLUSIONS: At low exposures, both methylhippuric acid and mandelic acid can be used as indicators of commercial xylene exposures. However at higher concentrations mandelic acid cannot be recommended as a biological indicator due to the saturation of mandelic acid produced by the co-exposure to xylene.

Benzene Derivatives↗