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PubMed1999

Biological monitoring of sterilizers and sterilization failures in Norwegian dental offices in 1985 and 1996.

It is essential that dental office sterilizers be regularly challenged with biological indicators (BIs) in order to prove that the test spores are being killed during sterilization. The aims of the study were to biologically monitor Norwegian dental office sterilizers and to identify factors contributing to sterilization failure. In 1985, participants received a packet containing: (i) 4 BI units; (ii) a set of instructions; (iii) a questionnaire concerning operation (including biological monitoring) of the office sterilizer(s), and (iv) a return-address envelope. In 1996, offices were sent (i) a survey which included demographic questions and inquiries concerning instrument sterilization processes; (ii) 2 sets of 3 BI units with instructions for their use on 2 different days; (iii) 1 control BI unit that was not to be processed, and (iv) a return-address envelope. Both private and public offices participated. Response rate to the 1996 study was 60%, which was 9.1% of all dental offices in Norway. Testing results indicated a 6.3% overall sterilization failure rate. Three out of 163 steam autoclaves (SAs) (1.8% of total) and 14 out of 109 dry heat (DH) ovens (12.8% of total) failed. DH ovens were over 7 times more likely to fail BI testing than were SAs (chi2, P < 0.01). Demographic or hygiene procedural factors could not be correlated to sterilization performance (chi2, P > 0.05). The failure rate for SAs (n = 216) in 1985 was almost 5 times greater than in 1996 (8.8% vs 1.8%). Improvement in sterilizer performance during the decade may be related to issuance in 1986 of Norway's 1st infection control guidelines for dentistry and greater awareness of infection control practices and/or to increases over the previous 10 years in the number of postgraduate courses offered in infection control. The current Norwegian guidelines on infection control practices in public health services, including dentistry, recommend regular biological monitoring of sterilizers without specifying how often. There is a lack of information among Norwegian dentists as to how frequently dental office sterilizers should be regularly monitored by BI.

Chi-Square Distribution↗

PubMed1993

Human biological monitoring of occupational genotoxic exposures.

Human biological monitoring is a valuable tool for exposure assessment in groups of persons occupationally exposed to genotoxic agents. If the monitoring activity covers genetic material the term genetic monitoring is used. The methods used for genetic monitoring are either substance specific, e.g. the quantitation of identified DNA-adducts or substance unspecific as is the measurement of DNA-repair. The sample material used for analysis must be well characterized and subject to uniform processing for comparison of the results. Confounding factors of smoking, age and sex must be well controlled for and the biomonitoring results should preferentially be linked with accurate ambient air monitoring. In persons occupationally exposed to styrene the endpoints of DNA-damage and DNA-repair in genetic monitoring are methods of choice in exposure situations above the current Danish (25 ppm) or Finnish (20 ppm) occupational exposure limit value of styrene in ambient air. The consideration of ethical issues in human genetic monitoring is an important but often overlooked aspect. This includes the scientific and preventional relevance of performing a test on individuals, pre- and post study information of donors and confidentiality as well as ownership of the results.

DNA Damage↗

PubMed1989

Biological monitoring of arsenic exposure of gallium arsenide- and inorganic arsenic-exposed workers by determination of inorganic arsenic and its metabolites in urine and hair.

In an attempt to establish a method for biological monitoring of inorganic arsenic exposure, the chemical species of arsenic were measured in the urine and hair of gallium arsenide (GaAs) plant and copper smelter workers. Determination of urinary inorganic arsenic concentration proved sensitive enough to monitor the low-level inorganic arsenic exposure of the GaAs plant workers. The urinary inorganic arsenic concentration in the copper smelter workers was far higher than that of a control group and was associated with high urinary concentrations of the inorganic arsenic metabolites, methylarsonic acid (MAA) and dimethylarsinic acid (DMAA). The results established a method for exposure level-dependent biological monitoring of inorganic arsenic exposure. Low-level exposures could be monitored only by determining urinary inorganic arsenic concentration. High-level exposures clearly produced an increased urinary inorganic arsenic concentration, with an increased sum of urinary concentrations of inorganic arsenic and its metabolites (inorganic arsenic + MAA + DMAA). The determination of urinary arsenobetaine proved to determine specifically the seafood-derived arsenic, allowing this arsenic to be distinguished clearly from the arsenic from occupational exposure. Monitoring arsenic exposure by determining the arsenic in the hair appeared to be of value only when used for environmental monitoring of arsenic contamination rather than for biological monitoring.

Arsenic↗

PubMedDate not supplied

Biological monitoring among benzene-exposed workers in Bangalore city, India.

Environmental and biological monitoring was carried out in the winter season of 2004 for 30 gasoline station workers (study subjects) and 30 office workers (controls) of Bangalore city, India. Personal air sampling was carried out in the breathing zone of workers using an Anasorb CSC sorbent tube (SKC 226-01) fitted to the low-flow personal samplers (PCXR4 and pocket pump Model No. 210-1002) at a flow rate of 200 ml min(-1) during the shift work of 8 h. The benzene content adsorbed in the sorbent tube (SKC 226-01) was desorbed with 1 ml of benzene-free carbon disulfide on a developing vibrator and later analysed by Trace GC fitted with MXT-624 column and flame ionization detector. The mean time weighted average benzene concentration found among study and controls was 1.10+/-1.08 and 0.070+/-0.035 mg m(-3), respectively. Biological monitoring for benzene exposure was performed by measuring trans,trans muconic acid (t,t-MA) in the end shift urine samples using HPLC-UV technique. End-shift urine samples (1 ml) were adjusted to pH 7-9 with phosphate buffer pH 7.4 passed through the preconditioned Q-SAX anion-exchange cartridge and the (t,t-MA) is extracted with 10% acetic acid and later analysed by HPLC-UV detection The mean t,t-MA found among study and controls were 563.16+/-281.81 and 266.88+/-110.65 microg g(-1) creatinine. About 50% of the study subjects (15) have higher t,t-MA values than the biological exposure index of the American Conference of Government Industrial Hygienist (ACGIH). Correlation is significant at 5% level (p<0.05) between personal air benzene concentration and urinary t,t-MA in the study group. Based on these findings, the t,t-MA can be used as a biomarker for benzene exposure.

Benzene↗

PubMed1988

[Biological monitoring of fluoride-exposed workers in Switzerland: development of the internal fluoride burden in the last 10 years].

In Swiss plants a risk of industrial fluorosis exists only for workers in the aluminum industry (electrolysis of Al2 O3, raffination of aluminium). Exposure to fluorides is assessed by ambient monitoring, by health surveillance (early detection of fluorosis) and by biological monitoring (urinary fluoride determinations, pre-shift und post-shift). The results of biological monitoring in the 4 plants in Switzerland are presented (1976/77-1986; 1977 264 workers, 1986 242 workers). During the period from 1976/77-1986 a significant reduction of the urinary fluoride excretion in exposed workers was observed. This reduction was correlated in time with technical measures to reduce external fluoride exposure of workers. Urinary fluoride excretion was within limits of biological exposure indices at the end of the observation period in all plants (on group base). Therefore the risk of industrial fluorosis seems to be eliminated in newly engaged workers and significant lowered in the other workers of the Swiss aluminium industry.

Body Burden↗

PubMed1989

[Assessment of exposure at the work site by biological monitoring].

Precise assessment of exposure to workplace chemicals is important for occupational disease prevention. Biological monitoring may be defined as the evaluation of the health risk of workers exposed to an industrial chemical by monitoring the internal dose, that means the amount of chemical effectively absorbed in the organism. Objectives, principal advantages and limitations of biological monitoring are discussed.

Air Pollutants, Occupational↗

PubMedDate not supplied

[The biological monitoring of occupational exposures to solvents by using their urinary concentrations].

For many years biological monitoring of occupational exposure to solvents is achieved via their specific urinary metabolites. In the last 10 years many publications have shown that the urinary concentrations of unchanged solvents are well correlated with environmental exposure and could therefore be used for biological monitoring. For acetone, methanol, methyl ethyl ketone and methyl iso butyl ketone, the American Conference of Governmental Industrial Hygienists and the Deutsche Forschungsgemeinschaft have proposed urinary concentrations of substance itself as biological exposure indices. A critical revision of the literature on this matter reveals discrepancies between the results obtained by different authors. The correlations between environmental data and respective solvents give excellent indices of correlation. However, the differences observed when comparing the regression lines obtained from different research groups are very wide. For example, for an exposure to toluene corresponding to 50 ppm, some authors found urinary concentrations equal to 35 micrograms/l, others found urinary concentration higher than 100 micrograms/l. Similarly for benzene, styrene and methyl ethyl ketone the differences were also marked. We have not identified an explanation for such different results. Biological data variability could help to explain part of these disagreements. It should also be remembered that for benzene, the analytical methodology performed in different conditions can give rise to very different results. The mechanisms of excretion of organic solvents in urine are discussed considering biological variability and analytical method problems. The current hypotheses do not allow a satisfactory interpretation of the literature results. In conclusion further experience is needed that will more clearly show which results better express the relationship between occupational exposure to organic solvents and their specific urinary concentrations.

Body Burden↗

PubMed2005

Improvement in the GC-MS method for determining urinary toluene-diamine and its application to the biological monitoring of workers exposed to toluene-diisocyanate.

OBJECTIVES: To develop a simple and sensitive GC-MS method for determining toluene-diamine (TDA) in urine and to apply the method for biological monitoring of workers exposed to toluene-diisocyanate (TDI). METHODS: After acid hydrolysis of 0.1 ml of urine, diluted tenfold with water, for 1.5 h, the free TDA formed was extracted with dichloromethane, and the heptafluorobutyric anhydride derivative was determined by GC-MS. We applied the method to the biological monitoring of 18 workers who were using an 80:20 mixture of 2,4-TDI and 2,6-TDI. RESULTS: 2,6-TDA and 2,4-TDA were simply determined in 7 min by GC-MS. TDA levels in post-shift urine were well correlated with personal exposure levels of TDI. The correlation was improved by correction with creatinine or specific gravity in the 2,6-isomer, but not in the 2,4-isomer because of low exposure levels. From the correlation equation, the 2,6-TDA level (corrected with creatinine), corresponding to the TDI level of 5 ppb, was calculated to be 31.6 mug/g Cre. TDAs in pre-shift urine also correlated significantly with the personal exposure levels of TDIs, although the slope of the correlations for pre-shift samples was 60%-70% of those for post-shift samples. The correlation between 2,4-TDA and 2,6-TDA levels was significant, although the levels of the 2,4-isomer were less than one-tenth of the 2,6-isomers in both air (personal exposure) and urine. CONCLUSION: The present method is simple and practicable and can be useful for biological monitoring of TDI workers.

Air Pollutants, Occupational↗

PubMed1999

New technologies in the use of exhaled breath analysis for biological monitoring.

Breath analysis is an attractive non-invasive procedure for screening workers exposed to solvents. It has been used in numerous laboratory based studies and for field research. Despite the obvious advantages in routine biological monitoring it has failed to become widely accepted as a tool in occupational hygiene. Recent advances in breath sampling and analysis are such that it is likely to become more widely used in the future. In this paper, the past 5 years have been reviewed to try to assess what developments might now contribute to the increased use of breath analysis in biological monitoring; in particular, the development of a selected ion flow tube mass spectrometer for real time direct analysis of trace gases in breath and the more immediately available and less expensive indirect methods involving collection devices with adsorbent tubes is important. The introduction of guidance values for biological monitoring with clear advice on sampling times and the recognition of the importance of quality assurance programmes will help improve confidence in the technique.

Breath Tests↗

PubMed1999

[The role of biological monitoring in the evaluation of the risk of from chemical compounds].

Over the years, the assessment of the risk to human health from occupational and environmental exposure to chemicals has become increasingly important. Exposure to chemicals, their biochemical effects and individual susceptibility can be estimated by biological monitoring carried out on potentially exposed subjects. Valid markers are needed to be effectively used within the framework of biological monitoring programs. Quality assurance, which includes all those activities necessary to provide adequate confidence that the results of laboratory test are reliable, is of the utmost importance. Among these activities the participation in external quality assessment schemes is strongly recommended. Biological monitoring has a key role also in the field of human reproduction since the level of exposure to many chemicals which are known or suspected to be reproductive toxicants can be assessed by specialized laboratories.

Environmental Monitoring↗

PubMed2006

Chlorpyrifos exposure and biological monitoring among manufacturing workers.

AIM: To use biological monitoring data to evaluate the soundness of job based exposure classifications. METHODS: The authors studied 52 chlorpyrifos manufacturing workers and 60 referent workers to compare chlorpyrifos exposure estimations from job titles and work areas to urinary excretion of 3,5,6 trichloro-2-pyridinol (TCP), a metabolite of chlorpyrifos. Work history records and industrial hygiene monitoring data were used to establish cumulative interim exposure. Chlorpyrifos exposure during the study year was assessed biologically by urinary excretion of TCP. RESULTS: Exposure as measured by three urinary TCP samples was significantly higher among the chlorpyrifos workers (188 microg/l) than it was for the referent subjects (7 microg/l). Urinary TCP also correlated well with specific exposure categories of negligible (0.73-1.98 mg/m3 days), low (1.99-4.91 mg/m3 days), and moderate (4.92-15.36 mg/m3 days). The weighted Kappa coefficient was 0.80 (95% CI 0.72 to 0.87) for the mean TCP over the study period. CONCLUSIONS: The estimates of chlorpyrifos exposure based on job classifications and industrial hygiene measurements were significantly related to urinary TCP excretion, indicating that the ambient estimates are useful for providing exposure estimates among chlorpyrifos manufacturing workers.

Adult↗

PubMedDate not supplied

[Biological monitoring of occupational exposure to airborne pollutants].

Biological monitoring of inert substances requires knowledge of the mechanisms regulating respiratory absorption. The authors examine the influence of parameters such as work load, exposure duration and biotransformation on the respiratory absorption of inert airborne pollutants in the workplace. Attention is also given to the possibility of using biological thresholds or Biological Equivalent Limits (BELs).

Air Pollutants, Occupational↗

PubMed1984

Biological monitoring in nickel refinery workers.

A study was carried out at the Clydach, Wales, refinery of INCO Europe Ltd, in which urinary and serum nickel levels were compared with results derived from personal atmospheric sampling during: (a) normal operating conditions; (b) after a prolonged lay-off; and (c) one month after resumption of normal activities. On an individual basis, poor correlations between atmospheric and biological monitoring were observed but when work groups were considered it was found that atmospheric insoluble nickel correlated with both urinary nickel (correlation coefficient = 0.86, p = 0.02) and serum nickel (correlation coefficient = 0.87, p = 0.02). Men using respiratory protection had biological levels which were approximately one-quarter of what would have been expected from the atmospheric figures and men working with soluble nickel salts had urinary nickel levels three times in excess of those expected. There was no statistical difference between observed results and those corrected for creatinine content or specific gravity, nor was there any difference between randomly collected or first morning urine samples. Biological monitoring of nickel workers can be considered as having a role to play in assessing whether protective measures at the place of work are functioning properly, and a tentative scheme is suggested which could make use of biological monitoring, together with atmospheric monitoring, in the occupational health care of refinery workers.

Adult↗

PubMed1988

Biological monitoring of occupational exposure in the chromate pigment production industry.

A survey of occupational exposure to hexavalent chromium in chromate pigment production was undertaken in factories producing lead chromate (PbCrO4) and strontium chromate (SrCrO4). Sampling pre and post-shift in a factory where SrCrO4 production had just started showed the optimum strategy for biological monitoring is the measurement of urinary chromium, in urine samples taken at the end of Friday shift and pre-shift the following Monday. However, short-term uptake may be assessed under these circumstances by the increase in urinary chromium over a shift. Body burden, representing long-term chromate exposure is best assessed by measuring chromium in whole blood or pre-shift urinary chromium at the beginning of the working week. Exceptionally high levels of chromium in blood (387-4160 nmol l-1) and urine (41-1250 nmol nmol-1 creatinine) as well as skin and nasal lesions, were discovered amongst the workforce at the strontium chromate plant. These contrasted with occupationally unexposed levels of less than 20 nmol l-1 and less than 1 nmol nmol-1 creatinine, respectively, and led to the continuation of the biological monitoring programme. At the same time, improved working practices and respiratory protection equipment were introduced. A steady elimination of chromium from whole blood with a half-life of approximately 24 days was found. This elimination rate was confirmed over a 14 day period when the workforce were completely removed from exposure. The study confirms the usefulness of biological monitoring in assessing the uptake of hexavalent chromium and control of exposure.

Chromates↗

PubMed1992

Biological monitoring in the occupational setting--relationship to cadmium exposure.

Statutory health surveillance of occupational exposure to cadmium exists in most Western countries. For biological monitoring, both indicators of internal dose and indicators of effect are available. Cadmium in urine is an indicator of chronic exposure and essentially reflects the body burden under low-exposure conditions and in the absence of renal damage. Whole blood cadmium is primarily a useful indicator for use in evaluations of recent exposures. Biological threshold limit values for cadmium in urine and blood are based on the correlation of biological levels with thresholds for renal dysfunction. The use of markers of high and low molecular weight proteinuria should be integrated into the health surveillance of cadmium-exposed workers. Priority should be given to the determination of albumin and of proteins such as beta 2-microglobulin, retinol-binding protein and alpha 1-microglobulin. Interpretation of biological monitoring data in terms of the threshold values requires a programme of periodic biological, medical and environmental monitoring.

Cadmium↗

PubMedDate not supplied

Biological monitoring: the role of toxicokinetics and physiologically based pharmacokinetic modeling.

This short review outlines the contribution of modeling techniques, particularly physiologically based pharmacokinetic (PBPK) modeling, in promulgating biological monitoring as a practical tool for the occupational health professional. The impact of modeling techniques is discussed in helping to establish the relevant biomarkers to measure, the appropriate time of sampling, and the relationship between atmospheric exposure limits and concentration of biological analyte. Of particular interest is the use of "population" PBPK techniques. These can explore the influence of physiological differences between workers or of particular susceptible subgroups (e.g., pregnant women, breast-feeding mothers, and infants) on the relationship between atmospheric exposure levels and biomarker concentration. Such techniques will become more widely used as biological monitoring guidance values (e.g., biological exposure indices, biological tolerance values) are increasingly established by various international professional and regulatory bodies.

Adult↗

PubMed1997

Diffusive sampling and biological monitoring of 2-bromopropane.

The possibilities to apply personal ambient air monitoring by diffusive sampling and biological exposure monitoring by urinalysis for 2-bromopropane or its metabolites were explored. The abilities of carbon cloth to adsorb 2-bromopropane was examined by experimental vapor exposure followed by solvent extraction and FID-GC. Urine from factory workers and rats exposed to 2-bromopropane were analyzed for 2-bromopropane, acetone and isopropyl alcohol by FID-GC, and for bromide ion by ECD-GC after chemical methylation. Carbon cloth adsorbed 2-bromopropane in a manner linearly related to exposures up to 1500 mg/m3 and to 8 h. The adsorption could quantitatively detect a 15 min peak exposure at 3,000 mg/m3. In rat experiments, analyses of urine samples collected over a 4-h period after termination of a 4-h exposure to 2-bromopropane at 500, 1,000 or 1,500 mg/m3 showed that acetone and bromide ion were excreted dose-dependently. Essentially, no 2-bromopropane or isopropyl alcohol was detected. When the analytical methods were applied to urine samples from 5 male workers exposed to 2-bromopropane at a low level (3 mg/m3 as a geometric mean), acetone and bromide ion levels were within respective normal ranges in four cases, but were higher than the upper limits of the normal ranges in the fifth case of a foreman who probably had the highest exposure. Thus, diffusive sampling is applicable to monitor exposure to 2-bromopropane. Urinalysis for acetone and bromide ion in combination appears to be a promising selective tool for biological monitoring of occupational exposure to 2-bromopropane.

Air Pollutants↗

PubMed2002

Biological monitoring of pesticide exposure: a review of analytical methods.

A wide range of studies concerned with analytical methods for biological monitoring of exposure to pesticides is reviewed. All phases of analytical procedures are assessed, including sampling and storage, sample preparation and analysis, and validation of methods. Most of the studies aimed at measuring metabolites or unchanged compounds in urine and/or blood as biological indicators of exposure or dose. Biological indicators of effect, such as cholinesterase, are also evaluated. The principal groups of pesticides are considered: organophosphorus pesticides, carbamate pesticides, organochlorine pesticides, pyrethroid pesticides, herbicides, fungicides and other compounds. Choice of the method for biological monitoring of exposure depends on the study population: a detection limit of 1 microg/l or less is required for the general population; higher values are adequate for occupationally exposed subjects. Interpretation of results is also discussed. Since biological indices of exposure are only available for a few compounds, biological reference values, established for the general population, may be used for comparison with levels of professionally exposed subjects.

Environmental Monitoring↗