Biological Monitoring Of Workers Research Articles

Microextraction techniques for occupational biological monitoring: Basic principles, current applications and future perspectives.

The application of green microextraction techniques (METs) is constantly being developed in different areas including pharmaceutical, forensic, food and environmental analysis. However, they are less used in biological monitoring of workers in occupational settings. Developing valid extraction methods and analytical techniques for the determination of occupational indicators plays a critical role in the management of workers' exposure to chemicals in workplaces. Microextraction techniques have become increasingly important because they are inexpensive, robust and environmentally friendly. This study aimed to provide a comprehensive review and interpret the applications of METs and novel sorbents and liquids in biological monitoring. Future perspectives and occupational indicators that METs have not yet been developed for are also discussed.

Exposure to Volatile Organic Compounds in Paint Production Plants: Levels and Potential Human Health Risks.

A wide range of volatile organic solvents, including aliphatic and aromatic hydrocarbons, alcohols, and ketones, are used in the production of paints, and they comprise more than 30% of the ingredients of paints. The present study was designed to evaluate the occupational exposure to 15 volatile organic compounds (VOCs, including benzene, toluene, ethylbenzene, xylene, styrene, n-hexane, n-heptane, n-nonane, trichloroethylene, tetrachloroethylene, n-butyl acetate, n-octane, n-decane, dichlorofluoromethane, and acetone) in Iranian paint production factories and subsequently, the associated health risks. The samples were collected from the respiratory zone of workers using the NIOSH 1501 method, and their qualitative and quantitative characterization was performed using gas chromatography-mass spectrometry and gas chromatography-flame ionization detector, respectively. The individual concentrations of VOCs ranged from 23.76 ± 0.57 µg m-3 (acetone) to 92489.91 ± 0.65 µg m-3 (m,p-xylene). The predominant compounds were m,p-xylene (up to 92489.91 ± 0.65 µg m-3), ethylbenzene (up to 91188.95 ± 0.34 µg m-3), and toluene (up to 46088.84 ± 0.14 µg m-3). The non-cancer risks of benzene, n-nonane, trichloroethylene, tetrachloroethylene, xylene, and ethylbenzene surpassed the reference value in most of the sectors. In addition, total lifetime risks of cancer were in the range of 1.8 × 10-5-3.85 × 10-3, suggesting that there was a risk of carcinogenesis in all studied sections, mainly due to ethylbenzene and benzene. Considering their high exposure concentrations and their associated non-carcinogenic and carcinogenic risks, biological monitoring of workers and the use of technical and modern engineering control measures are recommended.

Naphthol as A Biological Monitoring on Naphthalene Exposure in Workers

Introduction: Naphthalene is one of the chemicals that are widely used throughout the world, such as aircraft fuel, camphor, insecticides, and colouring agents in cosmetics. Exposure to naphthalene can cause health problems ranging from dermatitis and haemolytic anaemia to even the possibility of cancer of the respiratory tract, therefore it is necessary to carry out biological monitoring of workers at risk. The aim of this study is to find out which is the simplest and most reliable biomonitoring to use based on an evidence-based literature review. Methods: Literature search was conducted through electronic databases from PubMed, ProQuest, and Cochrane. The keywords used are worker, naphthalene, and biomonitoring. Initially, 273 articles were obtained, but after going through a selection process and manual search, seven articles were examined. Results: Based on the selected evidence-based literature, it was found that there was an increase in the level of naphthol in the urine in workers exposed to naphthalene who were examined during pre-shift and post-shift. Conclusion: Naphthol concentration in urine can be a non-invasive, easy, and reliable biomonitoring exposure of naphthalene. Although it is currently not possible to do this in Indonesia, this study shows the importance of biomonitoring to prevent occupational diseases due to this exposure.

Increased urine chromium concentrations in a worker exposed to lead chromate due to medicinal herb intake

Background: Hexavalent chromium compounds are sensitizers of the skin and lung. Chronic exposure to hexavalent chromium compounds is associated with respiratory effects and ulceration and perforation of the nasal septum. Such compounds are also considered carcinogens of the lung and nasal and paranasal sinus. Objectives: To demonstrate the importance of studying occupational and non-occupational exposure when assessing the concentration of substances in the urine. Case study: A study was conducted of environmental chromium concentrations in the workplace. In addition, an occupational medical examination was performed, recording activities inside and outside the workplace, eating habits, blood lead and urine chromium at the beginning and end of the workday. Results: One worker exposed to lead chromate presented high chromium concentrations in urine (up to 62 µg/l before the working day and 52 µg/l at the end of the working day). Environmental chromium concentrations in the workplace were below 0.25 µg/m3. In view of the results, a full study was conducted of the patient’s habits outside work. He reported having bought a kilo of a medicinal herb infusion at a street market three weeks previously. The concentration of total chromium in the prepared infusion was 12000 µg/l. The patient stopped consuming the medicinal herb. Subsequently, the urine chromium analysis was below 0.5 µg/l. Discussion and Conclusions: This case is interesting because it demonstrates that the consumption of medicinal herbs can interfere with biological monitoring of workers exposed to hexavalent chromium compounds. This may give rise to confusion and can also create legal problems for companies and workers. It is important to provide advice to workers and to investigate their habits outside work, especially when there is a discrepancy between environmental and biological values. In this case, the increase in urinary chromium is due to the consumption of medicinal herbs.

DNA damage and inflammatory response in workers exposed to fuels and paints

Workers exposed to fuels and paints may present alterations in several parameters. Thus, we assessed potential biomarkers, with the aim of detecting early changes in gasoline station attendants and painters. Blood samples were collected for the analysis of inflammatory and DNA damage markers, besides biochemical, haematological and oxidative stress parameters. Biochemical and haematological parameters, which are assessed with routine exams, showed few changes. However, these findings could mask the workers’ real health status. Besides, markers of oxidative damage were not modified. Levels of inflammatory parameters (cytokines and nitric oxide levels) and the DNA damage marker 8-hydroxydeoxyguanosine were significantly changed in the workers. Our results suggest that inflammatory and DNA damage parameters can be potential biomarkers for the biological monitoring of workers exposed to fuels and paints and may contribute to the development of occupational protection standards.

Exploring a new method for the biological monitoring of plastic workers exposed to the vinyl chloride monomer

Vinyl chloride monomer (VCM) is widely used in the production of polyvinyl chloride (PVC) plastics. VCM is recognized as a confirmed human and animal carcinogenic compound. Recent studies have reported poor health of plastic workers, even having exposure at concentrations below the permissible limit to VCM. There has not been any study regarding exposed workers to VCM in Iran. Similarly, no information exists as to the biological monitoring of such workers. The main purpose of this study was to conduct a thorough occupational and biological monitoring of Iranian plastic workers exposed to VCM.A total of 100 workers from two plastic manufacturing plants (A and B) in Tehran along with 25 unexposed workers as controls were studied. The personal monitoring of all nonsmoking workers exposed to VCM at two plastic manufacturing plants (A and B) was performed in the morning shift (8 a.m. to 4 p.m.) according to the National Institute For Occupational Safety And Health method no. 1007.Biological monitoring of workers was carried out through collection of exhaled breath of all exposed and control workers in Tedlar bags and with a subsequent analysis using gas chromatography-flame ionization detector.Not only the mean occupational exposure of workers to VCM at plant A was higher than the respective threshold limit value but also the statistical significance was higher than workers at plant B. Similarly, VCM concentration in exhaled breath of workers at plant A was also statistically significantly higher than at plant B. Correlation of occupational exposure of all workers to vinyl chloride with its concentration in exhaled breath was statistically significant.This is the first study on biological monitoring for exposed plastic workers to VCM using exhaled breath. On the basis of the results in this study, a novel method of biological monitoring of plastic workers was proposed.

소변 중 디아민을 이용한 디이소시아네이트 노출 근로자의 생물학적 모니터링

소변 중 디아민을 이용한 디이소시아네이트 노출 근로자의 생물학적 모니터링

The use of biomarkers in occupational health research, practice, and policy

Biomarkers are potentially useful tools for occupational health and safety research, practice, and policy. However, the full realization of this potential has not been achieved. In this paper, the progress made in these three usage areas is reviewed to identify what efforts can be taken to realize the full promise of biomarkers. Biomarker uses are described by a diverse taxonomy that builds on the categories of exposure, effect and susceptibility, and the continuum between exposure and disease prognosis. The most significant uses of biomarkers in occupational health have been in biological monitoring of workers. Other important uses have been in enhancing research and assessing mechanisms of action of occupational toxicants at low exposures.Seven critical areas will influence the extent to which the potential of biomarkers in occupational health and safety is realized. These include: (1) adequate investment in validation; (2) obtaining international agreement on exposure guidelines; (3) exploring the utility of biomarkers in regulation; (4) applying biomarkers to critical occupational safety and health questions; (5) developing the exposome; (6) utilizing biomarkers to address emerging occupational health issues; and (7) continuing to address the ethical and social justice issues related to biomarkers. Overall, if biomarkers are to make a major contribution to occupational health and safety then a more holistic approach to bringing them from the laboratory to practice will be needed.

Occupational Renal Dysfunction Among Asphalt Workers In Sharkia Governorate: An Epidemiological Study

Background: Occupational exposure to bitumen fumes emitted during hot application of asphalt carries the risk of exposure to significant amount of hydrocarbon compounds that may cause toxic nephropathy. Objectives: Investigation of renal dysfunction among asphalt-exposed workers and identification of some factors that may be associated with these renal effects. Subjects and methods : A cross-sectional study was carried out at one of the road paving sation in Sharkia Governorate. Ninety-four male asphalt workers and seventy-three non exposed workers, as controls, were included in the study. All participants were interviewed and answered a preconstructed questionnaire including personal and occupational characteristics, present and past medical history suggesting renal involvement. Weight, height and blood pressure were measured. Fasting blood and urine samples were collected from all participants. Urine was examined for presence of red blood corpuscles, leukocytes, total protein, microalbumin and pimicroglobulin. Serum creatinine was also estimated. Results: the results of this study revealed a significantly higher prevalence of renal manifestations among asphalt workers when compared with controls (OR = 50.1). Furthermore asphalt workers had significantly higher prevalence of abnormal renal nephrotoxic markers serum creatinine: 23.4%, total proteinuria 17%, microscopic hemaiuria: 11.7%, leukocyturia : 17%, microalbuminuria : 31.9% and p; microglobulinuria: 31.9%). The presence of both microglbuminuria and urinary cellular sediment seemed to occur nearly 9.5 times more than the presence of urinary sediment alone. Asphalt workers were more likely to have irreversible glomerular damage about 8.5 times more than the control subjects, while there was no statistically significant difference between. the two groups regarding the presence of irreversible tubular damage (P > 0.05). Duration of employment > 15 years was the only factor associated with occurrence of renal dysfunction. Conclusion: occupational exposure to asphalt during road paving was associated with renal dysfunction and may be responsible for diverse effects on both glomeruli and renal tubules. These dysfunctions were mostly related to the duration of exposure lo asphalt. So, it was recommended dial preplacement and periodic medical examinations, biological monitoring for workers, periodic environmental assessment, personal cleanliness, and regular use of protective equipments can be of a great help in minimizing the risk of renal dysfunction among asphalt workers. Key words: renal dysfunction, asphalt workers, nephrotoxin, glomerular damage

A Cluster of Neurological Signs and Symptoms in Soil Fumigators

Methyl bromide (CH 3 Br) is a practically odourless, highly toxic and penetrating volatile aliphatic hydrocarbon derivative that has been widely used in agriculture as a fumigant against rodents, insects, mites, and a range of pathogenic organisms in soil, compost, and timber. According to the Montreal Protocol on Substances that Deplete the Ozone Layer, it should have been phased-out of from use in developed countries by 1 January 2005. However, since an effective substitute does not exist, and its elimination would cause many problems in agricultural industries that are still heavily reliant on its use , it is still being employed for many purposes. Methyl bromide exposure can cause skin, kidney, and respiratory, liver and neurological damage in workers. Fatal and non-fatal poisoning accidents have been reported since 1948 and are still common both in developed 5) and in developing countries . Long-lasting neurological consequences resulting from occupational accidents are also well known and . To our knowledge, however, no long-term prospective study of exposed workers has ever been published, and the effects of prolonged, low-dose occupational exposure are seldom reported. Regular medical examination of exposed workers has been obligatory in Italy since 1956, and exposure assessment and biological monitoring of workers in compliance with European directives, have been required only since 2002. These regulations are not, however, always fully enforced in agriculture. Here we report a cluster of cases of neurological signs and symptoms of varying severity, in a sample of farm workers from the same company who were employed as fumigators to vaporising CH 3 Br in greenhouses or open fields.

Biological monitoring of workers after the application of insecticidal pyrethroids.

Pyrethroids are applied as insecticides throughout the world. Human metabolism of pyrethroids results in urinary metabolites that are suitable for biological monitoring. The aim of the study was to evaluate individual exposure due to occupational application of pyrethroids as a precondition for the assessment of health risks. Thirty-six workers who applied insecticides and other pesticides in Germany collected samples of their urine (24 h) after having used various pyrethroids (alpha-cypermethrin, cypermethrin, cyfluthrin, deltamethrin, tau-fluvalinate, permethrin, lambda-cyhalothrin) in agriculture, greenhouses or indoor pest control. Biological monitoring was carried out and metabolites were analysed in 61 urine samples by GC-MS: cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid ( cis-Cl(2)CA and trans-Cl(2)CA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid ( cis-Br(2)CA), 3-phenoxybenzoic acid (3-PBA) and 4-fluoro-3-phenoxybenzoic acid (FPBA). Forty-five urine specimens collected (24 h) from persons with no occupational exposure to pyrethroids served as controls. Concentrations were related to creatinine content and expressed as microgrammes per gramme creatinine. Control urine samples revealed a considerable background excretion of pyrethroid metabolites by the general population. The 95th percentile of the concentrations of Cl(2)CA and cis-Br(2)CA were 2.1 and 0.1 microg/g creatinine, respectively. FPBA was not detected in any control urine and was found in only one sample within the complete study. After occupational application of pyrethroids the highest concentrations of metabolites in urine samples were detected within the group of indoor pest-control operators. The maximum concentrations (median values) of Cl(2)CA, 3-PBA, and cis-Br(2)CA were 92.4 microg/g (1.8 microg/g), 57.5 microg/g (1.4 microg/g) and 1.1 microg/g (median below detection limit), respectively. Workers in greenhouses excreted metabolites with median concentrations as follows: 2.9 microg/g Cl(2)CA, 0.5 microg/g cis-Br(2)CA and 2.9 microg/g 3-PBA. Medians of the metabolite concentrations in specimens from agricultural workers were below the detection limit with regard to Cl(2)CA and cis-Br(2)CA, but the value was 0.6 microg/g for 3-PBA. Pest-control operators excreted significantly higher concentrations of Cl(2)CA and 3-PBA than workers in agriculture on a collective basis. Comparison of the excreted concentrations of metabolites with values of acceptable daily intake (ADI) of pyrethroids set by WHO revealed that the amount of pyrethroids that had been taken up during occupational application was not considerably higher than the ADI. As a consequence, we conclude that adverse health effects are not to be expected after workers' occupational exposure to pyrethroids in Germany, provided that the application is carried out properly. Good working practices need to be supported by adequate supervision with regard to occupational hygiene and medicine.

Analysis of Styrene and its Metabolites in Blood and Urine of Workers Exposed to both Styrene and Acetone

A purge-and-trap gas chromatographic (PT-GC) method for determining styrene concentrations in urine and blood samples has been used in the biological monitoring of workers exposed to styrene and acetone. Blood and urine samples were collected from 34 individuals exposed to both solvents at the end of a 4-h shift and measured for styrene in urine (Su), blood (Sb), and the two major urinary metabolites, mandelic acid (MA) and phenylglyoxylic acid (PGA). A second urine sample was taken at the beginning of the next shift. Environmental exposure was measured using passive personal monitoring and GC. Urinary excretion of MA and PGA was measured by high-performance liquid chromatography. The average exposures to styrene and acetone were 70.5 mg/m3 and 370.5 mg/m3, respectively. In end-of-shift samples there was a significant correlation between concentrations of Su and Sb and the metabolites PGA, MA (r = 0.714 and 0.788, p < 0.001 for Su and r = 0.644 and 0.566, p < 0.005 for Sb). A high correlation between Sb and Su (r = 0.732, p < 0.001) also existed. Poor correlations were found between Su and metabolites in samples collected at the beginning of the next shift (r = 0.491 and 0.474 for PGA and MA, respectively, p < 0.05). There was a better correlation between the biological parameters at the end of the shift and the environmental styrene (r = 0.841 for PGA, r = 0.834 for MA, r = 0.788 for Su, and r = 0.698 for Sb; p < 0.001) compared with those at the start of the shift (r = 0.81 for PGA, 0.675 for MA, and 0.650 for Su; p < 0.001). We found that the concentration of excreted metabolites decreased significantly when environmental concentrations of acetone increased (p < 0.05), particularly at the end of the shift. Although the best correlation with environmental styrene was obtained with the sum of PGA and MA at the end of the shift (r = 0.862, p < 0.001), urine and blood styrene were shown to be more useful biological monitoring indicators because their concentrations were not affected by acetone co-exposure.

Urinary 2-Ethoxyacetic Acid for Biological Monitoring of Workers Exposed to 2-Ethoxyethyl Acetate

Urinary 2-Ethoxyacetic Acid for Biological Monitoring of Workers Exposed to 2-Ethoxyethyl Acetate

Biological monitoring of workers exposed to carbon disulfide (CS2) in a viscose rayon fibers factory

Biological monitoring of workers exposed to carbon disulfide (CS2) in a viscose rayon fibers factory

Biological monitoring of workers exposed to carbon disulfide

Urinary 2-thiothiazolidine-4-carboxylic acid (TTCA) concentrations and corresponding personal breathing zone carbon disulfide (CS2) air concentrations were measured for worker populations at a Tennessee rubber product facility and a Virginia viscose rayon plant. At the rubber product facility, all of the 19 workers had urinary TTCA levels less than the limit of detection (LOD) of about 0.03 mg/L, equivalent to less than 0.5 ppm of CS2 in air. At the viscose rayon plant, five of six workers, although wearing half-mask cartridge respirators, showed increased urinary TTCA during the workshift. The cutters and spinners had the largest increases in urinary TTCA concentrations; they also had the highest breathing zone exposures to CS2. The TTCA concentrations for three cutters and spinners did not return to normal preshift levels of < 0.3 mg/g creatinine before the start of the next shift. The arithmetic mean respirator workplace protection factor (WPF) was 7.0 +/- 2.2. Increase in urinary TTCA concentration during the workshift and postshift urinary TTCA concentration reflected CS2 air concentration equally well. In conjunction with air monitoring results, urinary TTCA concentrations allow determination of the WPF afforded workers wearing respirators and identify workers not adhering to safety rules and good work practices. Workers at risk of adverse health effects from overexposure to CS2 for any reason may thus be identified.

Biological monitoring of workers exposed to low levels of 2-butoxyethanol.

(1) To assess the value of urinary butoxyacetic acid (BAA) measurement for the monitoring of workers exposed to low concentration of 2-butoxyethanol (BE); (2) to evaluate the in vivo effect of low occupational BE exposure on the erythrocyte lineage; and (3) to test the possible influence of genetic polymorphism for cytochrome P450 2E1 (CYP 2E1) on urinary BAA excretion rate. Thirty-one male workers exposed to BE in a beverage package production plant were examined according to their external (BE) and internal (BAA) solvent exposure. The effect of this exposure on erythrocyte lineage [red blood cell numeration (RBC), hemoglobin (Hb), hematocrit (Htc), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), haptoglobin (Hp), reticulocyte numeration (Ret) and osmotic resistance (OR)], hepatic [aspartate aminotransferase (GOT), alanine aminotransferase (GPT)] and renal [plasmatic creatinine, urinary retinol binding protein (RBP)] parameters was also investigated. DNA purified from whole blood was used for CYP 2E1 genotyping. Average airborne concentration of BE was 2.91 mg/m3 (0.59 ppm) with a standard deviation of 1.30 mg/m3 (0.27 ppm). There was a relatively good correlation between external and internal exposure estimated by measuring BAA in post-shift urine samples (average 10.4 mg/g creatinine; r = 0.55; P = 0.0012). Compared with a matched control group (n = 21) exposed workers had a statistically significant decrease (3.3%; P = 0.03) in Hct while MCHC was increased (2.1%; P = 0.02). No significant difference was observed either in other erythroid parameters or in hepatic and renal biomarkers. One exposed individual exhibited a mutant allele with increased cytochrome P450 oxidative activity which coincided with a very low urinary BAA excretion. Single determination of BAA in post-shift urine samples can be used to assess exposure to low levels of BE. A slight but significant effect on erythroid parameters suggesting membrane damage was observed in exposed workers. The influence of the genetic polymorphism for CYP 2E1 deserves further investigation for the interpretation of urinary BAA measurements.

Biological monitoring of workers' exposure to bromine.

The use of serum bromine concentration (SeBr) as a measure of exposure was examined in an occupational cohort. Associations with work site, department type, chemical handling, and occupation, as proxy measures of exposure, were studied. SeBr was associated with all of these measures. SeBr was also associated with various demographic characteristics (age, country of origin, and education) in men. In women, there was no association between SeBr and age, country of origin, or education. The use of SeBr as a measure of exposure is discussed. The conclusion is that the exposure to bromine can be assessed by regular monitoring of SeBr.

Coordinating Federal and State Lead Control Activities: The Connecticut Model for Integrated Lead Exposure Enforcement

Abstract Activities related to lead exposure control and enforcement occur at various levels of state and federal government. Many states have blood lead surveillance programs requiring laboratories and clinicians to report elevated blood lead levels to state lead registries. In Connecticut, the Adult Blood Lead Registry, operated by the Department of Public Health and Addiction Services, receives reports of blood lead levels in excess of 10 μg/dl from clinical laboratories. Further, the U.S. Department of Labor-Occupational Safety and Health Administration, through the General Industry and Construction Lead Standards, requires biological monitoring of workers. In Connecticut, the Department of Transportation, through the Connecticut Road Industry Surveillance Project, requires monitoring of worker blood lead levels by contract specification. In 1993 these four agencies joined together to form a single integrated enforcement network designed to control lead toxicity in workers throughout Connecticut. Usin...

Biological monitoring of workers exposed to N, N-dimethylfomamide. I. Methods of analysis.

Some methods for analysing N,N-dimethylformamide and its metabolites [hydroxymethyl-N-methylformamide, hydroxymethylformamide and N-acetyl-S-(N-methylcarbamoyl)cysteine] in the urine of exposed workers are described. Unchanged dimethylformamide was measured after pretreatment of urine (2 ml) with silica gel cartridges and elution with methanol. The gas chromatographic analysis using a nitrogen phosphor detector made it possible to detect N,N-dimethylformamide in urine even when workers were exposed to low concentrations of the solvent (about 1 mg/m3). N-Hydroxymethyl-N-methylformamide and N-hydroxymethylformamide were analysed as N-methylformamide and formamide respectively after direct injection of urine into the gas chromatograph. The injection port temperature played an important role in the gas chromatographic determination of these products. Reliable results were obtained when direct or split injections were performed at 250 degrees C. The splitless injection gave the same reliable results at 150 degrees C. In urine samples from occupationally non-exposed persons, N-methylformamide could not be detected. In contrast, formamide (or its precursor, hydroxymethylformamide) was present in every urine sample. Our results in respect of 19 urine samples analysed with the injection port of the gas chromatograph at 250 degrees C gave a mean of 8.6 mg/l of formamide. N-Acetyl-S-(N-methylcarbamoyl)cysteine was determined using a modified method for analysing organic acid in urine samples. The metabolite was extracted with ethyl ether in an acid environment, treated with a silylating reagent and measured by gas chromatography/mass spectrometry.

Biological Monitoring of Workers Exposed to Carbon Tetrachloride Vapor

Abstract Occupational exposure to carbon tetrachloride was studied by analysis of environmental air, blood, and urine from 55 workers operating in two chemical plants where carbon tetrachloride was used. For the measurement of environmental concentration of carbon tetrachloride (Ci), the ambient air was sampled using personal passive dosimeters. The activated charcoal was de-sorbed with carbon disulfide and injected into a gas cromatograph-mass spectrometer (GC-MSD). The biological monitoring of exposed workers was conducted by determining the concentration of carbon tetrachloride in blood and urine. Urine and blood concentrations of carbon tetrachloride were determined by headspace analysis using GC-MSD. Significant correlations were found between the environmental carbon tetrachloride concentration and the blood and urinary concentrations. The use of a regression equation between Cu (ng/L) and Ci (mg/m3) (Cu = 125.7 × Ci + 56.2) result in a value of Cu corresponding to threshold limit value-time-weighte...