Biomonitoring of low levels of exposure to styrene.
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Environmental Monitoring↗
Biomedical subjects
S Ghittori
Publications and source records attributed to S Ghittori.
Evaluation of occupational exposure to benzene by urinalysis.
Urinary phenol determinations have traditionally been used to monitor high levels of occupational benzene exposure. However, urinary phenol cannot be used to monitor low-level exposures. New biological indexes for exposure to low levels of benzene are thus needed. The aim of this study was to investigate the relations between exposure to benzene (A-benzene, ppm), as measured by personal air sampling, and the excretion of benzene (U-benzene, ng/l), trans,trans-muconic acid (MA, mg/g creatinine), and S-phenylmercapturic acid (PMA, micrograms/g creatinine) in urine. The subjects of the study were 145 workers exposed to benzene in a chemical plant. The geometric mean exposure level was 0.1 ppm (geometric standard deviation = 4.16). After logarithmic transformation of the data the following linear regressions were found: log (U-benzene, ng/l) = 0.681 log (A-benzene ppm) + 4.018; log (MA, mg/g creatinine) = 0.429 log (A-benzen ppm) - 0.304; and log (PMA, micrograms/g creatinine) = 0.712 log (A-benzene ppm) + 1.664. The correlation coefficients were, respectively, 0.66, 0.58, and 0.74. On the basis of the equations it was possible to establish tentative biological limit values corresponding to the respective occupational exposure limit values. In conclusion, the concentrations of benzene, mercapturic acid, and muconic acid in urine proved to be good parameters for monitoring low benzene exposure at the workplace.
Adult↗
Anesthetic in urine as biological index of exposure in operating-room personnel.
The aim of this study was to determine if a relationship existed between some inhalation anesthetics airborne exposure levels (Cl) and the concentration of anesthetics in samples of urine produced throughout the exposure time (Cu). The concentrations of nitrous oxide (N2O), halothane (fluothane), enflurane (ethrane), and isoflurane (forane) in the ambient atmosphere were determined in 190 operating theaters of 41 hospitals in Italy. Nitrous oxide, halothane, enflurane and isoflurane were detected in the urine of 1521 exposed subjects (anesthetists, surgeons, and nurses). The environmental measurements were performed using personal passive samplers, and the biological measurements were performed using the head space method. Significant correlations were found between the anesthetics concentration in urine produced during the shift collected after a 4-h exposure (Cu, microgram/L) and anesthetics environmental concentration (Cl, ppm). The results show that the urinary anesthetic concentration can be used as an appropriate biological exposure index. The biological values (urinary concentration values) proposed are the following: nitrous oxide, 25 micrograms/L, for an environmental value of 50 ppm; halothane, 97 micrograms/L, corresponding to 50 ppm of environmental exposure; 6.2 micrograms/L, corresponding to 2 ppm of environmental exposure; enflurane, 145 micrograms/L for an environmental exposure of 75 ppm and 5.6 micrograms/L for an environmental exposure of 2 ppm; isoflurane, 5.3 micrograms/L for an environmental exposure of 2 ppm. The values proposed are the respectively 95% lower confidence limit and therefore should be considered as a protection for the individual, especially if each biological value is corrected according to analytical variability of the measurements. In our opinion, the method of choice in the assessment of occupational exposure to inhalation anesthetics is the measurement of the urinary anesthetic concentration.
Adult↗
Low flow anaesthesia reduces occupational exposure to inhalation anaesthetics. Environmental and biological measurements in operating room personnel.
In the present study we evaluated the occupational exposure to N2O and isoflurane during open circuit (OC) (fresh gas flow > or = minute volume) and low flow (LF) (fresh gas flow = 1.5 l/min) anaesthesia. The effects of active scavenging and of a charcoal filter positioned on the exhausting branch of the ventilator on environmental and urinary concentrations of inhalation anaesthetics were also investigated. The study was carried out in the same operating room provided with non-recirculating air changes (10 per hour). It involved anaesthetists and nurses during routine activity. N2O and isoflurane concentrations (time-weighted average) were measured after 3-hour continuous exposure: 1) in the environment at the level of the personnel's breathing zone (Ci); 2) in the environment at the ventilator zone (C); 3) in urine (Cu). During OC anaesthesia without active scavenging the breathing zone concentration of both N2O and isoflurane was very high (194.6 +/- 15.2 and 5.0 +/- 0.4 ppm, respectively). The activation of the scavenging greatly reduced the breathing zone concentration of N2O (31.6 +/- 4.1 ppm) and isoflurane (1.7 +/- 0.2 ppm). LF anaesthesia (with active scavenging) significantly reduced the environmental concentration of both anaesthetics (Ci N2O and isoflurane 22.7 +/- 1.8 and 0.6 +/- 0.04 ppm, respectively). During LF anaesthesia the breathing zone concentration of N2O remained low, even without scavenging (22.7 +/- 1.8 ppm). Similar results were obtained by measuring N2O and isoflurane concentrations at the ventilator zone and in urine.(ABSTRACT TRUNCATED AT 250 WORDS)
Air Pollutants, Occupational↗
Determination of 2,5-hexandione by high-performance liquid chromatography after derivatization with dansylhydrazine.
A sensitive method for the determination of free and total urinary 2,5-hexandione (2,5-HD) using high-performance liquid chromatography with fluorescence detection was developed. After purification of urine with a disposable C18 cartridge, 2,5-HD was derivatized with dansylhydrazine; 1,3-diacetyl benzene (1,3-DAB) was added to the samples, as internal standard, prior to extraction. The resulting fluorescent adducts were separated on a reversed-phase column with a gradient mobile phase of 25 mM phosphate buffer (pH 6.4) and acetonitrile. The retention times of the 2,5-HD and 1,3-DAB derivatives were 9.4 and 13.7 min, respectively. The derivatives were detected by a fluorescence detector (excitation 340 nm, emission 525 nm). The mean recoveries of 2,5-HD and 1,3-DAB were 92.0 and 94.0%, respectively; the detection limit of 2,5-HD (signal-to-noise ratio of 3) was 5 micrograms/l in urine without hydrolysis and ca. 12 micrograms/l in hydrolyzed samples. The method was applied to 39 urine samples from workers exposed to n-hexane; the mean values were 2.597 mg/l (S.D. = +/- 0.758) for total 2,5-HD and 0.179 mg/l (S.D. = +/- 0.086) for free 2,5-HD. Urine samples of 22 non-exposed subjects showed a mean concentration of 0.437 mg/l (S.D. = +/- 0.109) and 0.022 mg/l (S.D. = +/- 0.011) for total and free 2,5-HD, respectively.
Acetonitriles↗
Biological monitoring of the occupational exposure to halothane (fluothane) in operating room personnel.
The concentration of halothane (fluothane) in the ambient atmosphere was determined in five operating theaters of two hospitals in Italy. The concentrations of halothane in the ambient air exceeded the NIOSH recommended time-weighted average exposure levels (median value: 10.38 mg/m3). Halothane was detected in the urine of 58 exposed subjects (anesthetists, surgeons, and nurses). A significant correlation was found between the halothane concentration in urine produced during the shift (Cu, micrograms/L) and halothane environmental concentration (CI, mg/m3) (Cu = 0.242 x CI + 3.51) (N = 58; r = 0.92; p less than 0.0001). The results show that the urinary halothane concentration can be used as an appropriate biological exposure index. The biological values proposed are: 92 micrograms/L, corresponding to a 50 ppm of environmental exposure; 6.5 micrograms/L, corresponding to 2 ppm of environmental exposure and 3.9 micrograms/L, corresponding to a 0.5 ppm of environmental exposure.
Adult↗
Acquired dyschromatopsia among styrene-exposed workers.
We investigated the occurrence of color vision loss in 75 styrene-exposed workers and in 60 referents. Color vision was evaluated by adopting the Lanthony D 15 desaturated panel, a test specifically suited to detect mild acquired dyschromatopsia. The results of the test were expressed as Color Confusion Index. Styrene exposure was evaluated with both environmental and biological monitoring. Airborne levels of the solvent were 3.2 to 549.5 mg/m3. In styrene-exposed workers color vision was significantly impaired when compared with referents matched for age. A significative correlation was found between environmental and urinary levels of styrene and Color Confusion Index excluding the influence of age in multiple regression analysis, indicating the possibility of a dose-effect relationship. The findings suggest that styrene can induce an early appearance of a dose-dependent color vision loss.
Adult↗
1,2-Dichloropropane hepatotoxicity in rats after inhalation exposure.
The hepatic effects of 1,2-dichloropropane (DCP) were investigated in male Wistar rats exposed to 15, 50, 100, 250, 450, 1000, 1300, 1800 or 4900 mg DCP m-3. At the end of a 4-h period of exposure, average blood DCP levels were 0.025 and 5.38 micrograms ml-1 in animals treated with 15 and 1300 mg m-3, respectively. Blood DCP concentrations were correlated with the air DCP concentrations in the inhalation chamber. At DCP concentrations of 100 mg m-3 or higher, the liver non-protein thiol (NPT) content was significantly reduced. Assays performed 20 h after 4-h DCP exposure showed that exposure to 100-1000 mg DCP m-3 had no effect on hepatic NPT levels. The NPT content increased only in the liver of rats exposed to higher (1300-4900 mg m-3) DCP concentrations. Treatment with DCP did not cause hepatic lipid peroxidation and did not modify total protein content. The observed changes in liver cell thiol homeostasis are likely to reflect the action of reactive intermediates formed during DCP metabolism. These changes can occur in rats following exposure to considerably low levels of DCP vapour.
Administration, Inhalation↗
Methyl ethyl ketone (MEK) in urine as biological index of exposure.
Fifteen human volunteers were exposed to methyl ethyl ketone (MEK) vapor at 11.9-621.8 mg/m3 for a period of 2 to 4 hours at rest (ten cases) and during light physical exercise (five cases). Subsequently 78 workers occupationally exposed to MEK in a manufacture of leather suitcases (median value: 75.5 mg/m3; geometrical standard deviation: 3.12 mg/m3; range: 6-790) were studied. The analyses were performed by means of a Gas Chromatograph (GC) Hewlett-Packard 5880 A connected with a Mass Selective Detector (MSD). The relative uptake (R) of MEK was about 0.54 (standard deviation: 0.05) and it keeps practically constant either at rest or during light effort (V < 30 L/min). A linear relationship existed in the experimentally exposed subjects between urinary concentration (Cu) and amount of MEK absorbed (U) (Cu = 3.05 x U-162.1; r = 0.95; n = 15) (Cu = micrograms/L; U = mg). Both in the experimentally exposed subjects and in the occupationally exposed workers, the urinary concentration of MEK shoved a linear relationship to the corresponding environmental time-weighted average concentration (CI). The correlation coefficients (r) were 0.93 in occupationally exposed subjects (regression equation: Cu = 0.004 x CI + 0.118; n = 78); Cu = mg/L; CI = mg/m3) and more than 0.93 in experimentally exposed groups. The findings indicate that the urinary concentration of MEK can be used as an appropriate biological exposure indicator.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
1,1,1-Trichloroethane (methyl chloroform) in urine as biological index of exposure.
Fifteen human volunteers were exposed to 1,1,1-trichloroethane (methyl chloroform) vapor at 72-495 mg/m3 for a period of 2 to 4 hours at rest (ten cases) and during light physical exercise (five cases). Subsequently 60 workers occupationally exposed to 1,1,1-trichloroethane in a refrigerator manufacturing plant were studied (median value: 178 mg/m3; geometrical standard deviation: 2.19 mg/m3). As expected, the relative uptake (R) of 1,1,1-trichloroethane decreased in the course of exposure at rest (R = 0.44 after 20 minutes of exposure; R = 0.26 after 240 minutes of exposure). Both in the experimentally exposed subjects and in the occupationally exposed workers, the urinary concentration of 1,1,1-trichloroethane showed a linear relationship to the corresponding environmental time-weighted average concentration. The correlation coefficients (r) were 0.95 in occupationally exposed subjects and more than 0.90 in experimentally exposed groups. A linear equation also existed between urinary concentration and amount of 1,1,1-trichloroethane absorbed (r = 0.88). The findings indicate that the urinary concentration of 1,1,1-trichloroethane can be used as an appropriate biological exposure indicator. In occupationally exposed subjects performing moderate work, the urinary 1,1,1-trichloroethane concentration corresponding to the time-weighted average of the threshold limit value was found to be 860 micrograms/L and its 95% lower confidence limit (biological threshold) 805 micrograms/L.
Adult↗
Evaluation of exposure to isoflurane (Forane): environmental and biological measurements in operating room personnel.
The concentration of isoflurane (Forane) in the ambient atmosphere was determined in 11 operating theaters of 5 hospitals in Italy. The concentration of isoflurane in the ambient air exceeds the recommended time-weighted average exposure levels (median value: 113 mumol/m3). Isoflurane was detected in the urine of 45 exposed subjects (anesthetists, surgeons, and nurses). A significant correlation was found between the isoflurane concentration in urine produced during the shift (Cu' nmol/l) and isoflurane environmental concentration (Cl' mumol/m3) (Cu = 0.243 X Cl + 3.712) (r = .90). The results show that the urinary isoflurane concentration can be used as an appropriate biological exposure index. The authors suggest a biological exposure index of 18 nmol/l (3.4 micrograms/l). This is the biological value obtained after 4 h of an average environmental exposure to 81 mumol/m3 (2 ppm).
Adult↗
Urinary concentration, environmental concentration, and respiratory uptake of some solvents: effect of the work load.
The physical demands of the workplace differ depending on specific jobs. This implies that workers exposed to the same environmental level of an airborne contaminant can absorb different amounts of it depending on their pulmonary ventilation. Starting from the relationship between the uptake (U) and the urinary concentration of six solvents (Cu) (acetone, styrene, toluene, xylenes, methylchloroform, tetrachloroethylene) and from the equation expressing their lung uptake (U = K.V.CI.R.T) the expected values of a biological index after a given time of exposure can be derived. Such values are a function not only of the environmental level of exposure (CI) but also of the pulmonary ventilation (V - dependent solvent) and of the retention index (R) (V - R dependent solvent).
Air Pollutants, Occupational↗
Methemoglobin and carboxyhemoglobin levels in smokers and non smokers.
The authors examined the blood of 856 subjects (377 smokers and 479 non smokers) in order to evaluate the levels of Methemoglobin (MetHb) in relationship to tobacco smoke. The Methemoglobin, Carboxyhemoglobin, Percent Oxyhemoglobin and Total Hemoglobin were measured using an automated spectrometer (IL 282 CO - Oximeter). The authors found that the levels of MetHb in the smokers exceed that in the non smokers: in fact the level of MetHb in the smokers (% MetHb = 0.63) was significantly greater than in the non smokers (% MetHb = 0.56), unlike what was reported in literature. The levels of Carboxyhemoglobin in the blood has been shown to be a useful marker of tobacco smoke absorption: a close relationship exists between COHb and cigarette smoking.
Adolescent↗
[Use of gas chromatography with flame ionization (GC-FID) in the measurement of solvents in the urine].
The urinary concentration of some solvents (acetone, cyclohexane, 1,2 dichloropropane, n-hexane, methyl ethyl ketone, perchloroethylene, styrene, toluene, 1,1,1, trichloroethane) was measured by means of a gas chromatography Hewlett-Packard 5890 supplied with a flame ionization detector (GC-FID, DANI HS 3950). The coefficient of variation of the method was lower than 5%. The sensitivity of the GC-FID was very similar to what of mass spectrometer detector (GC-MSD, HP 5970 A).
Acetone↗
The urinary concentration of solvents as a biological indicator of exposure: proposal for the biological equivalent exposure limit for nine solvents.
Organic solvents are generally volatile substances that are absorbed mainly through the lungs; they are eliminated chiefly through the lungs and kidneys. In urine they are present as metabolites and, in very little part, as parent compound. The urinary concentration of solvent (Cu) can be used for the biological monitoring of exposed subjects to evaluate their exposure and correlate with the Threshold Limit Value (TLV) during the working day. The authors report some results obtained with workers occupationally exposed to solvents. The results concern the correlation between urinary concentration (Cu, micrograms/L) vs. average environmental concentration (Ci, mg/m3) measured in the breathing zone. For each solvent studied (acetone, 2-cyclohexane, 1,2-dichloropropane, n-hexane, methyl ethyl ketone, perchloroethylene, styrene, toluene, 1,1,1-trichloroethane) the authors propose a Biological Equivalent Exposure Limit (BEEL) corresponding to the environmental TLV.
Air Pollutants, Occupational↗
Urinary elimination of acetone in experimental and occupational exposure.
Fifteen volunteers were exposed to an acetone vapor concentration of 964-8, 610 mumol/m3 (56-500 mg/m3) for 2-4 h in an exposure chamber. Ten subjects were at rest during the exposure, and five were exposed at alternate rest and light physical exercise. Subsequently 104 workers occupationally exposed to acetone were studied. The relative uptake averaged about 53%, and the ratio of the alveolar concentration to the environmental concentration averaged about 0.28. Both for the experimentally exposed subjects and the occupationally exposed workers the urinary acetone concentration showed a linear relationship to the corresponding environmental time-weighted average concentration. A linear equation also existed between urinary concentrations and the amounts of acetone absorbed. The findings enable a consideration of the urinary concentration of the unaltered acetone as an appropriate exposure indicator and the proposal of a "biological equivalent threshold" to be used in the field of biological monitoring.
Acetone↗
Urinary elimination of styrene in experimental and occupational exposure.
Twenty human volunteers were exposed to styrene vapor at 273-1 654 mumol/m3 (28.4-172.3 mg/m3) for a period of 1 to 3 h at rest (15 cases) and during light physical exercise (5 cases). Subsequently 51 workers occupationally exposed to styrene were studied during a workweek (median value 1 138 mumol/m3, geometric standard deviation 2.23). As expected, the relative uptake averaged about 65%, and the ratio of the alveolar concentration to the time-weighted average of the environmental concentration averaged about 0.15. Both in the experimentally exposed subjects and in the occupationally exposed workers the urinary styrene concentration showed a linear relationship to the corresponding environmental time-weighted average concentration. The correlation coefficients of the regression lines ranged between 0.88 (occupationally exposed group) and more than 0.93 (experimentally exposed groups). The regression coefficients were closely linked to the amount of styrene taken up and to the exposure times. The findings show that the urinary styrene concentration can be used as an appropriate biological exposure indicator whose meaning differs from that of other suggested indices. As an example, in occupationally exposed subjects performing moderate work the urinary styrene concentration corresponding to the time-weighted average of the threshold limit value is 815 nmol/l, and the 95% lower confidence limit (biological threshold) is 740 nmol/l.
Adult↗
Urine/air partition coefficients for some industrially important substances.
The urine/air and blood/urine partition coefficients (lambda) of 43 commonly employed organic solvents (Aliphatic, Cyclic, Aromatic and Halogenated Hydrocarbons, Ketones, Alcohols and Esters) are reported. The analyses were performed by the multiple equilibration method (constant pressure method) using a Hewlett-Packard 5880 gas chromatograph. The lambda values proposed can be employed in the field of biological monitoring of subjects occupationally exposed to solvents vapors.
Air Pollutants, Occupational↗