Saline/air, blood/air, olive oil/air, and tissue/air (lung, kidney, liver, brain, muscle, heart, and fat) partition coefficients were determined for nine aliphatic hydrocarbons: n-pentane, 2,2-dimethylbutane, 3-methylpentane, 2-methylpentane, methylcyclopentane, n-hexane, cyclohexane, 3-methylhexane, and n-heptane. Blood/air partition coefficients were found to range between 0-38 (n-pentane) and 1*9 (n-heptane) and the value of the tissue/air partition coefficients rose from n-pentane to n-heptane. The tissue/air partition coefficients were significantly correlated with the blood/air partition coefficients (r = 0.92-0.98). According to the slope of the regression lines, the mean solubility of the nine aliphatic hydrocarbons in the different tissues was higher than in blood by the factors: lung 1-4 (range 1-2-2-.1), heart 3.9 (range 0-5-4-5), liver 5-6 (range 5.5-13.5), kidney 5-2 (range 1.6-5.8), brain 6*5 (range 5-8-10.7), muscle 7*6 (range 1.8-8.8), and fat 205 (range 104-254). The blood/air and olive oil/air partition coefficients were significantly correlated with the boiling points and the molecular weights of the aliphatic hydrocarbons studied.The uptake and distribution of industrial solvents are important in the understanding of their pharmacokinetics, body burden, and physiopathological effects. A knowledge of the blood/air and tissue/ blood partition coefficients of these solvents will give some insight into the rate of pulmonary exchange and tissue kinetics. For a few products (cycloproprane, chloroform, diethyl ether, ethyl chloride, trichloroethylene) which in the past were used as anaesthetics, the solubility in blood and in the most important tissues have been reported.'2 On the other hand, for most compounds used as solvents in industry and in the home, although the solubility in water and in other solvents can be found in reports the solubility in blood or body tissues cannot, although the solubility of a few aromatic hydrocarbons, ketones, alcohols, and halogenated hydrocarbons in the blood and in olive oil has recently been studied.37We report on the findings of a study of the solubility of nine aliphatic hydrocarbons in blood, saline, olive oil, and in the most important human tissueslung, liver, kidney, fat, brain, heart, and muscle. We Materiais and methodsThe following solvents were used: n-pentane, 2,2-dimethylbutane, 2-methylpentane, 3-methylpentane, n-hexane, cyclohexane, methylcyclopentane, 3-methylhexane, and n-heptane. All were obtained from C Erba (Milan) and were more than 98% pure.Human tissues (lung, kidney, heart, brain, liver, muscle, and fat) were collected from two men who had died suddenly from a heart attack when aged 30 and 40 respectively. No histological abnormalities were found in the tissues used. The individual tissues were homogenised in saline and frozen at -75°C until the experiments. Stored human blood was obtained from a hospital blood bank.

Benzene was measured in blood and alveolar air of 168 men, aged 20-58 years, subdivided into four groups: blood donors, hospital staff, chemical workers occupationally exposed to benzene, and chemical workers not occupationally exposed to benzene. The group of exposed workers was employed in work places with a mean environmental exposure to benzene of 1.62 mg/M3 (8 hr TWA). Non-exposed workers were employed elsewhere in the same plant, with an environmental exposure to benzene lower than 0.1 mg/M3. Blood and alveolar air samples were collected in the morning, before the start of the work shift for the chemical workers. The group of exposed workers was found to be significantly different from the other three groups, both for blood and alveolar benzene concentrations. The mean blood benzene concentration was 789 ng/l in the exposed workers, 307 ng/l in the non-exposed workers, 332 ng/l in the hospital staff, and 196 ng/l in the blood donors. Apart from the exposed workers, blood benzene concentration was significantly higher in smokers than in non-smokers. The mean alveolar benzene concentration was 92 ng/l in the exposed workers, 42 ng/l in the non-exposed workers, 22 ng/l in the hospital staff, and 11 ng/l in the blood donors. Alveolar benzene concentration was significantly higher in smokers than in non-smokers in the groups of the hospital staff and non-exposed workers, but not in the blood donors and exposed workers. In the three groups without occupational exposure considered altogether, the alveolar benzene concentration correlated significantly with environmental benzene concentration measured at the moment of the individual examinations, both in the smokers (r = .636; p less than .001) and non-smokers (r = .628; p less than .001). In the same three groups and in the exposed workers, alveolar benzene concentration showed a significant correlation with the blood benzene concentration.

Benzene, toluene, cumene and styrene were measured in the breath and blood of two groups of individuals. The first group included individuals belonging to a hospital staff, the second group included chemical workers who were not exposed to the abovementioned chemicals. The chemical workers were examined in plant infirmaries on the morning before the start of the workshift, and the hospital staff in the hospital infirmaries. One environmental air sample was taken in the infirmaries for each individual at the moment of the biological samplings. The environmental concentrations of benzene and styrene were significantly higher in the infirmaries of the chemical plant than in the infirmaries of the hospital. On the other hand, the environmental concentrations of toluene and cumene were not significantly different in the plant infirmaries and in the hospital infirmaries. In the hospital staff the alveolar concentrations of benzene, toluene and styrene were significantly lower than those in the chemical workers. In the hospital staff the blood concentrations of benzene, toluene and styrene were not significantly different from those in the chemical workers. Only the blood cumene concentration was significantly higher in the chemical workers. In hospital staff, smokers showed alveolar and blood concentrations of benzene and toluene that were significantly higher than those measured in the non smoker hospital staff. With reference to chemical workers, only alveolar benzene concentration was significantly higher in smokers than in non smokers.(ABSTRACT TRUNCATED AT 250 WORDS)

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Acetone levels were measured by gas chromatography mass spectrometry (GC-MS) in environmental and alveolar air, blood and urine of 89 non-occupationally exposed subjects and in three groups of workers exposed to acetone or isopropanol. Acetone was detected in all samples from non-exposed subjects, with mean values of 840 micrograms/l in blood (Cb), 842 micrograms/l in urine (Cu), 715 mg/l in alveolar air (Ca) and 154 ng/l in environmental air (Ci). The ninety-fifty percentiles were 2069 micrograms/l in Cb, 2206 micrograms/l in Cu and 1675 ng/l in Ca. The blood/air partition coefficient of acetone was 597. Correlations were found in Cb, Cu and Ca. In specimens sampled at the end of the workshift from subjects occupationally exposed to acetone, a correlation was found in the blood, urine, alveolar and environmental air concentrations. The blood/air partition coefficient of acetone was 146. On average, the blood acetone levels of workers were 56 times higher than the environmental exposure level, and the concentration of acetone in alveolar air was 27% more than that found in inspiratory air. The half-life for acetone in blood was 5.8 h in the interval of 16 h between the end of the workshift and the morning after. The morning after a workshift with a mean acetone exposure of 336 micrograms/l, blood and urinary levels were 3.5 mg/l and 13 mg/l, respectively, which were still higher than those found in "normal" subjects. It can be concluded that endogenous production of acetone and environmental exposure to acetone or isopropanol do not affect the reliability of biological monitoring of exposed workers, even 16 h after low exposure.