[Biological monitoring of occupational exposure to acrylonitrile]. / Monitoraggio biologico delle esposizioni professionali ad acrilonitrile.

Acrylonitrile (ACN) is a solvent widely used in industry especially as raw material in the manufacturing of acrylic fibres, clothes and domestic furniture. It is also used in manufacturing of resins (ACN-butadiene-styrene...) and for production of nitrilic elastomers. Some researchers proposed the biological monitoring of occupational exposure to ACN by measuring the solvent in the urine, but results were widely spread especially in relation to the analytical method used. This article reports the main aspects that can reduce the variability of results. We checked several ACN solutions in water and urine after heating at 90 degrees C for 1, 3, 5, 8 and 16 hours. Water solutions maintained their ACN concentration in all the checked conditions, while urine concentrations of ACN in urine deceased during the conditioning time until 80% of their initial concentration. The analysis of ACN in urine provided by workers potentially exposed to ACN and by control subjects gave median results of 1.9 and 2.0 micrograms/g creat, without any statistical difference. The results split in relation to the smoking habit showed a statistic difference: the median values of ACN were 1.7 and 4.7 micrograms/g creat, respectively among the 175 non-smokers and 57 smokers.

[Acute poisoning with carbon dioxide: report of 2 fatal cases]. / Intossicazione acuta da anidride carbonica: descrizione di due casi mortali.

BACKGROUND: Carbon dioxide (CO2), a very high density gas, tends to stratify at the lowest levels of the atmosphere. It can be produced by neutral geothermal emissions, fermentative processes or by human and industrial activity. When carbon dioxide concentrations rise to a very high level in a confined and poorly ventilated space, the anoxic hazard is a very important cause of severe accidents that can involve workers and rescuers. At CO2 levels higher than 20% there is a very high risk of a fatal accident, also considering the odourless feature of this gas. OBJECT: Two fatal accidents in workers are described which occurred during inspection of a concrete well, built as a part of sewerage network in a rural area. In the weeks after the accident, composition and concentration of gases inside the well were analysed. We also considered the influence of an organic fertilizer called "pollina" which was found on the ground around the concrete well, in order to ascertain whether fermentation could alter the gas composition inside the well. METHODS: Samples of air and water were collected in the well and samples of the organic fertilizer (pollina) on the ground surrounding the concrete well were also taken. Different quantities of organic fertilizer (pollina) with or without water were incubated in airtight glass bottles and placed in a dark room at 20 degrees C temperature; analysis of air inside the glass bottles was performed after 7 and 18 days of incubation. All the samples of air and water were analysed by gas-chromatographic-mass-spectrometry. RESULTS: Analysis of the air samples collected inside the well after 2, 16 and 18 weeks after the accident showed a low concentration of O2 (range 4.2-9%), a high concentration of CO2 (range 5.9-12.3%), a normal level of N2 (range 78-85%) and a concentration of N2O between 0.03 and 0.19%. In water collected 2 weeks after the accident at the bottom of the concrete well, CO2 and N2O concentrations of respectively 222 mg/L and 2 mg/L were measured. In the bottles with "pollina" we found, at different times of incubation, high concentrations of CO2 (highest value 25.2%), low levels of O2 (lowest value 0.5%) and negligible concentrations of N2O (< 0.015%). CONCLUSIONS: All these findings suggest that the atmosphere inside the concrete well was altered by the fermentative processes of pollina. The death of the two workers, caused by a poorly oxygenated atmosphere with a high concentration of carbon dioxide, can be classified under the confined space hypoxic syndrome (CSHS).

Benzene in blood as a biomarker of low level occupational exposure.

The occupational airborne exposure to benzene of 150 workers employed in petrol stations and a refinery plant was assessed using personal sampling pumps. All workers provided blood samples after the end of work and on the following morning before resuming work. Benzene concentrations in the blood of 243 non-occupationally-exposed subjects were also measured. The median occupational benzene exposure for all 150 workers studied was 80 micrograms/m3. Overall median blood benzene of all workers was 251 ng/l at the end of the shift, and 174 ng/l the following morning. The benzene concentrations measured in blood collected the following morning proved to be significantly lower than those measured at the end of the shift. Median blood benzene for the 243 'normal' subjects was 128 ng/l, which was significantly lower than that measured in the workers before a new work shift. The median blood benzene concentration was significantly higher in smokers than in non-smokers, both in the general population (210 ng/l vs. 110 ng/l) and in the exposed workers at the end of the shift (476 ng/l vs. 132 ng/l) and the following morning (360 ng/l vs. 99 ng/l). End-of-shift blood benzene correlated significantly with environmental exposure; this correlation was better in the 83 non-smokers than in the 67 smokers. In non-smokers with the median benzene occupational exposure of 50 micrograms/m3, no difference was found in blood benzene concentration in exposed and non-exposed subjects.

Biological monitoring of acrylonitrile exposure.

This study reports the results obtained with the environmental and biological monitoring of 34 workers exposed to acrylonitrile (ACN). Occupational exposure was monitored during 8-h work shifts with both active and diffusive personal samplers which yielded comparable results. The median exposure was 78 micrograms/m3. The ACN concentration in urine collected at the end of the work shifts correlated significantly with the environmental exposure. The ACN concentration in the pre-shift urine samples (median 3.6 micrograms/l) was lower than that found in the post-shift samples (median 10.9 micrograms/l), but higher than in the urine of non-exposed people (median 0.45 microgram/l). Smoking is an important confounding factor in monitoring exposure to ACN. The ACN concentration in urine provides reliable information about occupational and non-occupational exposure to ACN. Aspects of the mechanism of ACN excretion in urine are also discussed.

[Environmental exposure and blood levels of benzene in gas station attendants. Comparison with the general population]. / Esposizione ambientale e livelli ematici di benzene negli addetti agli impianti di distribuzione carburanti. Confronto con la popolazione generale.

Environmental benzene levels were measured in 26 petrol stations using both active and passive stationary and personal samplers. Simultaneously, benzene levels were measured in the petrol station operators on blood samples collected at the end of the work shift and the following morning before starting work. The petrol stations belonged to various different oil companies and were studied both during the winter (9 stations) and in the summer (17 stations). The environmental levels measured with active samplers in the 26 stations were on average 256 ng/l, were significantly lower (98 ng/l) in winter and higher (326 ng/l) in summer. The blood levels of benzene in 77 workers at the end of the work shift were on average 548 ng/l, were significantly lower (306 ng/l) in winter and higher (651 ng/l) in summer. The following morning, blood levels of benzene were lower than those found at the end of the work shift, on average 249 ng/l in winter and 427 ng/l in summer. Smokers had higher benzene levels than non-smokers, both in winter at the end of the work shift (617/170 ng/l) and the following morning (506/137 ng/l), and in summer at the end of the shift (742/517 ng/l) and the following morning (535/233 ng/l). A comparison with a sample of 243 "normal" subjects of the general population showed that their mean blood level of benzene of 165 ng/l was significantly lower than the level found in petrol station workers the morning after the work shift (364 ng/l).

Nitrous oxide in blood and urine of operating theatre personnel and the general population.

Nitrous oxide (N2O) was assayed in 676 urine samples and 101 blood samples provided after exposure by operating theatre personnel from nine hospitals. The blood and urine assays were repeated in 25 subjects 18 h after the end of exposure. For 80 subjects, environmental N2O was also measured during intraoperative exposure. Mean urinary N2O in the 676 subjects at the end of exposure was 40 micrograms/l (range 1-3805 micrograms/l); in 10 of the 676 subjects, urinary N2O was in the range 279-3805 micrograms/l (mean 1202 micrograms/l). The 98th percentile was 120 micrograms/l. Mean blood N2O at the end of exposure, measured in 101 subjects, was 21 micrograms/l (median 16 micrograms/l, range 1-75 micrograms/l). Blood and urine N2O (1.5 micrograms/l and 4.9 micrograms/l, respectively) in 25 subjects, 18 h after exposure, was significantly higher than in occupationally non-exposed subjects (blood 0.91 microgram/l, urine 1 microgram/l). Environmental exposure was significantly related to blood and urinary N2O (r = 0.59 and r = 0.64, respectively). Blood and urinary N2O were significantly related to each other (r = 0.71), and were equivalent to about 25% of the environmental exposure level. The mean urinary N2O of 1202 micrograms/l in 10/676 subjects was not related to environmental exposure in the operating theatre. The highest urinary N2O levels measured in these 10/676 subjects could be explained by an asymptomatic urinary infection.

Blood toluene as a biological index of environmental toluene exposure in the "normal" population and in occupationally exposed workers immediately after exposure and 16 hours later.

Blood toluene was measured in a group of 100 workers occupationally exposed to a mean 8-h environmental toluene concentration of 128 micrograms/l (34 ppm), and in a group of 269 "normal" subjects without occupational exposure to toluene. The mean blood toluene of the workers at the end of the shift and the following morning, after 16 h, was 457 and 38 micrograms/l, respectively. The normal subjects had a blood toluene level of 1.1 micrograms/l. On the basis of the highly significant correlation between blood toluene and occupational exposure, it can be calculated that environmental toluene exposure of 188 and 377 micrograms/l (50 and 100 ppm) gives end-of-shift blood toluene levels of 690 and 1390 micrograms/l, respectively. The corresponding blood toluene levels on the following morning are 50 and 100 micrograms/l, respectively.

Blood and urine concentrations of chemical pollutants in the general population.

The concentration of 9 environmental chemical pollutants in the general population was measured in blood and urine. For the 9 different pollutants, the blood samples tested varied from 88 for acetone to 431 for benzene. Urine samples varied from 48 for styrene to 213 for n-hexane. Six of these agents (benzene, toluene, styrene, n-hexane, acetone and carbon disulphide) were present in all or almost all (100-94%) blood samples. The three chlorides (chloroform, trichloroethylene and tetrachloroethylene) were present only in 60-85% of samples. After acetone, with blood concentrations in microgram/1 (mean 840 microgram/l), the highest mean blood levels were those of toluene (1097 ng/l), chloroform (955 ng/l) and n-hexane (642 ng/l). Trichloroethylene and free carbon disulphide showed similar values (458 and 438 ng/l, respectively). Finally, benzene, styrene and tetrachloroethylene showed the lowest values (262, 217 and 149 ng/l, respectively). There was generally a significant difference between rural and urban workers in terms of blood benzene (200 ng/l vs 264 ng/l), trichloroethylene (180 ng/l vs 763 ng/l) and tetrachloroethylene (62 ng/l vs 263 ng/l). In a group of subjects potentially exposed to industrial solvents, classed as chemical workers, blood benzene, toluene, chloroform and n-hexane were significantly higher than in rural and urban workers. Smokers showed a significantly higher blood concentration than non-smokers for benzene (381 ng/l vs 205 ng/1), toluene (1431 ng/l vs 977 ng/l), and n-hexane (838 ng/l vs 532 ng/l). All or almost all urine samples (100-92%) contained all the compounds except trichloroethylene and tetrachloroethylene, present in 79% and 76% of samples, respectively (table 2). Urinary concentrations of all compounds did not differ significantly between rural and urban workers. Benzene and toluene were significantly higher in in urine of smokers than of non-smokers. Chloroform and n-hexane showed significantly higher urinary than blood values. Excluding acetone, with urinary and blood concentrations in pg/l, chloroform, toluene and n-hexane showed the highest mean concentrations both in blood and in urine.

[Solvent pollution in shoe factories]. / L'inquinamento da solventi nei calzaturifici.

In order to study solvent exposure in shoe factories, 43 kinds of glues and 22 solvent products used in footwear manufacturing were analyzed. A gas chromatographic spectrometric method was used to identify the mixtures of solvents contained in glues and their diluents. Acetone, ethylacetate and cyclohexane were the solvents more frequently found in glues. Cyclohexane represented on average about 40% of the solvent mixture. Methyl ethyl ketone, 3-methylpentane and 2-methylpentane were often present in glues (45-52% of the samples), but only in a few cases were they associated with n-hexane. N-hexane and methylcyclopentane were found in 32% of the glue samples. N-hexane represented 47% of the solvents only in one glue. Most of the glues contained less than 10% n-hexane. Other solvents (dichloropropane, toluene, trichloroethane, butyl acetate, iso-butyl acetate and 2,2-dimethylbutane) were found in few glue samples or in low percentages. The 22 solvents used as glue diluents were mainly acetone, ethylacetate, dichloromethane and methyl ethyl ketone. The results suggest that solvent exposure in shoe factories has changed compared with data reported about 10 years ago. Biological monitoring of shoe factory workers should measure exposures to the specific solvents found in each factory, especially acetone, cyclohexane, ethylacetate and methyl ethyl ketone.