Showing papers in "International Archives of Occupational and Environmental Health in 1985"

Reliability of urinary creatinine as a parameter used to adjust values of urinary biological indicators.

Abstract: The values of biological indicators used in biological monitoring are usually determined on spot samples of urine. In order to reduce the variations due to dilution, it is common practice to correct the values according to reference parameters, such as urinary creatinine concentration and specific gravity. The aim of the present study was to verify whether creatinine possesses the necessary characteristics for adjustment. The levels of creatinine were not influenced by diuresis, but, contrary to what was expected, the values of the metabolite showed marked intra- and interindividual variations. These data raise serious doubts as to the validity of creatinine as a parameter that can be used for adjustment purposes, and suggest that it would be advisable to ascertain for each biological indicator whether in fact adjustment is of any use. Lastly, since there was only a slight correlation between creatinine levels and specific gravity values, it is concluded that these two parameters cannot be used indifferently for adjustment.

1-Hydroxypyrene in human urine after exposure to coal tar and a coal tar derived product

Abstract: A method for isolating 1-hydroxypyrene from urine is described. The presence of 1-hydroxypyrene in urine was identified by fluorescence excitation and emission scanning after HPLC-separation. 1-Hydroxypyrene could be detected in the urine of rats following oral administration of as little as 0.5 μg pyrene. The dose-dependence of 1-hydroxypyrene in urine was evident after a wide range of pyrene dosing. After therapeutical coal tar treatment of dermatological patients the enhanced excretion of 1-hydroxypyrene was highly significant. Employees of a creosote impregnating plant showed an excretion pattern of 1-hydroxypyrene which could be related to their work. 1-Hydroxypyrene in urine of non-exposed people was very low, but detectable. It is suggested that the method reported is suitable for the assessment of uptake of man to pyrene, a compound that is commonly present in work environments which are associated with pollution of polycyclic aromatic hydrocarbons.

Blood protein conjugates and acetylation of aromatic amines: new findings on biological monitoring

Abstract: Internal stress of aromatic amines has so far been evaluated by their determination in blood or urine and by the degree of methemoglobin formation. Animal experiments have shown that these materials can form adducts and conjugates with proteins and nucleic acids. Our investigations show that these processes can also occur in human metabolism. For this the degree of such a formation of protein conjugates depends on an individually different potential for acetylation. In a positive sense it influences the magnitude and the rate of renal excretion of aminoaromates and their conjugates and metabolites formed by this metabolism. In contrast, only free nonacetylated aminoaromates can lead to the formation of conjugates with hemoglobin. These aminoaromates or their metabolites can then be detected quantitatively in intact erythrocytes during their lifespan. The degree of this protein conjugate formation correlates inversely with the magnitude of the acetylation potential depending on the availability of free non-acetylated aminoaromates. According to these results a clearer assessment of past stress or the presence of strain can be obtained with Biological Monitoring by a single determination of such hemoglobin adducts rather than by the traditional quantitative determination of aminoaromates or their metabolites in blood and/or urine or the methemoglobin concentration.

Serum lipid peroxide level and blood superoxide dismutase activity in workers with occupational exposure to lead

Abstract: We studied whether lead exposure increased the serum lipid peroxide (LPO) level and inhibited blood superoxide dismutase (SOD) activity in workers with occupational exposure to lead and rats injected with lead. We examined the following subjects: (1) manual workers (712 males) from 18 to 59-years-old in steel production with occupational exposure to lead, (2) office workers (155 males) without exposure to lead, (3) rats subcutaneously injected with lead in concentrations of 10 or 20 mg/kg as lead acetate. The nutritional intakes of manual workers and office workers were approximately equal. Serum LPO and high-density lipoprotein cholesterol (HDL-CL) levels in manual workers (LPO: 4.4 ± 1.9 nmol/ml, HDL-CL: 55.6 ± 14.2 mg/dl) were significantly higher than those in office workers (LPO: 4.0 ± 1.4 nmol/ml, HDL-CL: 53.0 ± 13.9 mg/dl). Serum LPO level in the manual workers increased with an increase of the lead concentration in the blood, while blood SOD activity decreased. Similar phenomena were observed in rats subcutaneously injected with lead acetate. Furthermore, the addition of lead at higher than 20-μM concentrations to non-treated rat liver microsomes increased NADPH-dependent lipid peroxidation, and these lead concentrations inhibited bovine erythrocyte SOD activity in vitro assay system. In conclusion, the present results seem to indicate that the increase of serum LPO level in workers with occupational exposure to lead is due not only to the stimulation of lipid peroxidation, but also to the inhibition of SOD activity by exposure to lead in the manufacturing processes.

Chromium bond detection in isolated erythrocytes: a new principle of biological monitoring of exposure to hexavalent chromium.

Abstract: Internal stress to chromium is only relevant in occupational medicine if it is due to the handling of hexavalent chromium. Cr(VI) ions, after uptake by inhalation or percutaneously are carried in the blood plasma and penetrate—depending on the concentration—into the erythrocytes. Due to the intracellular reduction to Cr(III) and the concurrent intracellular protein binding, the erythrocytes represent an easily accessible target organ for quantitative chromium determination after occupational exposure to Cr(VI) compounds. The results of an earlier experimental study indicate that human plasma too is capable of spontaneous reduction of Cr(VI) ions of up to 2 ppm to Cr(III). This plasma reduction capacity (PRC) can be increased and accelerated considerably by adding ascorbic acid (AA). These findings were supported in this investigation by proving a decreased binding of Cr(VI) inside the erythrocytes under the effect of AA. This leads to the assumption that only those Cr(VI) concentrations can penetrate the membrane of the erythrocytes and enter the cell which either come into contact with the membrane during the reduction process or exceed this limit concentration of 2 ppm. Only in these two instances can corresponding chromium findings be analyzed in isolated and washed erythrocytes. These results are compared with those obtained by conventional methods, such as Cr determination in the blood and/or urine. Our findings indicate that a single determination of chromium concentration in the erythrocytes will permit the monitoring of critical cases of Cr(VI) exposure. This is a new type of biological monitoring in the sense of a condensed longitudinal study, in order to find out whether threshold concentrations have been respected over a given period.

Biologic monitoring of workers exposed to silver.

Abstract: The smelting and refining of silver and the preparation of silver salts for use in photosensitized products can lead to occupational exposures to silver. Our objectives in this study were to determine the absorption and elimination of silver by workers exposed to different species of silver, to estimate the body burden of silver and to relate these findings to the potential development of argyria. Workers potentially exposed to silver (n = 37) and a similar number of controls (n = 35) participated in this study. Blood, urine, feces and hair samples were collected and were analyzed for total silver content by atomic absorption spectroscopy. The mean concentration of silver in the blood, urine and feces of silver workers was 0.011 μg/ml, < 0.005 μg/g and 15 μg/g, respectively; and of controls was < 0.005 μg/ml, < 0.005 μg/g and 1.5 μg/g, respectively. The concentration of silver in hair was markedly higher for the silver workers than for controls (130 ± 160 vs 0.57 ± 0.56 μg/g, respectively). The importance of these latter findings was questionable since airborne particles of silver can bind to hair and lead to apparent high values. Since silver is eliminated predominantly in the feces, fecal measurements were used as an index of exposure and as a means of calculating body burdens. Human exposure to metallic silver at the TLV (0.1 mg/m3) is expected to lead to a fecal excretion of about 1 mg of silver per day. Silver workers excreted an average of 0.3 mg of silver per day in feces, corresponding to a time weighted average workplace exposure of about 0.03 mg/m3. The incremental body burden of silver for silver workers and controls (the latter was derived entirely from food consumption) was calculated to be 14 and 2 μg/kg of body weight, respectively. Our findings indicate that generalized argyria is unlikely to occur in workers exposed to silver at the above exposure levels.

Biological monitoring of cobalt exposure, based on cobalt concentrations in blood and urine.

Abstract: Cobalt exposure level and its concentrations in blood and urine were determined for 175 hard metal workers. For control data, the cobalt concentrations in blood and urine were measured for 20 office workers. The exposed workers had significantly higher cobalt concentrations in both blood and urine. The relationships between exposure level and cobalt concentrations in blood and urine were linear and positive. The results clearly showed that the cobalt concentration in the blood or urine can be used as an exposure indicator. With cobalt exposure of 100 micrograms/m3, the cobalt concentration was 0.57 to 0.79 micrograms/dl in blood and 59 to 78 micrograms/l in urine with 95% confidence limits. In workers using respirators, the cobalt concentrations in the blood and urine decreased to 2/5 and 1/8, respectively, of those not using respirators.

Urinary cobalt as a measure of exposure in the hard metal industry.

Abstract: Twenty-six workers in a hard metal manufacturing plant were monitored by cobalt urinary and ambient air measurements during the first month after summer holidays. Cobalt determinations were performed utilizing AAS, with a preliminary chelation and extraction procedure for urinary samples. Almost all personal ambient air samples turned out to be under the cobalt dust TLV of 0.1 mg/m3. When restarting work after the holidays, urinary values did not differ from the control group. At the end of the first working week, urinary cobalt had increased four fold, then decreased to the original values on the following Monday before restarting work. Thereafter, the weekend was no longer sufficient to reduce the levels to normal urinary cobalt values. The values rose to the same level observed before the holidays, and dit not substantially decrease even after the weekend. End-shift urinary cobalt values showed a good relationship with present as well as with mean past exposure on the first and the fifth weekday, but the third day did not. The correlation was better with present exposure on Monday and with mean past exposure on Friday. The observed differences may be explained by the minor influence of recent exposure on present exposure on Monday. The highest values were found on Wednesday. We suggest the utilization of end-shift urinary cobalt determination as a measure of the present exposure on Monday, and of mean recent or preceding exposure on Friday.

The validity of urinary metabolites as indicators of low exposures to toluene.

Abstract: Exposure to toluene was studied in a group of 14 subjects working in a printing industry, who were exposed to this solvent only. Environmental monitoring was carried out using personal samplers for the whole workshift over three consecutive days. Toluene TWA concentrations ranged from 37 to 229 mg/m3. At the end of the workshift on each day of investigation, urine samples were collected for the determination of hippuric acid and ortho-cresol. Hippuric acid was also determined for urine before the workshift and on the Saturday and Monday mornings after the end of exposure; hippuric acid was also determined in 16 controls over the same five-day period. At the end of the workshift, hippuricuria levels in exposed workers always turned out to be statistically different from pre-workshift levels and those of the controls. The end-of-workshift hippuricuria levels of exposed workers were significantly correlated with the mean daily environmental concentration (TWA): in the three days of comparative study, we found r = 0.63 (P less than 0.05) on Day 1, r = 0.90 (P less than 0.001) on Day 2, and r = 0.87 (P less than 0.001) on Day 3. Ortho-cresol turned out to be correlated with daily exposure less significantly than hippuric acid: r = 0.49 (n.s.) on Day 1; r = 0.78 (P less than 0.001) on Day 2, and r = 0.65 (P less than 0.05) on Day 3. Using all available data (41 observations), a very significant correlation (P less than 0.001) was found between the TWA and both metabolites (r = 0.80 for hippuric acid; r = 0.68 for o-cresol). The values of the two metabolites in the end-of-workshift urine samples (41 observations) also turned out to be well correlated (r = 0.70; P less than 0.001). The authors conclude that hippuric acid is a valid test for evaluating even low exposures to toluene.

Problems concerning the usefulness of adjustment of urinary cadmium for creatinine and specific gravity.

Abstract: A previous study concluded that there are some doubts as to the validity of creatinine as a parameter for adjusting the values of biological indicators determined on spot samples of urine, since it is subject to marked inter- and intraindividual variations. Furthermore, since there was only a moderate correlation between creatinine levels and specific density, it can be assumed that these two parameters cannot be used indifferently for adjustment. Nevertheless, it seemed advisable to verify whether correction of cadmium values determined from spot samples offers any practical advantages. For this purpose, 105 subjects with occupational exposure to cadmium were examined. They collected their 24-h urine and spot samples separately at 8.00 h. There was a close correlation between CdU/spot samples and CdU/24 h. The correlation index was very similar both for CdU/spot values expressed in μg/l and for values adjusted according to creatinine or 1024 specific gravity. These results show that no particular advantages are offered by adjusting CdU according to creatinine or specific gravity.

Environmental Exposure To Cadmium and Renal-function of Elderly Women Living in Cadmium-polluted Areas of the Federal-republic-of-germany

Abstract: An epidemiological study was performed to assess whether environmental pollution by cadmium as found in cadmium-polluted areas of the Federal Republic of Germany is associated with an increased prevalence of biological signs of kidney dysfunction in population groups non-occupationally exposed to heavy metals. The study was run in two industrial areas known to be highly contaminated by cadmium, lead and other heavy metals, viz. Stolberg and Duisburg. Dusseldorf was selected as a reference area. As a study population we selected 65- and 66-year-old women (n = 286) who had spent the major part of their lives in one of these areas. The average cadmium levels in blood (CdB) and urine (CdU) revealed significant differences in exposure to cadmium in the order Stolberg > Duisburg > Dusseldorf. Serum creatinine levels were, on average, significantly higher in the Stolberg group than in the Duisburg and Dusseldorf groups. However, with respect to the urinary excretion of low molecular weight proteins (β 2-microglobulin, retinol-binding protein), albuminuria, total proteinuria, aminoaciduria, phosphaturia and some other biological findings, no significant differences between the study populations were noted. Similarly, the prevalence of clinically-confirmed hypertension as well as the relative frequency of hypertensive subjects (systolic ≥ 160 and/or diastolic ≥ 95 mm Hg) did not differ significantly among the three study groups. There was no exposure-reponse relationship between CdU and tubular proteinuria in the range of the CdU-levels found (0.1 to 5.2 μg/g creatinine). However, albuminuria tended to be increased at CdU levels > 2 μg/g creatinine.

Cardiorespiratory strain in jobs that require respiratory protection

Abstract: Twenty-one workers in the construction, foundry, shipyard, and metal industries, and nine firemen were studied in jobs that require the regular use of various industrial respirators. The subjects' heart rates (HR) were continuously recorded during 1 to 2 workshifts or during special tasks. Their oxygen consumption $$(\dot V_{{\text{O}}_{\text{2}} } )$$ and ventilation rates were measured during main work phases. The subjects' $$\dot V_{{\text{O}}_{{\text{2max}}} } $$ were determined by a submaximal bicycle-ergometer test. In construction and industrial jobs, when a filtering device or an air-line apparatus was worn, the subjects' mean HR-values ranged from 66 to 132 beats min−1, which is equivalent to a relative aerobic strain of 12 to 57% $$\dot V_{{\text{O}}_{{\text{2max}}} } $$ . In smog-diving and repair and rescue tasks with self-contained breathing apparatus and protective clothing, the corresponding mean values were 142 to 160 beats min−1 and 54–74% $$(\dot V_{{\text{O}}_{\text{2}} } )$$ , respectively. The field results were compared with those measured in the laboratory with the same type of respirator. The suitability of different respirators in practical work situations was then evaluated, as were the physical qualifications required of the wearer.

Exposure in welding of high nickel alloy.

Abstract: Nickel (Ni) levels in air during welding of high-Ni alloy (75% Ni) were very high (mean 0.44 mg/m3, range 0.07-1.1 mg/m3; 20 person-days of measurements). In six welders the Ni level in urine after four weeks of vacation was slightly but statistically significantly enhanced as compared to ten unexposed controls (means 8.7 vs 5.1 micrograms/l; P less than 0.005). The level on Monday mornings increased somewhat during a period of six weeks of high-Ni alloy welding (mean 13 micrograms/l; P less than 0.05). The level was slightly higher Thursday afternoon (mean 18 micrograms/l; P less than 0.0001). The data indicate the existence of a very slow pool of Ni in the body in addition to a faster one. There was no correlation between Ni levels in air and urine. Thus, in spite of the very high Ni levels in air, urinary Ni levels were thus of little use for biological monitoring of exposure and risk during high-Ni alloy welding. All eleven welders studied reported one or more symptoms (irritation of upper airways, headache, tiredness) as occurring more often (P less than 0.006) during high-Ni welding than when welding ordinary stainless steel. Lung-functions studies were normal.

Lung function and clinical findings in a cross-sectional study of arc welders. An epidemiological study.

Abstract: An epidemiological, cross-sectional study was conducted in order to assess non-neoplasic effects on the lung due to chronic exposure to arc welding fumes and gases. The study involved 346 arc welders and 214 control workers from a factory producing industrial vehicles. These workers (welders and controls) had never been exposed to asbestos. Respiratory impairments were evaluated by using a standardized questionnaire, a clinical examination, chest radiophotography and several lung function tests (spirometry, bronchial challenge test to acetylcholine, CO transfer tests according to the breath-holding and the steady-state methods, N2 washout test). The only significant differences between the welders overall compared to the controls were a slightly higher bronchial hyper-reactivity to acetylcholine and a lower lung diffusing capacity for CO in the welders. However, non-specific, radiologic abnormalities (reticulation, micronodulation) and obstructive signs were more frequent in the most exposed welders (welding inside tanks) than in welders working in well ventilated workplaces. The nature of the metal welded (mild-steel, stainless steel, aluminium) did not seem to have an influence on respiratory impairments. In the mild-steel welders, respiratory symptoms (dyspnoea, recurrent bronchitis) and obstructive signs were more frequent in the welders using a manual process than in the welders involved with the semi-automatic process (MIG). For all the workers (welders and controls), smoking had a markedly adverse effect on respiratory symptoms and lung function. Moreover, smoking seemed to interact with welding since CO lung transfer was more impaired in smoking welders than in smoking controls.

Breath analysis by API/MS--human exposure to volatile organic solvents.

Abstract: The expired breath of subjects, exposed for periods of ca. 90 min to atmospheres artificially contaminated with low levels of methanol, (ca. 100 ppm) toluene (ca. 50 ppm) or tetrachloroethylene, (ca. 50 ppm) was monitored during and after the exposure period using an atmospheric pressure ionization mass spectrometer, fitted with a direct breath analysis system. The retention of solvent by the subjects, estimated from steady state levels in the expired breath, averaged 82% of the inspired level for methanol, 83% for toluene and 87% for tetrachloroethylene. The elimination of unchanged solvent via respiration during the post exposure period followed first order kinetics with mean half life values of 24 min for methanol, 27 min for toluene and 79 min for tetrachloroethylene.

Automated testing of reaction time and its association with lead in children.

Abstract: Following Needleman et al.'s (1979) report of a correlation between tooth lead estimates in children and reaction time as measured by Rodnick and Shakow's (1940) delayed reaction time paradigm, a version of the procedure with two delay periods of 3 s and 12 s was developed for automated presentation and scoring on a VIC-20 microcomputer. Data are presented from a study of 300 children aged 6–14 years. Mean reaction time over six trials for each delay period related in a curvilinear fashion with age, but no relationships were found with sex or intelligence. Age-adjusted reaction time related significantly with blood-lead levels, but accounted for only about 1 per cent of the variance. The effect was mainly observed in younger (6–10 years) children in whom higher lead was associated with slower reaction time.

Human exposure to styrene. VI. Percutaneous absorption in human volunteers.

Abstract: In order to estimate the importance of skin resorption of styrene, as compared to pulmonary absorption, nine male volunteers were exposed for 10 to 30 min by dipping one hand in liquid styrene. Urine and breath were sampled periodically for metabolites (mandelic and phenylglyoxylic acids) and styrene analyses respectively. The results obtained show that the rate of absorption of styrene through the skin is very low, averaging 1 +/- 0.5 micrograms/cm2 X min. This rate seems to be affected by the duration of exposure. In conclusion, this study shows that skin resorption plays only a minor role in most practical situations.

Occupational exposure to toluene: neurotoxic effects with special emphasis on drinking habits.

Abstract: Neurotoxic effects of toluene were examined in 43 male rotogravure printers exposed to toluene (age 27–63, mean 41 years; duration of exposure 11–40, mean 22 years) and 31 male offset printers of the same age with slight exposure to aliphatic hydrocarbons. A neurological examination, tests for autonomic nervous function, electroencephalography, psychological tests and computerized tomography of the brain were carried out in addition to a standardized interview. Exposure levels were evaluated for each person separately on the basis of his work history and the results of an earlier study on exposure levels at the same printing shops. Besides a thorough history of alcohol consumption, information about the printers' drinking habits was obtained from the occupational health care centers of the printing shops. The examinations found only slight abnormalities, and there were no statistically significant group differences in the prevalences of abnormalities. No correlations between the abnormalities and the exposure indices were found either. One of the retired workers, however, who had been exposed to high toluene concentrations for over 40 years, had been diagnosed as having chronic organic solvent intoxication. Heavy drinkers of alcohol were clearly more common in the toluene-exposed group. This study detected no clinically significant abnormalities attributable to toluene alone among workers exposed to 68–185 ppm (mean 117) of toluene for over 10 years. The connection between alcohol consumption and toluene exposure is interesting and deserves further study.

Occupational liver injury. Present state of knowledge and future perspective.

Abstract: Epidemiological studies have mapped the occurrence of hepatitis B among health personnel with the use of specific serologic markers and thereby made rational preventive precautions possible. Follow-up studies have demonstrated the effect of this prevention, and the newly developed hepatitis B vaccine has further improved the possibilities for effective prophylaxis against occupational hepatitis B. On the other hand, there is the chemically induced occupational liver damage. Only a few of the thousands of industrially used chemicals have been sufficiently investigated for hepatotoxicity and the list of suspected and confirmed hepatotoxic agents is still growing. The worrisome example of vinylchloride-induced serious liver disease among PVC-workers, revealed after 42 years of industrial use by alert clinicians, calls for intensified activities in the field of occupational hepatotoxicity. However, the clinical, biochemical, and morphological features of liver disease are often vague and unspecific. A non-invasive, convenient quantitative liver function test is needed. Circumstantial evidence and a few epidemiological studies suggest that part of the so-called cryptogenic liver diseases, such as liver cirrhosis, may be caused by occupational exposure to chemicals. This should be further studied. Animal experiments have shown that one chemical agent may potentiate the hepatotoxic effect of another chemical agent. This should be the subject of investigations in the work environment, where exposure to various chemicals is the rule rather than the exception. Alcohol consumption may also interfere with the hepatotoxicity of occupationally used chemicals.

Occupational exposure to organophosphorus insecticides and synthetic pyrethroid.

Abstract: Dermal and respiratory exposure to pirimiphosmethyl, dimethoate and permethrin were determined for applicators and operators in greenhouse tomato spraying operations. Dermal exposure is several times higher than the degree of respiratory exposure. Dermal exposure in terms of different parts of the body shows significant differences. For applicators the exposure of hands, arms and legs is the greatest, and the operators are the most exposed on their hands and to a small extent on legs. This fact should be taken into account when providing the workers with suitable protective clothing. The carefully selected technology of spraying also has great significance in decreasing the degree of exposure. Because of the chronic toxicity of dimethoate, all possible methods should be taken to reduce exposure.

Evaluation of low exposure to styrene. II. Dermal absorption of styrene vapours in humans under experimental conditions.

Abstract: Four volunteers were exposed dermally to styrene vapours within the concentration range of 1300 to 3200 mg/m3. The increase in the levels of mandelic and phenylglyoxylic acids in urine after exposure was strongly noticeable. The dermal vapour absorption coefficient (α) was calculated: for styrene it was ca. 0.022 m3/h. It was calculated that the dermal absorption of the styrene vapours contributed about 5% to the amount absorbed in the respiratory tract under the same conditions.

Road traffic noise annoyance in Amsterdam.

Abstract: 3445 persons living in Amsterdam (1507 male and 1938 female), aged 41–43 years, participated in an investigation in which the relationship was studied between the (measured) road traffic noise in front of the houses in which the participants lived, and the (reported) resulting annoyance and sleep disturbance.

Occupational chronic exposure to organic solvents. XI. Alkylbenzene exposure of varnish workers: effects on hematopoetic system.

Abstract: Thirty-five spraymen, who were varnishing vehicles with alkyd-, phenol- and polyestervarnishes, which were dissolved in solvent mixtures mainly containing o-, m-, p-xylene and ethylbenzene, have been investigated. The concentrations of these solvents in air were 2.1, 7.9, 2.8 and 4.0 ppm on average. The levels of alkylbenzenes in blood and those of their metabolites in urine have been determined. At two of the six working places the spraymen were additionally exposed to n-butanol, respectively 1,1,1-trichloroethane, and several C9-aromatic hydrocarbons. Some of the lacquers contained lead pigments. Alterations of blood cell counts have been observed under the described conditions of exposure. On average the number of lymphocytes was higher than that of segmented granulocytes. Erythrocytes and hemoglobin level of the spraymen were lower than those of the controls.

Investigations on neurotoxicity of chemical substances at the workplace. VII. Longitudinal study with determination of nerve conduction velocities in persons occupationally exposed to styrene

Abstract: The aim of this longitudinal study was to investigate whether long-term exposure to styrene is associated with functional disorders of the peripheral nervous system. Eleven workers (age: 24 to 54 years) of a polyester resin boat industry were studied neurophysiologically and biochemically in 1980 and 1983. The duration of styrene-exposure varied from 3 to 7 years, with a median of 4 years. The control group was comprised of 11 non-styrene-exposed workers of similar age. Air Monitoring with passive samplers was performed on different days for each person. The mean styrene concentrations were 114, 97 and 92 ppm respectively and therefore in the magnitude of the current MAK-value of 100 ppm in the Federal Republic of Germany (FRG). For Biological Monitoring styrene in blood (S-B) and mandelic acid (MA) as well as phenylglyoxylic-acid (PGA) in urine were determined in post-shift samples. The median values for MA at four different sampling times were 816, 1660, 1101 and 1224 mg/g creatinine and for PGA 200, 273, 342 and 336 mg/g creatinine respectively. These levels were below the current "Biologischer Arbeitsstoff Toleranzwert (BAT-Wert)" for MA (2000 mg/l) and MA + PGA (2500 mg/l). The S-B concentrations ranged from 0.05 mg/l to 3.26 mg/l, with mean values of 0.92 and 0.70 mg/l. The nerve conduction velocities (NCV) of motor and sensory nerve fibers (N. ulnaris and/or N. medianus) showed no significant differences between styrene-exposed workers and age-matched control persons. There were no hints of "dose-effect-relationships" by correlation analyses. Furthermore the follow-up determination revealed no significant changes regarding NCV.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of acute exposure to increased levels of background industrial noise on cigarette smoking behavior.

Abstract: Automated objective measures of cigarette smoking behavior were recorded while research subjects performed a visual monitoring monetary reinforced operant task Subjects were required to wear headphones during all sessions During baseline sessions, subjects were exposed to 60 decibels (dB) of background noise During experimental sessions, subjects were exposed to 70, 80, or 90 dB of tape-recorded industrial noise via the headphones Following stabilization of cigarette puffing across sessions, subjects were exposed to different dB levels of industrial noise acutely for one session Results indicated that increasing dB levels of industrial noise exposure resulted in increased cigarette smoking behavior

Assessment of occupational exposure to 4,4'-methylene-bis-(2-chloroaniline) "MOCA" by a new sensitive method for biological monitoring

Abstract: A new specific and sensitive method for the urinary determination of 4,4'-methylene-bis-(2-chloroaniline) ("MOCA"), a known carcinogen in rats, mice and dogs, has been developed. After a brief study on rats to determine some peculiarities in "MOCA" urinary excretion, this method was used to assess occupational exposure in French industrial firms. Both the manufacture of "MOCA" and its use as a curing agent in the production of polyurethane elastomers were surveyed. "MOCA" excretion levels were distributed from non-detectable (less than 0.5 microgram/l) up to 1600 microgram/l. Concentrations of N-acetyl metabolites, when present, were largely lower than "MOCA" levels. The results seemed to reflect workers' overall exposure fairly. Preventive measures following analytical determinations often led to an obvious lowering of excretion levels.

Cardiovascular changes and hearing threshold shifts in men under complex exposures to noise, whole body vibrations, temperatures and competition-type psychic load

Abstract: This study deals with changes in the temporary hearing threshold (TTS2), heart rate (HR), R-wave amplitude (RWA), diastolic blood pressure (DBP), systolic blood pressure (SBP), pulse pressure (PP) and reaction time (RT) in subjects (n = 108) who, while working on a choice reaction apparatus, were exposed in an exposure chamber to combinations of noise and vibration at dry bulb temperatures of 20 degrees and 30 degrees C. The study was carried out as a type 2-3-3 factorial experiment, the number of the exposure combinations thus being 18. To find out the effects of competition-type psychic stress, some of the subjects were placed in a competitive group and some in a non-competitive group. The members of the competitive group were given financial encouragement and information on their progress during the test, whereas those in the non-competitive group worked at the rate they considered best without any monetary rewards or interim information. The noise classes were: no noise, a stable broadband (bandwidth 0.2-16.0 kHz) A-weighted noise of 90 dB not related to competition, and a stable broadband A-weighted noise of 90 dB related to competition about the fastest reaction time. The vibration classes were: no vibration, sinusoidal whole body vibration (Z-axis) at a frequency of 5 Hz, and stochastic broadband (bandwidth 2.8-11.2 Hz) whole body vibration (Z-axis). The acceleration (rms) of both vibrations was 2.12 m/s2. One experiment consisted of a control period of 30 min, three consecutive exposure periods of 16 min with an interval of 4 min, and a 15-min recovery period. The variance analysis model best explained the variation in TTS2 values at 4 kHz and second best the variation in TTS2 values at 6 kHz; it explained the variation in HR values third best, the variation in SBP values fourth best and the variation in PP values fifth best. On the other hand, the model explained least well the variation in DBP and RWA values. In general, the explanatory power of the model increased together with the number of exposures. The psychic stress caused by competition accelerated the growth of the TTS2 values, HR values and SBP values, when the subjects were simultaneously exposed to noise or to a combination of noise and vibration. An interesting finding for the continuation of the research project was that sinusoidal and stochastic vibration affected the cardiovascular changes, temporary hearing threshold and reaction times in different ways.

Respiratory symptoms associated with sulfur dioxide exposure.

Abstract: Exposures to sulfur dioxide (SO2) have been associated with progressive, dose-dependent bronchoconstriction in sensitive individuals. The clinical significance of such changes remains poorly characterized. We studied subjective responses following exposure to low level concentrations of SO2 (< 1 ppm) in a group of 10 healthy and 10 asthmatic subjects. The number and severity of complaints associated with SO2 increased with concentrations in both healthy and asthmatic subjects. Asthmatics indicated progressive lower respiratory complaints, such as wheezing, chest tightness, dyspnea and cough with increasing levels of SO2 while healthy subjects complained more frequently of upper airway complaints such as taste and odor with increasing levels of SO2. Exercise increased the frequency of lower airway symptoms in asthmatics but led to no increases in symptoms in healthy subjects.

Erythrocyte pyrimidine 5'-nucleotidase activity in workers exposed to lead, mercury or cadmium.

Abstract: The erythrocyte pyrimidine 5'-nucleotidase activity (P5N) was measured in workers exposed to lead, cadmium or inorganic mercury and the effect of lead on this enzyme activity was compared with that on the classical biological parameters (ALAD, ZPP, ALAU), reflecting the interference of this metal with the heme biosynthesis pathway. P5N is inhibited by lead but not by cadmium and mercury. The correlation coefficient between log P5N and lead in blood (PbB) amount to 0.79 (n = 278; PbB ranging from 4.9 to 73.5 micrograms/100 ml). The response of P5N to lead closely parallels that of ALAD.