K. H. Schaller

Analyses of hazardous substances in biological materials

SummaryThe interest of the Commission for the Investigation of Health Hazards of Chemical Compounds in Work Area of the German Science Foundation in practical, sensitive and specific methods for monitoring the limit values led to the establishment of the working group “Analytical Chemistry” in 1969. A loose-leaf collection “Analysen in biologischem Material” and 3 volumes of an English edition have since been published. In the meantime the German edition of “Analyses in biological materials” has been supplemented ten times, including 100 methods for the measurement of about 170 parameters; the English edition is in 3 volumes with 45 selected methods. The volumes include only standard operational procedures that are suitable for routine use. The reliability of the analytical procedures is defined and checked for these reasons and because they satisfy the requirements of statistical quality control. The analytical methods published by the Working Group “Analytical Chemistry” are recommended by pertinent guidelines and regulations for use in Germany.

Adsorptive voltammetric procedure for the determination of platinum baseline levels in human body fluids

SummaryAn extremly sensitive procedure for the determination of platinum in human body fluids is presented. A high pressure decomposition of the samples is followed by adsorptive voltammetric measurement. A detection limit down to 0.2 ng Pt/l sample allowed baseline levels of platinum in body fluids (urine: 0.5–15 ng/l, blood and blood plasma: ≤0.8–6.9 ng/l) to be evaluated. The concentration ranges in body fluids of occupationally exposed people were determined to 21–2900 ng/l (urine), 32–180 ng/l (blood) and 95–280 ng/l (blood plasma).

Exposure assessment in the hard metal manufacturing industry with special regard to tungsten and its compounds.

OBJECTIVES To assess the exposure to tungsten, cobalt, and nickel in a plant producing hard metals. The main components of hard metals are tungsten carbide and cobalt metal. According to recent studies, these two components may be responsible for both fibrogenic and carcinogenic effects. METHODS 87 workers were investigated (86 male, one female) with a median age of 42 (range 22–58) and a mean duration of exposure of 13 years (range 1–27 years). Stationary and personal air sampling, and biological monitoring were carried out. RESULTS Ambient monitoring yielded maximum tungsten concentrations of 417 μg/m3 in the production of heavy alloys. A maximum cobalt concentration of 343 μg/m3 and a maximum nickel concentration of 30 μg/m3 were found at the sintering workshop. The highest urinary cobalt concentrations were found in the powder processing department. The mean concentration was 28.5 μg/g creatinine and the maximum value was 228 μg/g creatinine. The maximum nickel concentration in urine of 6.3 μg/g creatinine was detected in the department producing heavy alloys. The highest tungsten concentrations excreted in urine were found in grinders and had a mean value of 94.4 μg/g creatinine and a maximum of 169 μg/g creatinine. Due to the different solubility and bioavailability of the substance, there was no correlation between the tungsten concentrations in air and urine on a group basis. CONCLUSIONS Despite its low solubility, tungsten carbide is bioavailable. The different bioavailability of tungsten metal and tungsten compounds has to be considered in the interpretation of ambient and biological monitoring data in the hard metal producing industry. The bioavailability increases in the order: tungsten metal, tungsten carbide, tungstenate. Only if both monitoring strategies are considered in combination can a valid and effective definition of high risk groups be derived.

Cross-sectional epidemiological study on neurotoxicity of solvents in paints and lacquers

SummaryIn a multi-disciplinary retrospective study we examined 105 house painters employed for at least ten years (median 27 years, range 10–36 years). Fifty-three workers from various professions (non-painters), who were matched with regard to age, occupational training and socio-economic status served as the control group. In both groups no cases of a clinically manifest polyneuropathy or encephalopathy were found. The neurophysiological examinations (EEG and NCV-measurement) showed no differences in painters and controls that would indicate adverse effects of organic solvents. There were no cases with neuroradiological findings of a diffuse cerebral atrophy. Furthermore the evaluation of certain brain structures (ventricular diameter, cella media index) of the CAT films did not reveal any significant differences. In the neurobehavioral tests significant differences in the results were only found in the subtests “change of personality” and “short term memory capacity” in a subgroup of painters with repeated prenarcotic symptoms at the workplace. Ambient air monitoring measurements at 30 representative work-places showed that the concentrations of the main components of the solvent-mixtures were well below the MAK-values. The results of the “Erlangen Painter Study” does not confirm former epidemiologic findings from other countries, mainly Denmark. However, there are some aspects, such as minor solvent exposure in German house painters, insufficient diagnostic and etiological procedures as well as mis-classifications which may explain the different experiences.

External quality assessment of human biomonitoring in the range of environmental exposure levels.

The number of human biomonitoring (HBM) applications for identifying and assessing the chemical exposure of the general population from the environment has distinctly increased during the last decade. An appropriate external quality assessment of the applied methods is essential to assure the accuracy and the comparability of HBM results. The international programme of the German External Quality Assessment Scheme (G-EQUAS) provides proficiency testing for most of the HBM parameters, which are commonly used for the assessment of the human exposure to chemicals. Since 1992, G-EQUAS provides intercomparison runs for biological monitoring parameters in the environmental exposure range twice a year, with a successive increase of parameter numbers. In round no. 45 (2010) 18 metals in blood, plasma and urine und 36 organic parameters in urine and plasma were provided. Additionally analyses of 4 haemoglobin adducts were offered. For each parameter, two samples with different concentrations of the biomarker were sent to the participants. The target values as well as the tolerance ranges were estimated on the basis of the results from reference laboratories. The successful participation was certified, if the participants results were within the tolerance ranges for both samples. The number of participants ranged from 3 to 37 international laboratories according to the individual parameter. The highest interest was observed for the detection of metals in blood, serum and urine, whereas only a few of the participants took part in the analyses of organophosphate metabolites and haemoglobin adducts. The rate of a successful participation ranged from 38 to 100%. Poor success rates were found for organophosphate metabolites, 1-naphthol and cotinine in urine. A training effect was observed for a group of laboratories which participated regularly in the analysis of organochlorinated compounds in serum.

On the Question of the Pathogenetic Importance of Cobalt for Hard Metal Fibrosis of the Lung

SummaryPulmonary fibrosis in hard metal grinders has been observed to an increasing degree in recent years. Most authors attribute the cause of this disease to the influence of the cobalt contained in hard metals. The present case dealt with a 36-year-old man who had been exposed to the grinding dust from sintered hard metal parts for more than 10 years. Biopsy of the lung revealed an advanced, active pulmonary fibrosis. In the biopsy specimens cobalt was determined by flameless atomic absorption. The cobalt content in the biological specimens of the patient (urine: 7.5 μg/l; lung: 1010 μg/kg wet weight) was significantly increased compared with the values measured in normal controls.

External and internal antimony exposure in starter battery production

In the production of lead batteries two antimony compounds occur: in the casting of grids antimony trioxide (Sb2O3), and in the formation of lead plates stibine (SbH3). Seven workers from the gridcasting area and 14 workers from the formation area were examined with regard to the antimony concentration in blood (Sb-B) and urine (Sb-U). Antimony air concentrations (Sb-A) were measured by means of personal air samplers. Urine samples were collected at the end of the working week, at the beginning (U1) and the end (U2) of the shift, and at the beginning of work following a weekend without Sb exposure (U3). At U2 among the casters the median Sb-A exposure was 4.5 (1.18–6.6) μg Sb/m3 and among the formation workers, 12.4 (0.6–41.5) μg Sb/m3. The exposure in both groups is more than 10 times lower than the present threshold limit values. The median Sb-B concentrations in the preshift samples was 2.6 (0.5–3.4) μg Sb/l for the casters and 10.1 (0.5–17.9) μg Sb/l for the formation workers. The average Sb-U values (U2) were 3.9 (2.8–5.6) μg Sb/g creatinine in the casting area and 15.2 (3.5 23.4) μg Sb/g creatinine in the forming area. Our investigation indicates that the two antimony compounds show virtually equal pulmonary absorption and renal elimination. The statistically significant correlations between Sb-A/Sb-B and Sb-A/Sb-U form the basis for proposals regarding appropriate biological exposure limits for occupational antimony exposure.

Determination of environmental caused chlorophenol levels in urine of the general population

SummaryA sensitive, specific and analytically reliable method for the determination of mono-, di-, tri- and tetrachlorophenols in human urine has been elaborated. After acid hydrolysis and a simultaneous steam distillation of the urine samples, spiked with an internal standard, the chromatographically concentrated chlorophenols have been derivatized with pentafluorobenzoylchloride and analyzed by capillary gas chromatography/mass spectrometry. The detection limits for the chlorophenols ranged from 0.2 to 2.5 μg/l. Using this method we were able to detect 4-MCP, 2,4-+2,5-DCP, 2,4,6-TCP, 2,4,5-TCP and 2,3,4,6-+2,3,5,6-TeCP in urine samples of a group of 258 men and women which had no known occupational contact to hazardous chemical substances. The 95 percentiles for the concentrations of these substances in the urine samples under investigation were 7.5 (4-MCP); 33.6(2,4-+2,5-DCP); 4,7 (2,4,6-TCP); 4,5 (2,4,5-TCP) and 22.2 (2,3,4,6-+2,3,5,6-TeCP) μg per liter. That means, that these chlorophenols are constituents of urine of the normal population in concentrations which in part are greater than that of pentachlorophenol (PCP).

Internal and external quality control in the toxicological analysis of blood and urine samples in the Federal Republic of Germany.

SummaryDue to a technical rule for dangerous agents (TRGS 410), issued by the Ministry of Labor in the Federal Republic of Germany in 1979, toxicological analyses in biological materials must be carried out under conditions of “statistical quality control”. This quality-control scheme provides internal and external control programmes. For internal quality control, the results of many years of experience with five commercially available control specimens and one “home-made” control have been evaluated. The control samples showed good, comparable results over a long period. Except in a few cases, there was good agreement between our results and the assigned values. Since 1982, the German Society of Occupational Medicine has offered eight intercomparison programmes for external quality. In samples from 80–90 laboratories, 6 metals in blood and around 20 inorganic and organic parameters in urine in 2 concentration adjustments have been analysed. Successful participation was certified if both results obtained for one parameter were within the tolerance range (assigned] value ± 3 SD). The average success rate was around 60%.

Percutaneous absorption of aromatic amines in rubber industry workers: impact of impaired skin and skin barrier creams.

Background: Several aromatic amines (AA) could cause bladder cancer and are an occupational hygiene problem in the workplace. However, little is known about the percutaneous absorption of chemicals via impaired skin and about the efficacy of skin protection measures to reduce internal exposure. Aims: To determine the impact of skin status and of skin protection measures on the internal exposure to AA in workers manufacturing rubber products. Methods: 51 workers occupationally exposed to aniline and o-toluidine were examined. The workplace conditions, risk factors for skin and the use of personal protective equipment were assessed by means of a self-administered questionnaire. The skin of hands and forearms was clinically examined. Exposure to aniline and o-toluidine was assessed by ambient air and biological monitoring (analyses of urine samples and of haemoglobin adducts). Results: Haemoglobin-AA-adduct levels in workers with erythema (73%) were significantly higher (p<0.04) than in workers with healthy skin (mean values: aniline 1150.4 ng/l vs 951.7 ng/l, o-toluidine 417.9 ng/l vs 118.3 ng/l). The multiple linear regression analysis showed that wearing gloves significantly reduced the internal exposure. A frequent use of skin barrier creams leads to a higher internal exposure of AA (p<0.03). However, the use of skincare creams at the workplace was associated with a reduced internal exposure (p<0.03). From these findings we assume that internal exposure of the workers resulted primarily from the percutaneous uptake. Conclusions: The study demonstrates a significantly higher internal exposure to AA in workers with impaired skin compared with workers with healthy skin. Daily wearing of gloves efficiently reduced internal exposure. However, an increased use of skin barrier creams enhances the percutaneous uptake of AA. Skincare creams seem to support skin regeneration and lead to reduced percutaneous uptake.