Urinary thioether of employees of a chemical plant

Is organic farming safer to farmers' health? A comparison between organic and traditional farming

Exposure to pesticides is a major public health concern, because of the widespread distribution of these compounds and their possible long term effects. Recently, organic farming has been introduced as a consumer and environmental friendly agricultural system, although little is known about the effects on workers' health. The aim of this work was to evaluate genetic damage and immunological alterations in workers of both traditional and organic farming. Eighty-five farmers exposed to several pesticides, thirty-six organic farmers and sixty-one controls took part in the study. Biomarkers of exposure (pyrethroids, organophosphates, carbamates, and thioethers in urine and butyrylcholinesterase activity in plasma), early effect (micronuclei in lymphocytes and reticulocytes, T-cell receptor mutation assay, chromosomal aberrations, comet assay and lymphocytes subpopulations) and susceptibility (genetic polymorphisms related to metabolism - EPHX1, GSTM1, GSTT1 and GSTP1 - and DNA repair-XRCC1 and XRCC2) were evaluated. When compared to controls and organic farmers, pesticide farmers presented a significant increase of micronuclei in lymphocytes (frequency ratio, FR=2.80) and reticulocytes (FR=1.89), chromosomal aberrations (FR=2.19), DNA damage assessed by comet assay (mean ratio, MR=1.71), and a significant decrease in the proportion of B lymphocytes (MR=0.88). Results were not consistent for organic farmers when compared to controls, with a 48% increase of micronuclei in lumphocytes frequency (p=0.016) contrasted by the significant decreases of TCR-Mf (p=0.001) and %T (p=0.001). Our data confirm the increased presence of DNA damage in farmers exposed to pesticides, and show as exposure conditions may influence observed effects. These results must be interpreted with caution due to the small size of the sample and the unbalanced distribution of individuals in the three study groups.

Genotoxic effects of tobacco chewing

Tobacco chewing is a widespread habit which leads to DNA damage. We are reporting a case of a tobacco chewer in which chromosomal aberrations, DNA breakage, buccal micronuclei and urinary thioether excretion level were studied. The study was carried out on a 28 year old male subject who is polio affected since his childhood. He has been chewing tobacco since the last 17 yrs @ 4 g, 08 times per day. The medical report of the subject indicates no abnormalities except post-polio paralysis in both lower limbs. He has no family history of any genetic disorder. He is not occupationally exposed to tobacco. The findings of the present investigation indicate increased incidence of chromosomal aberration % and micronuclei in buccal epithelial cells than the control values obtained from a subject of similar age and socioeconomic condition but not addicted to tobacco chewing. However, the urinary thioether values of the subject were lower than control values indicating a depression of the detoxification pathway.

Population monitoring for genetic damage induced by environmental physical and chemical agents

The short-term tests performed in vitro on different systems, from phage to human cells, or in vivo, on laboratory animals, allow only a qualitative estimate of the action of mutagenic agents, and the extrapolation of such experimental results to man may encounter many difficulties.Direct biomonitoring of populations exposed to chemicals could represent a more realistic approach for an evaluation of the hazards to man. Certain methods are still under development. Nevertheless, other ones can already by used routinely, e.g. the cytogenetic observations on peripheral blood lymphocytes and the Ames test for mutagenic substances in urine, and can provide useful suggestions how to set threshold limits for chemical substances encountered in the working environment.

Urinary screening for potentially genotoxic exposures in a chemical industry

Mutagenic activity, measured by the bacterial fluctuation assay and thioether concentration in urine from workers at a chemical plant producing pharmaceuticals and explosives, was determined before and after exposure. Of 12 groups only those exposed to trinitrotoluene (n = 14) showed a significant increase in mutagenic activity using Salmonella typhimurium TA 98 without any exogenous metabolic system. The same strain responded only weakly when the S-9 mix was used; with Escherichia coli WP2 uvrA no effect of exposure was observed. Urinary thioether concentration was higher among smokers than among non-smokers, but occupational exposure had no effect. Urinary mutagenicity testing may be a useful tool for screening potentially genotoxic exposures in complex chemical environments.

Mutagenicity studies in a tyre plant: in vitro activity of workers' urinary concentrates and raw materials

The possible contribution to urinary mutagenicity of occupational exposures in the rubber industry was studied by assaying the urine concentrates of 72 workmen (44 smokers) employed in a tyre plant. Twenty three clerks (16 smokers) engaged in the administrative department of the same factory served as presumptive unexposed controls. XAD-2 resin concentrates of urine samples were assayed in the plate incorporation test and in the microtitre fluctuation assay with Salmonella typhimurium strains TA1535, TA98, and TA100. Furthermore, the in vitro mutagenicity of the major raw materials in use at the plant was determined in the plate incorporation assay with S typhimurium strains TA1535, TA1537, TA98, and TA100. The results obtained from the urinary mutagenicity study show that smoking habits, but not occupation, were statistically significantly related to the appearance of a urinary mutagenicity that was detectable with strain TA98. A possible synergistic effect of occupation with smoking was observed among tyre builders who were also smokers. The study of the raw materials showed that three technical grade materials were weakly active as mutagens in strain TA98 in the absence (poly-p-dinitrosobenzene) or in the presence of metabolic activation (mixed diaryl-p-phenylendiamines and tetramethyltiuram disulphide). The latter chemical was also weakly active in strain TA100.

Spontaneous abortions and reproductive selection mechanisms in the rubber and leather industry in Finland

ABSTRACT Spontaneous abortions in hospitals were analysed from two sources—membership files of the Union of Rubber and Leather Workers (about 10 000 women) and records of the personnel of a rubber factory (about 1600 women). Two frequencies of spontaneous abortions were calculated for each population analysed: rate (No spontaneous abortions X 100/No pregnancies) and ratio (No spontaneous abortions X 100/No births). The two frequencies were increased for all union members compared with all Finnish women. The frequencies, however, did not appreciably differ when the pregnancies occurred during union membership as compared with the pregnancies before or after membership. The frequency of spontaneous abortions was higher for the short-time union members than for those employed for longer periods, but the increased frequency did not correlate with union membership. The employees of a rubber factory had slightly fewer spontaneous abortions on average than the community population. The women employed in the rubber factory for three to 23 months were found to have appreciably higher frequencies of spontaneous abortions than the women employed for longer periods. The present study showed the feasibility of using cases of spontaneous abortions in hospitals in an occupational study with longitudinal employment data. Women with short periods of employment appeared to have more spontaneous abortions than those with longer periods of employment suggesting the presence of selection mechanisms, perhaps with some analogies to the “healthy worker effect” in occupational mortality studies. The presence of such selection mechanisms deserve serious consideration in occupational reproductive epidemiology.

Urinary excretion of thioethers among low-tar and medium-tar cigarette smokers

The urinary excretion of thioethers was studied among smokers of medium-tar cigarettes (16.3 mg/cig.) and low-tar cigarettes (5.4 mg/cig.). The test persons (26 smokers and 11 nonsmokers) were healthy young men in the military service. The smokers had an increased excretion of thioethers into the urine (P = 0.002 with Mann-Whitney U-test) when compared with the nonsmokers. No differences in the amount of urinary thioethers were detected between the low-tar and medium-tar cigarette smokers. The smokers (varying from 2.0 to 8.5 mmol/mol creatinine) had more individual variation than the nonsmokers (varying from 1.5 to 4.5 mmol/mol creatinine). Furthermore, the individual variation in the group of low-tar cigarette smokers did not markedly differ from the individual variation of medium-tar cigarette smokers.

Increased urinary excretion of thioether in new rubber workers

ABSTRACT Urinary excretion of thioether before starting work and in the early work period in a rubber factory was measured in urine samples collected after one, two to four, and five or more months of starting work. The study population consisted of 84 new workers. The urinary excretion of thioether decreased after one month's exposure and increased thereafter up to five months. Measurement of urinary thioethers in groups of new workers is therefore informative of exposure to alkylating agents only after several months from starting work. This effect may be mediated by the induction of the pertinent metabolic pathway.

Enhanced excretion of thioethers in urine of operators of chemical waste incinerators

Thioether concentrations were determined in urine samples obtained from ten workers in the despatch department (n = 69), three chemical waste incinerator operators (n = 67), and an analyst (n = 21), all working in the same chemical plant. Urine samples (n = 196) obtained from non-exposed men, including smokers, served as controls. Enhanced excretion of thioethers was found in urine samples taken from incinerator workers at the end of work. A regular pattern in the time course of the urinary thioether excretion was shown by a non-smoking incinerator worker; end-of-work values were always higher than prework values. This phenomenon was not found in samples obtained from the analyst. These findings suggest that incinerator workers inhale or otherwise absorb electrophilic compounds or their precursors, which are subsequently metabolised to, and excreted as, thioethers in urine.

Correlation of urinary thioethers with chemical exposure in a rubber plant

Exposure to potentially alkylating in a rubber factory was measured by determining thioether concentrations in urine samples collected at the end of work on a Friday. The study population consisted of the total work force (113) in the production departments of a factory, and office clerks (111) in two factories of the same company. The highest excretion of thioethers was detected in female workers in the belt department who were exposed through the palmar skin. High excretion was also found in workers exposed to air-borne contaminants in the calender department and in workers in the raw material stores and chemical mixing sections. Lower values were found in this dispatching station and in the contaminant-free offices. Urinary thioether determination appears to be a reliable and easy method of assessing the exposure to certain rubber chemicals.