Monitoring Genotoxic Exposure in Uranium Miners

Abstract

Recent data from deep uranium mines in Czechoslovakia indicated that in addition to radon daughter products, miners are also exposed to chemical mutagens. Mycotordns were identified as a possible source of mutagenicity present in the mines. Various methods of biomonitoring were used to eaamine three groups of miners from different uranium mies. Cytogenetic analysis of peripheral lymphocytes, unscheduled DNA synthesis (UDS) in lymphocytes, and lipid peroxidation (LPO) in both plasma and lymphocytes were studied on 66 exposed miners and 56 cotrols. Throat swabs were taken frm 116 miners and 78 controls. Significantly increased numbers of aberrant cells were found in all groupsof miners, as well as decreased UDS values in lymphocytes and increased LPO plasma levels in comparison to controls. Molds were detected in throat swabs from 27% of miners, and 58% ofthese molds were embryotoxic. Only 5% of the control samples contained molds and none of them was embryotoxic. The following mycotoxins were isolated from miners' throat swab samples: rugulosin, sterigmatocystin, mycophenolic acid, brevianamid A, citreoviridin, citrinin, penicilic acid, and secalonic acid. These data suggest that mycotoxins are a genotoxic factor affecting uranium miners. Introduc#onUranium ore in Czechoslovakia is mined using very deep mines (1200-1600 m), which have warm temperatures and high humidity. The risk of occupational exposure in such mines has been related to the carcinogenic effect of radon daughter products, inducing lung cancer (1). To reduce this exposure to radon, ventilation in these mines was increased substantially in the period [1968][1969][1970][1971][1972]. As a result of this improvement the radon exposures in these mines are 1.0-1.5 x 10"°MeV per year and infrequently are as high as 3.0-4.0 x 10"' MeV (limit is 8 x 1010 MeV/year). In spite of the decreased exposure to radionuclides, lung cancer incidence among these uranium miners has not decreased.In 1970, Kusak et al. (2) put forward the hypothesis that radionuclides may be accumulated in molds growing in uranium mines. Because these molds also produce aflatoxin, we initially looked for evidence of aflatoxin exposure by using an assay for measuring aflatoxin-albumin adducts (3). However, in a pilot study on 20 blood samples, no increased adduct levels were 'Laboratory of Genetic Ecotoxicology, Institute of Experimental Medicine, Czechoslovak Academy of Sciences, 120 00 Prague, Czechoslovakia. observed (C. P. Wild, unpublished data). Samples from walls and woods in the uranium mines contained molds. Altogether, 90 types of molds were isolated, and 72 % ofthem were embryotoxic (genus Aspergillus, Penicillium, Fusarium) and mutagenic using the Ames test and SOS chromotest (4). From these samples we isolated the mycotoxins sterigmatocystin, mycophenolic acid, brevianamid A, citreoviridin, penicilic acid, aflatoxin BI and GI, rugulosin, and citrinin. Therefore, we hypothesized that these mutagenic mycotoxins may be another risk factor responsible for the continued high cance...

The role of oxidative stress in citreoviridin‐induced DNA damage in human liver‐derived HepG2 cells

“…CIT has been mostly identified primarily in moldy rice and corn in parts of Asia and South America (Rosa et al, ; Almeida et al, ). CIT has also been isolated from uranium mines and miners' throats (Sram et al, ). It has been shown that the contamination levels of CIT in grains were between 4.9 and 33.2 µg/kg in the target areas of China (Hou et al, ).…”