238 Trakia Journal of Sciences, Vol. 12, № 3, 2014 Trakia Journal of Sciences, No 3, pp 238-244, 2014 Copyright © 2014 Trakia University Available online at: http://www.uni-sz.bg ISSN 1313-7050 (print) doi:10.15547/tjs.2014.03.004 ISSN 1313-3551 (online) Original Contribution STUDY ON OXIDATIVE STRESS BIOMARKERS IN WORKERS OF THE COLLIERY INDUSTRY B. Grigorov 1 , M. Platikanova 2* , G. Nikolova 1 , Y. Karamalakova 1 , A. Zheleva 1 , V. Gadjeva 1 1 Department of Chemistry and Biochemistry, Medical Faculty, Trakia University, Stara Zagora, Bulgaria 2 Professional Diseases Section, Department of Hygiene, Infectious Diseases and Epidemiology, Medical Faculty, Trakia University, Stara Zagora, Bulgaria ABSTRACT The aim of the present research was to evaluate the effect of the surroundings on the oxidative status of workers in the mining industry. By means of two different analytical techniques have been investigated selected biomarkers of oxidative stress. By spectrophotometric methods have been studied the levels of lipid peroxidation products (MDA), catalase (CAT) activity, superoxide dismutase (SOD) activity in blood samples isolated from 30 vulcanizers exposed to trichlorethylene and 30 welders exposed to iron and manganese aerosols. Both real time biomarkers of oxidative stress such as levels of ascorbate radicals and reactive oxygen species (ROS) were also evaluated by electron paramagnetic resonance (EPR) spectroscopy. The control group consisted of 20 healthy volunteers at age close to that of the vulcanizers and welders was also studied. By the present research were demonstrated increased levels of the studied oxidative stress biomarkers in workers from colliery "Troyanovo-1" and "Troianovo-north" to "Collieries Maritsa Iztok" EAD compared with healthy volunteers. It was supposed that increased production of reactive oxygen species might due to harmful surroundings under which the workers operate. Key words: Trichloroethylene, vulcanisation, biomarkers, oxidative stress INTRODUCTION One of the main occupations in the colliery industry are machine operator curing of rubber products and welder. In the performance of their duties welders are exposed to the toxic effects of iron and manganese aerosols and vulcanizer to the toxic effects of trichloroethylene (TCE). By inhalation of TCE is absorbed approximately 37 - 64% trichloroethylene by the lungs (1, 2) TCE is well soluble in lipids and therefore accumulates in organs containing high levels of adipose tissue, such as, the lungs, liver, kidneys and central nervous system (3). The metabolism of TCE occurs largely in the liver followed by excretion primarily in urine or unchanged in expired air (4). Based on the epidemiologic and experimental data, it is considered that TCE is potential human health hazard for noncancer _________________________ *Correspondence to: Magdalena Platikanova, Faculty of Medicine, Trakia University, Stara Zagora, Professional Diseases Section, Department of Hygiene, Infectious Diseases and Epidemiology, mplatikanova@abv.bg toxicity to the central nervous system, kidney, liver, immune system, male reproductive system, and the developing fetus (5). Different epidemiological studies indicate neurobehavioural, reproductive, and respiratory effects in workers exposed to manganese (6). Neurobehavioural effects most often expressed as the disturbances in the control of movements of the hand. Various studies have shown neurochemistry of manganese toxicity affected the levels of dopamine as an initial increase in dopamine followed by a longer-term decrease in humans, monkeys and rodents by exposure to manganese (7). Some authors have suggested that manganese neurotoxicity due to excessive manganese in the oxidation of dopamine, resulting in free radicals and cytotoxicity (8). Purpose of the present study was to evaluate the oxidative status of workers in the colliery industry working under hazardous working conditions by assessing of biomarkers as lipid peroxidation products, catalase (CAT) activity,