Effects of occupational exposure to diesel exhaust on porphyrin metabolism in lymphocytes of workers employed at black coal and oil-shale mines.

Background: This pilot study was conducted to investigate biochemical effects of exposure to diesel engine exhaust at two mines. For this purpose, heme biosynthesis, and PP association with DNA (PP/DNA) in lymphocytes of miners exposed to diesel exhaust were determined.

Methods: The pilot study was carried out at a black coal mine in Czech Republic, and at an oil-shale mine in Estonia. The subjects were ten drivers from each mine, who were exposed to diesel exhaust (underground workers). Control groups consisted of ten maintenance workers from each mine (surface workers). The content of 1-nitropyrene (NP) in respirable dust was measured using GC-MS. The levels of PP, PP/DNA, heme, and activity of ferrochelatase (FC) were determined by spectrophotometry.

Results: The exposure to diesel exhaust evaluated as the level of NP associated to particulate matter in air. NP level was significantly higher in oil-shale mine compared with coal mine. The values of PP and PP/DNA in lymphocytes appeared to be significantly increased only in miners in the oil-shale mine. There was no difference in the levels of PP and PP/DNA and FC activity between surface workers and miners at the coal mine. The level of heme in lymphocytes of coal mine miners was significantly higher than in miners of the oil-shale mine. The activity of FC was significantly lower in underground workers compared to surface workers at this mine. High level of NP was accompanied by an increase of alterations in cells porphyrin metabolism in lymphocytes of miners.

Conclusions: Alterations of porphyrin and heme metabolism in peripheral lymphocytes may serve as biomarker in assessment of exposure to diesel exhaust effects.