Exposure to PAH compounds among cokery workers in the oil shale industry

The exposure of Estonian cokery workers to polynuclear aromatic hydrocarbons at an oil shale processing plant was assessed by occupational hygiene and biomonitoring measurements. To assess the external dose of exposure to polynuclear aromatic hydrocarbons, pyrene and benzo[a]pyrene concentrations were measured from the breathing zone of workers during a workshift. Skin contamination with pyrene and benzo[a]pyrene was assessed by skin wipe sampling. As a biomarker of exposure to polynuclear aromatic hydrocarbons and as an integral of all possible absorption routes of pyrene, 1-hydroxypyrene concentration was measured from post-shift urine samples. Eighteen percent of the personal air samples exceeded the Finnish threshold limit value of benzol[a]pyrene (10 micrograms/m3). Mean values for benzo[a]pyrene and pyrene were 5.7 micrograms/m3 and 8.1 micrograms/m3, respectively. Based on skin wipe sample analyses, the skin contamination was also obvious. The mean value of benzo[a]pyrene on the samples collected after the shift was 1.2 ng/cm2. In control samples, benzo[a]pyrene was not found. The mean value of urinary 1-hydroxypyrene concentration was 6.0 nmol/mmol creatinine for the exposed workers and 0.5 nmol/mmol creatinine for the controls. This study showed the usefulness of 1-hydroxypyrene as an indicator of internal dose of polynuclear aromatic hydrocarbons. We concluded that the cokery workers at the Kohtla-Järve plant are exposed to high concentrations of polynuclear aromatic compounds.