Environmental exposure to hydrogen sulfide in central Slovakia (Ruzomberok area) in context of health risk assessment.

The activities of the kraft pulp-mill in Ruzomberok have great impact on ambient air quality in the town and the neighboring villages. The malodorous sulfur compounds adversely contribute to the overall emission profile. The reduced sulfur proportion forms the inorganic and organic compounds containing sulfur atoms in their lowest oxidation condition (S2-). The total sulfur proportion reduced includes hydrogen sulfide, mercaptans, dimethyl sulfide, dimethyl disulfide and other sulfur compounds. Hydrogen sulfide (H2S)--as mentioned above--is of prime importance. The kraft pulp-mill has measured of hydrogen sulfide contained in ambient air since 2002. The environmental samples were collected in 7 localities in all their selection based on the geographic, climatic and demographic factors. Four exposure localities in the Ruzomberok neighborhood, have been defined by the specified criteria. Exposure assessment was made for each exposure locality by determination of the average daily inhalation dose. The average concentration of H2S reached 5.8 microg x m(-3) in the most polluted locality (Cernová, 2003). To complete the health risk assessment, the standard risk characterization procedure was made by the Hazard Quotient (HQ) calculation for hydrogen sulfide exposure. The highest level of HQ, almost 7, was identified in the event of a worst case exposure scenario (using the 95% concentrations), as for exposure group C. Statistically significant decrease of reported H2S levels was noted during the entire measurement period (-0.25/year, p < 0.001).