Internal and external tetrachloroethene exposure of persons living in differently polluted areas of Northrhine-Westphalia (Germany).

An epidemiological study was performed to measure the internal and external tetrachloroethene exposure of persons living in two differently polluted areas of Northrhine-Westphalia (Germany). Tetrachloroethene concentrations were determined in venous blood samples of 5- to 7-year-old children (n = 81) and 55-year-old women (n = 91) living in Essen, an industrial city located in the Ruhr area. 103 children und 131 women of the same age living in Borken, a small town north of the Ruhr area, served as reference group. Outdoor air samples were collected on passive samplers (sampling period: 4 weeks) from 70 measurement points per study area (about 2 km2, mean distance 100 m). In the course of a year these measurements were repeated three times to cover seasonal variations. Parallel to the outdoor measurement periods, indoor air concentrations were determined in the homes of those women from Essen and Borken, who donored a blood sample. Tetrachloroethene levels in blood were generally low with a geometric mean of 0.05 microgram/L in women and 0.021 microgram/L in children. Nevertheless, children and women living in the industrial area were found to have significantly higher tetrachloroethene levels in blood than those of the reference group. In both study areas blood levels of women exceeded those of children by a factor of 2. Participants living in the neighbourhood of a dry-cleaning shop had distinctly elevated blood levels. The same applied to persons who stored dry-cleaned clothes at home. Like the internal exposure, external exposure was also higher in Essen than in Borken. In both areas tetrachloroethene concentrations indoors exceeded those outdoors. Outdoor tetrachloroethence concentrations were significantly increased during the cold season, while the opposite was true for indoor levels. The correlation between indoor and outdoor exposure was found to be significant, while those between blood levels and outdoor exposure became only significant when people living next to a dry-cleaning shop were excluded. No significant relationship was observed between blood and indoor tetrachlorethene levels. It is concluded that the higher tetrachloroethene blood levels of the urban population result from the higher atmospheric concentrations in industrial areas with tetrachloroethene emitting sources like metal and textile industry. The fact that indoor air tetrachloroethene levels exceeded those outdoors can only be explained by the presence of additional indoor sources. Provided that women spend on average more time indoors than children the higher indoor air concentrations may be the reason for the higher blood tetrachloroethene levels found in women. Persons living near a dry-cleaning shop or storing dry-cleaned clothes at home showed a higher internal and external exposure to tetrachloroethene than other persons. In individual cases it can by far exceed the average exposure of the general population, so that health impairments can not be generally excluded.