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A total of 69 soil samples and 80 Bassia dasyphylla (sandwort) leaf and stem samples from Gobi desert land in the Wuda coalfield, Inner Mongolia, were analyzed. The results show that the average fluorine content in the soil of the coalfield area, the periphery of the coalfield area, and the Wuda urban area was 1250, 757, and 552 µg/g, respectively, which is higher than the background value. This suggests that the coal seam fire burning there, leads directly to fluorine pollution within a limited area. The average fluorine content in the leaves and stems of Bassia dasyphylla sampled immediately around the sites of the ongoing coal fire was 532 and 388 µg/g, respectively, while the concentration in leaf and stem samples collected in areas remote from the fire, but within the field, was 146 and 107 µg/g, respectively. This implies that this historic coal fire, which has been burning for the past 50 years, is responsible for a general deposition of fluorine in the local area. This result suggests that coal seam fires may also be a novel source of fluorine pollution in some urban areas. The scenario of urban areas being adjacent to coal seam fires is not limited to Wuda but is relatively common in northern China, and elsewhere. Whether or not there are other cities currently under the influence of coal seam fires merits further investigation. [ABSTRACT FROM AUTHOR]