Abstract
Inorganic mercury was detected at a level above the limit of Japanese water quality standard (0.5 μg·l-1) in well waters in Fukuoka city. Contamination due to industrial waste was not found in this area and the water quality was otherwise good for drinking.
Measurement of mercury gas in the soil have been used to investigate faults in geothermal areas, because such gas is thought to originate from magma along the faults. Although there are no geothermal areas, there are a lot of faults in Fukuoka City. Then, from the estimation which mercury in well water would come from magma, mercury concentration in soil gas and well water were measured in the polluted areas.
The polluted well waters were located along a line straight from north to south on the map and two mercury gas contour lines could be drawn in this area, and high mercury gas concentrations were detected near highly polluted well waters. From the results above, perhaps due to the presence of faults in this area the source of mercury in well water is thought to be mercury gas from magma.
