Abstract
Precipitates grow rapidly from underground water in limestone terrain of Okinoerabu Island located southern Kyusyu, Japan. In this island, Ca-rich underground water are used as drinking water which cause and effect choking toilet bowl and water pipes by the precipitates. In this study the precipitates were collected from toilet bowl at China-cho and from the water pipe of pump well at Akamine. Filamentous cyanobacteria are observed on the surface of the precipitates in both cases. These precipitates consist mainly of calcite with heavy metals, such as Cu, Zn, Mn, Fe and Pb which are concentrated from water. The accumulation of P and N are also detected at heavy metal layers by using EPMA. The precipitates can explain that biochemical conditions are favorable for carbonate formation. In human daily life the precipitates adhered to equipments are displeased as a dirt. However in this environments, the results suggest that microorganism can accumulate heavy metals from drinking water.
