A simple and easy method for the monitoring of environmental pollutants using oligotrophic bacteria

Sphingomonas paucimobilis KPS01, an oligotrophic bacterium isolated from so il, may be a useful tool for monitoring heavy metals. Previous methods rely ing on counting of viable cells require a relatively long time and some ski ll; we have developed a method based on optical density (O.D.) measurements which is significantly faster and does not require skilled personnel. The results of the O.D. and viable count methods were consistent; both methods detected heavy metals at concentrations ranging from 10(-3) to 10(-5) mmol l(-1) and identified heavy metal contamination in 13 of 18 river water samp les. Our results demonstrate that biological detection using this O.D. meth od and S. paucimobilis KPS01 may be useful for routine environmental monito ring of heavy metals, particularly in water sources.