The quality of environmental waters such as rivers is often deteriorated by various kinds of trace and unidentified chemicals despite the recent development of sewage systems and wastewater treatment technologies. In addition to contamination by particular toxicants, complex toxicity due to multi-component chemicals could be much more serious. The environmental situation in bodies of water in Japan led us to apply bioassays for monitoring the water quality of environmental waters in order to express the direct and potential toxicity to human beings and ecosystems rather than determinating concentrations of particular chemicals. However, problems arose from the fact that bioassays for pharmaceutical purposes generally required complicated, time-consuming, expert procedures. Also, a methodology for feedback of the resultant toxicity data to water environment management has not been established yet. To this end, we developed a novel bioassay based on the low-density lipoprotein (LDL) uptake activity of human hepatoblastoma cells. The assay enabled us to directly detect the toxicity of environmental waters within 4 hours of exposure. This is a significantly quick and easy procedure as compared to that of conventional bioassays. The toxicity data for 255 selected chemicals and environmental waters obtained by this method were organized by a mathematical equation in order to make those data much more effectively and practically useful to the management of environmental waters. Our methodology represents a promising example of applying bioassays to monitor environmental water quality and generating potential solutions to the toxicity problems encountered.
