Application of Biotests for Toxicity of Leachate and Evaluation Monitoring
Shino Mohri*, Hiroshi Nagashima**+, Yasuaki Miyahara**, Yoshiro Ono***Abstract
To develop a more applicable means to screen for toxicity, we have selected a battery of three biotests for a six-month monitoring period of the risk in leachate from a landfill site. To validate this battery, we measured genotoxicty, proliferation activity of MCF-7 and cytotoxicity of leachate, its treated effluent and receiving river waters once a week. A new measure, named Negative Dilution Factor (NDF) become apparent from umu-test. In the experiments genotoxicity was detected in leachates, and reduced through the treatment process. Leachate showed same seasonal changes in proliferation activity of MCF-7 cells in river samples. Since the average proliferation activity of MCF-7 cells in leachate was low, there may be little effect of leachates on the river. Cytotoxicity of leachate and treated effluent were stronger than river water but almost all of these toxicities were less than 50% inhibitiing. Cytotoxicity was observed in concentrated samples from a landfill site, but it derived from osmotic pressure by salinity. As the maximum cytotoxicity of treated effluent was 9 times that of upstream samples, it may be necessary to dilute treated effluent about 10 times for the management of impact on the environment.
Key words: leachate, umu-test, E-SCREEN assay, cytotoxicity test, monitoring