Cultured human-cell-based bioassay for environmental risk management

Toxicity assessment of treated wastewater using cultured human cell lines

Bioassay using cultured human cell lines was applied to an effluent of a wastewater treatment plant (WWTP) in Sapporo to assess their toxicity, and in order to investigate the fate of toxicity in the WWTP, bioassay of the water samples from several points in WWTP (influent, effluent, return flow from thickener, from dewatering process and from incineration process) was performed. We also applied bioassay to the mixture of the activated sludge from the investigated plant and artificial sewage. These results showed that the toxicity of the effluent was more intensive than the influent, and organic matter released from activated sludge bacteria during their decay process contributed to the increase of toxicity in the effluent.

Estimation of cytotoxicity to HEP-G2 cells of 255 environmental pollutants and water using QSAR (Quantitative Structure-Activity Relationship)

Although bioassays are considered to be a rational method for environmental management, the procedure is generally too complicated to be applied to daily water quality management. In this study, the feasibility of using for application of a conventional QSAR (Quantitative Structure-Activity Relationship) method was examined to estimate the cytotoxicity of various pollutants found in environmental water. logP, pKa, and molecular weight were chosen as the physico/chemical properties of the pollutants, and defined equations for estimating cytotoxicity based on multiple linear regression analysis between these properties and in vitro cytotoxicity data from our previous results. As a result, a method for estimating cytotoxicity of environmental pollutants that had a certain probability (R>0.8) for the 255 chemicals was successfully developed. Considerably high reliability was shown in the leave-one-out prediction of multi-regression analysis. In addition, the cytotoxicity of environmental water samples was estimated based on multi-regression analysis, using as our samples leachates from 25 landfill sites in Japan. The method developed in this study estimated quantitatively the cytotoxicity of the environmental water from chemical analysis data without conducting a cytotoxicity test.