1993 Volume 30 Pages 235-242
The Bacillus subtilis rec-assay which can detect DNA toxicity was applied to water samples from various points and non-point sources.
In the application of the assay, there are technical problems such as a concentration method of DNA toxic substances. In general, there is a close relationship between biological concentration factor and Pow (Octanol-water Partition Coefficient). Hydrophobic chemicals whose value of Pow is high, have more significant effects in ecological toxicity including DNA toxicity. This means that the selection of concentration methods of DNA toxic substances in water, should focus on better capacity of absorption of hydrophobic substances. Four kinds of resins, XAD-2, XAD-4, Blue-rayon and Sep-Pak Plus C18 were examined in the capacity of absorbing hydrophobic chemicals. XAD-2 and XAD-4 resins were found to be better among the four.
The application of the assay using XAD-2 resin was conducted for the samples of municipal sewage, primary treatment effluent, secondary treatment effluent, night soil treatment effluent, rain water and run-off water. We could detect DNA toxicity in all the samples, which means DNA toxic pollution extended widely in our environment.