Evaluation of blue-chitin column, blue-rayon hanging, and XAD-resin column techniques for concentrating mutagens from two Japanese rivers

Highly mutagenic water of the Katsura River, Kyoto, and moderately mutagenic water of the Asahi River, Okayama, were used to evaluate the efficacy of three concentration techniques, the blue-chitin column, the blue-rayon hanging, and the XAD-2 column. These two river waters have been shown to exhibit high mutagenicity in the assay with Salmonella typhimurium TA98 with metabolic activation. With this assay as a measure, two water samples from the Katsura, collected on different dates, and a sample from the Asahi were submitted to the column concentration techniques, blue-chitin and XAD-2. Blue-chitin was more efficient than XAD-2 for all of these samples: e.g., for one Katsura sample, the mutagenicity found was 913 +/- 53 (mean +/- SD, n = 3) revertants/500 ml with blue-chitin, and 419 +/- 129 (n = 3)/500 ml with XAD-2. Blue rayon (0.5 g) hung in the Asahi for 24 h gave 563 +/- 74 (n = 3) revertants, while the water spot-sampled at the start of the hanging showed 253 +/- 10 (n = 3) revertants per 5 liter with the blue-chitin column technique. We conclude that for quantitative measurement of the "Salmonella TA98 +/- S9' mutagens in these rivers, the blue-chitin column is more efficient and accurate than the XAD-2 column and that for judging the presence of mutagens, the blue-rayon hanging is the most sensitive and convenient among the three methods examined.