2005 Volume 51 Issue 6 Pages 645-657
To clarify the contamination levels of surface soil with mutagens in urban areas of Aichi prefecture, Japan, and Bangkok, Thailand, 60 and 67 surface soil samples were collected in Aichi and Bangkok, respectively, and mutagenicities of the organic extracts from these soil samples were examined in the Ames assay using Salmonella typhimurium (S. typhimurium) TA98 and TA100 with and without a mammalian metabolic system (S9 mix). Most of the soil samples collected in both areas showed mutagenicity in TA98 with and without S9 mix and in TA100 with S9 mix. Thirteen (22%) soil samples collected in Aichi showed high mutagenicity (more than 1000 revertants/g of soil) in TA98 with and/or without S9 mix, and six soil samples induced more than 4000 revertants/g of soil in TA98. Mutagenic potencies of most of the soil samples from Bangkok were moderate (100-500 revertants/g of soil) or low (less than 100 revertants/g of soil) in both strains with and without S9 mix, and only one sample induced more than 1000 revertants/g of soil in both strains. In the characterization of mutagens, organic extracts of two and one soil samples from Aichi and Bangkok, respectively, were separated on an octadecylsilyl (ODS) column for HPLC, and mutagenicities of the resulting fractions were examined using S. typhimurium YG1024 without S9 mix. For the two soil samples from Aichi, retention times of the distinct mutagenic fractions were similar at 40-74 min, and especially high mutagenicities were detected in three fractions corresponding to dinitropyrene isomers. In contrast, distinct mutagenicities were detected at retention times of 6-29 min for the sample from Bangkok, and marked mutagenicity was found in the fraction corresponding to another nitroarene. These results indicate that surface soils in urban areas in Aichi and Bangkok are commonly contaminated with mutagens, but major mutagenic constituents in the surface soils are different.
