Mutagenicity of Surface Sand in Park Sandboxes

Fine sand of less than 60 mesh in size collected from the sandboxes of 40 urban parks throughout the country was subjected to methanol extraction. The mutagenicity of the extract was then measured by the Ames (pre-incubation) method. Most of the samples exhibited mutagenicity, which varied in severity, by four orders of magnitude from the lowest to the highest. The study also indicated that mutagens such as those detected in the TA98 or YG1024 strain existed. High mutagenicity was observed under the condition where S9mix was not added, which suggested that contamination due to direct mutagens was worsening in the sandboxes in parks. By region, mutagenicity tended to be higher in highly populated regions with much industrial activity such as the Kanto area.