PAHs are the general term of the compounds, having two or more benzene rings. These are discharged from diesel motor gas, tanker accidents, oil emissions by cars, and so on. They float in the atmosphere, and it is considered that they are absorbed in soil as a result of rain. Generally, compounds that have two or three benzene rings show only toxicity, whereas these having four or more benzene rings show toxicity, carcinogenicity and mutagenicity. Especially, benzo(
a)pyrene was shown to be an agency of an endocrine disrupter. We investigated the action of 16 PAHs specified by the U.S. EPA in soil around Nara city. Soil was collected from different locations involving traffic and vegetation. Soil from three locations around our university were collected every month for investigating seasonal movement. PAHs were extracted from soil by soxhlet extraction with dichloromethane. They were then analyzed quantitatively by HPLC/UV. We classed PAHs by the number of rings, and examined the concentration and seasonal movements. All content of 16 PAHs in soils increased in proportion to traffic volume. At the same locations of traffic volume, the gravitation at a location with a plant with all 16 PAHs in soils was, furthermore, found to have a low concentration. There were different seasonal movements of the 2,3-ring and 4, 5, 6-ring PAHs. 4, 5, 6-ring PAHs have strong correlations each others(
r > 0.79), but there was no correlation between 2, 3-ring and 4, 5, 6-ring PAHs. As a result, the traffic volumes are exposition sources of 4, 5, 6-ring PAHs in soils.
抄録全体を表示