To test this theory, they collected leaf samples from the trees of the broadleaf maple tree (Acer macrophyllum) once in July, once in August and once in September. They also compared roads with different levels of traffic: an arterial road, a quieter parallel street where no buses drove, and a rural road.
The leaves of major roads were up to eight times more magnetic than those of the quieter back roads and even up to ten times more magnetic than the leaves of the land. Leaf samples as bioindicators therefore provide simple and quick information about the tendency of pollutants to be polluted on roads. This could, for example, be helpful in the planning and coordination of bike paths and bus routes: since people also inhale the particles, whereby they reach the lungs, it makes sense to guide cycle paths through streets with the least possible load.Bernie Housen and Luigi Jovane: Lecture at the Annual Meeting of the American Geological Society (GSA) in Portland. ddp / science.de - Mascha Schacht advertisement