English Abstract A research program has been designed to determine the
environmental quality of soil and groundwater along motorways. Samples of
forest litter, soil and shallow groundwater were taken at five motorway
roadside sites during the period October-November 1991. The samples were
taken at two distances from the motorway ; nearby (approximately 8 meters)
and far away (approximately 80 meters). Finding higher soil and groundwater
concenstrations of traffic-derived compounds at the shorter distance was
anticipated. The samples were analyzed for heavy metals (cadmium, lead,
nickel, copper and zinc). PAHs and VAHs (benzene, toluene, xylene and
ethylbenzene), Additionally, the chloride concentration in groundwater was
analyzed. In the forest litter the soil concentrations of lead, copper,
zinc and most PAHs were significantly higher near the motorway ; in the
underlying sandy soil this was found only for lead and some PAHs. In
particular, the lead and PAH soil concentrations in the forest litter
frequently exceeded the background levels. Only the chloride groundwater
concentrations were found to be significantly higher at the shorter distance
as the Dutch climate requires using de-icing salt during wintertime.
Traffic therefore has a certain influence on the soil and groundwater
quality along motorways. To find a significant distance-related effect on a
national scale more sites have to be sampled.