Measurements of the concentration of various water quality parameters in road-surface runoff have been made at an experimental catchment on the M1 motorway near Toddington, Bedfordshire. The amounts of particulate material and associated contaminant removed from the road surface by individual events are largely dictated by the intensity of rainfall and the total volume discharged. Seasonal differences in water quality are directly related to de-icing activities; in winter, salt is the principal constituent of runoff. During dry periods, vehicle generated air turbulence is considered to be an important pathway for the removal of material from the carriageway. As well as these more obvious qualitative findings quantitative information on pollutant loadings is also presented. Surface runoff on motorways is estimated to yield 1500 kg/km year of suspended solids, 4 kg/km year of lead, 126 kg/km year of oil and 18 g/km year of polynuclear aromatic hydrocarbons. (A)

Want to know more about this project?