WATER POLLUTION IN MOTORWAY RUNOFF

This is the first of a series of three articles on pollution of motorway runoff. The authors discuss the nature and the concentrations of pollutants present in motorway runoff. The materials originate from: vehicle exhaust emissions, including lead, vehicle lubrication system losses, degradation of tyres, corrosion of vehicles, oil, chemical spillage, road surface degradation, road surface cleaning/de-icing materials, atmospheric fallout (rainfall and aerial pollution). The origins and amounts of heavy metals, organic matter and salt pollutants are discussed. An outline is given of the way in which motorway runoff is collected. It is concluded that motorway runoff does not generally have an adverse effect on the receiving waters. Most components of road and vehicle-derived runoff pollution are inert and levels of contaminants are not likely to be high enough to cause significant pollution due to the diluting effect of the receiving waters. (TRRL)