The Science of the Total Environment, 93 (1990) 375-384 375 Elsevier AN INTEGRATED BUDGET FOR SELECTED POLLUTANTS FOR A MAJOR RURAL HIGHWAY C. NICHOLAS HEWITr* and MAHMUD B. RASHED Institute of Environmental and Biological Sciences, University of Lancaster, Lancaster LA1 4YQ (United Kingdom) SUMMARY A comprehensive study has been made of the fluxes of selected pollutants emitted from a major rural highway in NW England. Lead, cadmium, copper, the organic compounds of lead and 8 PAH species have been studied and their fluxes measured in bulk deposition samples in transects away from the road, in the road runoff waters and its associated sediments and in soil profiles. Data collected in detail over one year indicate that, in the case of lead, 8% of the emitted metal is removed in the drainage waters, 6% is deposited in the first 50 m adjacent to the rnotorway and ~86°/= is dispersed in the atmosphere away from the immediate vicinity of the road. Uncertainties in the emission rates of the other metals prevent such budget calculations being made. The amount of PAH removed away from the road environment by the atmosphere varies from -99% for the lowest molecular weight compounds to -70% for the heavier compound. INTRODUCTION Pollutants emitted by vehicles may enter one of three environmental pathways : (a) deposition on the road surface with possible subsequent removal by runoff waters or by resuspension of particulate material, (b) deposition in the immediate vicinity of the road or on the central reservation (median) of a motorway or (c) dispersal in the atmosphere away lrom the read. Although there have been many studies made of the behaviour of lead in the air, soils and vegetation adjacent to roads (e.g. ref. 1 ; ref. 2; ref. 3) surprisingly little attention has been paid to other pollutants or to approaching the behaviour of the pollutants in the framework of an emission - removal budget. The only previous such study (ref. 4) attempted to use data on deposition fluxes and drainage water concentrations for lead, cadmium and copper from the M6 motorway in NW England. However it suffered from the limitation of using two different sampling sites located 12 km apart. Here we use detailed data collected over one year at one site on the M6 motorway for deposition flux rates in transects away from the road, pollutant concentrations in the road runoff waters and its associated sediments and concentrations in soil profiles. The pollutants studied were lead, cadmium, copper, the organic compounds of lead and 8 PAH species. Whilst it is possible to make reasonable estimates of the emission rates of both inorganic and organic lead for the road, and hence calculate an emission-removal budget for the metal, large uncertainties exist in the emission rate estimates for the other metals. The dedved budget for the PAH species appears plausible suggesting that the emission estimates used for these compounds are reasonable. *To whom correspondence should be addressed. 0048-9697/90/$03.50 © 1990 Elsevier Science Publishers B.V.