『Abstract
　A comprehensive multi-media monitoring field investigation, which included: atmospheric, storm-water runoff, road sediment and soil samples, was carried out at two highway sites in Vancouver, Canada, focused on Cu, Fe, Pb, Mn, and Zn, due to their prevalence in most highway environments, both locally and worldwide. Metal potential bioavailability was evaluated through sequential extraction in the case of particulates and via exchange with a chelating resin for highway runoff. Road sediment showed in most cases a close resemblance with runoff and atmospheric metal concentrations (Fe＞Zn＞Mn＞Cu＞Pb), suggesting that road sediment is a useful indicator of current metal loadings and a key factor influencing the quality of urban watersheds. Metals showed increasing bioavailability with decreasing particle size in all samples. Thus, bioavailability was low in roaddust and roadside soils, intermediate in dustfall, and highest in atmospheric suspended particulates and runoff. Speciation analyses in different environmental media suggested that Zn is a metal of future potential concern. Zinc was second in concentration to Fe in most dust, air and water samples, and exhibited the highest mobility and potential bioavailability.

Keywords: bioavailability; highway; soils; runoff; dustfall; metals; atmospheric』

1. Introduction
2. Methods and materials
　2.1. Study sites
　2.2. Field methods
　　2.2.1. Road sediment collection
　　2.2.2. Dustfall collection
　　2.2.3. Total suspended particulates
　　2.2.4. Runoff measurement and sampling
　　2.2.5. Soil sampling
　2.3. Laboratory methods and analyses
　　2.3.1. Dust deposition
　　2.3.2. Total suspended particulates
　　2.3.3. Highway runoff
　　2.3.4. Sequential extraction in soils
　　2.3.5. Sequential extractions in atmospheric particulate matter
　　2.3.6. Metal analyses
3. Results and discussion
　3.1. Road sediment
　　3.1.1. Metal concentrations
　　3.1.2. Road sediment sequential extractions
　3.2. Dustfall
　　3.2.1. Metal concentrations
　　3.2.2. Dustfall sequential extractions
　3.3. Suspended particulates
　3.4. Particle size influence of potential bioavailability
　3.5. Highway runoff
　3.6. Roadside soil
　　3.6.1. Total metal concentrations
　　3.6.2. Metal partitioning in soils
4. Conclusions
Acknowledgements
References

• Breault,R.F. and Granato,G.E.(2000): A synopsis of technical issues of concern for monitoring trace elements in highway and urban runoff. U.S. Department of Transportation, U.S. Geological Survey, Open-File Report 00-422.
  ⇒http://ri.water.usgs.gov/fhwa/products/ofr00-422.pdf（NATIONAL HIGHWAY RUNOFF WATER-QUALITY DATA AND METHODOLOGY SYNTHESIS　PROJECT PRODUCTS RELEASED AS USGS OPEN-FILE REPORTS PENDING PUBLICATION AS FHWA REPORTS）
• Colman,J.A., Rice,K.C. and Willoughby,T.C.(2001): Methodology and significance of studies of atmospheric deposition in highway runoff. U.S. Department of the Interior, U.S. Geological Survey, Prepared in cooperation with the Federal Highway Administration, Open-File Report 01-259.
  ⇒http://ri.water.usgs.gov/fhwa/products/ofr01259.pdf（NATIONAL HIGHWAY RUNOFF WATER-QUALITY DATA AND METHODOLOGY SYNTHESIS　PROJECT PRODUCTS RELEASED AS USGS OPEN-FILE REPORTS PENDING PUBLICATION AS FHWA REPORTS）
• Hathhorn,W.E. and Yonge,D.R.(1996): The assessment of groundwater pollution potential resulting from stormwater. Infiltration Best Management Research Report, U.S. FHWA.
• Hodes,G., Thomas,V. and Williams,A.(2003): A Strategy to Phase-Out Lead in African Gasoline. Renewable Energy for Development, Stockholm Environment Institute, 16(3).
  ⇒http://www.princeton.edu/~vmthomas/red.pdf（Leaded Gasoline Phase-Out）
  ⇒http://www.sei.se/red/redoct2003.rtf
• Kobriger,N.P. and Geinopolos,A.(1984): Sources and migration of highway pollutants: Volume III. Research Report, Report FHWA/RD-84/059, U.S. Department of Transportation.
• Lasat,M.M.(2002): Phytoextraction of toxic metals: A review of biological mechanisms. Journal of Environmental Quality, 31, 109-120.
• Morrison,G.M.P. and Revitt,D.M.(1987): Assessment of metal species bioavailability and geochemical mobility in polluted waters. Environmental Techmology Letters, 8, 361-372.
• Pagotto,C., Remy,N., Legret,M. and Le Cloirec,P.(2000): Heavy metal pollution of road dust and roadside soil near a major rural highway. Environmental Technology, 22, 307-319.
• Sansalone,J.J., Buchberger,S.G. and Al-Abed,S.R.(1996): Fractionation of neavy metals in pavement runoff. The Science of the Total Environment, 189(190), 371-378.
• Sansalone,J.J., Steven,G., Buchberger,G. and Koechling,M.T.(1995): Correlations between heavy metals and suspended solids in highway runoff: Implications for control strategies. Transportation Research Record, No. 1483.
• Turer,D., Maynard,J.B. and Sansalone,J.J.(2001): Heavy metal contamination in soils of urban highways: Comparison between runoff and soil concentrations at Cincinnati, Ohio. Water, Air, and Soil Pollution, 132, 293-314.
• Young,G.K., Stein,S., Cole,P. Kammer,T., Graziano,F. and Bank,F.(1996): Evaluation and Management of Highway Runoff Water Quality. Office of Environment and Planning, FHWA, Washington, D.C.
• Yousef,Y.A., Harper,H.H., Wiseman,L.P. and Bateman,J.M.(1985): Consequential of heavy metals in highway runoff. Transportation Research Record, No. 1017.

• Federal Highway Administration (FHWA), U.S. Department of Transportation
• NATIONAL HIGHWAY RUNOFF WATER-QUALITY DATA AND METHODOLOGY SYNTHESIS　　http://ri.water.usgs.gov/fhwa/default.htm