Partitioning and granulometric distribution of metal leachate from urban traffic dry deposition particulate matter subject to acidic rainfall and runoff retention

• Published in: Water research (Oxford) Vol. 42; no. 15; pp. 4146 - 4162
• Main Authors: Sansalone, J., Ying, G.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.09.2008; Elsevier Science
• Subjects: acid deposition; Acid Rain; analysis; Anthropogenic; Applied sciences; arsenic; cadmium; calcium; chemistry; chromium; Cities; copper; drainage; Dry deposition; dry matter partitioning; Environmental Monitoring; Environmental Monitoring - methods; Exact sciences and technology; leachates; Leaching; lead; Louisiana; magnesium; Metals; Metals - analysis; Metals - chemistry; methods; Other industrial wastes. Sewage sludge; particulate emissions; Particulate Matter; Particulate Matter - analysis; Particulate Matter - chemistry; Pollution; rain; Rainfall-runoff; runoff; Specific surface area; traffic; urban areas; Wastes; Water Movements; Water Pollutants, Chemical; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; water pollution; Water treatment and pollution; watersheds; zinc; Louisiana; USA, Louisiana, Baton Rouge; Metals; Anthropogenic; Rainfall-runoff; Acid rain; Specific surface area; Leaching; Dry deposition; Atmospheric fallout; Urban traffic; Pollutant behavior; Dry matter; Urban area; Runoff water; Transport process; Hydrology; Watershed; Aerosols; Lead; Lixiviation; Air pollution; Phase partition; Leachate; Anthropogenic factor
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/j.watres.2008.06.013

Vehicular transportation coupled with urban hydrology is a significant source as well as vector of particulate matter (PM) and particulate-bound metal inventories in urban systems. This study examines the granulometric distribution of metals from dry deposition PM generated from 17 dryfall periods and equilibrium metal partitioning with runoff PM distribution from eight rainfall-runoff events at an urban inter-state watershed in Baton Rouge, LA. Dry deposition PM is a coarse non-uniform gradation with a d 50m = 304 μm and a peak surface area at 106 μm. Results indicate acid rain is not a significant metal contributor to runoff but is capable of leaching metals from PM to runoff. Retained runoff partitioning resulted in particulate-bound predominance for As, Cd, Cr, Cu, Pb, and Zn while Ca and Mg remained predominately dissolved. The finer PM fraction (<75 μm) generates the highest metal concentrations and the highest metal mass is associated with the coarser fraction (>75 μm). This coarse fraction is also the most labile when exposed to acidic rainfall; generating up to 90% of the total metal mass leached from the entire PM gradation. Comparing dry deposition and runoff PM of equal mass and size gradation, retained runoff PM is enriched with metals (except Pb). Results indicate the labile coarse fraction of dry deposition PM can be a significant source of metal leaching while runoff PM (mobilized dry deposition PM) stored in a BMP can be metal-enriched with the potential for re-leaching or scour.