TP7 Metallic and Organometallic Distribution and Effects
201 Oregon Ballroom
1:20 PM - 4:40 PM, Tuesday
() Dissolution of metals from brake pad wear debris under conditions simulating leaching in urban areas.
Sondhi, A1, Imhoff, P1, Allen, H1, Dentel, S1, 1 Department of Civil and Environmental Engineering, University of Delaware, Newark, DE, USA
ABSTRACT- Brake pads currently used in automobiles are high in metallic content such as Cu, Fe, and Ba. Metallic particles are released from automobiles in the urban environment as brake pads are abraded during normal driving conditions. These metals may have a deleterious effect on the biotic and a-biotic environment in water bodies fed by urban sources. In this study we are examining the dissolution of metals from brake pad particles in an effort to understand the amount and rate at which metals are dissolved from brake pad wear debris. Brake pad wear debris were collected from automobiles (natural) and abraded artificially in the laboratory from automobile brake pads (artificial). Wear debris were collected for four vehicles in high volume use and known to use brake pads of semi-metallic composition. Total metal content (Cu, Fe, Ba, Ca) in the brake pad particles (natural and artificial) for the four different sets was as follows: Cu content (g/g) was 5.8% (natural) vs. 12.70% (artificial), 1.09% vs. 12.80%, 1.51% vs. 3.79% and 7.26% vs. 10.35%. Fe content was 16.73% vs. 1.59%, 6.09% vs. 1.67%, 30.58% vs. 9.01% and 20.35% vs. 0.0%. Ba content was found to be 4.24% vs. 8.02%, 0.87% vs. 8.09%, 4.74% vs. 8.44% and 6.36% vs. 10.26%. Dissolution/leaching tests were conducted with a non metal complexing buffer solution. The dissolution of metals was strongly dependent on the hydrodynamics (mixing) of the system. Further dissolution studies are underway with different extracting solutions (buffered solutions with pH 4.3 or 7.2, and distilled de-ionized water) simulating leaching conditions in urban areas. We discuss these results and our efforts to predict metal dissolution from brake pad wear debris in urban watersheds.
Key words: dissolution, urban, metals