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San Joaquin County Community Diesel Engine Emission Control Technologies Development Department Platinum Based Additives Description: The most common platinum additives are actually bi-metallic additives consisting of Platinum in conjunction with another metal. Platinum additives lower balance temperature for traps facilitating regeneration. Platinum/cerium blends display a synergistic effect and drop balance — temperatures from 537-557°C to 327°C and are typically used at low dosage levels (less than 10 ppm). The low dosage results in decrease nano-particulate formation as compared to additives with higher effective concentrations(HEI, Attachment A, DieselNet 2000.02b). However,at this low concentration, it is possible that any increase in nano-particulate is masked by soot(Mayer 2002). Data for the one additive used alone show 25 percent reduction in particulate _ emissions as well as 35 percent reductions in hydrocarbons and 11 percent reductions in carbon monoxide. When used in conjunction with an oxidation catalyst reductions up to 50 percent are achieved and this number increased to 95 percent when the additive was coupled with a DPF. Up to a 20 percent decrease in NOx for certain fuel/technology/additive combinations have been reported. Fuel economy benefits of five to seven percent have been reported for heavy- duty diesel engines. Without a filter, six percent of the metal input is released from the engine after 1,000 hours of high load; a filter reduces the release of metal to less then one percent(DieselNet 2000.02b, HEI, Attachment A,Mayer 1999,Valentine 2002,Mayer 1998,Valentine et al. 2000,Khair, et al 1999, Fanick et al 2001,Vincent et al 2001). Current Use: Platinum based additives are in use in Europe with DPF systems — for both on and off road applications and stationary sources(Valentine 2002). Fate and Transport: Studies show an increase in platinum group element — concentrations in ambient air and dust since the introduction of catalytic converters. Catalytic converters contribute more platinum into the environment than other industrial sources. Levels up to 130 pg/kg are found in dust samples collected in Germany. Normal levels found in the earth's crust are on the order — of 5 gg/kg. Platinum is found in all particulate matter size ranges and has the potential of airborne transport(HEI, Attachment A, Zereine 2000,Veltz 1996, Artelt 1999,Artelt 1998,DieselNet 2000.02b). Health Risks: Platinum is toxic to some species and the effect of nano- particulate platinum fraction is poorly understood. There is evidence that an — inverse correlation exists between the diameter of the platinum particles and solubility. Platinum salts are known allergens at concentrations found in occupational settings. The United Kingdom's Department of Health reviewed platinum based diesel fuel additives and concluded there were minimal human health risks from FBCs. Bioavaliability studies show platinum partitioning to the lungs, lung macrophages, blood, liver,gastrointestinal tract and kidneys — depending on the route of exposure. Additionally bioavailability studies shows a significant fraction of ultrafine platinum particles are bioavailable. Long term ramifications of increased environmental platinum levels are inconclusive (Mayer 2002,Veltz 1996,Artelt 1999,Artelt 1998,Zereine 2000, DieselNet 2000.02b, HEI Attachment A, Committee on Toxicity of Chemicals 1996) DeSilva Gates Quarry Project — Draft Environmental Impact Report L_g Jas ostos.as