Arch. Environ. Contam. Toxicol. 27, 145-153 (1994) ARCHIVES OF Environmental Contamination a n d Toxicology © 1994 Springer-Verlag New York Inc. Availability of Elements in Leaded/Unleaded Automobile Exhausts, a Leaded Paint, a Soil, and Some Mixtures S. S. Que Hee Department of Environmental Health Sciences, University of California at Los Angeles Center for Occupational and Environmental Health, University of California School of Public Health, 10833 Le Conte Avenue, Los Angeles, California, 90024-1772, USA Received 30 December 1993/Revised:28 February 1994 Abstract. The availabilities of elements in some dust proximal sources of urban pollution were investigated. The sources were: leaded and unleaded automobile exhaust; leaded dry paint; one soil; and mixtures that included the leaded exhaust as a com- mon component. A miniaturized modified Tessier et al. leach- ing scheme was developed that showed little redistribution of the most available elements. Mn, Pb, S, and Sb were the most readily available in both the leaded and unleaded exhaust; C and Pb in the paint; and Mn and S in the soil. The available elements for the leaded exhaust predominated in its mixtures with evidence of redistributions for the three-component mix- ture. The environmental pollution (EP) toxicity procedure with five leachings was shown to be approximately equivalent to adding the water-soluble, exchangeable, carbonate, iron/ manganese oxide, and part of the organic fractions. Simulated acid rainwater leached elements up to the iron/manganese oxide fraction. The results have application to storm runoff and acid rain leaching of dusts, aerosols, wastes, and soils. Availability of compounds from soils, dusts, air particulate matter, and solid/hazardous wastes depends on volatilization, solubilization, degradation, oxidation, and absorption (Que Hee and Sutherland 1981). The most comprehensive chemical associations scheme (Tessier et al. 1979; Rapin et al. 1986) leaches chemicals sequentially. Sediments (Tessier et al. 1979; Elbaz-Poulichet et al. 1984; Rapin et al. 1986; Mahan et al. 1987), streetside/roadside dusts (Harrison et al. 1981), and polluted soils (Miller et al. 1986) have been investigated. Showing water pollution potential of wastes involves the environmental pollution (EP) toxicity test (Federal Register 1980, 1981) and the toxicity characteristic leaching procedure (TCLP) (Federal Register 1986). The leaching action of acid rain (Wood and Bormann 1974; Bennett 1985; Driscoll 1985) is also of concern. Metals from automobile exhaust emissions and dusts from sandblasted Pb-based paint exteriors may be leached by rains, and contribute to storm runoff. This study sought to: (1) develop a modified Tessier leaching scheme to characterize leaded/unleaded automobile exhaust dusts, a lead-based paint dust, and a soil; (2) test mixtures containing leaded exhaust for redistribution; (3) define how EP toxicity testing and leaching with a simulated acid rainwater were related to the modified Tessier scheme. Experimental Section Substrates Leaded automobile exhaust (LAE) and unleaded automobile exhaust (UAE) were from the United States Environmental Protection Agency as deposits on glass fiber filters from high- volume sampling (Northrop Services 1979; Bradow 1980; Ga- bele and Colotta 1981). Each sample was cull into 1-cm2 squares, and tumble shaken for 24 h. One hundred squares of UAE, 20 of LAE, and their corresponding filter blanks were used except as noted. The arithmetic means of LAE and UAE corrected for filter weights were 1.7 and 8.5 mg, respectively. Coefficients of variation (CV) were <10%. Fairview Forma- tion limestone soil (1 kg) was dried, and pulverized until it passed completely through a 1-mm sieve (Que Hee et al. 1985a). Dry leaded paint of high lead content was stripped from the exterior of a house and sliced. Both samples were dried, and mortared and pestled to pass through a 100-mesh (149-txm) sieve. Each was tumble-shaken overnight. Soil (SO) and paint (PA) masses were 182.3 and 16 mg, respectively. Mixtures contained LAE. Reagents Concentrated nitric acid (HNO3) and perchloric acid (HC104) were Ultrex distilled in Vycor (G. F. Smith). The following were from Fisher Scientific: ammonia water (NH4OH); ammo- nium acetate (NH4OAc); glacial acetic acid (HOAc); 30% hy- drogen peroxide (H202); hydroxylamine hydrochloride (NH2OH.HCI); sodium acetate trihydrate (NaOAc); and con- centrated hydrofluoric (HF), concentrated hydrochloric (HC1), and boric acids. Magnesium chloride hexahydrate (MgCI2) was from May and Baker Chemical. The standards (Spex Indus-