Tire-Wear Particles as a Source of Zinc to the Environment

Abstract

Tire-tread material has a zinc (Zn) content of about 1 wt %. The quantity of tread material lost to road surfaces by abrasion has not been well characterized. Two approaches were used to assess the magnitude of this nonpoint source of Zn in the U.S. for the period 1936-1999. In the first approach, tread-wear rates from the automotive engineering literature were used in conjunction with vehicle distance-driven data from the U.S. Department of Transportation to determine Zn releases. A second approach calculated this source term from the volume of tread lost during lifetime tire wear. These analyses showed that the quantity of Zn released by tire wear in the mid-1990s was of the same magnitude as that released from waste incineration. For 1999, the quantity of Zn released by tire wear in the U.S. is estimated to be 10 000-11 000 metric tons. A specific case study focused on Zn sources and sinks in an urban-suburban watershed (Lake Anne) in the Washington, DC, metropolitan area for a time period of the late 1990s. The atmospheric flux of total Zn (wet deposition) to the watershed was 2 microg/cm2/yr. The flux of Zn to the watershed estimated from tire wear was 42 microg/cm2/yr. The measured accumulation rate of total Zn in age-dated sediment cores from Lake Anne was 27 microg/cm2/yr. These data suggest that tire-wear Zn inputs to urban-suburban watersheds can be significantly greater than atmospheric inputs, although the watershed appears to retain appreciable quantities of vehicular Zn inputs.

Source Apportionment of Urban Particulate Matter using Hourly Resolved Trace Metals, Organics, and Inorganic Aerosol Components

“…Lin et al, 2005;Ntziachristos et al, 2007), and non-tailpipe emissions caused by abrasion of brakes (e.g. Councell et al, 2004;Lough et al, 2005;Schauer et al, 2006;Johansson et al, 2009;Pérez et al, 2010;Apeagyei et al, 2011;Song and Gao, 2011;Harrison et al, 2012). Dall'Osto et al (2013), for example, found a comparable brake dust factor characterized by Cu and Fe with a strong 30 diurnal pattern.…”

New Insights from Zinc and Copper Isotopic Compositions into the Sources of Atmospheric Particulate Matter from Two Major European Cities

“…4,5 ZnO is the dominant species emitted from tire-treads 6 and has been identified 59 in emissions from metal smelting along with ZnS. 7 Copper has likewise been linked to 60 multiple sources, including smelting, oil combustion, wood smoke and brake wear.…”

Evaluation of the vehicle contributions of metals to indoor environments

“…Tire-wear particles have been recognized as a source of Zn introduced into the environment near vehicle transportation routes. 24 Furthermore, Weckwerth 10 pointed out that Zn was one of the top two metals in absolute abundance in diesel soot. Cu has been previously identified as an important brake-wear metal.…”