EPA Fact Sheet: Risk Assessment of Spent Foundry Sands in Soil-Related Applications

Risk Assessment Results and Beneficial Use Implications

The U.S. Environmental Protection Agency (EPA), in conjunction with the U.S. Department of
Agriculture (USDA) and the Ohio State University (OSU), completed a risk assessment of silica-
based spent foundry sands in soil-related applications; specifically manufactured soil, soil-less
potting media, and roadway subbase, which is a foundation layer of roads.

The risk assessment indicates the beneficial use of silica-based spent foundry sands from iron, steel,
and aluminium foundries, in the evaluated uses, do not pose risks of concern to human health and
the environment As such, the EPA and the USDA support the beneficial use of these materials that
would otherwise go to waste because the constituent concentrations in the spent foundry sands are
below agency health and regulatory benchmarks.

Background on Risk Assessment

To address soil-related uses of spent foundry sands, the EPA, USDA, and OSU launched a
collaborative effort to evaluate the potential risks of using spent foundry sands and to encourage
beneficial use. The overall goals for the risk assessment were to:

•	Review the available information on spent foundry sands in soil-related applications;

•	Identify likely exposure pathways and receptors associated with various uses;

•	Use a combination of screening and modeling methods to determine whether the proposed
uses of spent foundry sands are protective of human health and the environment; and

•	Discuss the findings within the context of certain overarching concepts (e.g., the
complexities of soil chemistry) and provide conclusions.

Any conclusions drawn by this risk assessment should be understood within the limitations and
scope of the evaluation, including the following:

•	Only silica-based spent foundry sands from iron, steel and aluminum foundries are
evaluated in this assessment. In contrast, spent foundry sands from leaded brass and
bronze foundries often are regulated as hazardous waste. Spent foundry sands from non-
leaded brass foundries and spent foundry sands containing olivine sand also are not
evaluated in this risk assessment

•	In addition to spent foundry sands, foundries can generate numerous other wastes (e.g.,
unused and broken cores, core room sweepings, cupola slag, scrubber sludge, baghouse
dust, shotblast fines). This assessment, however, applies only to spent foundry sands as
defined in the assessment: molding and core sands that have been subjected to the
metalcasting process to such an extent that they can no longer be used to manufacture
molds and cores. To the extent that other wastes are mixed with spent foundry sands, the
conclusions drawn by this assessment may not be applicable.

Potential Benefits:

The EPA believes there is potential for growth in the beneficial use market for the evaluated uses,
resulting in substantial environmental benefits. Approximately 2.6 million tons of spent foundry
sand is beneficially used outside of foundries annually, with iron, steel and aluminum sands
representing 96 percent of the foundry sands that are beneficially used. Currently, only about 14
percent of those sands are beneficially used in soil-related applications.

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Environmental benefits from the beneficial use of spent foundry sands include reduced energy and
water impacts associated with food production, and reduced CO2 emissions associated with the
construction of roadways and other infrastructure. An EPA analysis provides estimates of the
environmental benefits that can be achieved with the beneficial applications that were studied in
this risk assessment Table 1 below presents the results of this analysis.

Table 1: Environmental Benefits of Spent Foundry Sand Beneficial Uses

Avoided
Impacts

Road Base

Manufactured Soil
Use

Total
avoided
impacts

Equivalencies

Energy
Consumption
(megajoules)

17,800,000

27,900,000

45,700,000

Annual electricity
consumption of 800
homes

Water
consumption
(1,000
gallons)

3,000

4,800

7.8 million
gallons

Amount of water to
fill 12 Olympic
swimming pools

C02
Emissions
(metric tons)

1,500

2,500

4,000 metric
tons

Removing 840 cars
from the road for
one year

Working Towards a Sustainable Future:

The risk assessment supports the EPA's ongoing efforts to advance Sustainable Materials
Management rwww.epa.gov/smml by demonstrating that the beneficial use of silica-based spent
foundry sands in soil-related applications can help reduce the environmental impacts associated
with food production as well as the construction of roads and other infrastructure.

The full risk assessment is available at: http: //epa.gov/waste/conserve/imr/foundry/index.htm

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