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Risk Assessment

Ecological Soil Screening Level (Eco-SSL) Guidance and Documents

EPA's Superfund program issued ecological soil screening levels (Eco-SSLs) for seventeen inorganic and four organic contaminants that are frequently found in soil at Superfund sites. For background information on the development of Eco-SSLs and how they should be used in the Superfund ecological risk assessment process, see the following Memorandum:

Numerical soil concentrations were updated in March of 2005 for antimony, barium, beryllium, cadmium, cobalt, dieldrin, and lead. The updates did not substantially change the final Eco-SSL values:

In April of 2005, numerical soil concentrations were presented for arsenic, chromium III, chromium VI, pentachlorophenol, and vanadium. Narrative statements were developed for aluminum and iron, metals which are often found at high concentrations under background conditions. Eco-SSL guidance updated in February of 2005 describes how these values were developed and how they should be used in screening ecological risks.

Eco-SSLs for copper and silver were released in 2006. In 2007, numerical soil EcoSSL concentrations were issued for DDT and metabolites, manganese, nickel, low and high molecular weight PAHs, selenium and zinc. The numerical soil copper, dieldrin and pentachlorophenol soil concentrations were updated in 2007, and the chromium III and chromium VI EcoSSLs were updated in 2008. Attachments 1-4, 4-1, 4-3 and 4-5 of the EcoSSL guidance were also updated in 2007.

The mammalian toxicity reference values developed for these contaminants can also be used in the baseline risk assessment for evaluating site risks. Following a peer-reviewed process, utilizing a large stakeholder group and reviewing every relevant published article to develop these Eco-SSLs, EPA expects that these new values will be widely accepted and used. The Guidance, the thirteen contaminant specific documents, and all the Attachments from the Guidance are available on-line at: Safer Chemical Research - Ecological Soil Screening Level.

    Availability of Eco-SSL Values- February 1, 2018    
Contaminant Plant Soil Invertebrates Mammalian Avian
Antimony No Yes Yes No
Arsenic Yes No Yes Yes
Barium No Yes Yes No
Beryllium No Yes Yes No
Cadmium Yes Yes Yes Yes
Chromium (III) No No Yes Yes
Chromium (IV) No No Yes No
Cobalt Yes No Yes Yes
Copper Yes Yes Yes Yes
DDT and metabolites No No Yes Yes
Dieldrin No No Yes Yes
Iron Narrative Statement
Lead Yes Yes Yes Yes
Manganese Yes Yes Yes Yes
Nickel Yes Yes Yes Yes
Low Molecular Weight PAHs No Yes Yes No
High Molecular Weight PAHs No Yes Yes No
Pentachlorophenol Yes Yes Yes Yes
Selenium Yes Yes Yes Yes
Silver Yes No Yes Yes
Vanadium No No Yes Yes
Zinc Yes Yes Yes Yes

No- Minimum required data not available to derive Eco-SSL
Yes- Eco-SSL was derived

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