United States
Environmental Protection
Agency
Office of Science and, Technology December 1995
43Q4 ' •" , : . EPA-822-F-95-004 '
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FACT-SHEET: . .
ADDITION OF DIOXINS/DDBENZOFURANS AND CO-
PLANAR PCB'S TO THE LIST OF POLLUTANTS
COVERED BY THE SEWAGE. SLUDGE-REGULATION
Summary
. The U. S.. Environmental Protection Agency (EPA) is required to identify, and set '.
limits for, toxic pollutants in sewage sludge that may present a risk to human health or the
environment. These limits are used by municipalities and others to help determine which :
practices (such as land application, surface disposal, and incineration) can be used to dispose
of sewage sludge or use it in a beneficial manner. Sewage sludge is a product of the . .
treatment of domestic sewage or the treatment of a combination of domestic sewage .and
industrial wastewater. ,
In February, 1993 under the authority of the Clean Water Act, EPA issued a ,
regulation that sets limits for nine toxic pollutants in sewage sludge. This regulation is known ,
as the "Round 1" sewage sludge regulation. As a follow-on action, EPA has identified two
additional toxic pollutants that, warrant further consideration to be included on this list of
pollutants. These pollutants are: Dioxins/dibenzofurans (all monochloro-to octochloro-
congeners) and Polychlorinated biphenyls (co-planar). Limits for these pollutants will be
established in a "Round 2" sewage sludge regulation.
The Round 1 Sewage Sludge Regulation
On February 19, 1993 EPA published the
Standards for the Use or Disposal of
Sewage Sludge (40 CFR Part 503) in the
Federal Register. These standards, which
are known as the Round 1 sewage sludge
regulation, contain the requirements that
have to be met when sewage sludge is
applied to the land;, placed on a surface
disposal site, placed in a municipal solid
waste landfill, or fired in a sewage sludge
incinerator.
This regulation was developed under the
authority of section 405(d) of the Clean
Water Act, as amended. It contains limits
for .nine metals in sewage sludge that is
land applied, three metals in sewage sludge
that is surface disposed, and five metals
for sewage sludge that is incinerated. •
These limits, together with the
management practices .included in the
regulation, protect human health and the
environment from adverse effects that may
result from these pollutants.
Candidate Pollutants for Round 2
In May 1993, under the terms of a consent
decree, EPA submitted to the court a list
of 31 candidate pollutants that wei;e being
considered for a Round 2 sewage sludge
regulation. These pollutants were selected
based on their frequency of detection in
EPA's 1988 National Sewage Sludge
Survey, on their observed concentrations in
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sewage sludge, and on their actual or
potential toxicity.
ROUND lx POLLUTANTS
Land Application V ' Stxrface Disposal
Arsenic Copper >rsen±a
Cadmium Lead - _ ' , Chromi«ia
Nickel Zirur ,,,"->'
Selenium Mercury - - / ' -
Molybdenum ;, ' , ,, ,
\> X"" .. v"*
Incineration. ' ;
Arsenic ,. Kickel
Cadmium V -% Lead *
Chromium
Risk Assessments for Round 2 Pollutants
Subsequent to submission of the list of
candidate pollutants to the court, EPA
conducted "screening" risk assessments to
determine which of the candidate pollutants
should be on the final list of pollutants.
Risk assessments were done for surface
disposal, land application, and incineration.
The methodologies from the risk assess-
ments for the Round 1 regulation were
used in the screening assessments along
with certain assumptions to estimate the
dose of a pollutant that a Eighty Exposed
Individual receives from exposure to
1 sewage sludge with a pollutant concen-
tration equal to the 95th percentile
concentration from the National Sewage
Sludge Survey. In the case of non-carcino-
genic pollutants, the estimated dose was
divided by the allowable dose (e.g., an
oral reference dose, or "RfD") to obtain a
Hazard Index for each pollutant. For
carcinogenic pollutants, a risk level was
calculated.
If the hazard index for a non-carcinogenic
pollutant was equal to or greater than one,
the pollutant was considered further for the
list of Round 2 pollutants. If the
mm^m calculated risk level for
carcinogenic pollutants was
[ greater than 1Q-4 (i.e., the chances
- of getting cancer are one in ten
thousand), the pollutant was
considered further for Round 2.'
Additions to the Final List
Based on the results of the
screening risk assessments and
various risk management
decisions, EPA concluded that two
of the 31 candidate pollutants
warrant further consideration for
regulation:
o Dioxins/dibenzofurans (all
monochloro- to octochloro-
congeners)
t
o Polychlorinated biphenyls (co-
planar)
On November 28, 1995, EPA notified the
court that these two pollutants warranted
further consideration for the Round 2
regulation. The notice also indicated that
EPA may add or delete pollutants at the
time the Round 2 regulation is proposed.
The Consent Decree requires that the .
Round 2 regulation be proposed by
December 1999, and published as final by
December 2001.
For additional information, contact Robert
M. Southworth on 202-260-7157.
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