United States
                Environmental Protection
Office of Science and, Technology      December 1995
43Q4   '      •" , :    .        EPA-822-F-95-004 '
              FACT-SHEET:       .                                   .
     .   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

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

  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   *
 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
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
        o  Dioxins/dibenzofurans (all
   monochloro-  to octochloro-
o  Polychlorinated biphenyls (co-

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.