x>EPA
www.epa.gov/ord
science in ACTION
BUILDING A SCIENTIFIC FOUNDATION FOR SOUND ENVIRONMENTAL DECISIONS
US EPA's Oil Spill Dispersant Screening Results
RAPID TESTING FOR POTENTIAL ENDOCRINE RELATED ACTIVITY & CYTOTOXICITY
The US Environmental Protection
Agency and the U.S. Coast Guard
have authorized BP to use oil spill
dispersants as one tool in the
response to the Deepwater Horizon
oil spill. Preliminary testing results
indicate that underwater use of
dispersants is effective at reducing
the amount of oil reaching the
surface and allows the use of less
dispersant than is needed once the
oil reaches the surface. However
because of the unprecedented
volume of dispersants being used on
the BP oil spill, there are questions
about the potential hazard of the
dispersants that have been used or
are being considered for use.
To address these questions, EPA
used innovative research nationwide
to conduct numerous rounds of tests
to compare eight of the 14
commercially available oil spill
dispersants for their relative
potential to be harmful to the health
of people and to aquatic species
living in the Gulf. The first round of
testing used fast, automated
screening tests from EPA's Toxicity
Forecaster (ToxCast), and the Tox21
federal partnership with the NIH
Chemical Genomics Center, to
compare each dispersant's potential
for endocrine activity and relative
toxicity to living cells. The
ToxCast/Tox21 screening results
have been published in the journal
Environmental Science and
Technology.
ToxCast/Tox21 screened the eight
dispersants for potential endocrine
activity due to the presence of the
chemical nonylphenol ethoxylate
(NPE) in some commercial
Dispersit SPC 1000
Nokomis 3-F4
Nokom is 3-AA
Zl 400
Sea Brat #4
Corexit9500
SAP-RON GOLD
JD2000
A * ^ °"
^ * ^ *
AV £
[^ W * O
\%\ ^Americamysis bahia
. !• ,/\Menidia beryllina
• • BlaER
T A •o °BlaAR
m •HepG2
A Iff 0
Hyi on
10
100
1000
10000
Figure 1: Toxicity data for the dispersants, combining data from 3 cell-based assays -with data
on aquatic species. Each horizontal band shows the data for one dispersant. Cytotoxicity
values (concentration at-which 50% lethality or effect is observed) are indicated by circles.
Aquatic species LC50 values are indicated by triangles. Note that all dispersants -were tested in
all assays, and missing data points indicate that no toxicity -was seen in that assay at the
highest concentration tested (1000 ppm). 95% confidence intervals are shown for all assays.
formulations. The presence of NPE
could lead to endocrine disruption
and impair reproductive function
and development.
EPA used over 80 rapid screening
tests from the ToxCast and Tox21
programs. These included multiple
estrogen receptor (ER), and
androgen receptor (AR) tests for
endocrine activity, and multiple tests
for cytotoxicity, which is a measure
of how toxic a chemical is to living
cells.
A wide range of dispersant
concentrations from 0.001 to 10,000
parts per million (ppm) were tested,
and overall results did not indicate
biologically significant estrogenic or
androgenic activity for the
dispersants, although weak activity
was observed for two dispersants in
one estrogen receptor test.
Cytotoxicity was observed at
concentrations above 10 parts per
million for all of the dispersants.
In summary, EPA's results indicated
that none of the eight dispersants
tested, including the product in use
in the Gulf, displayed biologically
significant endocrine disrupting
activity. The tested dispersants alone
had relatively low potential for
cytotoxicity, with JD-2000 and SAP-
RON GOLD being the least
cytotoxic.
These data from ToxCast and Tox21
tests were combined with additional
EPA studies in the report published
U.S. Environmental Protection Agency
Office of Research and Development
-------
June 30, 2010 entitled Analysis of
Eight Oil Spill Dispersants Using In
Vitro Tests for Endocrine and Other
Biological A ctivity.
In progress are EPA studies on fish
and shrimp to determine the relative
toxicity of the oil and the dispersants
to aquatic species in the Gulf of
Mexico. Initial results on this testing
were published June 30, 2010 in the
report Comparative Toxicity of Eight
Oil Dispersant Products on Two
Gulf of Mexico Aquatic Test Species.
ToxCast is a multi-year, multi-
million dollar effort that uses
advanced science tools to help
understand how human body
processes are affected by exposure
to chemicals. It currently includes
500 fast, automated chemical
screening tests that have assessed
over 300 environmental chemicals.
The screening tests do not use
animals to assess the potential
toxicity of a chemical. ToxCast type
tests are routinely used by the
pharmaceutical industry to study the
effects of drugs and by EPA to
assess environmental chemicals.
Tox21is a partnership between the
EPA, the NIH Chemical Genomics
Center, the National Toxicology
Program and the Food and Drug
Administration. The Tox21
collaboration pools federal agency
resources (research, funding and
testing tools) to develop ways to
more effectively predict how
chemicals will affect human health
and the environment. The goals are
to screen up to 10,000 widely used
environmental chemicals and drugs
through a battery of non-animal
based toxicity tests.
EPA's ToxCast and Tox21
screening tools are part of the
Computational Toxicology Research
Program (CompTox). The goal of
CompTox is to provide fast,
automated tests for screening and
assessing chemical exposure, hazard
and risk
For more information:
www.epa.gov/comptox
www. epa. gov/toxcast
www.epa.gov/BPSpill
References
Judson et al. (2010) "Analysis of
Eight Oil Spill Dispersants Using
Rapid, In Vitro Tests for Endocrine
and Other Biological Activity"
Environmental Science and
Technology
(http://pubs.acs.org/doi/abs/10.1021/
esl02150z)
Originating Organization for Fact
Sheet
EPA
Primary Author of Fact Sheet
Monica Linnenbrink
Secondary Authors of Fact Sheet
Robert Kavlock, David Dix and
Richard Judson
First/Lead Author of Paper
Richard Judson
Contact:
Monica Linnenbrink
Office of Research & Development
National Center for Computational
Toxicology
919-541-1522
linnenbrink.monica@epa.gov
U.S. Environmental Protection Agency
Office of Research and Development
------- |