United States
Environmental Protection
Agency
Environmental Research
Laboratory
Duluth MN 55804
Research and Development
EPA-600/S3-81-005 Apr. 1981
Project Summary
Intel-laboratory Comparison
Acute Testing Set
Armond E. Lemke
A multiple laboratory (6) set of tests
was conducted using a single Test
Standard Method. The tests consisted
of static and dynamic aquatic
bioassays with two species of fish and
static tests with Daphnia magna in
duplicate. The extreme values for any
one test were one order of magnitude
while the extremes of the means were
only a factor of 2.
This Project Summary was devel-
oped by EPA's Environmental Re-
search Laboratory, Duluth, MN
55804, to announce key findings of
the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
The U.S. Environmental Protection
Agency is required as part of the Toxic
Substances Control Act to make
decisions on the safety of any chemical
before it can be marketed. These
decisions must be based on various
types of information regarding human,
terrestrial and/or aquatic environ-
mental danger potential. The law
requires the potential manufacturers to
provide such information if requested
for cause by EPA. In the area of aquatic
toxicity, bioassay data is one of the
useful types of information that may be
required.
Methods and Materials
The bioassay literature has a rather
diverse amount of data on any one
chemical. In an attempt to reduce this
diversity it was decided to use a required
standard test to produce the needed
data. Estimations of expected diversity
of such a standard when used by a
variety of laboratories was needed.
To accomplish this a group of
contractors (4) and two experienced
EPA labs conducted a series of
bioassays with two chemicals
(endosulfan and AgNOa), and two
species of fish, fathead minnows
(Pimephales promelas) and rainbow
trout (Salmo gairdneri) and two types of
acute tests, static and dynamic in
duplicate for a test set of 96 96-hr
LC50s. The same laboratories also
conducted duplicate 48-hour acute
static tests with Daphnia magna with
both chemicals for a total of 24 tests.
The chemicals and test protocol were
the same for all laboratories. Each
provided their own water, test animals,
and chemical analytical support.
Results
The data set obtained revealed the
following: An extreme value within any
one test of one order of magnitude with
the organic endosulfan tests. The
means of the two duplicate tests
between all laboratories was just over
two times.
The silver results were approximately
the same with the exception of one
laboratory which had very hard (300 mg
CaCOa/l) water and , as expected, this
value was much higher. The species
difference was very large. The daphnia
were approximately 10 times more
Sensitive to the silver and 200 times less
sensitive to the endosulfan. Fish
species difference was only about three
times.
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Conclusions
The following conclusions were
drawn. If a standard protocol is followed
closely and a material is not water
quality dependent, a very precise set of
data can be expected. Species
sensitivity is highly variable and species
from widely diverse groups should be
tested. The mean of repeated tests (at
least two) apparently gives a number of
sufficient precision that can be
reproduced with confidence Extreme
care should be exercised in all
extrapolations especially between
diverse genetic groups.
This Project Summary was authored by Armond E. Lemke, who was also the
EPA Project Officer (see below).
The complete report, entitled "Interlaboratory Comparison: Acute Testing Set,"
(Order No. PB 81-160 772; Cost: $6.50, subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at: "•
Environmental Research Laboratory
U.S. Environmental Protection Agency
6201 Congdon Blvd.
Duluth, MN 55804
tr US. GOVERNMENT HUNTING OFFICE 1M1-757-012/7028
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
U S 90QJOQ
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