United States
Environmental Protection
Agency
Environmental Research
Laboratory
Duluth MN 55804
Research and Development
EPA-600/S3-83-077 Nov. 1983
Project Summary
Influence of Diet and
Body Lipids on the
Bioconcentration of Endrin from
Water in the Fathead Minnow
(Pimephales promelas)
Goran Dave and Patricia Kosian
The purpose of this study was to
quantify the importance of the fathead
minnow's (Pimephales promelas) body
lipid content and its composition in the
bioconcentration of a lipophilic chemi-
cal (endrin) from water.
For three months prior to exposure,
six groups offish were fed reference
research dietsibdntaining 0, 10, 15 or
20% (dry weight diet basis) lipids added
as corn oil and/or salmon oil. Two other
groups were fed frozen brine shrimp
(Artemia salina) at two ration levels.
Bioconcentration tests at two con-
centrations of endrin in water (0.11 and
0.1 Bfjg L"1) produced mean bioconcen-
tration factors (BCFs) of 1 S.OOOx after
14 days and 23,000x after 29 days
when expressed on a wet weight, whole
body basis. Corresponding mean BCFs
expressed on a lipid, whole body basis
were 190,000x and 340,000x.
Whole body BCFs expressed on a wet
weight basis ranged 8,000x - 21,000x
after 14 days exposure and 5,000x -
30,000x after 29 days exposure.
Independent of diet composition,
whole body BCFs expressed on a wet
weight basis were positively correlated
to the concentration of total fish body
lipids. When BCFs were expressed on a
lipid basis, they were instead negatively
correlated to the concentration of total
fish body lipids. From the limited
number of samples examined for each
diet group, no influence of diet lipid
source (corn oil, salmon oil and brine
shrimp lipids) could be found.
Results from this study were inter-
preted as follows: the greater the fishes'
body lipid content, the more endrin it
bioconcentrates rapidly and directly
from the water. Thus, fatter fish take a
longer time to reach equilibrium.
This Project Summary was developed
by EPA's Environmental Research
Laboratory, Duluth, MN, to announce
key findings of the research project that
is fully documented in a separate report
of the same title (see Project Report or-
dering information at back).
Introduction
In aquatic animals, bioconcentration of
chemicals can take place directly from
water or from food, though uptake from
water appears to be the predominant
route. Prediction of the bioconcentration
factor, BCF (the concentration in fish
divided by concentration in water at
steady state), from the partition coeffi-
cient between octanol and water has giv-
en good correlations for a wide variety of
chemicals, but for certain chemicals,
unexplained variations have been found.
The purpose of this study was to
estimate the relative importance of some
nutritional factors on the ability of the
fathead minnow to bioconcentrate a
lipophilic chemical, endrin, from water.
The nutritional factors studied were
dietary lipid content, composition, and
ration level.
Month-old fathead minnows were kept
in separate tanks for three months prior
to exposure to endrin. Eight groups were
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fed reference research diets with varying
lipid compositions (0 to 20% lipids) with
lipids coming from corn oil, salmon oil or
brine shrimp. Groups were exposed to
endrin under controlled conditions for 14
or 29 days. Whole fish samples were ho-
mogenized with Na2SC>4, placed in a chro-
matography column and the endrin
eluted from the column with hexane. Lip-
id content was determined by evapora-
tion of the solvent from the fraction and
weighing the residue. The lipid content
was calculated by equation 1. Endrin con-
tent was determined by gas chromatog-
raphy.
Lipid (%) = (gross weight-tare) (100)
(tissue weight) (0.96)
Results showed that the fatter the fish
were the more endrin was bioconcen-
trated. Bioconcentration factors after 29
days increased from 5 to 30 times when
expressed on whole-body weight, and
250 to 450 times when expressed on a
whole-body lipid basis.
Conclusions
Body lipid content had a significant ef-
fect on the bioconcentration of a lipophilic
chemical, endrin, in the fathead minnow:
1. The fatter the fish was, the more en-
drin it bioconcentrated directly from
water.
2. Bioconcentration factors (BCFs) after
29 days exposure ranged 5,000x -
30,000x (6-fold difference), when ex-
pressed on a whole body wet weight
basis.
3. When expressed on a lipid basis,
BCFs after 29 days exposure ranged
250,000x - 450,000x (2-fold dif-
ference).
4. BCFs calculated on a wet weight basis
were positively correlated to the lipid
content of the fish, but BCFs calcu-
lated on a lipid basis were negatively
correlated to the lipid content, indicat-
ing that the fatter the fish was, the
longer was the time needed to reach a
steady state.
5. The source of dietary lipid did not in-
fluence the results. It might have af-
fected lipid composition of fish, but
this was not investigated.
Recommendations
1. Bioconcentration factors (BCFs) for
lipophilic chemicals should be ex-
pressed on a lipid as well as a wet
weight basis, since BCFs for lipophilic
chemicals such as endrin can be
expected to be significantly affected
by the lipid content of the f ish. A fatter
fish is expected to show a higher resi-
due than a lean fish.
Since BCFs expressed on a lipid basis
are more uniform than those ex-
pressed on whole body weight, the
use of lipid-based BCFs would reduce
variations observed within a species
as well as between species.
Goran Dave is with the Department of Zoophysiology, University of Goteberg.
Sweden, and Patricia Kosian is with the University of Wisconsin, Superior, Wl.
James McKim is the EPA Project Officer (see below).
The complete report, entitled "Influence of Diet and Body Lipids on the Bioconcen-
tration of Endrin from Water in the Fathead Minnow fPimephales promelas,/,"
(Order No. PB 83-254 300; Cost: $8.50, 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
ftUS. GOVERNMENT PRINTING OFFICE: 1983-659-017/7211
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
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