Relationship between the lipid content of fish and their bioconcentration potential of 1,2,4-trichlorobenzene

Chemosphere, Vol.14, No.5, pp 545-555, Printed in Great Britain

1985

0045-6535/85 $3.00 + .00 ©1985 Pergamon Press Ltd.

RELATIONSHIP BETWEEN THE LIPID CONTENT OF FISH AND THEIR BIOCONCENTRATION H. Geyer, Gesellschaft

POTENTIAL OF 1,2,4-TRICHLOROBENZENE

I. Scheunert and F. Korte

fur Strahlen- und Umweltforschung

Institut fur Okologische Chemie D - 8042 Neuherberg Federal Republic of Germany and Institut fur Chemie der Technischen Universit~t M~nchen-Weihenstephan D - 8050 Freising-Weihenstephan ABSTRACT A significant positive correlation between the lipid content of eight fish species and their bioconcentration factor (BCF) of 1,2,4-trichlorobenzene is demonstrated. The log BCF value on a lipid basis is in good agreement with the log n-octanol/water partition coefficient.

INTRODUCTION

The importance of bioaccumulation of chemicals hazard

in organisms

is generally accepted. Among the species tested,

the most pronounced capacity for bioaccumulation. water as a major carrier of environmental Degradation/Accumulation animal species

recommended

in bioconcentration

to their potential

aquatic organisms

Considering

chemicals,

show

the importance of

the OECD Expert Group for

the use of fish as the representative

testing. The decision whether

for the determination of bioconcentration

there is a need

potential of a new chemical will be

based upon the simultaneous assessment of its relevant physico-chemical properties and its degradability:

New chemicals have to be tested with fish

before they can be introduced to the market (n-octanol/water

if they have a high lipophilicity

partition coefficient ~ 1 0 3 ) ,

volatility 1,2. Fish are an appropriate because of their capability

to bioconcentrate

cals such as HCB, DDT, PCB's and Mirex

545

low biodegradability

and low

test organism and a useful bioindicator lipophilic and persistent chemi-

(BCF ~ i0,000)

3 and also because,

546

especially

in some communities,

and therefore

could contribute

From field and laboratory potential algae) stage

of a chemical

is affected

fish are an important to bioaccumulation

studies

in aquatic organisms

by many factors,

salinity,

of bioconcentration chlorinated

phenols,

dissolved

3,9-12.

(e.g.

3-9. Environmental

The bioconcentration

factors

by the degree of ionization

organic chemicals

Recently Goerke 14 found in laboratory

are stored mainly

in various parts of the sandworm in different

parts of the animals

the degree

as regulated

in the deposited experiments

by the

lipids of

that the PCB

(Nereis virens) is strongly

such as

or chlorinated

was positively

with the lipid content o~ these parts. This indicates

distribution

and and

such as

of acidic chemicals,

such as benzidine

organisms. correlated

oysters

age, size, metabolism

oxygen and light can also influence

Lipophilic

concentration

in man.

fishes, mussels,

such as species,

or basic compounds,

anilines, is strongly affected pH of the water 12, 13

of chemicals

of human food

it is known that the bioconcentration

in the life cycle of the organism

temperature,

constituent

that the PCB

influenced

by the

lipid content of these parts. Investigations significant

in the aquatic environment

positive

organochlorine and mussels

correlation

residues

between

have shown that there exists a the bioconcentration

and lipid content

19. The high lipid content

of

as the main

higher HCB, DDT and PCB residues 2O

fish in the Rhine with lower lipid contents

Recently Langer trout,

(BCF_)

in some species of fish 15,16,1~,18

(10 - 32 %) was suggested

reason why eel from the river Rhine contained than other

factor

golden

21 investigated

the bioconcentration

ide, carp and minnow.

bioconcentration

of lindane

He found a positive

(~-HCH)

correlation

by

of

factors with lipid content of fish.

Investigations environment

of bioconcentration of ~-HCH by the mussel Mytilus edulis in the 19 by Ernst have shown that the coefficient of variation of the

bioconcentration

factor

bioconcentration

factors

is reduced

from 30 % to better

to lipid contents

instead of relating

If the uptake and the partition of chemicals bioconcentration factor.

in fish,

(extractable concentration

the relationship

in different

organic material),

in aquatic animals.

DATA

FOR BIOCONCENTRATION

The bioconcentration concentration

it to wet weight. the

factor

of a chemical

between bioconcentration

FACTORS

(BCF)

potential

species of fish and their lipid content

and the relationship

factors and the n-octanol/water

chemicals BASE

in lipids control

the

the lipid content of fish will be a very important

This paper examines

of 1,2,4-trichlorobenzene

than 16 % by relating

(BCFs)

is defined

between

partition

lipid-based

coefficients

bio-

of various

IN F I S H

as the quotient of the

in an organism divided

by the concentration

in the

547

Table I: INFLUENCE OF LIPID CONTENT (%) ON THE BIOCONCENTRATION OF 1,2,4-TRICHLOROBENZENE IN FISH FISH SPECIES

LIPID ( % )

BCFw a)

BCFL b)

REF.

Rainbow trout (Salmo gairdneri)

1.8

124

6,890

Carp (Cyprinus carpio)

2.2 2.2 2.2 2.2

190 200 220 455

8,636 9,090 i0,000 20,680

22

Rainbow trout (hatching)3.2 (Salmo gairdneri) 3.2

349 710 c)

10,906 22,188 c)

23 23

Carp (Cyprinus carpio)

4.4 4.4

460 540

10,455 12,270

22 22

Golden ide Leuciscus idus)

5.0

914

18,280

24

Zebra fish Brachidanio

5.2 5.2

730 810

14,040 15,580

Tilapia (Tilapia nilotica)

5.2 5.2

680 870

13,080 16,730

22

Guppy (female) Poecilia reticulata)

5.4 5.4

702 c) 756 d)

13,000 c) 14,000 d)

25 25

Bluegill sunfish (Lepomis macrochirus)

5.7 5.7

960 1,320

16,842 23,160

Guppy Poecilia

5.8 5.8

1,350 1,380

23,280 23,790

Rainbow trout (Salmo gairdneri)

7.7 7.7

1,300 1,600

16,880 20,780

Guppy (Poecilia

8.2 8.2

910 1,080

ii,I00 13,170

8.3 8.8

1,300 3,200 e)

15,660 36,364 e)

2,100

20,000

rerio)

reticulata)

reticulata)

Rainbow trout (Salmo qairdneri) Fathead minnow (Pimephales promelas) Mean + Standard Deviation (S.D.) Coefficient of Variation (C.V.)

10.5

5.2 ~ 2.2

f)

+

42

%

846.5 ~ 485 +

57

%

+

32

Factor on a wet weight basis

b) BCF L : Bioconcentration

Factor on a lipid basis

f) C.V. = SD x i00 Mean

analysis

]

I 22

26 26 27

15,403 ~ 4945

a) BCF w : Bioconcentration

c) 1,2,3-Trichlorobenzene d) 1,3,5-Trichlorobenzene e) Outlier, not included in statistical

]

%

BCF w x i00 Lipid ( % )

548

surrounding medium. trichlorobenzene

In order to compare the bioconcentration

in fish with their lipid content,

of 1,2,4-trichlorobenzene

on a wet weight basis

factors of 1,2,4-

the bioconcentration

(BCFw)

factors

in eight different

species of fresh water fish were taken from literature and summarized with references

in Table i.

Since the lipophilicity,

measured as the n-octanol/water

(Kow), of the three trichlorobenzene from each other 4.09;

(TCB)

(log KOW of 1,2,3-TCB:

and 1,3,5-TCB:

4.14)

25,26,31

partition coefficient

isomers does not differ significantly

4.11;

1,2,4-TCB:

range 3.93 - 4.18; mean:

the bioconcentration

factors of 1,2,3-TCB

and 1,3,5-TCB were also used. Recently Galassi and Calamari

23 measured

1,2,3- and 1,2,4-trichlorobenzene (Salmo gairdneri).

(TCB)

in the early lifestages of rainbow trout

These bioconcentration

trout were also included

the bioconcentration potential of

data obtained

from hatching

rainbow

in the correlation.

In this compilation only bioconcentration data which were obtained under flowthrough conditions

(steady-state)

and for which the lipid content of the fish is

given in literature were included. For conversion of the bioconcentration lipid content basis

(BCFL)

equation

factors from wet weight basis

(BCFw)

to

(i) was used:

BCF w x i00 BCF L =

(i) Lipid

(%)

These calculated BCF L values are also given in Table i.

RESULTS AND DISCUSSION

The data in Table 1 show that the bioconcentration (BCFw)

rainbow trout BCF

factors on a wet weight basis

increase with increasing lipid content. The BCF w values range from 124 in (1.8 % lipid)

to 2,100 in fathead minnow

(10.5 % lipid). The mean

value was 846.5 with a coefficient of variation of 57 %. The bioconcentra-

w tion factors on a lipid basis

(BCFL)

range from 6,890 to 23,790 with a mean

value of 15,403. Using a lipid weight basis for calculating bioconcentration factors reduced the coefficient of variation In this statistical analysis

from 57 % to 32 % of the mean.

the BCF w value of 3,200 for rainbow trout with 8.8

% lipid was omitted because this value is an outlier

(R-test by Nalimov;

99 %

significant level). The reason for the relatively great coefficient of variation of 32 % for the mean BCF L value may be due to the biological variability of the different species, analytical problems in the determination of TCB 28, different metabolism rates of TCB in different species

fish

fo fresh water fish, and/or to the

different methods for the determination of the lipid content

(extractable

549

organic

material).

extraction (2:1)

K6nemann

with hexane,

Langer

at room temperature

of Bligh

A modification

comparative

and Sch~tz

involves

23 used a soxhlet

24 used a mixture

extraction

of h e x a n e - a c e t o n e

and Niimi

26 used the method

with a mixture of chloroform

of the last method has been recommended

interlaboratory

is not known

and Calamari

(12 - 15 h), while Oliver

and Dyer 29, which

methanol.

25 and Galassi

work on b i o c o n c e n t r a t i o n

if all laboratories

used this method

and

in the

in fish 22,30;

however,it

for the d e t e r m i n a t i o n

of the

lipid content. The correlation

between

lipid content

factors on a wet weight basis regression

analysis,

(BCFw)

the following

(L %) of the fish and the b i o c o n c e n t r a t i o n is given

equation

BCF w = 166 x L N = 26;

r = 0.873;

This c o r r e l a t i o n

n~

L,J

at the 99.9

% level.

2400

/

200

1 6( z

0 ~-

,<

a linear

(%)

0 < 'ut.

I. Using

(2)

L = Lipid Content

is significant

in Fig.

was obtained:

120

iZ uJ

Z 0,~

80c

400

o l-- ~ e J ) 1

2

03'~" I 3

I

I

I

t

I

I

I

I

4

5

6

7

8

9

10

11

L,p,o

Fig.

i: C o r r e l a t i o n

weight)

between

of trichlorobenzene

The results of Langer

lipid content

reported

previously

results

for 1,2,4-trichlorobenzene. in golden

(%)

and the b i o c o n c e n t r a t i o n

in eight different

lindane 53).

cONTeNT

factor

21 for lindane are in line with our

The b i o c o n c e n t r a t i o n

factors

(BCFw)

ide ranged between 43 to 782 with a mean of 320.8 ~

If the b i o c o n c e n t r a t i o n

value was 13,510 ~ 224

( wet

species of fish

factors were calculated

(N=25). Using a lipid basis

on a lipid basis,

of

30.7

(N =

the BCF L

for the BCF values of golden

550

ide reduced the coefficient of variation

from 9.6 % to 1.7 %. The lipid content

of the four fish species ranged from 0.8 % to 7.4 %. The following equation for the bioconcentration

factor on a wet-weight

basis

(BCFw) of

~-HCH

in the four

fish species was obtained: BCFw= 160.5 x L - 79.2 N = 68; Another

r = 0.992;

L = Lipid content

(3)

(%).

important result of our work on 1,2,4-trichlorobenzene

the log of the bioconcentration

factors on a lipid basis

is the fact that

(log BCFL) , which range

from 3.82 - 4.30 with a mean of 4.19, are close to the log n-octanol/water partition coefficient of 1,2,4-trichlorobenzene

determined

method

(see reference 31). This result

(range:

3.93 - 4.18; mean log KOW: 4.09)

shows that the uptake and partition of chemicals the bioconcentration who obtained

into the lipid portions control

in fish. Our results confirm the calculations of Briggs 32

the same results by theoretical considerations

that the values of the bioconcentr~tion PCBS,

by the shake-flask

as found by several authors,

and who stated also

factors on a lipid basis for DDT and

were very close to

their KOW values.

CONCLUSIONS The OECD Guidelines

for Testing of Chemicals

of the bioconcentration carp,

fathead minnow,

33 recommend,

potential of chemicals,

rainbow trout,

different

zebra fish, guppy,

for the determination fish species such as

cat fish, etc. However,

this study has shown that the variability of BCF values of eight fish species significantly

reduced by relating the bioconcentration

is

factors to the lipid

content of the fish. For comparison of the bioconcentration potential of a lipophilic chemical

in different

fish species as well as in the same fish species,

it is therefore necessary that BCF values are normalized on a lipid basis. This has also been postulated by other authors 34,35,36 as a consequence of theoretical considerations.

In our opinion

lipid content greater

than 2 % are used for testing the bioconcentration

it is also necessary that only fish with a poten-

tial of lipophilic chemicals. As a future subject,

therefore,

further studies on the correlation between lipid

content of different

fish species and the bioconcentration

factor should be

carried out for various lipophilic chemicals. Since there are different methods for the determination of the lipid content (extractable organic material) recommended

in fish and other aquatic organisms,

that some of them 29,37,38 should be compared

out if the different homogenizing

it is

in a ring test to find

techniques and the variety of solvents have a

significant effect on the total amount of extractable material

(=lipids).

Investigations of Lemcke and Lampert 39 and others 40,41,42 have shown that the lipid content of Daphnia can change very rapidly with limited food consumption. Therefore,

we and others 43 suggest that bioconcentration

experiments with

Daphnia should also include determination of the lipid content of the organisms

551

or, at least, determination holds for all accumulation

of dry weight.

We think that this last statement

studies with aquatic

and terrestrial

means that the lipid content of such aquatic organisms the determination

of bioconcentration

and probably

organisms.

is an important

This

factor

in

also in toxicological

testing. ACKNOWLEDGEMENTS We thank Dr. M. Kitano, Dr. A.G.M. Willems, Neuherberg,

Chemicals

Inspection

& Testing

Duphar B.V., S-Graveland,

for valuable discussions

Institute,

Holland,

Tokyo,

and Dr. K. Bunzl,

Japan, GSF,

and comments.

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