Polycyclic aromatic compounds and saturated hydrocarbons in tissues of flatfish: Insight on environmental exposure

Marrne Environmental

0141-1136(95)00027-5

Research, Vol. 43, NO. 112, pp. I I-25, 1997 Copyright 0 1996 Eisevier Science Ltd Printed in Great Britain. All rights reserved 0141-l 136/97/$15.00+0.00

ELSEVIER

Polycyclic Aromatic Compounds and Saturated Hydrocarbons in Tissues of Flaffish: Insight on Environmental Exposure Jocelyne Hellou* & William G. Warren Science Branch Department of Fisheries and Oceans, P.O. Box 5667, St John’s, Newfoundland, Canada A 1C 5X 1 (Received I May 1995; revised version received

15 November

1995; accepted

15 November

1995)

ABSTRACT The concentration of polycyclic aromatic compounds (PACs) was investigated in muscle, liver and gonad of American plaice and yellowtail flounder collected in the northwest Atlantic. A broader range of PACs was detected in liver than in muscle or gonad of jatjish, including sulphur heterocycles indicative of a source of petroleum hydrocarbons. Lower levels of PACs were observed in ovaries than testes of same size fish and possibly negatively correlated to gonad indices. Different ratios were observed between parental and alkylated PACs. with species, location, tissue or season. The following concentration trend was consistently observed in muscle.. NA > C-INA

> C-2NA > C-3NA > C-4NA.

Saturated hydrocarbons represented by n-alkanes were anal_ysedin tissues of yellowtail pounder. Muscle and gonads had undetectable concentrations, while livers displayed a fingerprint predominated by biogenic alkanes. Copyright 0 1996 Elsevier Science Ltd

INTRODUCTION Polycyclic aromatic compounds (PACs), including parental and alkylated polycyclic aromatic hydrocarbons (PAHs), and sulphur heterocycles (PASHs) were analysed in tissues of two flatfish species. These benthic species, namely, American plaice (Hippoglossoides platessoides) and yellowtail flounder (Pleuronectes ferruginea) belong to the pleuronectidae family and represent the present and possibly the future of the fisheries catch, in the northwest Atlantic. PAHs can derive from combustion sources, coal and/or petroleum products, while PASHs are characteristic of petroleum sources of contamination (Friocourt et al., 1982; Kira et al., 1983; Neff 1985). It has been proposed that the bioavailability of PAC in the *Corresponding

author. II

12

J. HeNou & W. G. Warren

Morphometric NAFO(month)

3Ps (5) 3Ps (5) 3N 3N 30 30

(5) (5) (5) (5)

3L (8-9) 3L (8-9) 3L (8-9) 3L (8-9) 3L (8-9) 3L (8-9) 3Ps (4-5) 3Ps (4-5) 30 (45) 30 (4-5) NAFO,

divisions

Sex

Size

m

L

f m f m f

m f m f m f m f m f

TABLE 1 Measurements,

Length (cm)

Mean (Range)

Weight (g)

Liver index Gonad index (organ weight/fish weight) x 100

L L L L L

Yellowtail flounder 38(3&41) 527(441-661) 43(40-46) 926(563-1076) 41(38-46) 705(483-1038) 44(4@49) 899(6041178) 40(3844) 633(5 13-842) 43(4&50) 811(541-1255)

I .2(0.9-l .6) 2.2( I .7 -2.7) 1.2(0.8-l ,4) I .9( I S-2.4) 0.9(0.7-l. I) 2.1(2.0-2.5)

2.5(2.0-2.8) 16(12-19) 2.0( I .2-3.0) 10(1.4-16) 2.4(0.9-3.2) 10(10-14)

s S M M L L s s L L

American plaice 29(26-30) 205( 15&260) 29(25-32) 225( 132-306) 35(31-37) 367(221-505) 37(35-39) 421(392-556) 40(3844) 6 12(407-795) 42(4 l-44) 695(541b758) 29(26-35) 2 14( I 58-360) 32(26-36) 308( 155-459) 35(33-39) 360(281471) 43(3945) 666( 5 19-690)

2.2(1.1-3.5) I .9(0&3.4) 1.9(1&3.2) 3.2(1.94.1) 2.0( 1.2-2.8) 2.8( I .8-3.4) 1.3(0.8-l .4) 1.4(1.1-1.7) 0.6(0.4-0.9) 0.7(0.4-0.9)

2.4(0.7-3.8) 2.8(0.7-5.8) 2.6( I .5S5.7) 7.2(5.1-8.0) 2.8(1.74.1) 7.8(5.8&l I) 0.7(0.3-1.3) 0.5(0.3-0.8) 0.7(0.3-0.8) 2.4(0.3-2.9)

of the Northwest

Atlantic

Fisheries

Organization

(see Fig. 1); m, males; f, females;

S. small; M, medium; L, large.

aquatic environment is related to their source, where combustion-derived PAC present on particulates are less bioavailable than petroleum-derived PACs (Farrington, 1991). The physical
EXPERIMENTAL Biota

Fish were collected opportunistically biological surveys of various Northwest

during the Department of Fisheries and Oceans Atlantic Fisheries Organization (NAFO) divisions,

13

Aromatic polycyclics and saturated hydrocarbons in.flatjsh

56

48

46

42

40

76'

72.

70'

68'

66'

64'

62"

58'

56'

54'

52'

500

41p

46'

440

Fig. 1. Map of the Northwest Atlantic Fisheries Organization divisions (NAFO, number followed by letter). The Hibernia oil field is located on the Grand Banks. Cod were previously collected from NAFO divisions 25, 3K and 3Ps. Plaice were obtained from 3L, 3Ps and 30, while flounder were sampled in 3Ps. 3N and 30.

in 1991-93. Information regarding the sampling location, month and morphometrics is presented in Table 1 and a map in Fig. 1. Measurements taken consisted of fish length and weight, liver and gonad weight. These two organ weights were used to determine indices, i.e. (organ weight/fish weight) x 100. Only sexually mature fish were sampled and although size can be taken as a surrogate for age, it should be noted that females of both species grow faster than males, while American plaice are slower growing than yellowtail flounder (Pitt, 1973; Scott & Scott, 1988). All fish would have been above 4 or 5 years old (Scott & Scott, 1988). Samples of yellowtail flounder represent pools of tissues obtained from 7 fish (equal amount of tissue per fish) having similar morphometrics. Samples of American plaice were represented by pools of tissues from 7 to 13 fish with similar morphometrics (Table 1). Analysis

A series of 28 PACs were analysed in yellowtail flounder. These included the thalene (NA), acenaphthylene (AY), (PA), anthracene (AN), fluoranthene

liver, muscle and gonad of American plaice and 16 PAH recommended priority pollutants: naphacenaphthene (AE), fluorene (F), phenanthrene (FL), pyrene (PY), benz (a) anthracene (BaA),

14

J. Hellou & W. G. Warren

chrysene (CH), benzo (b) fluoranthene (BbF), benzo (k) fluoranthene (BkF), benz (a) pyrene (BaP), dibenz (a,h) anthracene (DahA), benzo (g,h,i) perylene (BghiP), indenopyrene (IP), C-l to C-4NA and PA, dibenzothiophene (DBT) and C-l and C-2DBT. Analyses were performed by Axys Analytical Services, Sidney, British Columbia using the experimental procedure outlined in Hellou et al. (1994a). Briefly, hydrocarbons are extracted using a caustic digestion in 50% KOH-MeOH, followed by solvent partitioning in pentane, purification on a silica column and analysis of fractions by GC-MS. Quality assurance/quality control involves several measures, including the performance of a blank and duplicate analysis with each batch of 610 samples, as well as recoveries of standards added to each sample. Linear saturated hydrocarbons, from C-12 to C-36 were also analysed in tissues of yellowtail flounder (only one species due to economical considerations). Sample detection limits varied with each injection and were between 0.01 and 0.09 rig/g,, wet wt. Reported concentrations were blank corrected. Ten duplicate analyses gave results varying between 0 and 66% (mean,lO%). Recoveries of deuterium-labelled NA, AE, PA, PY and CH ranged from 41% to 115% (means, 62, 70, 72, 79 and 78%, respectively). Recoveries of labelled n-C16, 24 and 36 were between 29 and 113% (means, 61, 81 and 66%, respectively). Conversion of tissue concentrations expressed in wet wt to dry wt values requires multiplication by a factor of five (75580% water). Lipid content was determined using the Bligh 8~ Dyer (1959) method. Statistics

Spearman’s rank correlation, which should be less affected by outliers than the Pearson product-moment correlation, was used for assessing the significance of relationships between parental and alkylated PAC and appropriate independent variables. The relationships, themselves, were estimated by robust regression, specifically biweight fitting (Mosteller & Tukey, 1977, section 14H).

RESULTS The mean PAC fingerprint observed in liver, muscle and gonad is displayed in Fig. 2 by species and sex. The summed concentrations of alkylated and parental PAC are reported in Table 2, by species and sex, for various size groups and locations. Comparison between tissues and chemical groups are presented in Tables 3 and 4. General observations

The naphthalenes predominated in all muscle, liver and gonad (75-80% of total PAH), except for the liver of American plaice caught in late summer (37%). Of the parental PAH analysed, NA, AE, F and PA were present in over 80% of samples, while FL, PY and CH were present in 30-50% of liver samples (mean detectable, 0.4, 0.4 and 0.9 rig/g,, respectively). These tetracyclic PAHs were not present in muscle and were detected in only 10% of the gonad (mean detectable, 0.4, 0.3 and 0.1 ng/g). No larger parental PAH than chrysene were detected in any tissue. The highest molecular weight alkylated PAH, C4PA was detected in half the liver samples of American plaice (mean detectable, 5.2ng/g). DBT derivatives were present in over 80% of liver samples of both species.

Aromatic polycyclics and saturated hydrocarbons inJlatjish

15

Polycydic Fvon-dc Compounds in muscle

wycydk

Ammatk CoinpcuM

ingonad

rl

Fig. 2. Mean concentrations of polycyclic aromatic compounds detected in over 80% of liver, muscle and gonad pools. Letters on the abscissa refer to chemical structures defined in the text (M, males; F, females.)

J. Hellou & W. G. Warren

16

TABLE

Concentration NAFO(month)

Sex

2

(ng/g, wet wt) of the Sum of Different PACs

Size par.

Muscle alk. tot.

par.

Liver alk.

tot.

par.

GlXZUd alk. got.

Yellowtail flounder 3Ps (5)

3Ps (5) 3N (5) 3N (5) 30 (5) 30 (5)

m f m f m f

L L L L L L

3L (8-9) 3L (8-9) 3L (8-9) 3L (8-9) 3L (8-9) 3L (8-9) 3Ps (4-5) 3Ps (4-5) 30 (4-5) 30 (45)

m f m f m f m f m f

S S M M L L S S L L

5.3

9.8

I5

5.6

6.6

12

20

5.2

5.2

10

23

16

6.2

4.7

II

6.2 3.8

3.2 5.6

9 9

I6 I1 8.5

1.5

16

36

8.2

14

3.9

39

5.2

10 26 5.8 I6 5.5 I4

1.7 6.9 3.5

6.1

II 2.5

19 6.4

II I6 1.9 I6 6.0 13 1.6 5.1

American plaice 34

34

68

8.9 41

50

34

26

33

59

8.2 44

52

23

1.2 21

34

38

31 7.0

30

4.0

5.4

9.4

3.4

4.0

1.4

I.5 29

31

2.3

2.5

4.8

2.5

3.1

5.6

8.6 66

75

2.3

6.2

8.5

1.8

4.4

6.2

5.1 13

19

1.3

1.9

3.2

5.3

7.1

I5

27

4.0

4.0

8.0

2.2

4.8

7.0

7.1

25

33

3.9

2.5

6.4

0.5

0.1

0.6

1.6

1.0

2.6

II 6.7

16 27 8.5 I5

2.4 0.9

0.8 I.1

3.2 2.0

I3

12

I50

71 188

NAFO, divisions of the Northwest Atlantic Fisheries Organization (see Fig. I); par., parental; alk., alkylated; tot., total; m, males; f, females; S, small; M, medium; L, large.

Relationship

between concentration

and morphometrics

Plots of parental and alkylated PAC versus the appropriate morphometric measurement (fish weight, liver index, gonad index) and lipid content exhibit apparent outliers (Fig. 3). With the exception of parental PACs in muscle versus muscle lipid content and alkylated PACs in gonad versus gonad indices, all estimated slopes were positive. However, only in the case of alkylated PACs in liver versus lipid content was the relationship well established (rank correlation = 0.770, n = 16) although the rank correlation for alkylated PAC in liver versus liver indices (0.412) just falls short of the 5% critical value (0.425). In most cases, the procedure identifies both the parental and alkylated PACs in muscle and gonad of small plaice as outliers. In the case of alkylated PACs, small and medium plaice appear as outliers. Liver concentrations Flounder and plaice from NAFO divisions 30 and 3Ps collected in the spring had higher concentrations of parental and alkylated PACs in liver than in muscle (Table 2). Comparing livers of American plaice of similar size, concentrations of alkylated PACs in fish collected from 3L were nearly twice the concentration of those from 3Ps and 30 (Table 2).

17

Aromatic polycyclics and saturated hydrocarbons in jatfish TABLE 3

Ratio of Parental to Alkylated PAHs in Tissues and Lipid Content of Tissues (%) NAFO

Sex

Size

Muscle

(%)

m f m f m f

L L L L L L

0.5

(0.8)

0.8

(0.5)

1 1 2 0.7

W) (0.5) (0.6) (0.4)

m f m f m f m f m f

s s M M L L S s L L

Liver

(%l

Gonad

i%/

I I 1

(6.0) (4.2) (6.8) (4.6) (3.8) (2.8)

0.7 2 0.5

(3.2) (2.2) (3.1) (1.4) (3.1) (1.9)

(15.2) (12.1) (13.2) (10.7) (14.9) (7.4) (9.0)

0.9 3 0.3 0.9 0.4 0.7

(1.9)

1 2 NND NND

(1.2) (1.0) (1.7) (1.3)

Yellowtail flounder 3Ps 3N 30

2

2 2

1 I 2

American plaice 3L

3Ps 30

I 0.8 0.7 0.9 0.8 0.4 0.7

(5.3) (3.2) (3.9) (7.4) (4.7) (5.2) (1.4)

0.5 NND 2

(1.5) (2.1) (3.5)

0.2 0.2 0.3 0.1 0.1 0.1 0.8 0.3

0.7 0.8

(10.5) (9.0) (10.3)

(I.3 (1.9) (1.5) (1.7) (1.4)

NAFO, divisions of Northwest Atlantic Fisheries Organization (see Fig.1); NND, nearly nondetected; the sum of parental or alkylated PACs is < I .O rig/g,, wet wt (Table 2).

PACs predominated over parental PACs in liver of plaice and this was more apparent in NAFO division 3L ( > 4x) than in 3Ps and 30 ( < 3 x). In contrast to the 3Ps and 30 samples, the 3L samples were obtained in August-September (Table 3). Parental PACs were in higher concentration than alkylated PACs in flounder. Alkylated

Muscle concentrations Concentrations in muscle of large flounder collected in the spring were all within the same range, regardless of sex or location (Table 2). In plaice, levels of PACs in small 3L fish were higher than medium and large 3L fish, small fish from 3Ps and large fish from 30. In yellowtail flounder, muscle to liver ratios were generally below 1, while there seems to be a size-related pattern in plaice (Table 4). Specifically, small plaice from 3L show higher concentrations of parental PAC in muscle than in liver (3 or 4x), but relatively little difference between the concentrations of alkylated PAC. However, in larger 3L plaice, muscle is depleted in parental and alkylated PACs, relative to liver (3 and 20x, respectively). Gonad concentrations Concentrations in ovaries appear lower than in testes of same size fish of one location. The relatively high values in small 3L plaice give the appearance of a relationship between

J. Hellou & W. G. Warren

18

TABLE 4

Muscle to Liver Ratio of Concentrations _ Parental

3Ps (5) 3N 30

3L

3Ps 30

m f m f m f

L L L L L L

m f m f m f m f m f

S s

M M L L s S

L L

for Different Summed Aromatics .~__ Alkylated

Yellowtail flounder 0.3 0.6 0.8 1 0.2 0.3 0.4 0.5 0.6 0.6 0.5 I American 4 3 0.6 2 0.3 0.3 0.4 0.3

NND 0.2

plaice 0.8 0.8 0.2 0.1 0.1

Total

Naphthalenes ~____

0.4 0.9 0.3 0.4 0.6 0.6

0.4 0.9 0.2 0.2 0.6 0.4

1 I

6 3 0.4 0.4 0.2

0.3 0.2

0.1

0.1 0.1

0.5 0.2

0.5 0.2

0.6 0.4

NND 0.1 .--

NND 0.2

NND 0.2

0.1

(see Fig. 1); NND, nearly nondetected; the sum of parental, alkylated, total PACs or naphthalenes (NA, C-l, C-2 and C-3NA) is < I .Orig/g,, wet wt (Table 2).

NAFO, divisions of the Northwest Atlantic Fisheries Organization

the concentration in gonad and muscle. Apart from this, no consistent decrease is apparent in gonad concentrations relative to muscle or liver.

increase or

Saturated hydrocarbons

Muscle and gonad of yellowtail flounder had undetectable concentrations of n-alkanes ranging from C- 12 to C-36. Liver displayed an odd/even predominance between C-26 and C-32, maximizing at C-29, along with a weaker range of shorter n-alkanes (Fig. 4).

DISCUSSION Important

considerations

The concentration differences observed with sex, fish weight, liver indices, gonad indices or lipid content must take into account the environmental and experimental variability. Kelly & Campbell (1994) reported an overall field variance of 150% when analysing for organochlorines in individual fish and 30% in pools of 25 fish. Hellou et al. (1994b) observed a decreasing coefficient of variation with increased exposure (> 100% to 50%), when analysing for total aromatics in laboratory-exposed fish. The expected environ-

Aromatic polycyclics and saturated hydrocarbons in flatjsh

(lam

‘i?/%)

uo!lwluamJ~

I

-

I$ I I I

_

I

0

* I

i $y 0

4

ijb -TI

’ ;t:

22

2

0

E I

2

0

I 2

I

z

I P

*

0

r-

(l?M '%/4U) uoymuaxIo~

c

c

P

s

(lam ‘%/4u) uogwuamo3

k

4

\

/

0

4

I

I

I

I

0

0

0

.cJ 40

I

0:

4 t

I “:_r 443

‘T

-

19

16

16

20

22

24

2%

28

30

32

34

n-alkanes Fig. 4. Fingerprint of n-alkanes detected in liver of yellowtail flounder. Numbers on the abscissa represent the carbon chain length of the linear alkanes. Letters on the right hand side of the figure represent NAFO locations followed by sex (M, males; F, females).

mental variability can therefore be higher tissues. It follows that reported correlations cally supported facts, They are listed hoping them, as well as to demonstrate the need for in biota.

than that observed for replicate analyses of represent possible trends rather than statistithat future studies will either confirm or deny more research to understand the fate of PACs

General trends Although the analysed aromatics ranged from bicyclic to hexacyclic parental and alkylated PACs, it is the smaller and more water soluble bicyclic PAHs, the naphthalenes, that predominated. There was a tendency for a decrease in concentration of aromatics with increased carbon branching. correlating with the expected decreased solubility and therefore bioavailability of the chemicals (May, 1980; McElroy et al., 1988). This observation appeared consistently in muscle tissue, for the naphthalenes where: [NA > C-1NA

> C-2NA

> C-3NA

> C-4NA].

Small variations in this pattern were observed in liver and gonad samples. More parental PAHs were detectable in liver, where concentrations also decreased with increasing molecular weight and decreasing solubility: [NA > AE > F > PA > FL-PY-CH]. The higher tendency of smaller PAHs with lower K,, to accumulate in tissues of biota has been explained by modelling studies (Lake et a/., 1990; DiToro et al., 1991; Hellou et ul., 1995). Only parental PAHs with log K,, between 3.35 for NA and 5.79 for CH were

Aromatic polycyclics and saturated hydrocarbons inJat$sh

21

detectable in liver (Miller et al., 1985; Mackay et al., 1992). Fewer PAHs were detected in muscle or gonad and these had a more restricted range of log K,,, up to 4.57 for PA. The lack of larger molecular weight PACs could reflect their higher tendency to metabolize and/or that equilibrium is not attained due to their slower uptake and lower concentration in water (Hellou et al., 1995). Liver concentrations

The concentration of alkylated PACs tended to increase with liver indices and lipid content, while the concentration of parental PACs showed little or no relationship (Fig. 4). Although parental and alkylated PAHs are metabolized (e.g. Krahn et al., 1992) higher levels in the environment and/or slower metabolic rates for the alkylated species might explain this difference. In the past, more exposure studies targeted parental PAH and our knowledge of the enzymatic response generated by alkylated aromatics is limited. More variability in the parental to alkylated PAC ratio was observed in liver of plaice than of yellowtail flounder (Table 3). Higher levels of alkylated PAC were observed in plaice collected in August-September compared to the same size plaice from April-May (Table 2). This difference could be related to exogenous (environmental) and/or endogenous (fish-related) variables. Plaice and flounder are reported to move into deeper waters in the winter and shallower in spring (Scott & Scott, 1988). This movement could be associated with different sediment grain size and/or concentration of contaminants. For a similar sediment concentration larger grain particles would have a lower organic carbon content than finer grain and increased contaminant bioavailability. On the other hand, nearshore sediments would tend to have higher PAC concentrations (Brun et al., 1991; Aceves & Grimalt, 1993; Simonich & Hites, 1994). In addition, NAFO division 3L is on the Grand Banks, close to the Hibernia oil field slated for petroleum exploration. It is possible that more underwater petroleum seeps into area 3L. Changes due to feeding, lipid content of tissue or metabolism have also to be considered. Flounder and plaice feed on polychaetes and crustaceans. Fish and molluscs can be added to the diet of plaice, while amphipods can be added to the diet of flounder (Scott & Scott, 1988). Food chain biomagnification would depend on the ability of each level to bioaccumulate versus biotransform PACs (Hellou, 1996). Polychaetes and amphipods are known to accumulate relatively high concentrations of PACs from sediments, but their higher abundance and/or contaminant load in the fall needs to be addressed. A difference in diet with age should also be considered. Positive correlations were observed between alkylated PACs and lipids in either males or females. A variation in lipid could also be seasonal (e.g. Holdway & Beamish, 1984). Metabolic rates of some fish species vary with season, e.g. winter flounder stops feeding during the winter and has lower respiration rates (Graham, 1985). A slower metabolism in the winter, possibly resulting in less biotransformation, would lead to higher levels of free contaminants in tissues. On the other hand, a higher uptake rate in summer could also lead to a higher bioaccumulation. Muscle concentrations

For both sexes, muscle of smaller American plaice from 3L displayed much higher PAC concentrations compared to larger fish (10x). This observation could indicate that

22

J. Hellou & W. G. Warren

younger fish are less able to metabolize PAC or have different uptake-elimination rates vs muscle surface area. It has been shown that, althcugh the gill ventilation rate and feeding increases with fish size, this is not proportional to fish volume (Gobas & Mackay, 1987; Clark et al., 1990). Only small male and female American plaice from 3L had relatively higher muscle to liver ratios (all >l), than the rest of the samples (Table 4). Saturated hydrocarbons

The fingerprint of n-alkanes in the environment is characteristic of their origin (Neff & Anderson, 1981; Volkman et al., 1992). There are limited data regarding the type of alkanes in sediments and biota offshore from the Island of Newfoundland and the present study is the first in finfish (Bieger, 1994). The oddeven predominance in liver of yellowtail flounder indicates a biogenic source of n-alkanes (Volkman et af., 1992; Steinhauer & Boehm, 1992). The bimodal distribution for the 3Ps fish would be assigned to marine algae (C-17) and higher plants (C-29). Samples from 3Ps and 3N possibly had lower levels of petroleum hydrocarbons, detected from the presence of evenly distributed n-alkanes of shorter chain length. If our assignment of the origin of the aromatics as petroleum derived is correct, then the lower concentration of the n-alkanes in water, due to their lower water solubility relative to the naphthalenes, explains their absence from tissues (Mackay, 1991). The fingerprint observed for the saturated hydrocarbons indicates the predominance of biogenic sources of saturated hydrocarbons in the northwest Atlantic. Comparison to other studies

The pleuronectidea results are comparable to those obtained for cod collected in the northwest Atlantic, where parental PACs were detected in very few cod, while alkylated PACs were predominant (Hellou et al., 1994a). Concentrations reported here are similar to those obtained for fish, including flounder species inhabiting the Atlantic, in the early 1980s (Boehm & Hitzer, 1982). The higher levels of specific PACs in muscle of plaice from 3L vs 3Ps and 30 are similar to higher levels of total PACs observed in muscle of cod from 3K compared to 25 and 3Ps (Hellou et al., 1994~). NAFO division 3K is adjacent to 3L, which overlaps the Grand Banks of Newfoundland, an area slated for petroleum exploration (Fig. 1). Source of hydrocarbons

It is possible to explain the PAC fingerprint observed in muscle of finfish by comparing it to a long-term dose-response study (Hellou et al., 1994b). Decreasing concentrations of NA and PA derivatives having an increasing degree of alkylation, along with decreasing concentrations of parental PACs having an increasing molecular weight, were observed in both studies. The ratio of alkylated derivatives differed in exposed and feral fish. The sum of NA to PA derivatives decreased from lower to higher exposure (> 1OO:l to 20:1), correlating with the weathering observed in the sediments fingerprint. The present ratio of NA:PA (5:l) could reflect exposure to less weathered Hibernia crude, such as from underwater seeps. A different source of oil, with more NA could also explain the present results. DBT and alkylated DBT were detected in both sets of samples and are indicative

Aromatic polycyclics and saturated hydrocarbons injatjsh

23

of petroleum sources of PAC (Friocourt et al., 1982; Kira et al., 1983). Also, the concentrations of C-l, C-2 and C-3NA correspond to the lower levels of exposure (Hellou et al., 1994b).

CONCLUSION PACs accumulated in tissues of two flatfish species from the northwest Atlantic. In liver, the level of alkylated PAC correlated with lipid content and liver indices more than the level of parental PAC. There was no clear relationship with the remaining tissues. The lower molecular weight PACs, the naphthalenes, predominated in all samples. Sulphur heterocycles, indicative of a petroleum source of hydrocarbons were also detected, while biogenic alkanes predominated in liver. In order to ascertain the role played by different variables on the bioaccumulation of PAC, it would seem important to undertake laboratory studies where conditions can be controlled.

ACKNOWLEDGEMENTS This research could only be accomplished with the help of the technicians and scientists of the Groundfish Division of the Department of Fisheries and Oceans who collected the finfish during the biological surveys. The authors would like to acknowledge their help and the funding from the Green Plan Toxic Chemicals Program.

REFERENCES Aceves, M. & Grimalt, J. 0. (1993). Seasonally dependent size distributions of aliphatic and polycyclic aromatic hydrocarbons in urban aerosols from densely populated areas. Environ. Sci. Technol., 27, 28962908. Bieger, T. (1994). Molecular and isotopic fingerprinting of aliphatic hydrocarbons in Conception Bay, Newfoundland. MSc thesis, Department of Earth Sciences, Memorial University of Newfoundland, 129 pp. Bligh, E. G. & Dyer, W. J. (1959). A rapid method of total lipid extraction and purification. Can. J. Biochem. Physiol., 37,91 l-917. Boehm, P. D. & Hitzer, P. (1982) Gulf and Atlantic Survey of Selected Organic Pollutants in Finfish. NOAA Technical Memorandum NMFS-F/NEC-13, US Department of Commerce, National Marine Fisheries Centre, Woods Hole, Massachusetts, 111 pp. Brun, G. L., Howell, D. G. & O’Neill, H. J. (1991). Spatial and temporal patterns of organic contaminants in wet precipitation in Atlantic Canada. Environ. Sci. Technol., 25, 12491261.

Clark, K. E., Gobas, F. A. P. C. & Mackay, D. (1990). Model of organic chemical uptake and clearance by fish from food and water. Environ. Sci. Technol., 24, 1203-1213. DiToro, D. M., Zarba, C. S., Hansen, D. J., Berry, W. J., Swartz, R. C., Corwan, C. E., Pavlou, S. P., Allen, H. E., Thomas, N. A. & Paquin, P. R. (1991). Technical basis for establishing sediment quality criteria for nonionic organic chemicals using equilibrium partitioning. Environ. Toxicol. Chem., 10, 1541-1583. Farrington, J. W. (199 1). Biogeochemical processes governing exposure and uptake of organic pollutant compounds in aquatic organisms. Environ. Health Persp., 90, 11 l-l 16.

24

J. Hellou & W. G. Warren

Friocourt, M. P., Berthou, F. & Picart, D. (1982). Dibenzothiophene derivatives as organic markers of oil pollution. Toxicol. Environ. Chem., 5, 2055215. Gobas, F. A. P. C. & Mackay, D. (1987). Dynamics of hydrophobics organic chemical bioconcentration in fish. Environ. Toxicol. Chem., 6, 495504. Graham, M. S. (1985). Oxygen Uptake and Delivery in Cold Temperate Marine Teleosts. PhD thesis, Department of Biology, Memorial University of Newfoundland. Hellou, J., Payne, J. F. & Hamilton, C. (1994a). Polycyclic aromatic compounds in Northwest Atlantic cod (Gadus morhua). Environ. Pollut., 84, 197-202. Hellou, J., Payne, J. F., Upshall, C., Fancey, L. L. & Hamilton, C. (1994b). Bioaccumulation of aromatic hydrocarbons from sediments: a doseeresponse study with flounder (Pseudopleuronectes americanus). Arch. Environ. Contam. Toxicol., 27, 4777485. Hellou, J., Upshall, C., Payne, J. F. & Hodson, P. V. (1994~). Polycyclic aromatic compounds in cod (Gadus morhua) from the Northwest Atlantic and St Lawrence Estuary. Sci. Tot. Environ, 145, 71-79. Hellou, J. (1996). Polycyclic aromatic hydrocarbons in marine mammals, finfish and molluscs. In: Interpreting Environmental Contaminants Concentrations in Animal Tissues, ed. N. Beyer & G. Heinz. SETAC Special Publication, Lewis, Michigan. pp. 229-250. Hellou, J., Mackay, D. & Fowler, B. (1995). Bioconcentration of polycyclic aromatic compounds from sediments to muscle of finfish. Environ. Sci. Technol., 29, 2555~2560. Holdway, D. A. & Beamish, F. W. H. (1984). Specific growth and proximate body composition of Atlantic cod (Gadus morhua). J. Exp. Mur. Biol. Ecol., 81, 1477170. Kelly, A. G. & Campbell, L. A. (1994). Organochlorine contaminants in liver of cod (Gadus morhua) and muscle of herring (Clupea harengus) from Scottish waters. Mar. Pollut. Bull., 28, 103-108. Krahn, M. M., Burrows, D. G., Ylitalo, G. M., Brown, D. W., Wigren, C. A., Collier, T. K., Chan, S.-L. & Varanasi, U. (1992). Mass spectrometric analysis of aromatic compounds in bile of fish sampled after the Exxon Valdez oil spill. Environ. Sci. Technol., 26, 116126. Kira, S., Izumi, T. & Ogata, M. (1983). Detection of dibenzothiophene in mussel, My!tilu.s edulis, as a marker of pollution by organosulfur compounds in a marine environment. Bull. Environ. Contam. Toxicol., 31, 518-525. Lake, W. J., Rubinstein, N. I., Lee, H. III, Lake, L. A., Heltshe, J. & Pavignano, S. (1990). Equilibrium partitioning and bioaccumulation of sediment-associated contaminants by infaunal organisms. Environ. Toxicol. Chem., 9, 109551106. Mackay, D. (1982). Correlation of bioconcentration factors. Environ. Sci. Technol., 16, 274-278. Mackay, D. (1991). Multimedia environmental models. The ,fugucity upproach. Lewis. Michigan, 257 pp. Mackay, D., Shiu, W. Y. & Ma, K. C. (1992). Illustrated Handbook of Physical-Chemical Properties and Environmental Fate ,for Organic Chemicals. Polynuclear Aromatic Hydrocarbons, Polychlorinated Dioxins and Dibenzofurans Vol. II. Lewis, Michigan. 597 pp. May, W. E. (1980). The solubility behavior of polycyclic aromatic hydrocarbons in aqueous systems. In Petroleum in the Marine Environment, ed. L. Petrakis & F. T. Weiss. Advances in Chemistry Series, Vol. 185, ACS, Washington, DC, pp. 1433192. McElroy, A. E., Farrington, J. W. & Teal, J. (1988). Bioavailability of polyaromatic hydrocarbons in the aquatic environment. In Metubolism of Polycyclic Aromatic Hydrocarbons in the Aquatic Environment, ed. U. Varanasi. CRC Press, Boca Raton, Florida, pp. l-40.

Aromatic polycyclics and saturated hydrocarbons inJiatjish

25

Miller, M. M., Waslk, S. P., Huang, G.-L., Shiu, W.-Y. & Mackay, D. (1985). Relationships between octanol-water partition coefficient and aqueous solubility. Environ. Sci. Technol.,

19, 522-529.

Mosteller, F. & Tukey, J. W. (1977). Data Analysis and Regression: A Second Course in Statistics. Addison-Wesley, Reading, MA. Neff, J. M. & Anderson, J. W. (1981). Response of Marine Animals to Petroleum and Specific Petroleum Hydrocarbons. John Wiley, New York, 177 pp. Neff, J. M. (1985). Polycyclic aromatic hydrocarbons. In Fundamentals of’ Aquatic Toxicology, eds G. M. Rand & S. R. Petrocelli. Hemisphere Publishing Corporation, NY, pp. 416454. Pitt, T. K. (1973). Food of American plaice (Hippoglossoides platessoides), from the Grand Bank, Newfoundland. J. Fish. Res. Bd. Can., 30, 1261-1273. Scott, W. B. & Scott, M. G. (1988). Atlantic fishes of Canada. Can. Bull. Fish. Aquat. Sci.. 219, 731.

Simonich, S. L. & Hites, R. A. (1994). Vegetation-atmosphere partitioning of polycyclic aromatic hydrocarbons. Environ. Sci. Technol., 28,939-943. Steinhauer, M. S. & Boehm, P. D. (1992). The composition and distribution of saturated and aromatic hydrocarbons in nearshore sediments, river sediments, and coastal peat of the Alaskan Beaufort Sea: implications for detecting anthropogenic hydrocarbon inputs. Mar. Environ. Res., 33, 2233253. Volkman, J. K., Holdsworth, D. G.. Neill, G. P., Bavor, H. J. Jr. (1992). Identification of natural, anthropogenic and petroleum hydrocarbons in aquatic sediments. Sci. Tot. Environ.,

112, 203-219.