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Effects of polynuclear aromatic hydrocarbons on fishes and shellfish: An overview of research in virginia
Marine Environmental Research 24 (1988) 237-241
Effects of Polynuclear Aromatic Hydrocarbons on Fishes and Shellfish: An Overview of Research in Virginia*
M. E. Bender, W. J. Hargis, Jr, R. J. H u g g e t t & M. H. Roberts, Jr Virginia Institute of Marine Science, School of Marine Science, College of William and Mary, Gloucester Point, VA 23062, USA
This paper discusses the following topics related to polynuclear aromatic hydrocarbon pollution in estuaries: (1) the use of oysters (Crassostrea virginica), hard clams (Mercenaria mercenaria) and brackish water clams (Rangia cuneata) in residue monitoring; (2) the effects of elevated P A H residues on oyster condition; (3) three years of field studies relating PAH sediment contamination to abnormalities in .fishes; and (4) laboratory bioassays jor effects and bioconcentration modeling. Oysters, hard clams and Rangia have been shown,from 3 years offield studies, to be good monitors of pollution inputs as one proceeds along salinity gradients from 25%o to 0"5%0. Effects o[' increased body burdens of PAHs are shown by a lowering of the oysters' condition index, as measured by lipid levels. Fishes inhabiting the Elizabeth River, VA, which is highly contaminated with PAHs, have abnormalities (cataracts, skin lesions, abnormal.fins, etc.). These abnormalities have higher incidence in regions of the river where the sediments are more heavily contaminated. Laboratory studies utilizing contaminated sediments have reproduced some of the abnormalities observed in the field. Bioconcentration of PA Hs from sediments has been studied with oysters and hard clams. Oysters generally accumulate three times the body burdens o[' clams exposed to the same suspensions. A faster depuration rate (k 2) .['or clams appears to be responsible for the higher equilibrium body burden o[" oysters.
The impetus for the series of studies outlined here arose from several avenues: (1) the general recognition that polynuclear aromatic hydrocarbons (PAHs) may be adversely affecting aquatic life; (2) the discovery of sediments heavily contaminated with PAHs in the Elizabeth River, Virginia; * VIMS Contribution No. 1439. 237 Marine Environ. Res. 0141-1136/88/$03"50© 1988ElsevierApplied Science Publishers Ltd, England. Printed in Great Britain
238
M. E. Bender, W. J. Hargis, Jr, R. J. Huggett, M. H. Roberts, Jr
(3) the later discovery that a number of fishes inhabiting the river had abnormalities which increased in frequency at stations whose sediments had high levels of P A H contamination; and (4) the recognition that a monitoring program was needed to determine P A H residues in organisms as one progresses along the salinity gradient in estuaries. Bieri et al., 1 described the chemical methods which were used to determine PAH residues reported here, and detailed the PAH contamination of surface sediments along the Elizabeth River estuary. They showed that PAH concentrations were highest near an abandoned and an operational wood treatment plant. Huggett et al., 2 provided additional data on sediment contamination with benzo(a)pyrene and discussed the distribution of abnormalities in fishes in relation to sediment contamination levels. Fisheries surveys were conducted during October, November and December of 1983 at 11 stations along the river. Depressions in biomass, total numbers of individuals and abundance of selected species occurred at the more contaminated stations. Even more dramatic was the increasing frequency at which abnormalities occurred. Fin erosion in hogchokers (Trinectes maculatus) and toadfishes (Opsanus tau) was observed in 11 and 30% of the specimens collected in the most contaminated areas. The incidence of cataracts in spot (Leiostomus xanthurus), croaker (Micropogonias undulatus) and weakfish (Cynoscion regalis) was 10, 18 and 21% respectively, in the contaminated zone. Since these initial surveys, additional studies have been conducted in the Elizabeth and an adjacent control area, the Nansemond. The results of these studies confirmed those of the early survey showing that the frequency of the most commonly observed lesions, i.e. fin and skin erosion and cataracts, were highest in the most heavily contaminated regions of the river. The presence of high levels of PAH contamination in sediments at particular sites does not demonstrate that the PAHs in the sediments are available to the biota. To determine the bioavailability of PAHs in the Elizabeth River, oysters from a clean system were transplanted to 5 stations along the river. Oysters were selected over fish because of their limited ability to carry out metabolic transformation of PAHs. Figure 1 shows the accumulation of total resolved PAHs as a function of location (distance upstream from Craney Island) along the river. Residues of 60#g/g were attained at the most contaminated station after a nine-week exposure period. Fishes collected from this area of the river showed the highest incidences of abnormalities. Oyster condition as estimated from lipid levels was depressed as P A H residues increased. The results of these studies and others 3'4 which implicate P A H contamination as a factor affecting fish population raise a number of questions. Of prime importance are: (1) what are the present levels of PAH contamination in aquatic systems; and (2) at what levels do effects occur?
Effects of PAHs on .fish and shellfish
239
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KILOMETERS Upstream from Craney Island F i g . 1.
Levels of total resolvedaromatics and lipids in oysters after nine weeksof exposure in the Elizabeth River.
To determine the extent of PAH contamination in lower Chesapeake Bay bivalve molluscs were selected as the sampling medium. In estuaries, however, the use of a single species as a monitoring tool is precluded by salinity or habitat limitations on species distribution. In Chesapeake Bay both Crassostrea virginica and Mercenaria rnercenaria occur throughout the polyhaline and mesohaline regions, but at any given location only one or the other species may be present. Rangia cuneata occurs in the upper-mesohaline and oligohaline salinity regimes. All three species are essential to any monitoring program within the estuarine system of Chesapeake Bay. Two studies, a field and a laboratory investigation, were initiated to evaluate the feasibility of utilizing these species as monitoring tools in estuaries. In the field studies, gonadally mature oysters and Rangia were collected along the salinity gradient in several Virginia tributaries of Chesapeake Bay in 1984, 1985 and 1986. During 1985 and 1986 oysters and Rangia were collected from adjacent stations in the James River to allow comparisons of residue levels. Levels of total resolved PAHs in oysters and Rangia from adjacent stations were very similar, 1.10 and 1-34 p p m (dry wt) spring of 1985, .1.3 and 1.8 ppm, fall of 1985 and 1.4 and 1.1 ppm, fall of 1986. Residues of individual compounds, e.g. pyrene, chrysene, benzo(a)pyrene, were also similar in the two species. Analysis of the data from these monitoring studies indicates that the two species can be utilized very effectively to monitor PAH contamination along
240
M. E. Bender, W. J. Hargis, Jr, R. J. Huggett, M. H. Roberts, Jr
the salinity gradient. Residue levels in these species: (1) were shown to differ between river systems, reflecting both point sources and the degree of urbanization of the watershed; (2) reflected different sources for individual PAHs within river systems; and (3) showed concentration gradients with distance in some rivers. Laboratory bioaccumulation studies were conducted to compare the accumulation of PAHs from contaminated Elizabeth River sediments by oysters and hard clams. The objectives of these experiments were to compare the equilibrium bioconcentration factors (BCFe), uptake rates (k0 and clearance r a t e s (k2) at two temperatures (15 and 25°C). The animals were exposed to contaminated sediments for 28days followed by a 28-day depuration phase. Three animals were sampled on days 3, 7, 14, 21 and 28 of each phase and analyzed individually for PAHs. Water samples were collected weekly from each treatment and analyzed for PAHs. The body burden data was analyzed statistically using a pharmacokinetic model as implemented by the BIOFAC computer programs of Blau and Agin. s The uptake and clearance rates, BCFe, and the oyster :clam ratio of BCFe for selected compounds and total PAH as calculated by this model, for the 25°C treatment, are summarized in Table 1. For both species, the equilibrium body burden calculated as the ratio of TABLE 1
Summary of Uptake and Clearance Rates, Bioconcentration Factor, and BCF Ratio for Oysters/Clams at 25°C Compound
Benzo(a)anthracene Benzo(a)fluorene Benzo(b)fluorene Benzo(a)pyrene Benzo(e)pyrene Benzo(gh~fluoranthene Benzofluoranthene Chrysene Fluoranthene Methylphenanthrene Methylpyrene Perylene Phenanthrene Pyrene Total PAH
Crassostrea virginica
Mercenaria mercenaria
kt
k2
BCF~
k1
k2
BCF e
1310 508 1410 639 790 1465 794 1187 821 529 2365 817 330 921 798
0.045 0.066 0-072 0'032 0-023 0-056 0.009 0.046 0.118 0-103 0-066 0-075 0.206 0.104 0.053
28846 8796 19666 19673 33731 26206 84217 26019 6965 5151 36074 10861 1604 8857 15190
2842 994 1190 361 2366 3384 1857 1190 1477 187 2002 1133 224 1587 556
0-172 0.167 0.162 0.087 0-148 0.145 0.180 0.162 0.213 0.115 0.148 0.161 0-114 0.194 0.137
16516 5943 7332 4143 15980 23306 10331 7335 6934 1628 13571 7059 1974 8172 4072
BCFo~,/BCFc~a, .
1.746 1.480 2.682 4"748 2'110 1.124 8.151 3"547 1.004 3-164 2-658 1"538 0"812 1"083 3-730
Effects of PAHs on fish and shellfish
241
uptake rate to clearance rate was slightly higher at the low temperature. Oysters accumulated about 3 times more total P A H than did clams at 15°C and about 3.7 times more total P A H at 25°C. For most individual compounds, the oyster:clam ratio ranged between 1 and 5. The difference in BCF e values between bivalve species and temperatures results primarily from differences in clearance rate, with clams having a significantly higher clearance rate than oysters. Rate of uptake was not affected by temperature nor were there species differences in uptake rates for most identified c o m p o u n d s in the contaminated sediment. The implications of these results are important to a monitoring program. The observed amounts of total P A H in hard shell clams used in field monitoring studies should be multiplied by a factor of three (3) for comparison to those observed amounts in oysters regardless of the time of year (i.e. temperature in the field). One can consider the concentrations found in feral bivalves to be good estimates of the BCF e since the time to reach this concentration is short, generally less than 90 days. Except in the vicinity of a recent spill, one can reasonably assume that if the bivalves have been at a given location for this period, they will have reached equilibrium with the environment. However, the equilibrium level may vary depending on the reproductive status of the animal.
REFERENCES 1. Bieri, R. H., Hein, C., Huggett, R. J., Shou, P., Slone, H., Smith, C. & Su, C-W. Intern. J. Environ. Anal. Chem., 26, 97-113 (1986). 2. Huggett, R. H., Bender, M. E. & Unger, M. A. In Fate and Effects of Sediment Bound Chemicals in Aquatic Systems (K. L. Dickson, A. W. Maki, and W. Bungs (eds). SEATC Special Publication Series, 327-41, Pergamon Press (1987). 3. Malins, D. C., McCain, B. B., Brown, D. W., Chan, S-L., Myers, M. S., Landahl, J. T., Prohaska, P. G., Friedman, A. J., Rhodes, L. D., Burrows, D. G., Gronlund, W. D. & Hodgins, H. O. Environ. Sci. Tech., 18, 705-13 (1984). 4. Black, J. J. J. Great Lakes Res., 9, 326-34 (1983). 5. Blau, G. E. & Agin, G. L. The Dow Chemical Co. Midland, Mi. 13pp. (memo) (1978).
Effects of Polynuclear Aromatic Hydrocarbons on Fishes and Shellfish: An Overview of Research in Virginia*
M. E. Bender, W. J. Hargis, Jr, R. J. H u g g e t t & M. H. Roberts, Jr Virginia Institute of Marine Science, School of Marine Science, College of William and Mary, Gloucester Point, VA 23062, USA
This paper discusses the following topics related to polynuclear aromatic hydrocarbon pollution in estuaries: (1) the use of oysters (Crassostrea virginica), hard clams (Mercenaria mercenaria) and brackish water clams (Rangia cuneata) in residue monitoring; (2) the effects of elevated P A H residues on oyster condition; (3) three years of field studies relating PAH sediment contamination to abnormalities in .fishes; and (4) laboratory bioassays jor effects and bioconcentration modeling. Oysters, hard clams and Rangia have been shown,from 3 years offield studies, to be good monitors of pollution inputs as one proceeds along salinity gradients from 25%o to 0"5%0. Effects o[' increased body burdens of PAHs are shown by a lowering of the oysters' condition index, as measured by lipid levels. Fishes inhabiting the Elizabeth River, VA, which is highly contaminated with PAHs, have abnormalities (cataracts, skin lesions, abnormal.fins, etc.). These abnormalities have higher incidence in regions of the river where the sediments are more heavily contaminated. Laboratory studies utilizing contaminated sediments have reproduced some of the abnormalities observed in the field. Bioconcentration of PA Hs from sediments has been studied with oysters and hard clams. Oysters generally accumulate three times the body burdens o[' clams exposed to the same suspensions. A faster depuration rate (k 2) .['or clams appears to be responsible for the higher equilibrium body burden o[" oysters.
The impetus for the series of studies outlined here arose from several avenues: (1) the general recognition that polynuclear aromatic hydrocarbons (PAHs) may be adversely affecting aquatic life; (2) the discovery of sediments heavily contaminated with PAHs in the Elizabeth River, Virginia; * VIMS Contribution No. 1439. 237 Marine Environ. Res. 0141-1136/88/$03"50© 1988ElsevierApplied Science Publishers Ltd, England. Printed in Great Britain
238
M. E. Bender, W. J. Hargis, Jr, R. J. Huggett, M. H. Roberts, Jr
(3) the later discovery that a number of fishes inhabiting the river had abnormalities which increased in frequency at stations whose sediments had high levels of P A H contamination; and (4) the recognition that a monitoring program was needed to determine P A H residues in organisms as one progresses along the salinity gradient in estuaries. Bieri et al., 1 described the chemical methods which were used to determine PAH residues reported here, and detailed the PAH contamination of surface sediments along the Elizabeth River estuary. They showed that PAH concentrations were highest near an abandoned and an operational wood treatment plant. Huggett et al., 2 provided additional data on sediment contamination with benzo(a)pyrene and discussed the distribution of abnormalities in fishes in relation to sediment contamination levels. Fisheries surveys were conducted during October, November and December of 1983 at 11 stations along the river. Depressions in biomass, total numbers of individuals and abundance of selected species occurred at the more contaminated stations. Even more dramatic was the increasing frequency at which abnormalities occurred. Fin erosion in hogchokers (Trinectes maculatus) and toadfishes (Opsanus tau) was observed in 11 and 30% of the specimens collected in the most contaminated areas. The incidence of cataracts in spot (Leiostomus xanthurus), croaker (Micropogonias undulatus) and weakfish (Cynoscion regalis) was 10, 18 and 21% respectively, in the contaminated zone. Since these initial surveys, additional studies have been conducted in the Elizabeth and an adjacent control area, the Nansemond. The results of these studies confirmed those of the early survey showing that the frequency of the most commonly observed lesions, i.e. fin and skin erosion and cataracts, were highest in the most heavily contaminated regions of the river. The presence of high levels of PAH contamination in sediments at particular sites does not demonstrate that the PAHs in the sediments are available to the biota. To determine the bioavailability of PAHs in the Elizabeth River, oysters from a clean system were transplanted to 5 stations along the river. Oysters were selected over fish because of their limited ability to carry out metabolic transformation of PAHs. Figure 1 shows the accumulation of total resolved PAHs as a function of location (distance upstream from Craney Island) along the river. Residues of 60#g/g were attained at the most contaminated station after a nine-week exposure period. Fishes collected from this area of the river showed the highest incidences of abnormalities. Oyster condition as estimated from lipid levels was depressed as P A H residues increased. The results of these studies and others 3'4 which implicate P A H contamination as a factor affecting fish population raise a number of questions. Of prime importance are: (1) what are the present levels of PAH contamination in aquatic systems; and (2) at what levels do effects occur?
Effects of PAHs on .fish and shellfish
239
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KILOMETERS Upstream from Craney Island F i g . 1.
Levels of total resolvedaromatics and lipids in oysters after nine weeksof exposure in the Elizabeth River.
To determine the extent of PAH contamination in lower Chesapeake Bay bivalve molluscs were selected as the sampling medium. In estuaries, however, the use of a single species as a monitoring tool is precluded by salinity or habitat limitations on species distribution. In Chesapeake Bay both Crassostrea virginica and Mercenaria rnercenaria occur throughout the polyhaline and mesohaline regions, but at any given location only one or the other species may be present. Rangia cuneata occurs in the upper-mesohaline and oligohaline salinity regimes. All three species are essential to any monitoring program within the estuarine system of Chesapeake Bay. Two studies, a field and a laboratory investigation, were initiated to evaluate the feasibility of utilizing these species as monitoring tools in estuaries. In the field studies, gonadally mature oysters and Rangia were collected along the salinity gradient in several Virginia tributaries of Chesapeake Bay in 1984, 1985 and 1986. During 1985 and 1986 oysters and Rangia were collected from adjacent stations in the James River to allow comparisons of residue levels. Levels of total resolved PAHs in oysters and Rangia from adjacent stations were very similar, 1.10 and 1-34 p p m (dry wt) spring of 1985, .1.3 and 1.8 ppm, fall of 1985 and 1.4 and 1.1 ppm, fall of 1986. Residues of individual compounds, e.g. pyrene, chrysene, benzo(a)pyrene, were also similar in the two species. Analysis of the data from these monitoring studies indicates that the two species can be utilized very effectively to monitor PAH contamination along
240
M. E. Bender, W. J. Hargis, Jr, R. J. Huggett, M. H. Roberts, Jr
the salinity gradient. Residue levels in these species: (1) were shown to differ between river systems, reflecting both point sources and the degree of urbanization of the watershed; (2) reflected different sources for individual PAHs within river systems; and (3) showed concentration gradients with distance in some rivers. Laboratory bioaccumulation studies were conducted to compare the accumulation of PAHs from contaminated Elizabeth River sediments by oysters and hard clams. The objectives of these experiments were to compare the equilibrium bioconcentration factors (BCFe), uptake rates (k0 and clearance r a t e s (k2) at two temperatures (15 and 25°C). The animals were exposed to contaminated sediments for 28days followed by a 28-day depuration phase. Three animals were sampled on days 3, 7, 14, 21 and 28 of each phase and analyzed individually for PAHs. Water samples were collected weekly from each treatment and analyzed for PAHs. The body burden data was analyzed statistically using a pharmacokinetic model as implemented by the BIOFAC computer programs of Blau and Agin. s The uptake and clearance rates, BCFe, and the oyster :clam ratio of BCFe for selected compounds and total PAH as calculated by this model, for the 25°C treatment, are summarized in Table 1. For both species, the equilibrium body burden calculated as the ratio of TABLE 1
Summary of Uptake and Clearance Rates, Bioconcentration Factor, and BCF Ratio for Oysters/Clams at 25°C Compound
Benzo(a)anthracene Benzo(a)fluorene Benzo(b)fluorene Benzo(a)pyrene Benzo(e)pyrene Benzo(gh~fluoranthene Benzofluoranthene Chrysene Fluoranthene Methylphenanthrene Methylpyrene Perylene Phenanthrene Pyrene Total PAH
Crassostrea virginica
Mercenaria mercenaria
kt
k2
BCF~
k1
k2
BCF e
1310 508 1410 639 790 1465 794 1187 821 529 2365 817 330 921 798
0.045 0.066 0-072 0'032 0-023 0-056 0.009 0.046 0.118 0-103 0-066 0-075 0.206 0.104 0.053
28846 8796 19666 19673 33731 26206 84217 26019 6965 5151 36074 10861 1604 8857 15190
2842 994 1190 361 2366 3384 1857 1190 1477 187 2002 1133 224 1587 556
0-172 0.167 0.162 0.087 0-148 0.145 0.180 0.162 0.213 0.115 0.148 0.161 0-114 0.194 0.137
16516 5943 7332 4143 15980 23306 10331 7335 6934 1628 13571 7059 1974 8172 4072
BCFo~,/BCFc~a, .
1.746 1.480 2.682 4"748 2'110 1.124 8.151 3"547 1.004 3-164 2-658 1"538 0"812 1"083 3-730
Effects of PAHs on fish and shellfish
241
uptake rate to clearance rate was slightly higher at the low temperature. Oysters accumulated about 3 times more total P A H than did clams at 15°C and about 3.7 times more total P A H at 25°C. For most individual compounds, the oyster:clam ratio ranged between 1 and 5. The difference in BCF e values between bivalve species and temperatures results primarily from differences in clearance rate, with clams having a significantly higher clearance rate than oysters. Rate of uptake was not affected by temperature nor were there species differences in uptake rates for most identified c o m p o u n d s in the contaminated sediment. The implications of these results are important to a monitoring program. The observed amounts of total P A H in hard shell clams used in field monitoring studies should be multiplied by a factor of three (3) for comparison to those observed amounts in oysters regardless of the time of year (i.e. temperature in the field). One can consider the concentrations found in feral bivalves to be good estimates of the BCF e since the time to reach this concentration is short, generally less than 90 days. Except in the vicinity of a recent spill, one can reasonably assume that if the bivalves have been at a given location for this period, they will have reached equilibrium with the environment. However, the equilibrium level may vary depending on the reproductive status of the animal.
REFERENCES 1. Bieri, R. H., Hein, C., Huggett, R. J., Shou, P., Slone, H., Smith, C. & Su, C-W. Intern. J. Environ. Anal. Chem., 26, 97-113 (1986). 2. Huggett, R. H., Bender, M. E. & Unger, M. A. In Fate and Effects of Sediment Bound Chemicals in Aquatic Systems (K. L. Dickson, A. W. Maki, and W. Bungs (eds). SEATC Special Publication Series, 327-41, Pergamon Press (1987). 3. Malins, D. C., McCain, B. B., Brown, D. W., Chan, S-L., Myers, M. S., Landahl, J. T., Prohaska, P. G., Friedman, A. J., Rhodes, L. D., Burrows, D. G., Gronlund, W. D. & Hodgins, H. O. Environ. Sci. Tech., 18, 705-13 (1984). 4. Black, J. J. J. Great Lakes Res., 9, 326-34 (1983). 5. Blau, G. E. & Agin, G. L. The Dow Chemical Co. Midland, Mi. 13pp. (memo) (1978).