[show abstract][hide abstract] ABSTRACT: Cytochemical responses in the digestive tissue of Mytilus edulis complex fed a microencapsulated mixture of PAHs (composed of phenanthrene, fluoranthene and benzo[a]pyrene) or PCBs (Aroclor 1254) were evaluated. Lysosomal membrane labilization period and lipofuscin content of digestive tissue were significantly decreased and increased, respectively, after 30 days of exposure to PAHs but not PCBs. NADPH-ferrihemoprotein reductase activity in the digestive tissue was significantly increased after 30 days exposure to both PAHs and PCBs, whereas catalase activity was significantly increased only after exposure to PCBs. Neutral lipid content and gamma-glutamyl transpeptidase activity of digestive tissue of mussels were significantly increased and decreased, respectively, after 30 days exposure to both PAHs and PCBs when compared to untreated mussels, but were not significantly different when compared to mussels treated with com oil representing the vehicle control. Exposure to PAHs induced peroxisome proliferation in the digestive tissue of M. edulis complex. The observed cytochemical responses in the digestive tissue of M. edulis complex exposed to PAHs and PCBs in the laboratory are comparable to the cytochemical responses observed in the digestive tissue of mussels collected in the field from sites contaminated with predominantly PAHs and PCBs.
Comparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology 05/2013;
[show abstract][hide abstract] ABSTRACT: In a study evaluating the effects of exposure to xenobiotic compounds on ovarian development in English sole (Parophrys vetulus), prespawning females were sampled from four sites in Puget Sound, Washington, during the 1986 and 1987 spawning seasons. Two sampling sites had high concentrations of xenobiotic compounds in the sediment, while the other sites were less contaminated. The following factors associated with ovarian maturation were measured: ovarian developmental stage, ovarian atresia, gonadosomatic index, plasma estradiol, and plasma vitellogenin as estimated from alkali-labile phosphorus. Contaminant exposure was assessed by measuring concentrations of fluorescent aromatic compounds in the bile, hepatic aryl hydrocarbon hydroxylase (AHH) activity, and hepatic polychlorinated biphenyl levels, and liver tissue was examined histologically for the presence of suspected toxicopathic lesions. Female English sole from the heavily contaminated sites were significantly less likely to undergo gonadal recrudescence and had lower mean levels of plasma estradiol than females from the less contaminated sites. The risk of inhibited gonadal recrudescence was significantly increased in sole with elevated hepatic AHH activity, and AHH activity was also significantly negatively correlated with plasma estradiol level. These findings suggest that contaminant exposure may interfere with ovarian development in female English sole.
Canadian Journal of Fisheries and Aquatic Sciences 04/2011; 45(12):2133-2146. · 2.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: Investigation of the interactive effects of representatives of three classes of compounds was performed, using English sole (Parophrys vetulus) as the test organism, juvenile fish were exposed orally to cadmium chloride and Aroclor 1254 (PCB), either independently or simultaneously, for a 4-wk period, followed by exposure to seawater-accommodated No. 2 diesel fuel for 2 wk. Blood was collected for analysis of serum constituents, and tissue samples were examined for histological changes. Hepatocellular necrosis, regeneration, and karyomegaly were observed. Differential lesion prevalences were observed among the exposure groups, with high proportions among cadmium-exposed fish, low proportions among PCB-exposed fish, and intermediate proportions in combination cadmium- plus PCB-exposed fish. Levels of aspartate aminotransferase activity and magnesium in the sera of these groups exhibited similar patterns. Depressed serum calcium levels in both PCB-exposed and cadmium- plus PCB-exposed groups were found after the first week, and lower serum albumin concentrations occurred in all cadmium- and PCB-exposed groups following the third week. Subsequent exposure to No. 2 diesel fuel produced few effects in any of the exposure groups. The observed antagonistic effect of Aroclor 1254 against cadmium toxicity emphasizes the importance of employing multiple as well as single contaminant exposure in toxicity studies.
Canadian Journal of Fisheries and Aquatic Sciences 04/2011; 42(12):1870-1880. · 2.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: Are smolt-to-adult return rates (SARs) for wild steelhead (i.e., sea-run rainbow trout, Oncorhynchus mykiss) and wild Snake River spring-summer Chinook salmon (Oncorhynchus tshawytscha) related to changes in the Columbia River plume at the time that juvenile migrants enter the ocean? We used three-dimensional (3D) numerical models of the baroclinic circulation in the Columbia River estuary-plume-shelf system to simulate within-season variation in plume size and location, comparing the results with SARs for each day that juvenile salmon entered the ocean for 1999-2003. We found that steelhead benefited from the plume environment at a narrow window of time around their ocean entry. However, when large-scale ocean conditions turned unfavorable, the contribution of local plume conditions to the overall variability in steelhead survival became not significant. A similar evaluation revealed that the plume did not affect survival of Chinook salmon, at least at the fine scale of variability considered. The differential response between the two species is consistent with observed and previously reported behavioral characteristics they exhibit. We speculate that steelhead mainly use the plume to move quickly away from coastal habitats and the predation pressures associated with this environment, for a more direct migration than Chinook salmon to ocean habitats in the Gulf of Alaska.Les taux de survie du saumoneau à l'adulte (SARs) des truites arc-en-ciel anadromes (Oncorhynchus mykiss) sauvages et des saumons chinook (Oncorhynchus tshawytscha) de printemps-été de la Snake sont-ils reliés aux changements dans le panache du Columbia au moment où les jeunes saumons pénètrent dans l'océan? Nous avons utilisé des modèles numériques tridimensionnels (3D) de la circulation baroclinique dans le système estuaire-panache-plate-forme du Columbia pour simuler la variation au cours de la saison de la taille et de la position du panache, en associant les résultats aux SAR pour chaque jour où les jeunes saumons ont pénétré dans la mer en 1999-2003. Les truites arc-en-ciel anadromes ont tiré bénéfice de l'environnement du panache pendant une courte période au moment de leur arrivée dans l'océan. Cependant, lorsque les conditions océaniques à grande échelle sont devenues défavorables, la contribution des conditions du panache local à la variabilité globale de la survie des truites arc-en-ciel anadromes est devenue non significative. Une évaluation similaire a montré que le panache n'affecte pas la survie des saumons chinook, au moins à l'échelle fine de la variabilité considérée. Les réponses différentes des deux espèces sont en accord avec les caractéristiques comportementales observées présentement et signalées antérieurement chez elles. Nous croyons que les truites arc-en-ciel anadromes utilisent le panache pour s'éloigner rapidement des habitats côtiers et des pressions de prédation qui leur sont associées, afin de migrer plus directement que les saumons chinook vers les habitats océaniques dans le golfe de l'Alaska.
Canadian Journal of Fisheries and Aquatic Sciences 09/2010; 67(10):1671-1684. · 2.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: Caspian terns Sterna caspia breeding in the Columbia River estuary exploit Pacific salmon Oncorhynchus spp. as prey, consuming millions of outmigrating juvenile salmonids annually. We analyzed recoveries of salmonid passive integrated transponder (PIT) tags from the East Sand Island tern colony to calculate predation rates (% of available fish taken) on 4 Columbia and Snake River steelhead O. mykiss Evolutionarily Significant Units (ESUs). A life cycle modeling approach was used to estimate potential increases in ESU population growth rate (λ) given potential reductions in Caspian tern numbers on East Sand Island. Reducing tern predation on steelhead ESUs by 50 – 100% increased λ from 0.8 to 2.5%, depending on the ESU and the reproductive contribution of hatchery fish, and assuming no compensatory mortality. This is comparable to survival improvements modeled for hydropower improvements in the basin but less than those modeled for harvest reductions. Reducing avian predation as part of an effort to reduce all sources of mortality may assist in ESU recovery. A thorough understanding of such predator–prey relationships is needed to manage conflicts between predators and their threatened and endangered Pacific salmonid prey.
Endangered Species Research 01/2007; 3:11-21. · 2.26 Impact Factor
[show abstract][hide abstract] ABSTRACT: Although the adverse impact of pathogens on salmon populations in the Pacific Northwest is often discussed and recognized, little is currently known regarding the incidence and corresponding significance of delayed disease-induced mortalities. In the study reported herein, we surveyed the presence and prevalence of selected micro- and macroparasites in out-migrant juvenile coho salmon Oncorhynchus kisutch and Chinook salmon O. tshawytscha from 12 coastal estuaries in the Pacific Northwest over a 6-year period (1996–2001). The major finding of this study was the widespread occurrence of pathogens in wild salmon from Pacific Northwest estuaries. The six most prevalent pathogens infecting both juvenile Chinook and coho salmon were Renibacterium salmoninarum, Nanophyetus salmincola, an erythrocytic cytoplasmic virus (erythrocytic inclusion body syndrome or erythrocytic necrosis virus), and three gram-negative bacteria (Listonella anguillarum, Yersinia ruckeri, and Aeromonas salmonicida). The most prevalent pathogen in both Chinook and coho salmon was N. salmincola, followed by the pathogens R. salmoninarum and the erythrocytic cytoplasmic virus. Statistically significant differences in the prevalence of R. salmoninarum and N. salmincola were observed between Chinook and coho salmon. Based on the prevalence of pathogens observed in this study, disease appears to be a potentially significant factor governing the population numbers of salmon in the Pacific Northwest. Development of a detailed understanding of the principal components influencing the ecology of infectious disease will aid in the development of management and control strategies to mitigate disease in and hence further the recovery of salmon stocks listed under the Endangered Species Act.
Journal of Aquatic Animal Health 12/2004; 16(4):186-196. · 1.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: Previous studies have shown that juvenile chinook salmon Oncorhynchus tshawytscha exposed in the field or the laboratory to polychlorinated biphenyls (PCBs), an anthropogenic stressor, are immunosuppressed. It is not known whether simultaneous exposure to natural stressors can increase this immunosuppression. To examine the effects of natural and anthropogenic stressors on immune function, we infected juvenile chinook salmon with metacercariae of the trematode Nanophyetus salmincola by exposing the fish to infected freshwater snails Juga plicifera. Infected (>300 metacercariae per fish) and noninfected salmon were then injected with either the commercial PCB mixture Aroclor 1254 or an acetone–emulphor carrier. B cell function was examined by in vitro hemolytic plaque-forming cell (PFC) assay. Nanophyetus salmincola infection resulted in significantly lower anterior kidney primary PFCs and lower splenic secondary PFCs. The combination of N. salmincola infection and Aroclor 1254 exposure caused a lower anterior kidney primary PFC response than did either stressor alone. The immune function of juvenile chinook salmon was also measured by challenging them with the marine bacterium Listonella anguillarum (formerly known as Vibrio anguillarum). Fish infected with N. salmincola had higher mortalities than noninfected fish when challenged with L. anguillarum. These experiments demonstrated that N. salmincola infection in juvenile chinook salmon can impair immune function and disease resistance. The findings also show that in combination these natural and anthropogenic stressors can have a greater negative effect on salmon health than either stressor alone.
Journal of Aquatic Animal Health 03/2003; 15(1):1-12. · 1.55 Impact Factor
[show abstract][hide abstract] ABSTRACT: A selected suite of cytochemical parameters in Mytilus edulis are altered in response to field and laboratory exposure to chemical contaminants. These biomarkers include lysosomal stability, nicotinamide adenine dinucleotide phosphate (NADPH)-ferrihemoprotein reductase activity, liposfuscin deposition, and accumulation of lysosomal and cytoplasmic unsaturated neutral lipid. Normal variations in physiological processes (influenced by exogenous seasonal changes in temperature, salinity, food availability, etc.) may alter the sensitivity of these biomarkers to contaminant exposure. To address this issue, M. edulis (complex) were sampled monthly from a reference nonurban site (Coupeville, Penn Cove) and a polluted urban site (Seacrest, Elliott Bay) in Puget Sound, WA, for a period of 15 months. Physiological measurements including total length, total weight, somatic and mantle weights (an indication of gonadal development and reproductive status), condition index, and the presence or absence of hemic neoplasia (HN, or leukemia) were recorded. Significant differences in lysosomal stability, lysosomal and cytoplasmic unsaturated neutral lipids, lipofuscin deposition, and NADPH-ferrihemoprotein reductase activity in cells of the digestive gland or digestive tubules were generally found in mussels taken throughout the year from Seacrest compared to mussels sampled from Coupeville, consistent with exposure to chemical contaminants. No seasonally influenced suppression of the entire suite of parameters as measures of contaminant exposure was evident. Therefore these biomarkers can be used to evaluate contaminant exposure in mussels throughout the entire year.
Archives of Environmental Contamination and Toxicology 02/2003; 44(1):43-52. · 2.01 Impact Factor
[show abstract][hide abstract] ABSTRACT: Juvenile chinook salmon (Oncorhynchus tshawytscha) and chum salmon (Oncorhynchus keta) accumulate polycyclic aromatic hydrocarbons, polychlorinated biphenyls and other chemical contaminants in tissues, fluids and stomach contents while utilizing contaminated estuaries of Puget Sound during their out-migration from fresh water to open ocean. Field studies show that they have impaired health (reduced immunocompetence, increased mortality after disease challenge, reduced growth) resulting from migration through these areas. A series of laboratory investigations has shown that all of these effects can be elicited by exposure to either specific compounds or classes of compounds present in the contaminated waterways, or to complex mixtures of chemicals extracted from the sediments of the waterways. These results provide corroboration for a cause-and-effect relationship between impaired health of Pacific salmon and their exposure to chemical contaminants from urban estuaries. Specific information on the nature of the dose–response relationship is lacking, but studies are planned to address that question. With the impending listing of Pacific salmon stocks in Puget Sound under the Endangered Species Act, these studies take on added significance.
Marine Environmental Research - MAR ENVIRON RES. 01/2000; 50(1):468-468.
[show abstract][hide abstract] ABSTRACT: Neurotoxic pesticides are known to contaminate surface waters that provide habitat for salmonids, including some listed for protection under the U.S. Endangered Species Act. Despite their widespread use, the impacts of these pesticides on the neurological health of wild salmon are not well understood. Of particular concern are the organophosphate and carbamate insecticides that block synaptic transmission by inhibiting neuronal acetylcholinesterase. Here we assess the effects of diazinon, an organophosphate insecticide, on alarm pheromone in - duced antipredator responses and homing behavior in chinook salmon (Oncorhynchus tshawytscha ). Nominal exposure concentrations (0.1, 1.0, and 10.0 mg·L-1) were chosen to emulate diazinon pulses in the natural environment. In the antipredator study, diazinon had no effect on swimming behavior or visually guided food capture. However, the pesti- cide significantly inhibited olfactory-mediated alarm responses at concentrations as low as 1.0 mg·L-1. Similarly, homing behavior was impaired at 10.0 mg·L-1. Our results suggest that olfactory-mediated behaviors are sensitive to
Canadian Journal of Fisheries and Aquatic Sciences 01/2000; 57:1911-1918. · 2.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: Two common problems in applying and interpreting invertebrate bioassays and fish biomarkers in sediment toxicology are the wide gap between significant effects concentrations determined by these two approaches, and a general lack of ecological context. We have devised an exposure system that is able to reconcile much of the disparity between invertebrate bioassay and fish biomarker results by incorporating realistic ecological processes based on deposit feeding and predator-prey interactions. This system relates the disturbance of interest (sediment contamination) to biologically meaningful effects in a resource of interest (marine flatfish) via a realistic contaminant vector (a deposit-feeding polychaete worm). In this pilot study, polychaetes (Armandia brevis) were exposed for 28 days to clean sediments supplemented with benzo(a)pyrene (BaP), para-para dichlorodiphenyldichloroethylene (pp'DDE), Aroclor 1254, or field sediments collected from two sites in Puget Sound, Washington, contaminated predominantly with polcyclic aromatic hydrocarbons (PAHs) or chlorinated compounds. Exposed worms were then fed live to juvenile English sole (Pleuronectes vetulus) for 10 or 12 days. At the end of the exposure period, fish were measured for length and weight, sacrificed, and preserved for either routine histopathology and immunohistochemical analysis of cytochrome P450 1A induction, or 32P post-labeling determination of hepatic PAH-DNA adducts. Growth of predatory flatfish was lower than reference in all but one of eight groups fed contaminant-exposed polychaetes; however, statistically significant reductions in growth were only observed in three of these eight groups, at least in part due to low statistical power. Juvenile sole from all contaminant-exposed groups showed increased expression of CYP1A, and fish exposed to BaP-exposed worms showed clear evidence of hepatic PAH-DNA adducts. This method allows the concurrent evaluation of sediment contamination at multiple biological and ecological levels. These results indicate that sediments determined to be nontoxic by common invertebrate bioassays may have the potential to cause adverse effects at higher trophic levels.
Marine Environmental Research 01/2000; 50(1-5):527-33. · 2.34 Impact Factor
[show abstract][hide abstract] ABSTRACT: Saltwater-adapted juvenile chinook salmon (Oncorhynchus tshawytscha) exposed in the laboratory to various aromatic and chlorinated hydrocarbons representative of those found in urban estuaries in Puget Sound have a higher susceptibility to infectious disease relative to carrier-exposed juveniles. Disease susceptibility was assessed by examining the temporal percent cumulative mortality in juvenile chinook salmon after exposure to the marine pathogen, Vibrio anguillarum. Aromatic and chlorinated compounds tested included a sediment extract from the Hylebos Waterway predominantly composed of butadiene-like compounds (CHWSE), a model mixture of polycyclic aromatic hydrocarbons (PAHs), hexachlorobutadiene (HCBD), a PCB mixture (Aroclor 1254), and a single PAH, dimethylbenz[a]anthracene (DMBA). The effect of these compounds on disease susceptibility was tested in two separate trials. In Trial I, the percent cumulative mortality in salmon exposed to bacteria after exposure to either CHWSE, HCBD, or the model mixture of PAHs ranged from 28 to 31%, as compared to 16% in the acetone:emulphor control group at 7 days after challenge. In Trial II, the cumulative mortality in salmon ranged from 46 to 49% after exposure to either DMBA or the PCB mixture compared to 25% in the acetone:emulphor control group at 9 days after challenge. These results suggest that juvenile chinook salmon migrating to the ocean through a contaminated estuary experience immunodysfunction, characterized by lowered resistance to disease, which potentially could affect survival of populations that are particularly threatened.
Marine Environmental Research - MAR ENVIRON RES. 01/2000; 50(1):470-471.
[show abstract][hide abstract] ABSTRACT: The relationship between hemic neoplasia, a blood cell disorder in bivalve molluscs, and chemical contaminants was evaluated in the common mussel (Mytilus edulis complex). Hemic neoplasia (HN) is endemic to mussel populations in Puget Sound. The prevalence of hemic neoplasia ranged from 0 to 30% in mussels from nine sites in Puget Sound, Washington. Organic chemical contamination in sediment from these sites range from 0.1 to 64.0 ppm of polycyclic aromatic hydrocarbons (PAHs) and 0.07 to 0.50 ppm chlorinated hydrocarbons. No relationship between the body burden of environmental contaminants and the prevalence of HN in mussels was identified. To evaluate the short-term ability of chemical contaminants to induce HN in mussels, mussels, from a site where mussels were previously determined to be HN free, were fed microencapsulated PAHs (composed of a mixture of phenanthrene, flouranthene, and benzo[a]pyrene) or PCBs (Aroclor 1254) and the prevalence of HN was assessed after 30 days of exposure. Although an apparent increase in HN prevalence (20 to 30%) was observed in all treatments groups except the untreated controls, no significant difference in the prevalence of HN was observed between the control group of mussels fed corn oil (vehicle) and mussels fed either PAHs or PCBs in corn oil. A long-term (180-day) exposure study was conducted to evaluate the influence of PAHs or PCBs in modulating the prevalence of HN in a mussel population already exhibiting a moderate HN prevalence. Mussels, from a site where mussels were previously determined to exhibit a background prevalence of HN, fed microencapsulated PAHs, PCBs, and corn oil (vehicle) over a long time period (180 days), revealed an apparent increased prevalence of HN (30 to 40%) above the low levels (20%) initially present. However, no significant difference in the prevalence of HN was observed between the control group of mussels fed corn oil (vehicle) and mussels fed either PAHs or PCBs in corn oil. Although chemical contaminants have been proposed as a modulating factor in the development and promotion of HN in bivalve molluscs from environmentally stressed and degraded habitats, we find no evidence that chemical contaminants induce or promote the development of HN in the mussel M. edulis complex.
Journal of Invertebrate Pathology 04/1999; 73(2):135-46. · 2.67 Impact Factor
[show abstract][hide abstract] ABSTRACT: As in mammals, macrophages play a vital role in the destruction of infective organisms in fish. The current study was done to determine if exposure to polycyclic aromatic compounds (PACs), a group of chemical contaminants commonly found in the sediments of urban marine areas, alters the ability of peritoneal macrophages (MØs) from English sole (Pleuronectes vetulus) to produce cytotoxic reactive oxygen intermediates (ROIs). Initially, assay conditions including concentration of MØs, type of in vitro stimulant, tissue culture media, and incubation time were optimized to measure production of superoxide anion (O2−), the progenitor ROI, in English sole MØs. English sole were then injected with an organic solvent extract of a PAC-contaminated sediment equivalent to 20 g sediment (about 860 μg selected PACs) per kg fish, via their dorsal lymphatic sinus. Peritoneal MØs were harvested on days 1, 3, 7, and 14 post-injection. Elicited peritoneal MØs from English sole injected with the sediment extract produced significantly more O2− after stimulation in vitro with either opsonized zymosan on days 3 and 7 after exposure, or phorbol myristate acetate on day 7 when compared to the vehicle-injected or uninjected fish. Macrophages of fish injected with the vehicle responded comparably to those from uninjected individuals. No differences in the basal amounts of O2− production from activated peritoneal MØs were observed among the treatment groups. This study demonstrates that exposure of English sole to PACs altered macrophage production of O2−. Although the direct effects of the enhanced production of this ROI are unknown, the higher levels of superoxide anion production within peritoneal macrophages may contribute to immunodysfunction and oxidative damage in P. vetulus.
[show abstract][hide abstract] ABSTRACT: Bioaccumulation of chlorinated hydrocarbons (CHs) from field-contaminated sediments by two infaunal invertebrates, Rhepoxynius abronius (a non-deposit feeding amphipod) and Armandia brevis (a nonselective, deposit-feeding polychaete), was examined and species responses were compared. Sediments were selected over a large geographical area of the Hudson-Raritan estuary to assess the potential for bioaccumulation from a typical urban estuary. Unlike polycyclic aromatic hydrocarbons (PAHs) from these sediments, concentrations of CHs in interstitial water (IW) indicated that partition coefficients (Koc) were generally as expected, especially when based on predicted, nonsorbed, interstitial water CH concentrations (IWfree). Correlations between amphipod and polychaete tissue residues revealed that these species were responding similarly to a gradient of CH concentrations in sediment. While tissue residues and BAFloc (lipid/organic carbon normalized bioaccumulation factor) values for the trichlorobiphenyls were similar for both species, accumulation in the polychaete was three to 10 times higher for the more hydrophobic PCBs, which was attributed to differences in the route of exposure. A negative correlation between the bioaccumulation factor (BAF) and total organic carbon (TOC) was found for both species, which was expected according to equilibrium partitioning theory. Because it was assumed that the amphipod was not feeding in these tests and the polychaete was ingesting sediment, comparison of their tissue residues and bioaccumulation factors was useful for highlighting the importance of sediment ingestion, especially for short-term, nonequilibrium exposures. These results may also help elucidate the limitations associated with assessing bioaccumulation and the resultant toxic response in standard 10-day toxicity tests with similar invertebrates.
Archives of Environmental Contamination and Toxicology 12/1997; 33(4):388-400. · 2.01 Impact Factor
[show abstract][hide abstract] ABSTRACT: Sediments in the Hudson-Raritan estuary are known to contain high concentrations of anthropogenic contaminants, and marine organisms from this region exhibit numerous contaminant-related effects. To assess the pattern of sediment toxicity in depositional areas of this region, and to compare lethal and sublethal end points for different bioassay organisms, three benthic marine invertebrate species were exposed to sediments from 17 sites in the Hudson-Raritan estuary. Growth and mortality of the polychaete Armandia brevis and the sand dollar Dendraster excentricus were measured in all 17 sediments, while mortality and reburial ability of the amphipod Rhepoxinius abronius were assessed in nine sediments. Growth of polychaetes was determined by measuring the difference in weight after a 20-d exposure, whereas growth of sand dollars was assessed by measuring the difference in length and weight after a 28-d exposure. Amphipod mortality and reburial tests were conducted using the standard 10-d sediment bioassay. Significant growth reduction of polychaetes and sand dollars occurred in 11 of 17, and 3 of 17 sediments, respectively. Polychaete weight and sand dollar length correlated inversely and significantly with total sediment concentration of polycyclic aromatic hydrocarbons, polychlorinated biphenyls, and some selected elements. In contrast, significant mortality of polychaetes and amphipods occurred in 1 of 17 and 2 of 9 sediments, respectively, and impaired reburial ability of amphipods was not observed. Results of this study demonstrate that sediment contamination at depositional sites with the Hudson-Raritan estuary has potential to cause deleterious biological effects in indigenous benthic organisms. In addition, sublethal growth bioassays using polychaetes and sand dollars appear to be more sensitive in measuring the effects of sediment contamination than does the mortality-based bioassay using the amphipod Rhepoxinius abronius.
[show abstract][hide abstract] ABSTRACT: The leukoproliferative (LP) response of splenic leukocytes from the marine benthic fish English sole (Pleuronectes vetulus) stimulated with the mitogens lipopolysaccharide (LPS), concanavalin A (Con A), and pokeweed mitogen (PWM) was examined as a biomarker of immunotoxic effects. English sole were exposed to contaminants, either by injection of an organic-solvent extract of a sediment containing polycyclic aromatic compounds (PACs) or placed for up to 5 weeks on a reference sediment containing 0.15 to 1.5% (v/v) of the PAC-contaminated sediment. English sole either injected with the contaminated extract or held on PAC-contaminated sediment had an augmented response to Con A. The LP response to LPS showed no relationship to PAC exposure in laboratory-exposed fish, while PWM showed no consistent relationship to exposure to PACs. In a field study, English sole captured from an urban area in Puget Sound, Washington, USA, contaminated with PACs and other chemical contaminants had a significantly augmented LP response to Con A and PWM in comparison to the LP response in fish from a nonurban reference site. Fish from another nonurban site also had an augmented LP response to Con A, indicating that the elevation of the Con A LP response can also result from factors other than chemical contaminant exposure. In addition, English sole from this site also had an augmented LP response to LPS, whereas fish from urban sites did not exhibit an augmented LP response to LPS. Overall, the results demonstrated that although the LP response in splenic leukocytes of English sole to Con A was linked to contaminant exposure, the LP response to Con A did not exhibit high specificity as an indicator of chemical contaminant exposure. However, the concerted use of Con A, LPS, and PWM allowed for identification of apparent chemical contaminant-induced alterations of the LP response in English sole from an urban area of Puget Sound.