Joseph M. O'Connor

PCB dynamics in Hudson River striped bass. II. Accumulation from dietary sources

Abstract Young-of-year striped bass were administered known doses of 14C-labeled Aroclor 1254 in natural food (Gammarus tigrinus) by gavage. PCB accumulation from the gut and elimination from the whole-body were determined empirically for single-dose and multiple-dose studies. The data have been applied to models describing absorption site kinetics and fluctuations in whole-body burden at ‘steady state’. Those variables critical to the calculation and understanding of bioaccumulation factors, namely growth, metabolic rate, and dose, are discussed in the context of the kinetic model results.

Aquatic pollution problems, North Atlantic coast, including Chesapeake Bay☆

Abstract Pollutant effects on fishes and fisheries of the North Atlantic may be estimated from biological and biochemical responses to pollutant exposure and the incidence of pollution-related disease in aquatic organisms. Indirect and potential effects on ecosystems may be estimated from the accumulation of contaminants in biota. Based upon increases in pollutant-related disease and bioaccumulation of contaminants, marine biota in the North Atlantic region show evidence of deleterious, pollution-related effects. However, the plethora of contaminants discharged to the marine environment makes it impossible to determine which agents, or combinations of agents, have the greatest effect. Marine and estuarine sediments show a history of contaminant input. More than 300 aromatic hydrocarbons have been detected in the Chesapeake Bay, and polychlorinated biphenyls (PCBs) occur in sediments in parts of New Bedford Harbor at levels measured in percent. Major sites of marine contamination are Boston, New Bedford, Providence, New York, Baltimore Harbor, and the Elizabeth River, Virginia. Biota in these and other areas show increased burdens of many contaminants, including PCBs, pesticides, phthalates, metals and aromatic hydrocarbons. In general, the gradient of contaminant levels decreases offshore. Contaminant burdens result from discharges to rivers and ocean, marine dumping and atmospheric fallout. Health advisories have been posted in some regions regarding the consumption of striped bass, bluefish and lobster, and the effects of chlordecone (kepone) spills on fisheries in the James River are felt after more than 10 years. What the long-term biological effects of these contaminants will be is not fully known. Biological effects of pollutants include alterations in biochemical, respiratory, and immune functions, as well as changes in population structure and developmental or structural abnormalities. Fishes and invertebrates exposed to organic contaminants may be induced to produce higher levels of enzymes capable of transforming many contaminants to more polar, but occasionally more toxic, metabolites. The induction of biotransformation enzymes has been suggested as a link in the etiology of disease among marine and estuarine fishes in highly contaminated areas. Surveys show high incidences of diseases in fishes from New England, Long Island Sound, the Hudson River estuary/New York Bight and the Elizabeth River, Virginia. The most common diseases generally affect the liver, although cataracts and pollution-related disorders of the skin and gills occur. Neoplasia, including benign and malignant growths, has been documented for flatfish as well as for tomcod in the Hudson River estuary. Epidemiological studies and statistical analyses support the concept of an environmental etiology for disease in fishes from contaminated areas.

A mathematical model of PCB bioaccumulation in plankton

Abstract In batch experiments exposing individual plankton constituents to Aroclor 1254 PCB, the rate at which the organism approaches partitioning equilibrium appears to be partly size-dependent while the extent of PCB accumulation is species-specific. The sorptive desorptive kinetics of PCB in these experiments can be described mathematically by a first-order expression. Employing this expression in a model plankton food web permits examination of the role of feeding and sorptive processes in determining PCB body burden under various environmental conditions. When ingestion rates exceed desorption and excretion rates, a consuming organism accumulates PCB above levels predicted by equilibrium partitioning relationships. Feeding-induced oscillations in PCB body burden could thus obscure the reduction of soluble PCB concentration which determine a “baseline” PCB body burden. Unless referenced to a specific set of biological and environmental conditions, the importance of direct partitioning from water vs. food uptake appears to be a moot topic.

Fate of 7,12-dimethylbenz(a)anthracene in rainbow trout,Salmo gairdneri

Polycyclic aromatic hydrocarbons (PAH) are contaminants of surface waters and sediments, especially near urban centers. Although aquatic biota accumulate PAHs from environmental sources, metabolism may be rapid, and biota sampled from contaminated areas often have concentrations lower than might be estimated from bioconcentration factors. In some cases PAH metabolism by aquatic biota may create reactive intermediates, some of which have been related to chronic effects in fishes. This report describes the fate and distribution of 7,12-dimethylbenz(a)anthracene (DMBA) after oral administration to rainbows trout (Salmo gairdneri). Emphasis has been placed on the disposition of DMBA among tissues and on DMBA transformation in the hepatobiliary system.

Response of the estuarine amphipod Gammarus daiberi to chlorinated power plant effluent

Abstract The amphipod Gammarus daiberi was subjected to plume drifts and laboratory exposures to chlorinated power plant cooling water effluent. Behavioral reactions to unchlorinated and chlorinated effluent were examined in an avoidance trough. During plant chlorination, the amphipods survived 1-h exposures to full-strength cooling water effluent (ΔT = 7.3–9.3 °C, 0.05 m l−1 total chlorine). Test groups of G. daiberi drifted through the discharge plume during chlorination displayed no increased immediate or latent mortalities. One-hour static bioassays revealed an initial TL50 value of 1.85 mg l−1 total chlorine, which decayed to 0.2–0.5 mg l−1 during the exposure period. At ambient temperatures of 26.4–26.6 °C, the amphipods avoided unchlorinated effluent at ΔTs > 3.3 °C. At lower ambient temperatures (15.3–15.7 °C), no avoidance was observed at a 7.1 °C ΔT. Chlorinated discharge water was avoided by G. daiberi at both ambient temperatures.

Polychlorinated biphenyl dynamics in hudson river striped bass. I. Accumulation in early life history stages

Abstract Polychlorinated biphenyl (PCB) burdens in larval striped bass, Morone saxatilis , from the Hudson River estuary and laboratory determinations of PCB accumulation in larval and juvenile striped bass are presented. Hudson River fish contained variable amounts of PCBs, from below detection (0.05 gm/g dry weight) to 7.07 μ/g. More PCBs similar to Aroclor 1254 than Aroclor 1016 were found. Larval and young-of-year fish exposed to [ 14 C]Aroclor 1254 ([ 14 C]PCB) in water and sorbed to suspended particles and sediments accumulated PCBs at linear rates during the first 24 h of exposure. Larvae exposed in river water accumulated body burdens related to exposure concentrations. Similar accumulation rates and body burdens in larvae exposed in filtered (0.45 μm pore size) river water showed that accumulation resulted from the uptake of dissolved PCB. PCB accumulation in larvae exposed to [ 14 C]PCB on suspended particles resulted from uptake of PCB desorbed from particles. PCB burdens in larvae exposed to sediment-sorbed [ 14 C]PCB resulted from desorption of sediment-bound PCB and maintenance of solubility equilibrium with the water. The linear relationship between the initial PCB concentration in water and accumulated PCB in fish from each exposure suggested that accumulation resulted from equilibrium partitioning between water and fish. There are indications that PCB burdens in river fish reflect the solubility-equilibrium based accumulation determined in these studies.

Uptake, retention, and elimination of PCB (Aroclor 1254) by larval striped bass (Morone saxatilis)

Larval striped bass removed PCB from Hudson River water rapidly and nearly completely. The final whole-body concentration resulting from 48 h exposure to a single dose of /sup 14/C-Aroclor 1254 was 5.9 ..mu..g g/sup -1/ dry weight (HRW) and 5.0 ..mu..g g/sup -1/ dry weight (FHRW). Final concentrations in fish exposed to PCB in HRW and FHRW were not significantly different (p > 0.05). The transfer of PCB from water to fish was at a maximum at 48 h in HRW, at which time the fish had accumulated about 60% of the PCB available in the system (600 ng).

Dynamics of polychlorinated biphenyls in striped bass from the Hudson river. III. tissue disposition and routes for elimination

Striped bass were exposed to14C-polychlorinated biphenyls (PCB) in single-dose and multiple-dose experiments. Samples were analyzed to determine rate constants for PCB elimination from individual tissues, PCB concentration in tissues, the proportion of the PCB burden retained and the proportion of the cumulative dose retained by each tissue at various times after exposure. An experiment was also conducted to determine both the potential for secondary PCB uptake in dietary exposure studies and the relative tissue disposition of PCBs assimilated from dietary sources as compared to direct water uptake. PCBs were present in the tissues of striped bass within 6 h after administration of a single dose. Certain tissue compartments, such as the liver/gall bladder, accumulated PCBs over a period of 48 h even though the whole-body burden had decreased between 24 and 48 h. Except for the gills, elimination rate constants for all tissues were similar and were similar to the whole body elimination rate constant. Elimination during the first few hours following exposure to PCBs may be due to equilibrium partitioning from the gill to the environment. The multiple-dose study showed that PCB burdens in striped bass continued to increase with dosing. However, tissue-specific rate constants for PCB elimination led to an increased flux of PCB out of tissues, and an overall decline in the percent of the cumulative dose remaining in the body 48 h after administration of each dose. The most likely route for PCB elimination from striped bass was from tissues to the liver and thence to the intestine via the bile. There were no differences in the tissue disposition of PCB related to route of exposure.

In vivo kinetics of benzo(a)pyrene and 7,12-dimethylbenz(a)anthracene assimilation and metabolism in rainbow trout

Abstract Benzo( a )pyrene (BaP) and 7,12-dimethylbenz( a )anthracene (DMBA) are polycyclic aromatic hydrocarbons (PAH) that occur in a variety of environmental media. BaP and DMBA are indirect-acting mutagens and carcinogens, and both induce neoplasia in fishes. 1,2 BaP has been used to study PAH-induction of mixed function oxidase systems and PAH metabolism in fishes; 3,4 studies of DMBA in fishes are limited to analyses of tissue disposition 5 and induction of drug-metabolizing enzymes. 6 We report here the results of comparative studies of BaP and DMBA assimilation, elimination, tissue disposition and metabolism in rainbow trout after administration of known doses of these contaminants via the digestive tract.

Measurement of the effect of Aroclor 1254 on the respiration of Gammarus using potentiometric respirometry

Abstract The effect of exposure to Aroclor 1254 on the respiration rate of single Gammarus was determined using potentiometric respirometry. Exposure to 25 μg l −1 PBC for 44 h was found to significantly reduce the respiration rate of scuds when measured immediately after the exposure. The utility of potentiometric respirometry for measuring sublethal stress is discussed.