Bruce B. McCain

Neoplastic and other diseases in fish in relation to toxic chemicals: an overview☆

Field studies were conducted over a 5-year period in Puget Sound to investigate etiological relationships between prevalences of hepatic neoplasms in bottom-dwelling marine fish, with emphasis on English sole (Parophrys vetulus), and concentrations of toxic chemicals in sediments and bottom fish. Statistically significant correlations were found between prevalences of hepatic neoplasms and (1) sediment concentrations of aromatic hydrocarbons, and (2) concentrations of metabolites of aromatic compounds in the bile. n nA significant difference was also found between the concentrations of N-oxyl derivatives of nitrogen heterocycles (free radicals) in liver microsomes of English sole with liver lesions compared to sole without liver lesions. These N-oxyl free radicals were apparently metabolically derived from complex suites of nitrogen heterocycles present in Puget Sound environments. n nRecent evidence suggests that aromatic free radicals (possibly derivatives of aromatic hydrocarbons) may also be bound to hepatic DNA isolated from English sole with liver neoplasms collected in several polluted areas of Puget Sound. Such evidence for xenobiotic-DNA interactions has thus far not been obtained for fish from reference areas and for lesion-free fish from polluted areas. Various laboratory studies designed to evaluate the etiology of the liver neoplasms have also yielded evidence that is consistent with the view that high molecular weight aromatic hydrocarbons play a significant role in the etiology of hepatic tumors in the bottom-dwelling fish. n nAssociations between chemical exposures and diseases in other marine species from southern California and Boston Harbor are also discussed. Similar relationships between liver and skin neoplasms in selected bottom feeding fresh water species and sediment-associated chemicals are also presented.

Overview of studies on liver carcinogenesis in English sole from Puget Sound; evidence for a xenobiotic chemical etiology I: Pathology and epizootiology

Livers of wild English sole (Parophrys vetulus) from polluted waterways and embayments of Puget Sound, Washington, are affected by a spectrum of multiple, co-occurring idiopathic hepatic lesions, including neoplasms, putative preneoplastic foci of cellular alteration, and unique degeneration conditions. Results from a statistical analysis of the patterns of co-occurrence of these lesions in wild English sole indicate that these lesions represent morphologically identifiable steps leading to the development of hepatic neoplasms. This sequence parallels the lesion progression in experimental models of chemically induced liver carcinogenesis in rodents. The hypothesis that these lesions in wild English sole can be caused by exposure to certain xenobiotic hepatotoxic and hepatocarcinogenic compounds in Puget Sound is based on: a) statistical associations between levels of aromatic hydrocarbons (sigma AHs) in sediment and prevalences of these idiopathic liver lesions, b) the contribution of sigma AHs in accounting for the variability in hepatic neoplasm prevalence in a logistic regression model, c) elevated odds ratios for several idiopathic hepatic lesion types in sole from polluted sites in Puget Sound, d) significant correlations between prevalences of idiopathic hepatic lesions and levels of fluorescent metabolites of aromatic compounds (FACs) in bile of English sole, and e) experimental induction of putatively preneoplastic focal lesions in English sole injected with a PAH-enriched fraction of an extract from a contaminated urban sediment from Puget Sound, that were morphologically identical to lesions found in wild English sole from the same site.

Toxicopathic hepatic lesions as biomarkers of chemical contaminant exposure and effects in marine bottomfish species from the northeast and Pacific coasts, USA

Abstract Relationships between toxicopathic hepatic lesions and chemical contaminants in sediments, stomach contents, liver and bile were evaluated in English sole, starry flounder and white croaker from 27 sites on the Pacific Coast, and winter flounder from 22 sites on the Northeast Coast of the USA, as part of the NOAAs National Benthic Surveillance Program (NBSP). Prevalences of and relative risks for most toxicopathic lesions were significantly higher in fish from contaminated sites in Puget Sound, the Los Angeles area, and San Francisco and San Diego Bays on the Pacific Coast, and in Boston Harbor, Raritan Bay and certain urban sites in Long Island Sound on the Northeast Coast. Exposure to polycyclic aromatic hydrocarbons (PAHs), PCBs, DDTs, chlordanes and dieldrin were significant risk factors for all lesion types in Pacific Coast species. In winter flounder from the Northeast Coast, exposure to PAHs, DDTs or chlordanes were significant risk factors only for hydropic vacuolation, nonneoplastic proliferative and nonspecific necrotic lesions, and less commonly for neoplasms and foci of cellular alteration. Risk of hepatic disease generally increased with fish age, but sex was rarely a risk factor. Temporal trends analyses of hepatic lesion prevalences in starry flounder, white croaker and English sole from NBSP sites on the Pacific Coast failed to detect any significant monotonic increases or decreases in lesion prevalence. Recent studies utilized a two-segment ‘hockey-stick’ regression technique applied to NBSP data to determine threshold levels of sediment PAHs, which are clearly associated with toxicopathic hepatic lesions in English sole. Significant chemical threshold levels for these lesions are in the vicinity of 500–1000 ppb ΣPAHs in sediment, values considerably lower than those reported for other techniques. Application of this dose-response model to these subacute and chronic lesions involved in hepatocarcinogenesis, provides nonlethal sediment quality assessment endpoints for contaminant concentrations that may have long term health implications for chronically exposed native fish populations. Overall, these relationships provide strong evidence for environmental contaminants as etiologic agents for hepatic lesions in several marine bottomfish species, and clearly indicate their utility as biomarkers of contaminant-induced effects in wild fish, whether in national and regional biomonitoring programs or within the injury assessment phase of the legal process of assessing damage to fishery resources.

Inducibility of spawning and reproductive success of female english sole (parophrys vetulus) from urban and nonurban areas of puget sound, Washington

Abstract Vitellogenic female English sole were sampled from four areas in Puget Sound that varied in the nature and degree of chemical contamination. The fish were then injected with an analogue of Luteinizing Hormone Releasing Hormone (LHRH) in the laboratory to induce spawning. Ability to spawn, time to spawn, larval viability, and initial concentrations of plasma estradiol and vitellogenin [measured as alkaline-labile protein associated phosphate (ALP)] were assessed. In general, low initial plasma estradiol and ALP concentrations and subsequent reproductive impairment were most common in English sole from sites where levels of sediment contaminants [e.g. polycyclic aromatic hydrocarbons and polychlorinated biphenyls (PCB)] and measures of contaminant exposure in fish (hepatic PCB concentrations and aryl hydrocarbon hydroxylase activity) were highest, and where pollution-associated liver lesions in fish (i.e. neoplasms, foci of cellular alterations, specific degeneration/necrosis, and storage disorders) were most prevalent. Additionally, the time to spawn was found to be inversely correlated with initial plasma estradiol concentrations. Spawning success was found to be positively correlated with initial plasma estradiol and ALP concentrations as determined by logistic regression analysis; nearly 62% of the variability in the spawning response could be accounted for by these factors. Fertilization success was also found to be positively correlated with initial ALP concentrations, whereas fish captured from contaminated sites produced lower proportions of normal larvae. Overall, these findings suggest that contaminant exposure may result in poor reproductive success of female English sole. This may be related to a hormone imbalance or to slower ovarian development (non-synchronous timing) of female English sole from contaminated sites.

Suppression of immunological memory in juvenile chinook salmon (Oncorhynchus tshawytscha) from an urban estuary

In this present study, juvenile chinook salmon were collected from a contaminated urban estuary, the Duwamish Waterway, as well as from a non-urban estuary, the Nisqually River estuary, to determine if exposure to toxic chemicals affects immunocompetency. Juvenile chinook salmon were also sampled from the two hatcheries that release salmon into these estuaries. The ability of anterior kidney (AK) and splenic (SP) leucocytes from primed and unprimed juvenile salmon from the Duwamish Waterway, Nisqually River estuary, and their respective hatcheries to produce a primary and secondary in vitro plaque-forming cell (PFC) response to the hapten, trinitrophenyl (TNP) was examined. Trinitrophenyl-keyhole limpet haemocyanin (TNP-KLH) was added in vitro to AK leucocytes or as TNP-lipopolysaccharide (TNP-LPS) to both AK and SP leucocytes. The primary AK and SP plaque-forming cell response to TNP in salmon from the estuaries or hatcheries was not significantly different. Primed AK leucocytes from salmon collected from the hatcheries and the non-urban estuary were able to produce a heightened secondary response to TNP-KLH; in contrast, primed AK leucocytes from salmon collected from the urban estuary were unable to produce a secondary PFC response to TNP-KLH. Anterior kidney leucocytes from salmon collected from all four areas were able to produce a heightened secondary PFC response to TNP-LPS. However, the AKs plaque-forming cell response generated in primed chinook salmon collected from the urban estuary to TNP-LPS was significantly lower than that produced in salmon from the hatchery. This suppressed PFC response in primed AK cells to TNP-LPS was not observed in primed AK leucocytes from salmon collected from the non-urban estuary and its hatchery. These results suggest that the cells involved in generating immunological memory to TNP-KLH and TNP-LPS were affected in salmon exposed to contaminants in the urban estuary, with cells which generate memory to TNP-KLH being more affected. The PFC responses of primed SP leucocytes from salmon collected from the Duwamish Waterway and Nisqually River estuaries, stimulated in vitro with TNP-LPS were not significantly different. The consequence of suppressed immunological memory in disease resistance of juvenile salmon is currently unknown.

Status, correlations and temporal trends of chemical contaminants in fish and sediment from selected sites on the Pacific Coast of the USA

Abstract The National Benthic Surveillance Project (NBSP), a component of NOAAs National Status and Trends Program, monitored sediment and bottomfish for chlorinated hydrocarbon pesticides (CHs), PCBs and polycyclic aromatic hydrocarbons (PAHs) at selected urban and nonurban sites along the west coast of the USA from 1984 to 1993. This project successfully generated an extensive data set to evaluate the recent status and trends of environmental quality in coastal waters. This article summarizes and interprets the status of selected PAHs, PCBs and CHs in surficial sediments and selected species of bottom-feeding fish for 50 sites in Alaska, Washington, Oregon and California for the first 7 years (1984–1990) of the NBSE. The highest concentrations of most sediment-associated organic contaminants were present in the most highly urbanized areas, and many of the organic contaminants were bioaccumulated by indigenous marine fish species. The concentrations of PAHs and CHs in sediments generally correlated with levels of these compounds or their derivatives in bottom-dwelling fish. Assessment of trends in the concentrations of chlordanes, dieldrin, DDTs, PAHs and PCBs for the 7 year period from 1984–1990 suggest that, since the mid-1980s, concentrations of the persistent CHs, such as PCBs and DDTs in sediment and fish, show no consistent temporal trends, whereas levels of PAHs, which are nonpoint source contaminants, showed consistent increases at both nonurban and urban near-coastal sites.

Uptake of aromatic and chlorinated hydrocarbons by juvenile chinook salmon (Oncorhynchus tshawytscha) in an urban estuary

A study was conducted to assess the potential for uptake of toxic chemicals by down-stream migrant salmon in an urban estuary. Juvenile chinook salmon (Oncorhynchus tshawytscha) were collected from the Duwamish Waterway (located in Seattle, Washington) and from the Nisqually River (a reference site). The mean concentrations of aromatic hydrocarbons and polychlorinated biphenyls (PCBs) in the stomach contents (food organisms) of salmon from the Duwamish Waterway were approximately 650 times and 4 times, respectively, higher than those in salmon from the Nisqually River. Similarly, the mean concentration of bile metabolites of aromatic compounds which fluoresce at benzo[a]pyrene wavelengths was 24 times higher in the urban salmon compared to the reference salmon, whereas the mean concentration of PCBs in liver of urban salmon was 3 times higher than that in reference salmon. The study clearly demonstrated that, during their residency in this urban estuary, juvenile chinook salmon bioaccumulate substantial levels of toxic chemicals. The possible effects of these chemical exposures on the health and survival of this species are not presently known.

Chemical contamination and associated liver diseases in two species of fish from San Francisco Bay and Bodega Bay

Starry flounder (Platichthys stellatus), white croaker (Genyonemus lineatus) and sediments were collected annually from selected sites within San Francisco Bay, and a reference site in Bodega Bay between 1984--1991. Fish livers were examined for toxicopathic lesions and analysed for selected chlorinated hydrocarbons (CHs) such as PCBs, DDTs, chlordanes and dieldrin; sediment and fish stomach contents were analysed for polycyclic aromatic hydrocarbons (PAHs) and CHs; and bile was analysed for PAH metabolites. Sediment concentrations of PAHs, PCBs and DDTs; bile concentrations of PAH metabolites; and liver concentrations of PCBs, dieldrin and chlordanes were generally significantly higher at all San Francisco Bay sites compared to the Bodega Bay reference site. For both species, hydropic vacuolation of biliary epithelial cells was the most prevalent liver lesion detected and was statistically associated with sediment and tissue concentrations of PAHs or their metabolites, PCBs, DDTs, chlordanes and dieldrin. Temporal trends analyses showed that at Hunters Point, sediment PAHs and CHs increased between 1984--1991, while liver concentrations of CHs decreased. Liver concentrations of dieldrin in starry flounder decreased at all three San Francisco Bay sites

Multidisciplinary assessment of pollution at three sites in Long Island Sound

Winter flounder (Pseudopleuronectes americanus) were sampled from three sites located near Norwalk, New Haven, and Niantic, Connecticut, in Long Island Sound during February 1987, to evaluate the degree of chemical contamination and to determine possible effects of contaminant exposure. At each site, sediment and infaunal invertebrates were also collected and analyzed for trace metals and organic chemicals. Specimens of liver and kidney from winter flounder were examined for histopathological conditions, including the presence of macrophage aggregates in liver tissue. Liver samples were also analyzed for DNA damage (i.e., the formation of adducts between DNA and chemical contaminants). Blood samples were collected and analyzed for erythrocyte micronuclei. The sampling site near New Haven was determined to be the most affected site, from the standpoints of greater chemical contamination and possible effects on winter flounder. Concentrations of aromatic hydrocarbons (AHs) and polychlorinated biphenyls (PCBs) were highest in sediment from this site, and the highest prevalences of the histopathological changes and DNA alterations were also found in the livers of winter flounder from this site. No differences in the concentrations of contaminants in fish or in frequencies of erythrocyte micronuclei in fish blood were found between sites. None of the sites sampled had contaminant levels or prevalences of lesions as high as previously found at other East Coast locations (e.g., Boston Harbor, Massachusetts, Raritan Bay, New York). Overall, our results indicate moderate levels of pollution at two of the urban sites in Long Island Sound and provide a framework for expanded studies to better define the extent and impact of chemical pollution in Long Island Sound.

Chemical contaminant exposure and effects in four fish species from Tampa Bay, Florida

Concentrations of selected anthropogenic chemical contaminants and levels of pollution-related biological effects were measured during three consecutive years (1990–1992) in hardhead catfish (Arius felis), Gulf killifish (Fundulus grandis), longnose killifish (F. majalis), and red drum (Scieaenops ocellatus) from 12 subtidal and intertidal sites in Tampa Bay and nearby Sarasota Bay. Each species was collected from at least four sites. Compared to nonindustrialized sites, concentrations of PCBs, DDTs, and alpha-chlordane in liver, and of fluorescent aromatic compounds in bile, were highest in fish from sites in or near Hillsborough Bay, the most industrialized portion of Tampa Bay. The results of analyses for two biochemical markers of contaminant-induced effects in fish, hepatic cytochrome P4501A activities and levels of hepatic DNA adducts, also showed the highest levels to be in all four fish species from sites in the vicinity of Hillsborough Bay. Liver lesions, considered to be pollution-associated in several other bottom-feeding fish species, were found in hardhead catfish and longnose killifish, exclusively from sites in Hillsborough Bay. Overall, concentrations of selected contaminants and their derivatives in the four target fish species generally reflected concentrations of these contaminants found in sediment. The biochemical and histopathological responses demonstrated that chemical contaminant concentrations in the vicinity of Hillsborough Bay are sufficiently high to cause adverse effects in indigenous fish species. The results, collectively, showed that the extent of contaminant exposure and biological effects in fish from sites in Tampa Bay were low to moderate compared to more urbanized coastal sites of the United States. *** DIRECT SUPPORT *** A01BY073 00009