Donald W. Brown

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. A 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. Recent 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. Associations 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.

High-performance liquid chromatographic method for isolating organic contaminants from tissue and sediment extracts

Interest in the assessment of the anthropogenic contamination of the marine environment has accelerated in recent years. Existing methods to analyze environmental samples (e.g., sediments or tissues) for trace amounts of organic contaminants such as aromatic hydrocarbons and chlorinated compounds are tedious and costly. We report a rapid, efficient high-performance liquid chromatography (HPLC) procedure which uses a size-exclusion column to separate the analytes of interest from interfering compounds in the sample matrix. Analytical results from the HPLC method were, in general, comparable to a gravity-column method which had been used for several years. The HPLC method had several other advantages: improved precision; the ability to monitor chromatographic conditions; the potential for automating analyses; and reduced consumption of solvents and other materials.

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.

A method for analysis of butyltin species and measurement of butyltins in sediment and English sole livers from Puget Sound

Abstract A method for the determination of tetra-, tri-, di- and monobutyltin in marine sediments and in tissues from English sole was developed. The method utilized dichloromethane/tropolone extraction of the butyltins, derivatization with hexylmagnesium bromide, and a silica/alumina column cleanup prior to gas chromatographic/mass spectrometric (GC/MS) analysis. A number of quality assurance measures were incorporated in the method. Mean recoveries of the surrogate spike tripentyltin from sediment and tissue reference materials ranged from 96% to 110%. The method was applied to sediments and livers of English sole collected in Puget Sound, Washington state. Total butyltin concentrations in sediments ranged from 1000 ng/g were found in some sediments. Butyltins were also determined in livers from English sole captured at sites where sediments were contaminated with butyltins. Dibutyltin (at concentrations up to 870 ng/g dry weight as Sn) was the predominant butyltin species found in the livers.

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.

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

Exposure of juvenile chinook and chum salmon to chemical contaminants in the Hylebos Waterway of Commencement Bay, Tacoma, Washington

The Hylebos Waterway is an industrialized waterway ofCommencement Bay, Tacoma, Washington, that is severelycontaminated with aromatic and chlorinatedhydrocarbons in the sediment. Juvenile chinook (Oncorhynchus keta) and chum salmon (O.tshawytscha) inhabit this waterway for a few days orweeks during their outmigration from freshwaterstreams to saltwater. The purpose of thisinvestigation was to determine to what degree juvenilechum and chinook salmon captured from the HylebosWaterway might bioaccumulate organic contaminants. These levels of exposure will be compared to previousstudies where such exposures have been linked tobiological dysfunction in juvenile salmon. Theresults showed that juvenile chum and chinook salmonfrom the Hylebos Waterway take up a wide range ofchemical contaminants, compared to fish fromhatcheries or reference estuaries. These contaminantsinclude high and low molecular weight polycyclicaromatic hydrocarbons (PAHs), polychlorinatedbiphenyls (PCBs, including the toxic congeners 105 and118), hexachlorobutadiene (HCBD), hexachlorobenzene(HCB), DDTs, heptachlor, and several pesticides. Immunohistochemical examination of the gill and gut injuvenile chum salmon from the Hylebos Waterway showedthe induction of the P450 metabolizing enzyme. Moreover, concentrations of contaminants in juvenilechinook and chum salmon from the Hylebos Waterway arecomparable to levels previously shown to be associatedwith biological injury in juvenile chinook salmon,such as impaired growth, suppression of immunefunction as demonstrated by reduced B cell function,and increased mortality following pathogen exposure.

Metabolism of 2, 6-dimethylnaphthalene in starry flounder (Platichthys stellatus) exposed to naphthalene and p-cresol

Abstract Juvenile starry flounder (Platichthys stellatus) were force-fed naphthalene, p-cresol, or a mixture of naphthalene and p-cresol in daily doses of 0.3–0.4 mg/kg body weight, for 6 consecutive days. On the 8th day, each fish was force-fed a dose of 12–15 mg/kg of 2,6-dimethyl[14C]naphthalene (DMN). Twenty-four hours later, the fish were killed and 14C-labelled metabolites in the bile were isolated and identified by thin-layer chromatography. Most of the biliary metabolites were recovered as conjugates, principally as glurosides and glucuronides. Analyses of the nonconjugated metabolites and metabolites resulting from enzymatic hydrolysis of the conjugates provided identification of four metabolites of DMN: 2,6-dimethyl-3-naphthol; 2,6-dimethyl-3,4-naphthoquinone; trans-3,4-dihydroxy-3,4-dihydro-2,6-dimethylnaphthalene (dihydrodiol); and b-methyl-2-naphthalenemethanol (alcohol). Enzymatic hydrolysis of the glucuronides yielded two metabolites: the alcohol, representing metabolism at a methyl substituent, and the dihydrodiol, representing oxidation of an aromatic ring. Exposure to naphthalene and/or p-cresol led to a significant reduction (P

Improved interlaboratory comparisons of polycyclic aromatic hydrocarbons in marine sediment

Abstract Interlaboratory precision in the analyses for polycyclic aromatic hydrocarbons (PAHs) in samples from the marine environment has improved substantially over the past decade. Early interlaboratory comparisons of analyses for PAHs in reference sediment showed variations in the data by as much as a factor of 10 among established laboratories. During our 6-year study, such disparities have progressively decreased, through better and more uniform analytical procedures. In the latest intercomparison, the range of interlaboratory relative standard deviations (RSDs) improved better than twofold to 15–36% for 18 PAHs in a natural sediment prepared as a reference material. The improvement is attributed to (a) use of a specific, improved extraction and cleanup procedure, (b) use of calibration and internal standards from common preanalyzed supplies, and (c) preparation and use of a detailed standard methods manual. The results open the way to the establishment of statistically sound quality control programs among the participating laboratories and more rigorous monitoring of the marine environment.