Donald W. Brown

Bioavailability and biotransformation of aromatic hydrocarbons in benthic organisms exposed to sediment from an urban estuary

Phylogenetically diverse benthic organisms [amphipods (Rhepoxynius abronius and Eohaustqrius washingtonianus); clams (Macoma nasuta); shrimp (Pandalus platyceros); fish (Parophrys vetulus)] were exposed to an urban estuarine sediment [ 16 ppm of two to six benzenoid ring aromatic hydrocarbons (AHs)] to which trace amounts of [3H]benzo[a]pyrene (BaP) were added. The techniques used to assess uptake and metabolism of AHs were gas chromatography/mass spectrometry (GC/MS) for AHs, high-pressure liquid chromatography/fluorescence spectrometry for AH metabolites in fish bile, and radiometric analyses for biotransformation of [3H]BaP. Generally, the extent of metabolism of [3H]BaP (M. nasuta < E. washingtonianus < R. abronius I P. platyceros N P. vetulus) was negatively correlated to tissue concentrations of AHs (three to six ring), except that amphipod species accumulated higher concentrations of AHs than did clams, indicating that other factors (e.g., feeding strategy and rate of excretion) also influenced accumulation of AHs. Radiometric and GC analyses for BaP in both sediment and tissues suggested that not all of the BaP (and presumably other AHs) extracted chemically from sediment was bioavailable.

Toxic chemicals, including aromatic and chlorinated hydrocarbons and their derivatives, and liver lesions in white croaker (Genyonemus lineatus) from the vicinity of Los Angeles

High concentrations of toxic chemicals in sediment and white croaker (Genyonemus lineatus), as well as liver diseases (e.g., carcinomas) in this species, were found in the Los Angeles area. The highest concentrations of aromatic hydrocarbons (AHs) in the sediment were in San Pedro Bay, and the highest concentrations of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) derivatives were in sediment from near the White Point sewer outfall. Concentrations of AHs, polychlorobiphenyls (PCBs), and DDT derivatives were generally higher in food organisms from the croakers stomach than in sediment. Moreover, croaker from San Pedro Bay and White Point were substantially contaminated with DDT derivatives and metabolites of aromatic compounds, compared to croaker from the Hyperion outfall and Dana Point. The evidence suggest that the observed pathological conditions of the liver were associated with exposure of the croaker to toxic chemicals, which occurred, at least in part, through the ingestion of contaminated food organisms.

Sediment-associated contaminants and liver diseases in bottom-dwelling fish

High concentrations of chemicals have been found in sediments from urban areas of Puget Sound. Hundreds of organic chemicals (including certain aromatic hydrocarbons [AHs] and various chlorinated compounds) were identified. Statistical methods were used to evaluate possible relationships between the chemistry data and fish diseases. Positive correlations were found between the frequencies of liver neoplasms (e. g., hepatocellular carcinoma) and other liver lesions in English sole (Parophrys vetulus) and concentrations of AHs in sediment; such correlations were not found with chlorinated hydrocarbons. Strong evidence was also obtained to show that many organic chemicals in sediment are bioavailable to bottom-dwelling fish. Stomach contents (consisting mainly of benthic invertebrates) from English sole had concentrations of a number of AHs similar to those in the sediment from which the fish were taken. In these same fish, metabolites of many aromatic compounds were found in bile using a procedure combining HPLC with fluorescence detection. Further, the concentrations of certain xenobiotic metabolites in bile were correlated positively with the occurrence of liver neoplasms in English sole.

Rapid analysis of naphthalene and its metabolites in biological systems: Determination by high-performance liquid chromatography/fluorescence detection and by plasma desorption/chemical ionizations mass spectometry

A rapid procedure for the determination of naphthalene and its metabolites in bile of rainbow trout and mice is described. The integrated analytical techniques combine high-performance liquid chromatography/ultraviolet fluorescence detection and plasma desorption/chemical ionization mass spectrometry for identification and quantitation. After separation by reverse-phase liquid chromatography, naphthalene and its metabolites are detected and quantitated by ultraviolet fluorescence spectrometry. Identification of two metabolites is confirmed by mass spectrometry. A direct insertion probe tip for a conventional chemical ionization mass spectrometer was modified to obtain spectra of thermally labile compounds. A spectrum of less than 100 ng of naphthyl glucuronide, a labile glucuronic acid conjugate of 1-naphthol, was obtained with this system.

Results Of The National Benthic Surveillance Project (Pacific Coast): 1987

During the fourth year (1987) of the Pacific Coast portion of the National Benthic Surveillance Project (NBSP), a multiyear study of chemical contaminants and associated fish diseases at selected sites on the Pacific Coast of the United States, two embayments (San Diego Bay and San Francisco Bay) were selected for more intensive sampling in order to evaluate the magnitude of pollution problems in these bays, and to better define the spatial distribution of chemical contamination and biological effects. The results of the intensive studies in San Francisco Bay not only supported our previous findings that the sites in the central portion of the bay (e.g., Hunters Point) generally had sediments and fish with the highest levels of many contaminants compared to the other open bay sites, but the site in the Oakland Estuary was identified as one of the most contaminated on the Pacific Coast. The prevalence of a type of pollutionassociated liver lesion (specific degeneration/necrosis) in white croaker from the Oakland Estuary site was significantly higher than that for croaker from any other of the sites in or near San Francisco Bay. For San Diego Bay, the high concentrations of chemical contaminants and high prevalences of fin erosion previously found at the South San Diego Bay site were also found at the nearby site next to National City. In addition, a high prevalence of liver neoplasms was detected in black croaker from the North Bay site. Concentrations of many contaminants in sediments were generally lower at the Shelter Island site close to the mouth of the bay compared to the two sites in the southern part of the bay and the North Bay site. The results of the intensive studies conducted in San Francisco Bay and San Diego Bay have augmented our understanding of the environmental conditions within these bays. Such information is essential for effective management of the marine resources these bays support.

Tributyltin Contamination Of Sediment And English Sole From Puget Sound

Sediment and English sole (Parophrys vetulus) from Puget Sound were analyzed for butyltins using a method developed in our laboratory. This method measures all four butyltin compounds in both sediment and tissues, and includes a number of quality control (QC) procedures. Total butyltin concentrations in sediment from five sites ranged from < 3.3 ng/g to 700 ng/g wet weight as tin. In English sole liver, total butyltins ranged from non-detectable to 250 ngfg wet weight as tin, while the greatest concentration found in muscle was 11 ng/g. A significant difference was observed between the butyltin profiles of muscle and liver. Although tributyltin was the predominant butyltin in muscle (and sediments), over 90% of the butyltins found in liver were present as dibutyltin. Because tributyltin is generally more toxic than dibutyltin, this difference in butyltin profile is potentially significant for fish exposed to butyltins.