Sin-Lam Chan

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.

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.

Sublethal And Lethal Effects In Two Marine Organisms, A Juvenile Echinoderm And A Larval Fish, Exposed To Contaminated Sediments

A number of federal and state agencies are concerned with assessing the toxicity of sediment-derived xenobiotics to marine organisms. Toxicity is one of the major factors considered when, for example, disposal of dredged sediments from urban waterways is desired. To measure toxic effects of sediments, bioassays that use the marine amphipod, Rhepoxinius abronius (1, 2), the oyster larva, Crassostrea gigas (3), and the luminescent bacterium, Photobacterium phosphoreum (MicrotoxB) (4) have been commonly employed. However, only a limited number of organisms representing few phyla are currently available in bioassays. Mortaliity of organisms is often used to assess the effects of talxicants, but reliance on mortality as the sole measure of toxicity can seriously underestimate deleterious effects of xenobiotics. Sublethal indicators, such as poor growth, may provide more sensitive measures of the effects of toxicants, yet sublethal effects of toxicants on marine: organisms have not generally been well established, and sublethal indicators have rarely been employed in sediment bioassays. Neither has the relative sensitivity of sublethal and lethal effects been rigorously compared.

Results of the 1984-85 National Benthic Surveillance Project: West Coast

Bottomfish and sediments were collected from 18 sites including a number of reference sites on the U.S. West Coast during the first year of the multiyear National Benthic Surveillance Project. Sediments and fish were analyzed for toxic chemicals, and fish were examined for diseases. Wide variations in the concentrations of aromatic hydrocarbons (AH), polychlorinated biphenyls (PCB), DDT and related compounds, and selected metals in sediments were found within locations ( i .e., embayments in the vicinity of major cities) and between locations. Concentrations of chemicals in tissues were generally less variable than those in sediments, apparently reflecting the ability of fish to integrate chemical sources over large geographical areas. Prevalences of diseases (i.e., fin erosion and liver lesions) were usually highest in fish exposed to the highest levels of environmental contaminants.

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.