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332 records · Page 19Linked to original sources

Herons and egrets as proposed indicators of estuarine contamination in the United States

The National Contaminant Biomonitoring Program of the U.S. Fish and Wildlife Service Includes the sampling of freshwater fish, starlings, and duck wings. In order to include an estuarine component, herons and egrets are being evaluated. Organochlorine concentrations were measured In eggs and chicks of Snowy Egrets Egretta thula, Great Egrets Casmerodius albus, and Black-crowned Night-Herons Nycticorax nycticorax collected In Rhode Island, Texas, and California. Chicks of all species at all locations accumulated DDE and polychlorinated biphenyls (PCBs), and accumulation rates may serve as the basis for an indicator program of estuarine contamination. Biochemical re-sponses of embryos and chicks were also evaluated. Microsomal arylhydrocarbon hydroxylase and benzyloxyresorufin-O-dealkylase activities in livers of 10-day-old night-heron chicks were elevated at a contaminated site in San Francisco Bay, CA, when compared to a 'reference' site in Vlrginia. Quantification of liver enzyme activities may serve as a rapid cost-effective biomarker of pollutant exposure.

Book chapter

A new database on contaminant exposure and effects in terrestrial vertebrates for natural resource managers

The Biomonitoring of Environmental Status and Trends (BEST) program of the Department of the Interior is focused to identify and understand effects of contaminant stressors on biological resources under their stewardship. Despite the desire of many to continuously monitor the environmental health of our estuaries, much can be learned by summarizing existing temporal, geographic, and phylogenetic contaminant information. To this end, retrospective contaminant exposure and effects data for amphibians, reptiles, birds, and mammals residing within 30 km of Atlantic coast estuaries are being assembled through searches of published literature (e.g., Fisheries Review, Wildlife Review, BIOSIS Previews) and databases (e.g., US EPA Ecological Incident Information System; USGS Diagnostic and Epizootic Databases), and compilation of summary data from unpublished reports of government natural resource agencies, private conservation groups, and universities. These contaminant exposure and effect data for terrestrial vertebrates (CEE-TV) are being summarized using Borland dBASE in a 96- field format, including species, collection time and site coordinates, sample matrix, contaminant concentration, biomarker and bioindicator responses, and source of information (N>1500 records). This CEE-TV database has been imported into the ARC/INFO geographic information system (GIS), for purposes of examining geographic coverage and trends, and to identify critical data gaps. A preliminary risk assessment will be conducted to identify and characterize contaminants and other stressors potentially affecting terrestrial vertebrates that reside, migrate through or reproduce in these estuaries. Evaluations are underway, using specific measurement and assessment endpoints, to rank and prioritize estuarine ecosystems in which terrestrial vertebrates are potentially at risk for purposes of prediction and focusing future biomonitoring efforts.

Book chapter

Inter-relation of cytochrome P450 and contaminants burdens in sibling heron embryos and nestlings

Hepatic cytochrome P450-associated monooxygenase activities were measured in 11-day-old nestling black-crowned night-herons (Nycticorax nycticorax) collected from a reference site (next to the Chincoteague National Wildlife Refuge, Virginia) and three polluted sites (Cat Island, Green Bay, Lake Michigan, Wisconsin; Bair Island, San Francisco Bay, California; West Marin Island, San Francisco Bay, California). Activities of arylhydrocarbon hydroxylase (AHH) and benzyl-oxyresorufin-O-dealkylase (BROD) weremodestly elevated (<three-fold) in nestlings from polluted sites. Concentrations of p,p?DDE, other organochlorinepesticides and total PCBs in nestlings were greatest at contaminated sites, although much lower than found in concurrently collected eggs and pipping embryos. At these low pollutant concentrations there was little correlation between monooxygenase activity and contaminant levels in nestlings. These observations markedly contrast the pronounced monooxygenase induction (up to 85-fold) and its significant correlation with total PCBs, arylhydrocarbon receptor-active PCB congeners and toxic equivalents in concurrently collected night-heron embryos that were often siblings of the nestlings. The present findings suggest that cytochrome P450-associated monooxygenase activity of heron nestlings may have only limited value as a biomarker of exposure at this rapid-growth life stage.

Society of Environmental Toxicology and Chemistry,

Effects of lead in nestling black-crowned night-herons (Nycticorax nycticorax) experimentally dosed in the field

Lead is a known environmental toxicant, and poisoning resulting from the ingestion of lead shot has been well-documented in many species of waterfowl. However, much less is known regarding exposure and effects of free environmental lead in species of birds other than waterfowl. In an attempt to evaluate toxicity of lead to herons and to determine the usefulness of feathers as a non-invasive exposure-monitoring tool, black-crowned night-heron nestlings were dosed with lead to determine its distribution among tissues, and its effects on biochemical biomarkers, growth, and survival. Five-day-old heron nestlings (one per nest) at Chincoteague Bay, Virginia were given a single intra-peritoneal injection of dosing vehicle (control; N=7) or one of three lead solutions (as lead nitrate) (10, 50, or 250 mg/kg body weight of nestling; N=7 per dose) chosen to represent levels below, at, and above those found in moderately-polluted environments. All nestlings treated with lead exhibited dose-dependent inhibition of delta-aminolevulinic acid dehydratase (ALAD) activity compared to controls, and nestlings treated with the highest concentration showed a reduced carcass weight compared to controls. Of several measures of oxidative stress that were analyzed, significant differences were found between low- and high-dosed nestlings in hepatic total thiol and protein-bound sulfhydryl concentrations. No differences in survival were detected between dosed nestlings, controls, or uninjected siblings. Lead concentrations in several matrices, including feathers, are being determined to assess distribution among tissues and will also be examined for relationships with measures of effect.

Society of Environmental Toxicology and Chemistry,

Soda Lake-Painted Rock(!) Petroleum System in the Cuyama Basin, California, U.S.A.

The Cuyama basin, located in the central California Coast Ranges, was formed by extension during early Miocene time and was filled with a variety of nonmarine, marginal marine, and neritic to bathyal marine sediments. Low sulfur oil is produced primarily from the lower Miocene Painted Rock Sandstone Member of the Vaqueros Formation along a structural trend parallel to the Russell fault, which was active from 23 to 5 Ma. A major fold and thrust belt beginning about 3 Ma formed the Caliente and Sierra Madre ranges and partially obscures the Miocene extensional basin. Stable carbon isotope and biomarker data indicate that the lower Miocene Soda Lake Shale Member of the Vaqueros Formation is the predominant source rock for the oil in the Cuyama area. Burial and thermal history modeling shows that oil generation began in middle-late Miocene time and that oil migrated into existing traps. Younger traps that formed in the overthrust are barren of oil because migration occurred prior to the development of the fold and thrust belt or because subthrust oil was unable to migrate into the overthrust.

Book chapter

Geochemistry of Eagle Ford group source rocks and oils from the first shot field area, Texas

Total organic carbon, Rock-Eval pyrolysis, and vitrinite reflectance analyses performed on Eagle Ford Group core and cuttings samples from the First Shot field area, Texas demonstrate these samples have sufficient quantity, quality, and maturity of organic matter to have generated oil. Furthermore, gas chromatography and biomarker analyses performed on Eagle Ford Group oils and source rock extracts as well as weight percent sulfur analyses on the oils indicate the source rock facies for most of the oils are fairly similar. Specifically, these source rock facies vary in lithology from shales to marls, contain elevated levels of sulfur, and were deposited in a marine environment under anoxic conditions. It is these First Shot Eagle Ford source facies that have generated the oils in the First Shot Field. However, in contrast to the generally similar source rock facies and organic matter, maturity varies from early oil window to late oil window in the study area, and these maturity variations have a pronounced effect on both the source rock and oil characteristics. Finally, most of the oils appear to have been generated locally and have not experienced long distance migration.

Texas

A survey of molecular marker compounds in sediments of San Francisco Bay, California

An areal survey of surficial sediments in San Francisco Bay has been conducted to evaluate the presence of extractable organic compounds. Molecular marker compounds studied include hydrocarbons (PAH's), chlorinated pesticides, and other organic compounds that provide information on sources of organic input into the Bay. Fairly uniform source profiles are seen throughout the Bay. Biomarker profiles contain mature constituents indicating anthropogenic influences and extensive sediment reworking. The dominant input signatures in San Francisco Bay sediment are those of anthropogenic PAH's from combustion and other sources, and long chain n-alkanes and n-aldehydes from terrigenous vascular plants. A comparison of the sums of the combustion PAH's and the terrigenous n-alkanes shows that an anthropogenic influence is dominant in the most urban parts of the Bay close to shore, and in mid-Bay channel areas, and a terrigenous signature is dominant nearshore in San Pablo Bay and at the southernmost station in South Bay.

California

Comparison of cytochrome P450 1A induction in blood and liver cells of sea otters

Sea otters in oiled areas of western PWS had elevated levels of cytochrome P450 1A (CYP1A), a biomarker of hydrocarbon exposure, measured in blood samples collected from otters in 1996- 98. In summer 2001, as part of project 01423, we have proposed to resample CYP1A in blood from sea otters in oiled and unoiled areas of PWS. Herein we describe a complementary effort to project 01423. We propose also to sample liver from the captured sea otters, for assays of CYP1A, and for examination of histopathological changes. Liver CYP1A levels will be compared to those measured in blood from the same individuals. We will also assay for CYP1A in archived frozen liver samples from sea otters that were oiled and died in 1989, to enable comparison of current levels of CYP1A induction with levels in sea otters that had a known high degree of oil exposure. The results of this study will provide a basis for comparison of cytochrome P4501A induction in sea otters in 1989, in 1996-98, and in 2001, and will help determine if there is a decline in CYP1A levels over time.

Alaska