Susanne J. McDonald

Human Contamination of the Marine Environment-Arthur Harbor and McMurdo Sound, Antarctica.

Polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCBs), pesticides, and trace metal concentrations in McMurdo Sound and Arthur Harbor, Antarctica, sediments and marine biota are reported. Biomarkers of contaminant exposure, biliary metabolites and EROD assays, were also measured. Hydrocarbon and trace metal contamination are generally limited to within hundreds of meters of human settlements. Local releases of fossil fuels, disposal of waste materials, and aging of ship and station structures contribute to contamination. High concentrations of PCBs were detected in sediments (250-4200 ng g{sup -1}) and organisms (up to 420 ng g{sup -1}) from Winter Quarters Bay (WQB). Trace metal and PAH sediment concentrations rarely exceed levels known to cause toxic effects in marine organisms, whereas PCBs in WQB often do. Biological responses to exposure include the formation of PAH metabolites and the inducement of the P4501A detoxification system in fish. Induction of EROD activity in in vitro rat hepatoma H4IIE cell bioassays by tissue extracts correlated with known levels of PCB contamination in invertebrate tissues. Local sources of contaminants greatly exceed those attributable to long-distance atmospheric transport. 31 refs., 4 figs.

Hydrocarbon contamination on the Antarctic Peninsula: I. Arthur harbor—Subtidal sediments☆

Abstract Near-field contamination in Arthur Harbor can be traced to spills, ship and boating activities, and run-off. Soil samples from Palmer Station and Old Palmer Station contain hydrocarbons derived from diesel fuel, lubrication oil, and hydraulic fluid. The majority of contamination in subtidal sediments around Palmer Station is due to diesel fuel spills. Subtidal sediments below an abandoned open incineration site also contain combustion-derived polynuclear aromatic hydrocarbons (PAH). Soils collected at Old Palmer Station were also contaminated with diesel fuel residues and combustion-derived PAH. High concentrations of these contaminants were detected in nearby subtidal sediments. Small amounts of diesel fuel contamination are detectable throughout Arthur Harbor. Despite being abandoned for years, soils in the vicinity of Old Palmer Station and Base N represent the most concentrated source of contaminants in Arthur Harbor. Environmentally sound practices at Palmer Station have helped to minimize localized contamination.

Comparative toxicity of oil, dispersant, and oil plus dispersant to several marine species

Dispersants are a preapproved chemical response agent for oil spills off portions of the U.S. coastline, including the Texas-Louisiana coast. However, questions persist regarding potential environmental risks of dispersant applications in nearshore regions (within three nautical miles of the shoreline) that support dense populations of marine organisms and are prone to spills resulting from human activities. To address these questions, a study was conducted to evaluate the relative toxicity of test media prepared with dispersant, weathered crude oil, and weathered crude oil plus dispersant. Two fish species, Cyprinodon variegatus and Menidia beryllina, and one shrimp species, Americamysis bahia (formerly Mysidopsis bahia), were used to evaluate the relative toxicity of the different media under declining and continuous exposure regimes. Microbial toxicity was evaluated using the luminescent bacteria Vibrio fisheri. The data suggested that oil media prepared with a chemical dispersant was equal to or less toxic than the oil-only test medium. Data also indicated that continuous exposures to the test media were generally more toxic than declining exposures. The toxicity of unweathered crude oil with and without dispersant was also evaluated using Menidia beryllina under declining exposure conditions. Unweathered oil-only media were dominated by soluble hydrocarbon fractions and found to be more toxic than weathered oil-only media in which colloidal oil fractions dominated. Total concentrations of petroleum hydrocarbons in oil-plus-dispersant media prepared with weathered and unweathered crude oil were both dominated by colloidal oil and showed no significant difference in toxicity. Analysis of the toxicity data suggests that the observed toxicity was a function of the soluble crude oil components and not the colloidal oil.

Fine-scale distribution of methanotrophic mussels at a Louisiana cold seep

Abstract Extensive aggregations of methanotrophic mussels (Mytilidae: Bathymodiolus -like) were found in a 60×300m zone on the 640m isobath of the Louisiana slope. Within the aggregations, living mussels occurred in dense curvilinear clusters up to 5m in length. Defunct clusters, consisting of gaping and disarticulated valves, were also common. Comparison of length frequency distributions and mean densities of mussel clusters demonstrated that recruitment of juvenile mussels was ongoing in certain clusters and completely lacking in others. Surface sediments within the zone were characterized by dark patches and linear depressions, apparently associated with seeping hypersaline fluids. Pore fluids in surface sediments contained elevated salt concentrations (289% of ambient sea water), concentrations of ammonia up to 1.6mM, and up to 3mM H 2 S.

Exposure of killifish to benzo[a]pyrene: comparative metabolism, DNA adduct formation and aryl hydrocarbon (Ah) receptor agonist activities

Benzo[a]pyrene (BaP) elicited a dose-response induction of hepatic CYP1A1 gene expression in killifish characterized by increased CYP1A1 mRNA levels, ethoxyresorufin O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH) activities. There were marked differences in the maximally-induced EROD (1529 pmol mg−1min−1) and AHH (377 pmol mg−1 min−1) activities and these differences were observed at all ume points and at concentrations of BaP from 1 to 50 mg/kg. Treatment of killifish with BaP did not significantly affect binding of [125I]epidermal growth factor (EGF) to hepatic plasma membranes containing the EGF receptor. There was a dose-dependent increase in formation of DNA adducts in killifish treated with 1-50 mg/kg of BaP. Two-dimensional thin-layer chromatographic analysis of the [32P] labeled adducted nucleoudes revealed one major spot. In a time course study over a period of 2–14 days, the relative DNA adduct levels in fish treated with 5 mg/kg BaP were constant. The most sensitive indicator of exposure to BaP was the dose-dependent formation of biliary metabolites in which there was a > 40-fold increase (compared to untreated animals) in fluorescent metabolites formed at the lowest dose of BaP (1 mg/kg) used in this study. Killifish expressed relatively high levels (203 fmol/mg) of the nuclear aryl hydrocarbon (Ah) receptor which was isolated from nuclear extracts of fish treated with [3H]-2,3,7,8-tetrachlorodibenzo p-dioxin. The nuclear Ah receptor complex sedimented at 6.0 S which was similar to that observed in other animal species. Based on their CYPIA1 induction response to BaP and Ah receptor levels, the results of this study indicate that killifish are highly Ah-responsive.

Assessing Aromatic Hydrocarbon Exposure in Antarctic Fish Captured Near Palmer and McMurdo Stations, Antarctica

Since little is known about the effects of contaminants on Antarctic organisms, the effects of polynuclear aromatic hydrocarbons (PAH) on Antarctic fish were evaluated. Fish captured near Palmer Station on the Antarctic Peninsula exhibited induced ethoxyresorufin O-deethylase (EROD) activities and elevated concentrations of biliary PAH metabolites compared to fish from control sites. Naphthalene and phenanthrene PAH metabolite levels were significantly higher in the bile of fish captured near McMurdo Station than in fish from remote sites in McMurdo Sound. Laboratory experiments were conducted in which Notothenia gibberifrons were treated with benzo[a]pyrene (BaP) and diesel fuel Arctic (DFA). Although DFA is composed primarily of 2- and 3-ring PAH which are not known to be potent CYPIA inducers, the maximal hepatic EROD activity of DFA-treated fish was approximately 80% of that observed in BaP-treated fish. Additionally, 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) were determined for hepatic extracts of laboratory-dosed and field-captured fish using rat hepatoma H4IIE cell bioassays. The TEQ values of H4IIE cells dosed with hepatic extracts of DFA-treated fish correlated more closely with hepatic concentrations of 3-ring and >3-ring PAH than with 2-ring and ΣPAH concentrations. However, bioassay-derived TEQs were higher than expected based on the measured levels of ≥3-ring PAH in the hepatic extracts of DFA-treated fish. The TEQs for hepatic tissue extracts of BaP-treated fish paralleled tissue concentrations of PAH. The TEQs for field captured fish were significantly lower than those derived from dosed fish extracts.

Hydrocarbon contamination on the Antarctic Peninsula: II. Arthur harbor—Inter- and subtidal limpets (Nacella concinna)

Abstract Accidental and operational releases of hydrocarbons during activities in support of scientific bases in the Antarctic can contaminate organisms in close proximity to these locations. Intertidal and subtidal limpets in Arthur Harbor were found to contain elevated levels of polynuclear aromatic hydrocarbons near Plamer and Old Palmer Stations. Contamination was highest in the intertidal and decreased with increasing water depth in the subtidal. The highest concentrations of tissue contamination were found in intertidal areas associated with high levels of onshore soil contamination. Limpets (Nacella concinna) preferentially incorporated the more water soluble aromatic compounds suggesting exposure to dissolved contaminants in run-off rather than particulates or slicks. This was in contrast to subtidal sediments that were primarily contaminated with freshly spilled diesel fuel. While contamination was present near stations, the concentrations observed are 1–2 orders of magnitude lower than the initial contamination caused by the Bahia Paraiso diesel fuel spill in 1989.

Gas chromatographic-mass spectrometric analysis of polycyclic aromatic hydrocarbon metabolites in Antarctic fish (Notothenia gibberifrons) injected with Diesel Fuel Arctic

Fish (Notothenia gibberifrons) collected in pristine Antarctic sites were injected with Diesel Fuel Arctic (DFA). Gas chromatography/mass spectrometry (GC/MS) was used to identify and quantify polycyclic aromatic hydrocarbon (PAH) metabolites obtained from hydrolyzed fish bile. The concentrations of naphthols (NPH), phenanthrenols (PHN), dibenzothiophenols (DBT), and total PAH metabolites (∑PAH) vary with time. The response curve (production of PAH metabolites vs. time) resembled a Sigmoid curve, with an initial low response at 24 h followed by a rapid rise in production of PAH metabolites (55.74 μg/g) 120 h after exposure to DFA. PAH metabolites identified include NPH, PHN, and DBT and their alkylated derivatives, reflecting the composition of the DFA to which the fish were exposed. The GC/MS technique is highly sensitive, particularly in the detection of multi-ring PAH metabolites. The results suggest that analysis of PAH metabolites is a valuable tool for environmental monitoring and assessment of exposure to petroleum.

Evidence of polycyclic aromatic hydrocarbon (PAH) exposure in fish from the Antarctic peninsula

PAH exposure was assessed in fish from Arthur Harbor, Antarctica and sites remote from human activities by measuring the concentrations of polycyclic aromatic hydrocarbon (PAH) metabolites in bile and PAH in tissues and stomach contents. The highest concentrations of biliary metabolites and tissue PAH were present in fish captured near an Argentine supply ship (Bahia Paraiso) that ran aground in Arthur Harbor in 1989. The presence of biliary PAH metabolites in fish collected near Palmer Station, a small US scientific station in Arthur Harbor, suggests low level exposure to contaminants. However, PAH tissue concentrations in fish from Palmer Station were similar to those from remote sites. Both tissue PAH and metabolite concentrations were low in fish captured at sites remote from human activities. The confirmation of PAH metabolites in the bile of fish from Arthur Harbor is direct evidence that the presence of humans has resulted in Antarctic fish being exposed to petroleum-derived PAH.

The use of toxicity bioassays to monitor the recovery of oiled wetland sediments

Six toxicity assays were compared to determine their efficacy in assessing toxicity dynamics during a wetland bioremediation study. The toxicity bioassays used were the Microtox 100% elutriate test, Microtox Solid Phase Test (SPT), amphipod assay, P450 reporter gene system, Toxi-ChromoPad test and a Salmonella/microsome assay. Oiled sediments were analyzed for toxicity in the petroleum biostimulation experiment conducted along the San Jacinto River, near Houston (TX, USA). The bioassays were evaluated for their ability to measure acute toxicity, chronic toxicity, and the mutagenic potential of amended oiled plots as compared to oiled and unoiled control plots. Amendments were diammonium phosphate alone or in combination with potassium nitrate, which served as an alternate electron acceptor. With exception of the Toxi-ChromoPad and Salmonella tests, the bioassays exhibited a significant increase in toxicity after oil application. Microtox bioassays detected significant sediment toxicity up to 29 d after oil and amendment application. The Microtox solid phase test results correlated strongly with gas chromatography-mass spectrometry analyses of total target saturate and aromatic hydrocarbons. The amphipod assay detected initial toxicity with a decline to day 70, followed by a significant increase in toxicity on day 140 in plots receiving nutrient amendments, which may be in response to excessive nutrient application. Low levels of enzyme induction were observed with the P450 reporter gene system assay in all oiled sediments throughout the study, suggesting low but persistent levels of polycyclic aromatic hydrocarbons. Of the six tests, the two Microtox tests and the amphipod test showed the most potential in evaluating petroleum toxicity in wetland sediments.