Edward S. Gilfillan

Identification of petroleum sources in an area impacted by the Amoco Cadiz oil spill

Samples of oiled sediment and tar were taken at locations in the area of Brittany, France known as the ‘Pink Granite Coast’. Each sample was analysed for hydrocarbons by gas chromatography and gas chromatography/mass spectrometry to determine the probable source of any petroleum residues present. The results show numerous recent inputs of various petroleum products including crude oils and light fuel oils at various locations. By 1985, the data indicate that the contribution from remaining weathered residues of Amoco Cadiz oil to the hydrocarbon baseline is small compared to more recent inputs of petroleum.

Shoreline ecology program for Prince William Sound, Alaska, following the Exxon Valdez oil spill. Part 3: Biology

This study describes the biological results of a comprehensive shoreline ecology program designed to assess ecological recovery in Prince William Sound following the Exxon Valdez oil spill on march 24, 1989. The program is an application of the ``Sediment Quality Triad`` approach, combining chemical, toxicological, and biological measurements. The study was designed so that results could be extrapolated to the entire spill zone in Prince William Sound. The spill affected four major shoreline habitat types in Prince William Sound: pebble/gravel, boulder/cobble, sheltered bedrock, and exposed bedrock. The study design had two components: (1) one-time stratified random sampling at 64 sites representing four habitats and four oiling levels (including unoiled reference sites) and (2) periodic sampling at 12 nonrandomly chosen sites that included some of the most heavily oiled locations in the sound. Biological communities on rock surfaces and in intertidal and shallow subtidal sediments were analyzed for differences resulting from to oiling in each of 16 habitat/tide zone combinations. Statistical methods included univariate analyses of individual species abundances and community parameter variables (total abundance, species richness, and Shannon diversity), and multivariate correspondence analysis of community structure. 58 refs., 13 figs., 9 tabs.

Tissue distribution and depuration of tributyltin for field-exposed Mytilus edulis

Abstract The disposition of tributyltin (TBT) within Mytilus edulis tissues and the depuration of TBT from various organs was determined for field populations of animals chronically exposed to environmental sources of TBT. Analysis of dissected organs demonstrated that TBT accumulated to the greatest extent in gill tissue, with TBT concentrations approximately twice that of whole-animal homogenates. A transplant study showed that the depuration of TBT from gill tissue and digestive gland tissue is a biphasic two-compartment process involving a rapid TBT loss process and a concurrent slower TBT depuration process. Whole-body and gonadal tissue depuration followed a slower monophasic depuration process. Depuration half life values ranged from 2.2–5.3 d for the fast depuration component and 28–69 d for the slow component.

Shoreline ecology program for Prince William Sound, Alaska, following the Exxon Valdez oil spill. Part 1: Study design and methods

This paper describes the design and analysis of a large field and laboratory program to assess shoreline recovery in Prince William Sound following the Exxon Valdez oil spill. The study was designed so that results could be generalized area-wide (biology, chemistry) or habitat-wide (toxicology) and projected forward in time (chemistry). It made use of the sediment quality triad approach, combining biological, chemical, and toxicological measurements to assess shoreline recovery. Key aspects of the study include the following: coordinated field sampling for chemical, toxicological, and biological studies; stratified random sampling (SRS) as a basis for spatial generalization; periodic sampling to assess trends, including sites with worst-case conditions; analysis of oil-spill effects on hundreds of species; statistical methods based on normal and non-normal theory, consistent with the structure of the data, including generalized linear models and multivariate correspondence analysis. 45 refs., 5 figs., 4 tabs.

Use of remote sensing to document changes in marsh vegetation following the Amoco Cadiz oil spill (Brittany, France, 1978)

Image analysis of historical aerial photographs was used to examine the effects of the Amoco Cadiz oil spill and resulting clean-up on marsh ecology. Two heavily oiled marsh systems were compared. The marsh which received no clean-up recovered to its prior condition. The marshes in the system cleaned by sediment removal were extensively altered as a result of changes in intertidal height of the sediment surface.

Use of NaK ratios in leaf tissues to determine effects of petroleum on salt exclusion in marine halophytes

Abstract The relationship between sediment hydrocarbon concentration and leaf Na K ratios has been examined in two marine halophytes, Rhizophora mangle and Spartina alterniflora. The plants examined were exposed to petroleum hydrocarbons in the field. Elevated Na K ratios were observed in the leaves of both species of halophytes. The degree of elevation of the Na K ratios was related to the concentration and state of weathering of petroleum in the sediments in which the plants were growing. The mechanism of damage appears to be similar in both species. Elevated Na K ratios appear to result from damage to root membranes.

HYDROCARBON DISTRIBUTION AND WEATHERING CHARACTERISTICS AT A TROPICAL OIL SPILL SITE

ABSTRACT A study was performed on the state of an oil spill site on the southwest coast of Puerto Rico. The location of the study was Bahia Sucia, the site of the Zoe Colocotroni spill of 17 March,...

LONG-TERM FATE OF DISPERSED AND UNDISPERSED CRUDE OIL IN TWO NEARSHORE TEST SPILLS

ABSTRACT The fate and effects of two nearshore discharges of Murban crude oil at Long Cove, Searsport, Maine in August 1981 were studied following a one-year, pre-spill baseline study of the test a...

A Comparison of Shoreline Assessment Study Designs Used for the Exxon Valdez Oil Spill

Shoreline assessment studies may be used after an oil spill to determine whether an injury has occurred and estimate the extent of injuries. Design of these studies generally cannot meet the randomization and replication requirements of classical experimental designs. For example, oil spills cannot be replicated, nor can oiling be applied randomly to experimental units (sites). Furthermore, species counts and other measures of abundance generally do not meet the assumptions of normal theory models. This leaves the statistician and principal investigators the task of finding design and analysis strategies that take into account these departures from standard statistical practices. This paper examines the study design, analysis methods and statistical power (i.e. the ability to detect oil spill effects) of three shoreline assessment programs conducted after the Exxon Valdez oil spill (Exxons Shoreline Ecology Program, the Exxon Valdez Oil Spill Councils Coastal Habitat Injury Assessment study, and NOAAs Biological Monitoring Survey) and shows that the types of techniques used are influenced by study objectives.

LONG-TERM WEATHERING OF AMOCO CADIZ OIL IN SOFT INTERTIDAL SEDIMENTS

ABSTRACT Samples of sediment were taken at intervals between 1979 and 1986 from soft sediment locations in the Aber Benoit, an estuary heavily impacted by the Amoco Cadiz oil spill of 1978, and from a comparable reference site outside the spill zone. Each sample was analyzed for aliphatic hydrocarbons by capillary gas chromatography. The data demonstrate the progressive weathering of the Amoco Cadiz oil resulting in an assemblage of biogenic hydrocarbons similar to the reference site by 1986 at all but the most heavily impacted locations. The data indicate that any residues of weathered Amoco Cadiz oil present in 1985-86 were in the final stages of degradation.