Tracking Exxon Valdez Oil from Beach to Deep-Water Sediments Of

Exxon Valdez Oil Spill Symposium Abstracts

Tracking Exxon ValdezOil from Beachto Deep-WaterSediments of X: Prince William Sound, Alaska Paul R. Carlson and Keith A. Kvenvolde U,S.Geologicut Survey

Prince William Sound, a large, com- aliphatic and aromatic hydrocarbons. plex-fjord-type estuarine system,owes In May1989, wesampledbottomsedi- its configuration to plate tectonicsand ment at 20 stations along the oil spill multiple episodesof glaciation. Gravel trajectory from Bligh Reef southwest beachesdominate exposedsegments of through PrinceWilliam Sound 5 sites! bedrock islands whose steep submarine and along the Kenai Peninsula sites!. slopes are covered with gravelly to Each site was chosen after a 3.5 kHz muddy sediment. Submergedmorainal acoustic profile line was run across the ridges consistof relict diamicts, indicat- prospective sample area Carlson and ing rapid tidal currentsthat sweepaway Reimnitz, 1990!. Most acoustic profile modern fin sediment. Between bedrock lines over box-core sample sites showed and morainal highs of the fjord floor, relatively thick accumulations of post- numerous deepbasins to water depths glacial, unconsolidated mud which is of 800 m! contain Holocene diatom-rich accumulatingin the deep basins today. mud up to 200m thick. Minor amounts Some sites were selected on seafloor of coarsesediment are being introduced highs, and cores from these sites con- into the estuary from a few fjord-head tained pebbly sandy muds, principally a deltas and as bottom load from the Cop- glacial moraine substrate. Oil contami- per River Delta through Hinchinbrook nation could not be positively identified Entrance. The dominant sedimentary in sediment at any of the 15 deep-water materialaccumulating today in this fjord sites sampled two months after the spill. complex is fine suspended sediment Only at one site, near the south end of which is being deposited in deep sedi- Prince William Sound, northeast of ment sinks throughout the sound at rates Latouche Island, did the sediment ex- that vary from 0.3-0.4cm/yr Bothneret tract have chemical indicators of pos- al. 1990!. Much of the insular slopeand sibleoil contamination,but the presence the fjord walls are kept bare of fine sedi- of spilled oil could not be verified Rapp ment settling from the water column by et al., 1990!. complex current circulation within the Nine deep-water sites, originally estuary. sampled in 1989, were occupied 14 We have undertaken four sediment months after the spill in May 1990. No sampling cruisessince the ExxonValdez visible signs of oil were present in the oil spill in March 1989.The cruises May deep-water sediments, but a consistent 1989,May 1990,August 1990,and June increasein the terpane ratios C23/C30 1992!were planned to sample the bot- may be a consequenceof oil-spill con- tom sedimentalong the spill trajectoryto tamination Kvenvolden, et al., 1991!. follow the geological fate of the spilled Relative changes in deep-water samples oil, Sedimentsamples were analyzedfor from 1989 to 1990 in the pristane/phy-

43 ~ Fateand Toxicity: Tracking Oil from Beachto Deep-Water

taneratios suggestchanges in the depo- across the adjacent insular slopes and sitional environment which may or may then collected bottom sediment at sites not be due to the effectsof the oil spill. selectedfrom the profiles. Rapid degra- Seventeenmonths after the spill Au- dation of n-alkanes and isoprenoid hy- gust1990!,six islands Elring ton,Knight, drocarbons limits their usefulness for Eleanor, Smith, Naked, and Storey! and tracking oil in shallow or deep water their insular slopes were investigated sediment. Some of the biomarker char- Carlson et al., 1991!, We found some oil acteristics, such as tricyclic-tetracyclic on all of the beaches we visited. The oil terpane-triplet patterns and sterane/ wasin a varietyof formsincluding sheens diasterane distributions, suggest addi- of oil on water that percolated from the tion of spilled oil to sedimentat elevenof beach sediment; thin coatings of oil on the shallow water stations occupied in sediment or rocks; brown sticky mousse- 1990 Kvenvolden, et al. 1991!. All of like patcheson sedimentand driftwood; these samples are located off beaches and tar or asphalt-like pavements or that were heavily impacted by North patcheson rocks. In the caseof the tar, Slope crude oil spilled from the Exxon two chemically similar samples were Valdez. However, none of the shallow found about 100km aparton the beaches water samplescontained visible tracesof of the north side of Storey Island, and on the spilled oil. the northwest side of Elrington Island. Thirty eight months after the oil spill These tars were not from the Exxon Val- June 1992!, we found oil from the 1989 dezspill becausethey had different ali- spill on beachesof Naked,Green, Knight, phatic biomarker and aromatic hydro- Evans, and Latouche Islands, as well as carbon distributions and markedly tar from other sources. On the same heavier carbon-isotopic compositions cruise,five deep water sites previously than either the spill oil or the oiled sedi- occupied in both 1989and 1990,were ments collected from the beaches visited reoccupied. Samplesfrom thesebeach in August 1990. This tar exhibits the and deep water stations are currently characteristics of oil from the Monterey under investigation. Formation in California Kvenvolden et Prince William Sound circulation is al,, in press!. Theother oil sampleshave stronglyinfluencedby theAlaska Coastal steraneand hopanebiomarker distribu- Current. This current is affected by fresh tions similar to those of a spilled North water discharge which, according to Slopecrude oil samplesecured from the Royerand others 990!, was at a record tanker;however, the oilsfrom thebeaches low in March 1989,the time of the spill. are at various stagesof alteration as evi- They concluded that the spilled oil ad- denced by hydrocarbon distributions. vancedthrough the sound more slowly Forexample, alkylated naphthalenes and than it would have in a normal year. phenanthrenes,as well asn-alkanes and Under these conditions of lower dis- isoprenoidhydrocarbons, have partly or charge,the amount of suspendedsedi- completelydisappeared Kvenvolden, et ment carried by streams draining the al., 1991!. large glaciers bordering the Gulf of After sampling the island beaches, Alaska was probably below normal. we ran high-resolution acousticprofiles Floatingoil, evenafter losing volatiles,is Exxon Valdez Oil Spill Symposium Abstracts

not dense enough to sink, unless bonded ment of Prince William Sound along the oil to particulate matter. If the amount of spill trajectory.In: P.R.Carlson ed.!. Sedi- ment of Prince William Sound, beach to deep particulate matter is low, the probability fjord floor, a year after the ExxonValdez oil ofbonding decreases.This processmight spill. U.S.Geological Survey, Open-File Re- explain the absenceof the spill oil in the port 91-631,pp 1-30. deep-water samplescollected on the 1989 Carlson P.R. and E. Reimnitz. 1990. Character- cruise. On the other hand, if the lower ization of sample sites along the oil spill trajectoryin PrinceWilliam Sound and the fresh-water discharge caused the "flow Gulf of Alaska. In: P.R. Carlson and E. through" to be slowed, the oil would Reimnitz eds.!. Bottom sedimentalong oil have more time to attach to sedimentary spill trajectory in Prince William Sound and particles. However, the general absence along Kenai Peninsula, Alaska. U.S. Geo- of oil in the deep sediment sinks two logical Survey, Open-File Repor t 90-39A, 23 P- months after the spill suggests that the Kvenvolden,K.A., J.B.Rapp, and F.D.Hostettler first scenario is more likely. By the sec- 1991.Tracking hydrocarbons from theExxon ond summer after the spill, there is evi- Valdezoil spill in beach, shallow-water, and dence that traces of oil are migrating deep-water sediment of Prince William from the oil-impacted beachesdown the Sound, Alaska. In P.R. Carlson ed!. Sedi- ment of Prince William Sound,beach to deep insular slopes, and meager evidence that fjord floor, a yearafter the ExxonValdez oil deep basin sediment is showing some spilL U.S.Geological Survey Open-FileRe- trace amounts of oil contamination. The port 91-631,p.69-98. samples collected in June 1992 should Kvenvolden, K.A., F.D. Hostet tier, J.B.Rapp, and show whether or not hydrocarbon con- P.R. Carlson. in press!. Hydrocarbon in oil tamination from the March 1989oil spill residues on beaches of islands of Prince Wil- liam Sound Alaska. Marine Pollution Bulle- has reached the deep-water sediment tin. sinks of the fjord. Rapp,J.B., F.D. Hostettler, and K,A. Kvenvolden 1990. Comparisonof ExxonValdez oil with References extractable material from deep water bottom Bothner, M.H., C.M. Parmen ter,and A.B. Brown. sediment in Prince William Sound and Gulf 1990. Plutonium and 210Pb activities in two of Alaska. In: P.R.Carlson and E. Reimnitz cores from Prince William Sound. In: P,R, eds.!.Bottom sedimentalongoil spill trajec- Carlson and E. Reimnitz eds.!. Bottom sedi- tory in Prince William Sound and along Kenai ment along oil spill trajectoryin PrinceWil- Peninsula,Alaska. U.S.Geological Survey, liam Sound and along Kenai Peninsula, Open-FileReport 90-398, 26 p. Alaska. U.S. Geological Survey, Open-File Royer, T.C., J.A. Verrnersch,T.J. Weingartner, Report90-39D, 10 p. H.J.Niebauerand R.D. Muench.1990. Ocean Carlson,P.R., P.W. Barnes, E. Hayden,and B.A. circulation influencing the ExxonValdez oil Carkin. 1991.Morphology and bottom sedi- spill. Oceanography 3:3-10.

45 ~ Fate and Toxicity: Characterization of Residual Oil

Characterization of Residual Oil in Prince William Sound, Alaska 3.5 Years Later PauleneO. Roberts',Charles B. Henry Jr,', Edward B. Overton', and Jacqueline Miche12 'Louisiana StateUniversity 'ResearchPlanning, Inc

Three and a half years after the T/V ered a variety of microenvironments at Exxon Valdez spill, petroleum still per- Knight, Smith, Perry, Latouche, Block, sists on many of the beaches used as and Crafton Islands, The types of weath- study sites in Prince William Sound. ered oil found on these beach surfaces Presented are the preliminary results of ranged from mousse,asphalt pavements, chemical weathering of residual North water surface sheens, to rock stains and Slope crude in an intertidal subarctic flake. The subsurface samples consisted environment as viewed from an inte- of heavy to light oil residue found in grated chemical weathering and physi- boulder to pebble and sand beach mate- cal transport prospective, Residual oil rial. This range of oil types indicates samples collected on various beaches significantly different physical, cherni- during August 1992are compared to the cal and biological degradation processes original T/V Exxon Valdez cargo oil. are occurring and may have been influ- Weathering studies of oil degrada- enced by natural weathering and the tion indicate the most resistant compo- beach cleaning techniques. For clear in- nents often associated with long-term dications and statistical references to the chronic toxicity are the polycyclic aro- extent of weathering, the samples were matic hydrocarbons PAHs!. ThesePAH analyzedby detailed GC/MS to charac- compounds are used as weathering indi- terize and source-fingerprint the residual cators when the normal hydrocarbons oils collected. are weathered beyond detection. The The GC/MS analysis were completed co11ectionlocations were part of a long- by selective/multiple ion monitoring, term study with the objective of having a focusing on normal alkanes and PAH dose corroboration between geological compounds such as alkyl ate d observations and chemical analysis so dibenzothiophenes, phenanthrenes, that interpretations would include an naphthobenzothiophenes, pyrenes, and understanding of the physical setting and chrysenes,fluoranthene, anthracene,and processeswhich have contributed to the various benzopyrenes. Several of these weathering fates. components are often associated with Due to the great diversity of beach long-term chronic toxicity. These PAH environments impactedbythe T/V Exxon compounds comprise less than 2% of Valdezoil spill, an abundance of trapped original T/V Exxon Valdez oil. GC/MS oil pockets exposed to various degreesof has the sensitivity and capability of se- energy and biological activity were cre- lectively analyzing these compounds by ated, These areas of various exposure the individual peaks or grouping alky- and energy are defined as microenviron- lated compounds. The quantitative re- ments. The August 1992 sampling cov- sults from the analysis have been nor-

~ 46 Exxon Valdez Oil Spill Symposium Abstracts malized for the compositional differences the C-2 and C-3 alkylated homologues of related to weathering and highlighted these compounds that persist. The alky- for relative toxicities. lated naphthobenzothiophene, pyrene All of the samples collected during and chrysenes appear to be the most August 1992 exhibit some degree of persistent aromatic hydrocarbons. Ad- weathering, In general thick residual oil ditional contribution of combustion- without sediments, such as crevice sourced PAHs were detected in some of samples, were only slightly weathered the trace level samples. as characterized by evaporative loss of A general trend is that the rate of the normal alkanes less than nC-12. Close degradation is proportional to the con- examination of the nC-17/pristane and centration of oil in the sample. Subsur- nC-18jphytane ratios suggest some se- face oil and thick oil deposits persist lective microbial degradation has oc- since they are protected from the physi- curred, Samplesof light oil oily residue! ca1processes which breakup the oil into in coarse beach surface material have smaller fragments, creating a greatersur- been highly weathered, as evident by face to volume ratio which aids the natu- significant alteration of the normal al- ral rate of weathering by evaporation, kanes by microbia1 degradation. The dissolution, photomxidation, and bio- PAH pro61e show considerable deple- logical oxidation biodegradation!. tion of the 2-ring naphthalenes and sig- Therefore a majorlimitation tobiodegra- nificant reduction of the 3-ring phenan- dation is the availability of oil to the threnesand dibenzothiophenes; itisonly microbial community. Fateand Toxicity: Toxicity of Intertidal and Subtidal Sediments

Toxicity of Intertidal and Subtidal SedimentsContaminated by the Exxon Valdez Oil Spill DouglasA. Wolfe',Margaret M, Krahn',Ed Casillas', K. John Scott', John R. Clayton, 5 Jr.', John Lunz', JamesR. Payne',and Timothy A. Thompson' 'NationalOceanic and Abnospheric Administration 'ScienceApplications International Corporation 'Sound Etroironrnentai Services, Inc.

This study was conducted under the and with a whole sediment test using the auspices of the State-FederalNatural amphipod Ampeliscaabdita. The 1990 Resources Damage Assessment pro- toxicity testswith amphipods indicated grams. The study was designed to: that: 1! intertidal toxicity was substan- a! demonstrate and quantify the toxicity tially greater than subtidal toxicity; 2! of oiled environmental samples, using mortality was correlatedwith hydrocar- standard toxicity tests; and b! determine bon concentrationsmeasured by UVF in the extent to which any observed toxicity intertidal sediments, but not at other may be attributed to oxygenated, polar depths; and 3! meanmortality for inter- products in weathered oil versus the tidal sedimentsat ten exposedsites in- parent hydrocarbons found in fresh sideof PrinceWilliam Soundwas signifi- crude!. cantly higher than for six referencesites. To estimate the toxicity potential of Significant amphipod toxicity relative sedimentsoiled by the ExxonValdez oil to controls! was demonstrated in inter- spill, standardized toxicity tests were tidal sediments from the following sam- applied to intertidal and subtidal sedi- pling sites all notably oiled, listed in ment samplestaken during thecruisesof order of dedining toxicity!: Northwest the Fairweather in 1989, the Davidson in Bay,Snug Harbor, Block Island, Chugach 1990,and TheBig Valleyin 1991.In 1989, Bay, ChenegaIsland, Sleepy Bay, and the sediment toxicity EC-50's deter- Tonsina Cove. No statistically signifi- mined by Microtox.! was significantly cant toxicity was detected in any sub- rank correlated with hydrocarbon con- tidal sediment samples in 1990,and mean centration, determined by ultraviolet mortalities in subtidal sediments were fluorescence UVF!, in intertidal samples not significantly different between ex- from 42 sites in Prince William Sound posed and referencesites. and impacted portions of the Gulf of In 1991,the mortality of test amphi- Alaska. Toxicity measuredby Mlcrotox. podsrelative to controlsexhibited a lower in subtidal -20m! sediments also rangethan in 1990-50.5%, comparedto showeda generallydecreasing trend with 0-98.7%!,but becausecontrol mortality increasingdistance from the spill center, was lower and less variable than in 1990, as did hydrocarbon concentrations mea- the threshold for statistically significant sured by UVF. differences from controls occurred at Toxicity was estimated in 1990 1 lower levels of mortality. Among the sites in PWS and 8 outside! and 1991 4 eight oiled sites sampled, significant tox- sites in PWS! with a sediment elutriate icity to amphipods was found at Snug testusing larval oystersCrassostrea gigas, Harbor & 20m!, SleepyBay & 6 m!, ExxonValdez Oil Spill SymposiumAbstracts

Northwest Bay & 6 m!, Herring Bay tographyshowed that thewater andsedi- &6m!, Disk Island & 20m!, and Bay of mentsamples from Bayof Islescontained Isles m!. Subtidal m! sediments substantial quantities of petroleum hy- weregenerally as toxic as intertidal sedi- drocarbons representing moderately ments. However, significant toxicity to weatheredpetroleum as evidencedby amphipodswas also found at two of the absence of n-alkanes below C12 and ab- six reference sites sampled: Drier Bay , senceor depletion of mono- and di-aro- 6 & 20 m! and Mooselips Bay m!. matic compounds in the aromatic frac- Significant mortalities of oyster larvae tion!. The pore water sample from were also detected with shallow sedi- Mooselips Bay was essentiaoy free of mentsfrom oiled [SleepyBay m!, Bay petroleum hydrocarbons. of Isles m!, ChenegaIsland & 6 m! Thearomatic and polar fractionsfrom and Block Island & 20 m!] and refer- both siteswere systematically tested with ence sites [Drier Bay m!, Mooselips a varietyof toxicity tests Microtox., SOS Bay m!, MacLeod Harbor m! and Chromotest., bivalve larval survival and Rocky Bay m!]. As a result,the mean normal development, anaphase aberra- toxicities for the oiled and reference sites tions and sister chromatid exchange in in 1991were not significantly different developingbivalve larvae,and teratoge- for either amphipods or oyster larvae. nicity and anaphase aberrations in The observed patterns of toxicity are con- salmonembryos! to determine the rela- sistentwith thegeneral decline of hydro- tive toxicities of the two chemical frac- carbons in the intertidal zone over the tions. Both the aroma.tic and polar frac- period 1989-1991,and with the concomi- tions from Bay of Isles sediment samples tant transfer of hydrocarbonsinto shal- were consistently more toxic than analo- low subtidal sediments, These results gousfractions from MooselipsBay based suggest a significant dedine in oil-re- on Microtox~ and SOS Chromotest~, and lated toxicity between 1990 and 1991, abnormality, anaphaseaberration, and concurrent with the removal and disap- sister chromatid exchange responses in pearanceof the lower molecular weight bivalve larvae, The polar fraction from aromatic compounds. the Bay of Isles porewater samples also To explore which fractions of petro- exhibited greater toxicity for most end- leurn were potentially most toxic, large points than the analogoussamples from samplesof intertidal sediments kg! Mooselips Bay. For the aromatic frac- and interstitial porewatersamples 14- tions from pore water, however, the dif- 170 liters! were collected in September ferences in test results between the Bay 1990from a heavily oiled site Bay of Isles of Isles and Mooselips samp1eswere gen- on Knight Island! and an unoiled site erally insignificant, and the toxicities Mooselips Bay on Montague Island!, approximated that of accompanying The pore waters and sediments were method blanks, extractedexhaustively with a mixtureof In the Bay of Isles samples, the polar methylene chloride and ethyl acetate, and aromatic fractions elicited approxi- and the extractswere subsequentlyfrac- mately equivalent toxic responsesin the tionated by liquid column chromatogra- sediment extracts, while the polar frac- phy into aliphatic, aromatic and polar tion was usually slightly more toxic for components. Analysis by gas chroma- the porewater extracts. There were no

49 ~ Fate and Toxicity: Toxicity of IntertidaI and Subtidal Sediments

consistentpatterns, however, to distin- mentsby the time our sampleswere col- guish responsesto water and sediment lected in faH 1990. samples. For example, EC-50'sfor the Oxidation productsof aromaticcom- Microtox responsewere 10g and 23g pounds in petroleum are produced dry weight! of sediment for the aro- through microbial metabolismand pho- matic fractionsfrom the two Bayof Isles tooxidation, and intermediary metabo- samples,while those for the polar frac- litesof polynucleararomatic compounds tions fram the same samples were 8.9g are known to be genotoxic. Very little and 65g, respectively. Analogous EC- work has beenpublished on thesecom- 50'sfor the two water samplesfrom Bay pounds, but some of them could un- of Isles were 1150 ml and 445 ml for the dergo bioaccumulationand exert toxic- aromatic fractions and 154 ml and 393 ml ity to marine organisms. The present for the polar fractions,respectively. The studies show, however, that very low toxicity test resultswith the fractionated genotoxicresponseswere associated with extracts showed greater differences be- petroleum in the sediments and pore tween Bay of Isles and Mooselips than water from Bay of Isles. were found in the 1990 field survey, in Previousstudies also suggestedthat which Bayofhles sedimentsampleswere oxidation products were unlikely to ex- not significantly more toxic either to ert significant short-term effects under amphipodsor to oysterlarvae than those ambient conditions. For example, al- from Mooselips Bay. This difference though the toxicities of phenol and p- probably reflectsthe heterogeneousdis- cresol! were found to be intermediate tribution of oil in beach sediments. Over- betweenthose of naphthaleneand tolu- all, the results of these toxicity tests on ene naphthalene-5xphenol-2xtoluene!, thesehighly concentratedfractions indi- Korn et al. 985! concluded that the cateverylowsediment toxicity compared phenols were not major contributors to to sediments from industrial or urban the toxicity of water-soluble fractions areas, where Microtoxl EC-50's may be WSF! of oil, because the concentrations 2-3 orders of magnitude lower. of toluene and naphthalene were respec- These toxicity measurements tend to tively about 50x and 2x-7x higher than confirm previous observationsand con- that of phenolic compoundsin the WSF. clusions that the acute toxicity in crude Similarly, Malins et al. 985! identified oil is causedprimarily by low-molecular oxidized products of phenanthrene,in- weight aromatic constituents. In short- cluding carbonyl, quinone, and carboxy- term exposures,molar toxicity appears lic acid derivatives, in seawater after UV to increasewith numberof aromaticrings irradiation of a phenanthrene "slick" for i.e., benzene< naphthalene< phenan- 120 hours. threne!, at least up through 3-ring com- About half of the oxidation products pounds, and alsowith the extentof sub- of phenanthrene in the seawater after stitution i.e.,benzene < toluene< xylene this UV irradiation were not extractable < ethylbenzene,etc.! Rice et al., 1977!. with methylene chloride, indicating oxi- All of these more toxic constituents are dation to highly water-solubleproducts. lost during earlier stages of petroleum VV irradiation of No. 2 fuel oil in a flow- weathering, and were significantly de- through,agitated system caused less than pleted in Prince William Sound sedi- a 2-fold increase in total extractable or-

~ 50 Floe Valdex Oil Spill Symposium Abstracts ganic materials compared to an stituents,whether presentin the parent unirradiated SWAF!, and no differences oil or formed as a result of degradation in were observedin mortalities of English the environment, do not pose a signifi- soleembryos exposed for 48hours. Irra- cant additional risk of toxicity or mu- diation under static conditions, however, tagenicity to marine organisms. enhanced the extractable organic mate- References rial in the SWAF about 23-fold to 161 Korn, S., S. D. Rice, D, L. Cheatham, and D. W, ppm!, andsubstantialmortalityoccurred, Brown. 1985. Contribution of phenol and p- with an apparent EC-50of about25 ppm. cresol to the toxicity of crude oil to pink Preparationof SWAFsfrom Prudhoe salmon Oncorhynchusgorbuscha! fry andkelp Baycrude oil under identical conditions, shrimp Exalts suckleyi!.pp. 447-458In: F.J. Vernberg,F. P.Thurberg, A. Calabrese,and however, produced no differences W. Vernberg eds,! Marine pollution and between flow-through and static physiology: Recent advances. Belle W. conditions either in levels of total Baruch Library in Marine ScienceNo. 13. extractable organic materials or in Univ. South Carolina Press, Columbia, mortalities of English sole embryos. Malins, D. C., S.-L. Chan, R. C. Clark, Jr., and U. Varanasi. 1985. The nature and biological Malins et al. 985! concluded that these effectsof weatheredpetroleum. U. S, Dept. studies provided no evidence that Commerce, NOAA, OCSEAP Final Reports. photooxidation would under most 29:231-285. NOAA Ocean Assessments Di- conditions significantly enhance the vision, Anchorage, Alaska. toxicity of petroleum in the marine Rice, S. D., J.W. Short, and J. F. Karinen. 1977. A review of comparativeoil toxicity and com- environment. parativeanimal sensitivity. pp. 78-94ln: D. Along with theresults presentedhere, A. Wolfe ed.! Fate and effects of petroleum previous studiessuggest that polar con- hydrocarbonsin marineorganisms and eco- systems,Pergamon Press, New York. Fate and Toxicity: Microbial Activity in Sediments

Micmbial Activity in Sedimentsfollowing the T/V ExxonValdez Oil Spill JoanF. Braddock',Jon E. Lindstrom', ThomasR. Yeager',Brian T. Rasley',Gregory g Winter' and Edward J. Browne ' Universityof AlaskaFairbanks 'AlaskaDepartment ofFnvironrnental Conservation 'University of Northern Imua

Shortly after the grounding of the tine environmentare perturbed with oil, Exxon Valdez on 24 March 1989, the Na- this distributionreflects theextent, move- tional Oceanicand Atmospheric Admin- ment and persistenceof the contamina- istration NOAA! organized a multi-in- tion. vestigatorcruise to documentthe extent We sampled 38 sites within Prince of oil contamination of coastal habitats in William Sound throughout a three year Alaska. This first survey cruise was fol- period following the oil spill. In these lowed by five seasonalcruises over the sampleswe measurednumbers of hy- next 2 yearsorganized as a jointeffort of drocarbon-degrading microorganisms NOAA and the Alaska Department of and mineralizationpotentials of radiola- Environmental Conservation. The pur- belled hydrocarbon fractions in shore- poseof thesesurvey cruiseswas to docu- line sediments and subtidal surface sediment oil concentration distributions and ments at depths to 100m. Depending on assessthe relative ecologicalimpacts of the cruise,up to 6 isobathswere sampled the spill to intertidal and subtidal areas. for each site; intertidal m!,3 m, 6 m,20 Assessmentof microbial populations m,40m,and100m. Atthe0m,3m,6m, was an important componentof the sur- and20 m isobathssediment sampleswere veyssince a majorfate of petroleumcon- made up of subsamplescollected from taminants in marine environments de- eight random locations along a 30 m pends on the abHity of microorganisms transect parallel to shore by shore party to use hydrocarbonsas a sourceof car- or SCUBA divers. The 40 m and 100 m bon and energy Leahy and Colwell, sampleswere collectedby Van Veen or 1990!. Additionally, patterns of hydro- Smith-Maclntyregrabs and subsampled carbon mineralization activity and dis- from the surface of the sediment. The tribution of hydrocarbon-degradingmi- number of hydrocarbon-degradersin croorganismscan be used as an indica- eachsample was estimatedby using the tion of in situ biodegradation of petro- SheenScreenmost probablenumber tech- leum Madsen et al., 1991!. Measure- nique which uses disruption of an oil ments of total numbers of hydrocarbon- film to indicatethe presenceof hydrocar- degrading microorganismsand assays bon-metabolizing microorganisms for the mineralization potential of hy- Brown and Braddock, 1990!. Radio- drocarbonfractions bythesepopulations respirometry was used to assaythe hy- provide evidenceof the presenceof hydrocarbon-oxidation potential of micro- drocarbonsthat canbe utilized by microorganisms in sediment slurries Brown organisms.When sedimentsfrom a pris- et al., 1991!. The compounds [1-'4C]- Exxon Valdez Oil Spill Symposium Abstracts hexadecane, [1,+,8!-'4C]-naphthalene carbon-degradersfound in 1978 Roubal and [9-'4C]-phenanthrenewere used as and Atlas, 1978!. In fall 1989 all 14 shore- paradigms of' aliphatic and polycyciic line sitessampled in this study had high aromatic hydrocarbons. Hexadecane numbers of hydrocarbon-degraders, potentials were determined after 2-day rangingfrom 3,6x 103to 5.5x 10'cells/g incubations. Tweed-y naphthaleneand dry weight sediment;reference sites had phenanthrenepotentials were univer- a medianof 38 cells/g dry weight sedi- sally very low and referencesites sites ment, Statistically significant higher known not to have been oiled by the numbers of hydrocarbon-degraders were Exxon Valdezoil spill! were generally 0 or observed at these oiled sites than at the near 0 after 10 days for all cruises. For reference sites. Median numbers of hy- these reasons, 8- or 10-day incubations drocarbon-degrading microorganisms were used for naphthalene and phenan- on the shorelines in Prince William Sound threne data. Significant differences at decreasedfrom 1989through 1991.How- the 95% confidence level! for numbers of ever, there werestill several shorelines in hydrocarbon-degradersor mineraliza- the summerof 1991that had > 10'hydro- tion potentials at a sitecompared to the carbon-oxidizingbacteria jg dry weight reference sites were determined by the sediment. In the summer of 1989, num- Mann-WhitneyU Test Zar, 19S4!. bers of hydrocarbon-degradersin sub- Thenumbers of hydrocarbon-degrad- tidal surface sediments at depths greater ing bacteria vary by several orders of than 6 m were below the detection limits magnitude among sites and dates of the assay < 13/g dry weight sedi- sampledafter the ExxonValdez oil spill. ment!. However, at some sites by the Rangesfor numbers of hydrocarbon-uti- summer of 1990,there were measurable lizing bacteriaduring 1989in this study numbers of hydrocarbon-degradersat were similar to those found for the Amoco all depths beachthrough 100rn!. Data Cadizoil spill Ward et al., 1980!.Micro- from the summer of 1991 show a trend bial studies in Alaskan coastal sediments toward much lower total numbers of conducted before the Exxon Valdez oil hydrocarbon-degradersfor all sitesand spill are limited in number, A 1975-1977 depths,implying that conditions are no survey of Cook Inlet and the Gulf of longer favorable for biodegradation or Alaskafound the highestmean numbers that biodegradablehydrocarbons are no of hydrocarbon-oxidizing bacteria de- longer present. termined by a plate count method to be The median 2-day hexadecane min- 8,4 X 103cells/g dry weight of sediment eralizationpotentials maintained a fairly at a site in upper Cook Inlet near several constant level through the fall of 1990 oil wells Roubal and Atlas,1978!. These and then dropped dramatically by the authors hypothesized that sediments summerof 1991.In spring andsummer containing10' to104 oil-degrading bacte- of 1990many sites,even at depth, had ria/g dry weight probably had a previ- potentialsfor hexadecanemineralization ous history of oil exposurefrom either significantly greater than the reference biogenic or polluting sources. sites. However, in the fall of 1990only a In the summer of 1989, eleven shore- few sites had potentials significantly line sites in Prince William Sound ex- greater than the referencesites. By the ceeded the maximum value for hydro- summerof 1991potentials ofhexadecane Fateand Toxicity: Microbial Activity in Sediments

mineralization were low at all sites. The The numbers and activity of thesemicro- reduction of the hexadecane mineraliza- organismsare good indicators of expo- tion potentials may be due to a decrease sure of sediments in Prince William in numbers of microorganisms accli- Soundto hydrocarbonsand may be use- mated to hydrocarbon biodegradation ful indicators of the mobilization of hy- or a decrease in the hexadecane remain- drocarbons with time. The increase of ing in the sediment, or some combina- numbersof hydrocarbon-degraderscom- tion of the two factors. paredto likely pre-spillvalues, coupled Median potentials of polycyciic aro- with high mineralization potentials for matic hydrocarbons PAH! oxidation hexadecaneand phenanthrene,also pro- increased with time from the summer of vide evidence of rapid acclimation of 1989reaching a maximum in 1990and naturally occurring microbial popula- then dropping to much lower levels in tions for biodegradation of these com- 1991. The potentials for phenanthrene pounds in most sediments. mineralization were slightly greater References when mineralization potentials for naph- Brown, E. J. and J. F. Braddock. 1990, Sheen thalene and phenanthrenewere run on Screen,a miniaturized most probable num- the same sediment samples Fall, 1989!. ber method for enumerationof oil-degrad- This finding is supported by a previous ingmicroorganians.Appl. Environ, Microbiol. study of polluted sediments in Boston 569895-3896. Brown, E. JS, M. Resnick, C. Rebstock, H. V. Harbor, Massachusetts,where naphtha- Luong and J. E, Lindstrom, 1991. UAF lene turnover times in the Harbor were radiorespirometric protocol for assessing found to exceed those for phenanthrene hydmcarbonmineralization potential in en- Shiaris, 1989!. The difference in poten- vironmental samples. Biodegradation2:121- 127. tials between phenanthreneand naph- Leahy,J. G. and R. R. Colwell. 1990.Microbial thalene seen in Prince William Sound is degradationof hydrocarbonsin the environ- unlikely to exclusively account for the ment. MicrobioL Rev. 54:305-315. increasein mineralization potentials of Madsen, E. L., J, L. Sinclair and W. C. Ghiorse. PAH between summer of 1989 and sum- 1991. In situ biodegradation:microbiologi- mer of 1990. Mineralization potentials cal patternsin a contaminatedaquifer. Sci- ence 252MG-833. for phenanthreneremained high through Roubal,G. and R.M. Atlas. 1978. Distribution of the fall of 1990but declined substantially hydrocarbon-utilizingmicroorganisms and by thesummer of 1991,The data for the hydrocarbon biodegradation potentials in summer of 1991 show that there were Alaskacontinental shelf areas. AppL Environ, still many sites with high phenanthrene MicrobioI. 35:897-905. Shiaris, M. P. 1989. Seasonalbiotransformation oxidation potentials relative to the refer- of naphthalene, phenanthrene, and ence sites. However, the absolute values benzo[alpyrenein surficial estuarinesedi- for mineralization potential were much ments.Appl. Environ. Microbiol,55: 1391-1399. lower than for previous cruises. Ward, D. M., R. M. Atlas, P. D. Boehm and J. A. The objective of our study was to Calder.1980. Microbial biodegradation and chemical evolution of oil from the Anloco document the impact of the KxxortValdez spill. Arnbio9:277-283. oil spill on the population and activity of Zar, J. H. 1984. Biostatisticalanalysis, 2nd Ed. hydrocarbon-degradingmicroorganisms Prentice-Hall,New Jersey. in sediments in Prince William Sound. Exxon Valdez Oil Spill Symposium Abstracts

Contamination of Subtidal Sedimentsby Oil From the Exxon Ualdez in Prince William Sound, Alaska C. E. O'Clair, J. W. Short and S. D. Rice NationalOceanic and Atmospheric Administration

The purpose of this project was to Geographicaldistribution: assessthe degree of petroleum hydro- Petroleumhydrocarbons were found carbon contamination of subtidal sedi- to have contaminated subtidal sediments ments from 32 locations in Prince Will- over a broadgeographic range in Prince iam Soundresulting from the ExxonVal- William Sound from the north end of dezoil spill. In this paper we summarize Eleanor Island to southern Elrington Is- somegeographical, bathymetric and tem- land. Lower intertidal m! sediments poral trends resulting from analysisof werecontaminatedby Exxon Valdez oil at data collected during the first 2 years no fewer than nine locations in 1989 and following the oil spill. 12 locations in 1990. Subtidal sediments We sampled sediments intertidally werecontaminated by ExxonValdez oil at and at five subtidal depths in the range 0- no fewer than 12 locations where oil had 100 m in summer and 0-20 m in spring come ashore oiled locations! in 1989 and and fall. Shallow sediments -20 m! 1990. Those locations constituted 67% of were collectedby beachteams or divers oiled locations studied in 1989 and 86% on 30 m transects laid along the appro- of those oiled locations studied in 1990. priate isobath. Deep sediments0 and Contamination of subtidal sediments by 100 m! were collected with grabs. Trip- Exxon Valdez oil at oiled locations reached licate composite sediment samples were a depth of at least20 m at sevensites in collected at each station. Sediments were 1989 and at 14 sites in 1990. sampled in May, July, Septemberand Bathymetric distribution: November 1989 and in June, July and Thegreatest concentrations of Exxon September1990. Oil concentrations,re- Valdez oil in benthic sediments were ported in mg/g ppt!, are estimatesof found in the lower intertidal region equivalent concentrationsin sediments m!. An averageconcentration n=3! as of original fresh! ExxonValdez oil and high as 24.7mg/g was found.at 0 m on are based on a weathering model devel- Disk Island in July 1989, The greatest oped in conjunctionwith principal com- concentrations of Exxon Valdez oil in sub- ponentsanalysis PCA;Shortand Heintz, tidal sediments were found at the shal- theseproceedings!. Exxon Valdez oil con- low depths. The highest concentration centrations less than 25 p.g/g sediment recorded was 5,2 mg/g in a sediment are not detected using this model be- samplecollected at about 3 m at Sleepy causecorresponding concentrationsof Bay in September1989. Concentrations individual polynuciear aromatichydro- of ExxonValdez oil exceeding 1.0mg/g in carbons on which the model is based subtidal sediments occurred at nine lo- approach analytical method detection cations in 1989 and reached a depth of limits of about 1 ng/g. 20 m at Eshamy Bay in July 1989. How-

55 ~ Fate and Toxicity-. Contaminabon of Subtidal Sediments

ever, no significant difference was found moved to greater depths over time. in theconcentration of oil betweendepths Northwest Bay and Herring Bay showed at oiled sites in July when all depths significantdecreases p<0.01 and p<0.001 were sampled!. In 1990the highest con- respectively! in the concentration of oil centration of oil in subtidal sediments in sediments at mean lower low water recorded was 4.3 mg/g at 20 m at Fox m! between May 1989and September Farm in September. Concentrations of 1990. Atboth sites, the oil concentrations oil exceeding 1.0 mg/g were found at in sediments collected at 3 m did not twolocations Herring Bay and Fox Farm! change significantly between May 1989 reaching a depth of 20 m at both sites. and September 1990. At Northwest Bay In July 1990when all depths were the concentration of oil in sediments at 6 again sampled oil concentrations in sedi- m peaked = 0.95 mg/g, p<0.05! in Sep- ments at oiled sites were greater p<0.0 l! tember 1989, whereas oil concentrations at 3 and 6 m than at greater depths. The in sediments at 20 m showed no signifi- majority of sediments from 40 and 100m cant change during the study period. At were found not to be contaminated with Herring Bay no significant change oc- Exxon Valdez oil. Where contamination curred in oil concentrations in sediments was found it was at relatively low con- at 6 m during the study period, but concentrations &.43mg/g,1989; <0.45mg/ centrations changed at 20 m reaching a g, 1990! of oil. maximum = 0.55mg/g, p<0.05! in Sep- tember 1990. Temporal distribution: Oil wasdetected insubtidalsediments Examination of temporal changesin at a number of locations in Prince Will- the contamination of sedimentsby oil iam Sound butconcentrations weremark- revealed that detectable quantities of edly lessthan in sedimentsamples from Exxon Valdez oil moved over time to shal- heavily oiled intertidal sites. Oil became low subtidal depths at locations with broadly distributedin subtidalsediments heavilyoiled shorelines.At SleepyBay during the first 2 years following the no significant trend was seenin the con- ExxonValdez oil spill. Oil concentrations centration of oil in sediments at mean attained their highest values in the low lower low water m! betweenMay1989 intertidal and shallow subtidal -20 m! and September1990. Nevertheless, over regions. the same period of time subtidal sedi- Sediments collected at 40 and 100 m ments at 3, 6 and 20 rn in Sleepy Bay were for the most part not contaminated showed increasingoil concentrationsto with Exxon Valdez oil. There was some a peak concentrationfollowed by a de- indication that some movement of oil dine to levelscomparable to earlypost- down slope took place at heavily con- spiDlevels or less. At the 3 m depth the taminated sites. Although oil concentra- peak p<0.05! occurred in September tions in subtidal sediments were prob- 1989. The peak occurred in November ably not acutelytoxic to most organisms, 1989at 6 m p<0.005!and 20m p<0.01! the low-level oil concentrations were and persistedat 6 m until June 1990. widespread, persistent over the 2-year At Northwest Bay and Herring Bay period, and would be a sourceof chronic also there was some evidence that oil exposure to subtidal communities. KxxonVatdex Oil Spill Symposium Abstracts

Determination of Petroleum-Derived Hydrocarbons in Seawater Followingthe Exxon Valdez Oil Spill I: Analysisof SeawaterExtracts JeffreyW. Short and PatriciaRounds NationalOceanic and Atmospheric Administration

We analyzed samplesof subsurfaceconfidenceinterval, n = 3! at Snug Har- seawater within Prince William Sound bor, and rangedfrom 1,92+0.40ji,g/L to following the Exxon Vtddezoil spill, to 5.23 + 1.27 pg/L at sampling stations evaluate the extent of water contamina- nearheavily oiled beachesof Northwest tion by petroleum hydrocarbons.These Bay,Herring Bay, southeastEleanor is- sampleswere collectedin three groups land, north Smith island, and the Bay of beginrung1,3, and 5 weeksfollowing the Isles, These summed PAH concentra- oil spill. Triplicate samples were col- tions include PAH's from any source, lected from depths of 1 and 5 metersat and do not distinguish PAH's associated the 30 locationssampled, which ranged with particulateoil and dissolved PAH's. from heavily oiled locations to control Elevated PAH concentrations were also locations that were not affected by the detected atseveral more open-water sites spill. All three of the triplicate samples between Knight and Montague islands. were analyzed from the first group of At all these sites, summed PAH concen- samplescollected, but only one of the trations were slightly higher at the 1 m three triplicate samples was analyzed depths than at the 5 m depths. from each of the subsequent two groups. In contrast, summed PAH's werelow- Each 900 ml seawater sample was ex- est at sampling stations that were near tracted twice with a total volume of 75 ml the margin or else were distant from the dichloromethane within 5 minutes of path of the spilled oil through the Sound. initial collection, then stored at -20' C PAH concentrations typically ranged until analysis. from 0.4+ 0.2 to 1.5+ 0.6 p,g/L seawater Thesesamples were analyzedusing at these locations. single ion mode gas chromatography- The relative concentrations of indi- massspectrometry GCMS/SIM! for the vidual PAH's differed markedly among most abundant 2 to 5 ring polynuclear the sampling sites. At sites near the aromatic hydrocarbons PAH's! in the margin or distant from the path of the spilled oil, and using gas chromatogra- spilled oil, naphthalene was the predomi- phy-flame ionizatio detectionfor alkane nant PAH compound detected, account- hydrocarbonsincluding pristane, phy- ing for 40%to100% of the summed PAH's tane, and the normal alkanes of 10 to 30 found. Although naphthalene was con- carbonatoms C10to Cg. sistently detectedat both 1 mand 5 m at During the first sampling period, these sites, other PAH's were only spo- summed PAH's were highest at sam- radically detectedat concentrationsnear pling stations adjacent to beachesthat detection limits. wereheavily contaminated by thespilled However, at sites near heavily oiled oil. Summed PAH concentrationsranged beaches,or at the more open-water sites up to 6.60 + 0.62 pg/L seawater 95% between Knight and Montague islands

57 ~ Fateand Toxicity: Determinationof Petroleum-DerivedHydrocarbons in Seawater

where elevated PAH concentrations were results. The second conclusion derives found, numerous PAH's were simulta- from the ubiquity of naphthaleneat a neously detectedat concentrationssub- minimum apparent concentration of stantially abovedetection limits. Naph- about 0.4 pg/L seawater;a similar pat- thaleneaccounted for generallyless than tern of naphthalenedetection persisted 40% of the PAH's found at these sites, in the secondand third sampling peri- and the proportion decreasedwith in- ods. creasingsummed PAH concentrations. We estimated total PAH's attribut- At sitesnear heavily oiledbeaches, or able to Exxon Valdezcrude oil in samples at the more open-water sites between where PAH's are strongly correlated. Knight and Montagueislands where el- This estimate is the sum of measured evated PAH concentrations were found, PAH's except naphthalene; plus an relative concentrations of detected PAH's amountofnaphthalene proportional with are very highly correlated with corre- measured amounts of 'l- and 2-methyl- sponding relative PAH concentrations naphthalene,consistent with this same of Exxon Valdez crude oiL Product-mo- proportion in ExxonValdez crude oil. In ment correlation coefficients of PAH's in everycase, the naphthalene calculated in Exxon Valdez crude oil and in samples this manner as attributable to Exxon Val- from these sites generally range from dez crude oil is less than the measured 0.85 to 0.95 P < 0.001! with 14 to 18 amount of naphthalenein the sample. PAH's induded in the correlation but Exxon Valdez oil PAH's EVO-PAH! with naphthaleneexcluded!.Also, PAH's arequantitatively parallel with summed that are absentor presentat low relative PAH's: EVO-PAH concentrationsranged concentrations in Exxon Valdez crude oil up to 6.24+ 0.63pg/L seawaterat Snug were not detected in these samples. Harbor, and rangedfrom 1.26+0.40 pg/ We conclude from these results ! L to 4.72+ 1.18p.g/L at sampling stations that Exxon Valdezcrude oil is the proxi- nearheavily oiled beachesof Northwest mate sourceof PAH's in sampleswhere Bay, Herring Bay, southeastEleanor is- measured PAH's are elevated and land, north Smith island, and the Bay of strongly correlated with Exxon Valdez Isles. Elevated EVO-PAH concentrations crude oil PAH's, and ! that an addi- were also detected at several more open- tional sourceof naphthaleneis presentin water sites between Knight and allsamples,suggestingan unknown sam- Montague Islands. At all these sites, pling contaminationsource for naphtha- EVO-PAH concentrations were gener- lene only. The first conclusionderives ally somewhathigher at the 1 m depths from the dose association of samples than at the 5 m depths. containingelevated PAH concentrations EVO-PAH concentrationsgenerally with areas directly impacted by the declined with time. At most sites, EVO- spilled oil, the strong correlationof rela- PAH concentrations dedined by a factor tive PAH concentrations in thesesamples of 2 or more from the first to the second and in the spilled oil, the generalabsence sampling period, and by more than a of these PAH's in samples from areas factor of 2 from the second to the third marginal or distant from the path of the sampling period. Exceptions included spilled oil, and the absenceof a plausible sites where oiled beach dean-up activi- alternativeexplanationof these observed ties had commenced, such as at Herring

58 Exxon Valdez Oil Spill Symposium Abstracts

Bay or Snug Harbor, where EVO-PAH forces to the seawaterphase and to the concentrations increased slightly by the remaining oil phase, and by the relative second sampling period at some depths. concentrations of the PAH's in the oil. EVO-PAH's were not evident at any Differences of these attractive forces open-water site after the first sampling among PAH's are approximately pro- period, and were generally less than 1 portional with molecular surface area, p.g/L seawaterat any site by the third which varies by less than a factor of 2 sampling period. among the EVO-PAH's naphthalene Comparisonof EVO-PAH concentra- through CX phenanthrene!,whereas the hons and.C through C n-alkane con- relative concentrations of these com- centrations suggests the presence of at pounds in the oil vary more than 30-fold. least some particulate oil in the samples Initial dissolution rates are therefore that contained EVO-PAH's, To estimate mainly determined by relative concen- relative proportions of dissolved and trations in the oil. In contrast, solubility particulate EVO-PAH's, we calculated is not an important factor because con- an aromatic hydrocarbon enrichment centrations attained by dissolved PAH's factor AHEF! as the ratio of EVO-PAH are well below solubility limits, and the measured in a sample,and the minimum volume of affected seawater in Prince expected EVO-PAH based on measured William Soundis much greaterthan the C through Cn-alkane hydrocarbons. volume of the spilled oil, thereby guar- At sites where PAH's are strongly corre- anteeing that solubility limits of EVO- lated with Exxon ValdezPAH's, this AHEF PAH's are never approached. ranged from 0.69 to 5.99. Values of this Although readily detectable, these AHEF near 1 areconsistent with particu- concentrations of EVO-PAH's are well late oil, whereas values substantiaBy below levels that are acutely toxic to above 1 indicate dissolved PAH. How- marine fauna. On the other hand, these ever, this AHEF index is not rigorous data demonstrate that PAH's from Exxon indicator of parhculate oil, because val- Vatdez crude oil were available to sub- ues near 1 may by chance be due to surface marine fauna the first few weeks dissolved EVO-PAH's present with odd following the oil spill, especiallyin near- carbon-numbered alkanes derived from shore,near-surface waters that are par- natural sources. ticularly productive areasbiologically. The relative concentrations of dis- In addition, if mononuclear aromatic solved EVO-PAH's suggests they are hydrocarbons had been measured in determined by dissolution kinetics, and addition to the PAH's that were mea- not by solubility of individual PAH's. sured, total aromatic hydrocarbon con- Relative dissolved PAH concentrations centrations in the seawater column de- that correlate strongly with thoseof Exxon rived from spilled ExxonValdez oil would Valdezcrude oil, suggeststhat the com- almostcertainly have been higher, possi- positionof dissolvedPAH's matchesthat bly exceedingthe Stateof Alaska water of the oil. The initial relative rates of quality standard of 10 pg/L seawater, dissolution of individual PAH's are de- becausemononuclear aromatic hydro- termined by differences among indi- carbons are much more abundant than vidual PAH's of molecular attractive PAH's in crude oil.

59 ~ Fateand Toxicity: Methods for DeterminingCrude Oil Contamination

Methods for Determining Crude Oil Contaminationin Sediments and Biota After the Exxon VaIdez Oil Spill MargaretM. Krahn, Gina M. Ylitalo, Douglas G. Burrows, Jon Buzitis, Sin-Lam Chan g and Usha Varanasi NationalOceumc and Atmospheric Administration.

Thegrounding of the ExxonValdez on to bile for excretion, AC metabolites must March 24,1989 spilled almost11 million be measured in these animals to estab- gallonsof PrudhoeBay crude oil PBCO! lish their exposureto PBCO.Concentra- into the waters of Prince William Sound, tions of metabolites were estimated in Alaska. As part of the Natural Resource bile of fish and marine mammals using a DamageAssessment effort, thousands reverse-phasehigh -performanceliquid of samplesof sediment and biota were chromatographic HPLC! screening collected to determine the distribution of method that measured fluorescence at thespilled crude oil andthe exposureof wavelength pairs specific for 2- and 3- the marine animals. Therefore, the use of ring petroleum-relatedACs Krahn et aL rapid, low-cost analyticalmethods, gen- 1992!. Then, GC/MS was used to vali- erally known as screeningmethods, to date the HPLC screening results by mea- estimate concentrationsof petroleum- suring concentrationsof individual me- related aromatic compounds ACs! in tabolites of petroleum-related ACs, e.g., sampleswas vitally important to thepro- alkylated naphthols and phenanthrols, duction of timely information in the in these animals. Because the concentra- emergencyresponse. Screeningmeth- tions of metabolites measured by HPLC ods can rapidly processlarge numbers screeningand sums of AC metabolites of samplesto provide a semiquantitative from GC/MS were highly correlated, estimate of contaminant concentrations the bile screening method was validated and thus, allow ranking of samplesby as an effective tool for estimating con- degreeof contamination. Accordingly, centrations of AC metabolites. Screen- the most contaminated samples can be ing for crude oil in sediments locatedbyscreenmg;then, detailed analy- Followingthe Exxon Valdez spill, thou- ses,e.g.,gas chromatography/mass spec- sands of sediment samples were col- trometry {GC/MS!, can be focused on lected to determine the degree and dis- the selectedsamples to confirm thepres- tribution of the oiling. Becauseanalyz- ence of contaminants. Screeningfor ing all thesesamples by GC/MS would metabolites of ACs in fish and marine be excessively expensive and time-con- mammals suming,priorities for analysesneeded to Thousands of samples of fish and beset. Therefore, a size-exclusion HPLC marine mammals were collected from method used previously to measureAC the ExxonValdez spill areato determine contaminants in urban sediments Krahn the exposureof these animalsto PBCO. et al. 1991! was employed to determine Because fish and marine mammals ex- concentrations of PBCO in more than 400 tensively metabolizemost ACs in their sediment samples, Sediments from a livers and themetabolites are transferred large number of sites in the spill area Exxon Valdez Oil Spill Symposium Abstracts were surveyed and many were found to establishedby examining GC/MS re- be contaminated by PBCO Krahn et al. sults. For example,evidence of PBCO submitted!. Similar to the results for contamination in fish and marine mam- bile, summed concentrations of indi- mals was provided by identifying high vidual ACs in the sediments determined proportions of certain bile metabolites by GC/MS were found to be higMy cor- i.e., the alkylated naphthols, phenan- related with the concentrations of ACs throls and dibenzothiophenols!that re- measured by HPLC screening method. sult from the metabolic conversion of Thus, the utility of the rapid HPLC ACs that are characteristic of PBCO screening method has been extended to Krahn et al. 1992!. analyzing sediment samples for the ACs The HPLC chromatograms from characteristic of crude oil, thereby di- sediment are easierto interpret than those recting priorities for GC/MS analyses. from bile. These chromatographic pat- As a result, the overall costsof the analy- terns are less variable than those from ses have been reduced, while still pro- bile, because the size-exclusion chroma- viding the necessary detailed data in a tography is stableand becausesediment timely fashion. screeningmeasures the ACs themselves. Establishing source of contamination Many of the confoundingfactors present in the bile chromatograms due to spe- by HPLC and GC/MS analyses cies- specific differences in degree of When fish or marine mammals were metabolism or excretion of metabolites exposed to PBCO in the field or injected are not found in the sediment chromato- with PBCO in the laboratory, the chro- grams. However, HPLC chromato- matographic patterns were similar, but graphic patterns were not consistent some differences were also apparent. amongall the extracted sedimentsfrom Variations in bile chromatographic pat- the Prince William Sound area. The dif- terns can occur because of variations in ferenceswere not due solely to the de- the degree of exposure of individual gree of weathering of the crude oil, but animals to the oil or to species-specificreflected different sources of ACs, e.g., differencesin metabolism of the petro- crude oil or diesel fuel Krahn et al. sub- leum ACs. mitted!. In addition, physical factors from the For example,the chromatogramsof chromatographic processitself, such as Herring Bay and Knight Island sedi- the chromatography column used, the ments,two sitesthat were heavily oiled, condition of the column or the acidity of were nearly superimposablewith those the mobile phase, can affect the appear- from weathered PBCO. Furthermore, anceof a chromatogramin reverse-phase the chromatographicpatterns from the HPLC. Therefore, due to both the vari- Herring Bay and Knight Island sedi- ability of the metabolic process in vari- mentswere very different from thoseof ous fish species and to the variability of other sources of contamination e.g., the reverse-phase chromatography of diesel fuel or marine lubrication oil! that the metabolites, the HPLC chromato- might be found in Alaskan sediments. graphic pattern of bile can only suggest In contrast, results from screening sedi- the type of contamination. However, the ments from MacLeod Harbor and Olsen source of contamination can often be Bay, sites not in the direct path of the Fateand Toxicity: Methodsfor DeterminingCrude Oil Contamination

spill, revealedlow concentrationsof ACs contaminant sources.As a result, expen- and an HPLC chromatographic pattern sive GC/MS resourcescan be effectively that resembled that of diesel fuel, The allocated. This approach combining contaminant source suggestedby HPLC HPLC screeningfor petroleum-related screeningof thesesediments could often ACs or their metabolites in sediment be confirmed by comparing the identi- and bile with confirmation of contami- ties and proportions of the ACs deter- nant concentrationsin selectedsamples minedby GC/MS to similar characteris-by GC/MS has proven useful in estab- tics of the probable sources. For ex- lishing the extent of damageto natural ample, evidencefor PBCOas the source resourcesfollowing the ExxonValdez oil of contamination in many Prince Will- spill, iam Sound sediments e.g,, those from References Herring Bay and Knight Island! was Krahn, M. M., D.G. Burrows, G.M. Ylitalo, D.W. provided by identifying in thesesamples Brown, C. A. Wigren, T. K. Collier, S.-L. the high proportions of the alkylated Chan and U. Varanasi. 1992. Mass spectro- metric analysis for aromaticcompounds in naphthalenes, phenanthrenes and bile of fish sampledafter the ExxonValdez oil dibenzothiophenesthat arecharacteris- spill. Environ. Sci,Technol. 26:1'l6-126, tic of this crude oil Krahn et al. submit- Krahn, M.M., G.M. Ylitalo, J.Joss and S.-L.Chan. ted!. 1991,Rapid, semi -quantitative screening of The HPLC screening methods have sedimentsfor aromatic compounds using sonic extraction and HPLC/fluorescence important rolesin evaluating anthropo- analysis. Mar. Environ. Res. 31:175-196. genic contamination in samplesof bile Krahn,M.M., G. M, Ylitalo, J.Buzitis, S,-L, Chan, and sediment. First, samples containing U. Varanasi, T. L. Wade, T. J. Jackson,J. M. AC contaminantscan be rapidly ranked Brooks, D, A. Wolfe and C.-A. Manen. sub- by degreeof contaminationand second, mitted. Comparisonof HPLC/fluorescence screeningand GC/MS analysisfor aromatic HPLC chromatographic patterns can compoundsin sedimentssampled after the provide a basis for suggestingpossible ExxonVaMez oil spill. Environ. Sci.Technol.

~ 62 ExxonVatdez Oil Spill SymposiumAbstracts

Qualitativeand QuantitativeDetermination of ExxonValdez Crude Oil in SedimentSamples Using Principal Component Analysis of Hydrocarbon Data JeffreyW. Shortand Ronald A. Heintz NationalOceanic and Atmospheric Administration

We have developed a model for sedi- accounts for more than 96% of the data ment hydrocarbondata that maybe used variance, First-order rate constants for to ! distinguish ExxonValdez oil con- hydrocarbon analyte losses were esti- tamination from other sourcesof hydro- mated using this data subset, and the carbons, ! estimate the original amount relative magnitudes of these constants of Exxon Vatdez oil in sediments when indicatesthat the weathering processis present, and ! determine the relative predominantly kinetically controlled, degreeof weathering of a sample, The where the rate of lossof aromatichydro- model is derived from an assumptionof carbonanalytes decreases with extentof first-order loss kinetics of each of the alkyl substitution. hydrocarbonanalytes employed, where Use of this model as an interpretive principal componentanalysis is used to aid and asa unifying framework will be identify a weatheringpattern that is char- presented,together with resultsof the acteristic of spilledExxon Valdezcrude applicationof the model to hydrocarbon oil. When applied to consistent sedi- data derived from over 2,200 Natural ment hydrocarbon data setsderived from ResourceDamage Assessment sediment samplesthat were collectedfrom known hydrocarbonsamples collectedfrom 1989 oiled beaches,one principal component through 1991.

63 ~ Fateand Toxicity: SubhdalTransport of Hydrocarbonsand Sediments

NearshoreSubtidal Transport of Hydrocarbonsand SedimentsFol- lowing the ExxonValdez Oil Spill David M. Sale', JamesGibeaut', and Jeff Short', g 'SrunuOtterEnvironmental Consulting, Bellinghmn, Vlashington 'Uruversityof Texasat Austin 'National Oceanicand AtmosphericAdministration

From 1989-1992, subtidal sediment -7m depth! Boehmet al.,1987!.While traps were placed in Prince William the bulk of stranded shoreline oil was Sound to capture settling organic and removed from Prince William Sound mineral particulate matter offshore of beachesin 1989and 1990,by a combina- oiled and unoiled shorelines. As a com- tionof treatmentactivities, natural physi- ponentof water quality, settling particu- calprocesses and biodegradation, anum- lates were collected to: ! determine if ber of locations have intertidal subsur- petroleum hydrocarbons were present; face oil lenses that are still fluid at least and ! to learn more about subtidal sedi- during summer months! and that are ment transport processesaffecting sedi- persistent because of protection from ments at the study sites, surface weathering processes. Sedimentation of hydrocarbons is a Persistence and mobilization of rapid and important fate of spilled oil. spilled oil is related to physical andbio- Estimates of accumulation in the sub- logical processes,such aswave, tide and tidal include 8-10% of the Amoco Cadiz oil wind energy,microbial degradationand off the Brittany Coast Gundlach et aL, bioturbation. Sediment grain size and 1983! and 10-15% of the unrecovered oil quantity and compositionare among Tsesis oil in the Swedish archipelago many interactingvariables Blount,1978; Qohanssonet al,, 1980!, Oil can sink by Gundlach et al., 1978!. Oil eroded from adsorption to sediment, possibly by elec- contaminatedshorelines and entering the trostatic bonding to fine-grained clay water column may settlein thenearshore micelles Bassin and Ichiye, 1977!, and subtidal or move into deeperwaters be- through uptakeby zooplanktonand sub- fore settling depending on particle size sequent deposition in fecal pellets and shape, settling velocity,wave en- Co no ver, 1971!. Salinity, clay ergy, tidal current velocities, and minerology,and the presenceof organic longshore currents Gundlach et. al, matter which maymask adsorptionsites! 1978!. After settling on the benthic sur- can affect the adsorption Meyers and face, oiled sediments can continue to be Quinn, 1973!. moved by bottomcurrents, resuspended Oiled beaches act as a reservoir from by wave-inducedoscillatory currents,or which hydrocarbons may be removed be buried deeper into the benthic sedi- by erosion and depositedinoffshoresedi- mentsby bioturbation. ments. Ten percent of theoil strandedon A laboratory study by Bragg et al. untreated shorelines after the Baffin Is- 990! usingoiled sedimentsfrom Prince land Oil Spill project was transported William Sound shorelines found that the into shallow offshore subtid.al sediments formationof an emulsion of micron-sized Exxon ValdexOil SpiH Symposium Abstracts mineral particles, polar componentsof depositional events, and define back- oil residue and seawater impeded the ground hydrocarbonconcentrations and adhesion of oil to the larger rocks on.the depth of petroleum hydrocarbon con- shorelines,allowing natural removal by tamination. Sedimentsamples from the waves and tidal flushing. Bragg con- upper 2 cmof benthic sedimentsaround cluded that since the emulsion flo par- each trap were taken to evaluate grain tides were composedmainly of seawa- size distributions andhydn~bonchem- ter and fine-grained sediments, they istry. The relative contribution of sub- would be transported great distances tidal transport processes bed-load, sal- beforesettling and would be widely dis- tation and suspension! Visher 1969; persed. While this is supported by Stokes Middleton, 1976! and delineation of ero- Law of settling velocities for individual sional and depositional even ts fine sedimentgrains, sedimentsmay be Sundborg, 1956! will be estimated by trapped in estuaries as physicochemical evaluation of grain size distributions and flocculation with other particles in the inspection of the sediment cores. water column produce settling rates an In addition, approximations of wave order of magnitudegreater than theindi- energyat particular sitesare being calcu- vidual grains Drake,1976;Kranck,1975!. lated from hindcasts using the Auto- Methods matedCoastal Engineering System U.S. Sediment traps have been used after Army Corpsof Engineers,1991!and wind oil spills to monitor settling particulates data from the National Oceanic and At- for oil contamination Tsesisspill in 1977, mospheric Administration and National Johansson et aL, 1980! and to determine Weather Service stations in Prince Will- sedimentation rates in embayments iam Sound. Results from the hindcasts Lund-Hansen, 1991!and the open ocean will provide wave parameters from WoodsHole,1989!. For this study,base- which bottom stresses can be derived mounted sediment traps consisting of Komar, 1974!. Bottom stress calcula- PVC pipe, 15 cm in diameter and 1.2 tions combinedwith grain size data will meters tall were deployed at sites in allow estimations of the likelihood. of Prince William Sound representing a sedimentresuspension and transporta- variety of oiling and coastal conditions. tion by waves. The traps were placed at 10, 15, and 20 Results meterwater depthsoffshore of oiled and Two years after the spill, elevated unoiled shorelines. Divers retrieved and concentrationsof petroleum hydrocar- redeployed the traps at approximately 3 bons were consistently found in trapped month intervals from November 1989 suspendedparticles near initially heavily through mid-March 1992. Sediments oiled shorelines. Sediments retrieved wereimmediately filtered from the traps from thetraps at five sitesin August 1990 on the vesseland sampleswere frozen showedpetroleum hydrocarbon patterns for laterhydrocarbon chemistry and grain consistent with Exxon Valdez crude oil, size analysis. with thehighest concentrations at heavily Benthic core sampleswere taken at oiled Sleepy Bay, and lowest at the each of the sediment trap locations to unoiled control site in Port Fidalgo, indi- evaluate the sedimentary processes at cating an association of petroleum hy- work at the sites, such as erosional and drocarbons and trapped sediments with

65 ~ Fateand Toxicity: SubtidalTransport of Hydrocarbonsand Sediments

oiled shorelines. of the sediment trap and benthic samples This associationpersists in sediments arecurrently beingevaluated and will be capturedover the winter of 1990-91at 13 related to the hydrocarbon results for sites retrieved in March 1991!, The pat- each site and d.eployment period to cor- tern of hydrocarbonsis substantiallyal- relate sedimentology with petroleum tered however, with consistent and sub- hydrocarbons. Benthic sediment core stantial enrichment of chrysenesrelative stratigraphy will be evaluatedfor back- to the other aromatic hydrocarbon classes ground chemistry and any depositional at eachtrap location. While the reasons events. Grain size frequency distribu- for this alteration of aromatic hydrocar- tions are being evaluated for an under- bon patternsis not well understood,the standingof transportmechanisms ateach pattern could reflect complex weather- site. ing processes. References The highest concentrationsof petro- Bassin,N. J., and T. Ichiye. 1977. Floccuiation leum hydrocarbons found in March 1991 behavior of sediment and oil emulsions. J. werein trappedsediments from offshore Sedim. Petrol,, vol 47<2!,pp. 671-677 of heavily oiled locations in Northwest Blount, A 1978. Two yearsafter the Metulaoil Bay,Sleepy Bay and SnugHarbor, while spill, Strait of Magellan,Chile - oil interac- tion with coastal environments. Tech. Rept. the lowest concentrations were atunoiled No.'16-CRD,Coastal ResearchDivision, Dept. or lightly oiled locationsin EshamyBay, of Geology,Univ. of SouthCarolina, Colum- Stockdale Harbor and Port Fidalgo, This bia, S.C., 214 p. pattern againdemonstrates a clearasso- Boehm, P. D., M, S. Steinhauer, D. R. Green, B. ciation between concentrations of petro- Fowler, B. Humphrey, D. L. Fiest, W. J. Cretney, 1987.Comparative fate of chemi- leum hydrocarbons in trapped sediments cally dispersed and beachedcrude oil in and degreeof oil impact on the adjacent subtidal sediments of the Arctic nearshore. shoreline. Several sites with high con- Arctic, vol 40, supp. 1, 987!, pp. 133-148 centrations in trapped sediments have Bragg,J. R., S. H. Yang,J. C. Roffall. 1990. subsurface oiling: a persistent lower-in- Experimentalstudies of natural cleansingof oil residue from rocks in Prince William tertidal subsurface lens of fluid oil docu- Soundby wave/tidal action. ExxonProduc- mented by ADEC shoreline surveys as tion Research Co., Houston, Texas. late as June 1992! remains at Northwest Conover, R. J. 1971. Some relations between Bay, and significant subsurfaceoil has zooplanktonand BunkerCoil in Chedabucto been noted on shoreline segments in Bayfollowing the wreckof the tankerArroar. Sleepy Bay. Benthic sedimentsamples Jour. Fish. Res.Bd., Canada, vol, 28, pp. 1327- 1330. collected adjacent to the sediment traps Drake, D. 1976. Suspended sediment transport in August 1990 also indicate elevated on shelves. In Stanley, D,J, and Swift, D.J. P. petroleum hydrocarbon concentrations eds!, Marine Sediment Transport and Envi- at trap sitesadjacent to oiled shorelines. ronmental Management,Wiley and Sons. Chap,9, pp 127-158. Further conclusions await the results of Gundlach, E. R., C. H. Ruby, L. G. Ward, A. E. remaining hydrocarbon analysis. Blount, I. A. Fischer and R. J. Stein. 1978. Hydrocarbon chemistry analysis of Someguidelinesfor oil-spill controlin coastal theremainingsediment trap, benthic and environments: based on field studies of four core samples will be completed by Janu- oil-spills. in Proc. of 1977ASTM Sympos. on Chem. dispersantsfor the Control of Oil ary 1993, Results of grain size, Spills, Amer. Soc. Testing and Materials, minerology and organic carbon analyses KxxcmValdez Oil Spill Symposium Abstracts

Philadelphia,Penn. 32p. Middleton, G.V. 1976. Hydraulic interpretation Gundlach, E. R, P. D, Boehm, M. Marchand, R. of sandsize distribution. J.Geol., 84, pp. 405- M. Atlas, D.M. Ward, D.A. Wolfe. 1983. The 26 fate of AmocoCadiz oil. Science,vol. 221, pp. Sundborg,A. 1956.The river Klaralven:a study 122-129. of fluvial processes.Geogr. Ann.,38, pp. 127- Johansson, S., U. Larsson and P. Boehm. 1980. 316. The Tsesisoil spill: Impact on the pelagic U. S. Army Corps of Eny'neers. 1991. Auto- ecosystem.Mar. Poliut, Bull,,II0!,284-93. mated coastalengineering system ACES!. Komar,P. 1974.On the comparisonbetween the AutomatedCoastal Engineering Group, Re- threshold of sediment motion under waves search Division, Coastal Engineering Re- and unidirectional currents with a discus- search Center CERC!, U,S, Army Engineers sionof thepractical evaluation of the thresh- Waterway Experiment Station, Vicksburg, old. J. Sed. Petr., 45: 362-67. Miss. Softwarecompatible on IBM PC/AT. Kranck, K. 1975. Sediment deposition from Two volumes of manuals: Users Guide and fiocculated suspensions. Sedimentology Technical Manual. 975! 22:1 l1-123. Visher, G. S. 1969. Grain size distributions and Lund-Hansen, L. C. 1991. Sedimentation and depositional processes,J, Sed. PetroL,39,pp. sediment accumulation in a low-energy 1074-1106. embayment.J. Coast.Res. 7!, 969-980. Woods Hole Oceanographic Institution. 1989. Meyers, P. A. and J. G, Quinn, 1973. Association Sedimenttrap technologyand sampling.U.S, of hydrocarbons and mineral particles in Global Ocean Flux Planning Report Number saline solution. Nature, 244.23-24. 10, August, 1989. 94 pages.

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