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1.
Polycyclic aromatic hydrocarbons (PAH) have been measured in mussel tissues in early spring and summer since 1993 throughout Prince William Sound (PWS) and the Gulf of Alaska (GOA). Season-specific thresholds were established at reference sites to identify ‘above background’ total PAH levels. Thresholds were estimated using one-sided 99% tolerance limits. Thresholds were similar across reference sites but differed by an order of magnitude across seasons. Trends in total PAH since 1998 were assessed for sites impacted by the 1989 Exxon Valdez oil spill or the Alyeska Marine Terminal. Summer samples exhibited no trends; early spring samples declined. In early spring, all sites were judged ‘recovered’ by 2004; in summer, one site in western Prince William Sound and two in the western GOA exceeded thresholds by 11 ng/g dry weight or less. Robust estimation methods prevented bias from observations affected by unknown releases or laboratory errors.  相似文献   

2.
A field study was conducted in 2003 to estimate the areal distribution and concentrations of polycyclic aromatic hydrocarbons (PAH) in intertidal sediments at sites of past human and industrial activity (HA sites) in Prince William Sound (PWS), Alaska, the site of the 1989 Exxon Valdez oil spill. More than 50 HA sites, primarily in western PWS, were identified through analysis of historic records and prior field studies, and nine sites were selected for detailed surveys. The areal assessment process consisted of seven steps: (1) identify site from historic records and field surveys; (2) locate visual evidence of surface oil/tar at a site; (3) prepare a site map and lay out a sampling grid over the entire site with 10-m grid spacing; (4) excavate pits to 50 cm depth on the grid; (5) perform a field colorimetric test to estimate total PAH (TPAH) in sediments from the wall of each pit and record the results in the ranges <1 ppm; 1-10 ppm; >10 ppm TPAH; (6) expand grid size if necessary if elevated PAH levels are detected colorimetrically; (7) select 20 samples from each site for same-day shipboard PAH analysis by immunoassay (SDI RaPID PAH) and, based on these results, select sediment samples from each site for full PAH analysis in the laboratory to identify PAH sources. A total of 416 pits were dug at the nine sites. Nine acres of sediments with TPAH >2500 ppb dry wt. were mapped at the nine sites. TPAH concentrations obtained by immunochemical analysis of 181 samples from the nine sites ranged from 20 to 1,320,000 ppb (wet wt.). The contaminants are mixtures of petroleum products (2-3 ring PAH) and combustion products (4-6 ring PAH) unrelated to the 1989 Exxon Valdez oil spill. Mussels and clams collected at these sites have elevated levels of PAH that are compositionally similar to the PAH in the sediments. These findings indicate that at least a portion of the sediment PAH is bioavailable. The PAH sources at these historic industrial sites are chronic. They include relict fuel oil tanks and works located above and within the intertidal zone, with contamination at some locations extending into nearshore sub-tidal sediments. This study shows how a hierarchical approach can be used to quickly and successfully map, quantify, and subsequently, identify sources of PAH in shoreline sediments.  相似文献   

3.
Sampling zooplankton is a useful strategy for observing trace hydrocarbon concentrations in water because samples represent an integrated average over a considerable effective sampling volume and are more representative of the sampled environment than discretely collected water samples. We demonstrate this method in Port Valdez, Alaska, an approximately 100 km(2) basin that receives about 0.5-2.4 kg of polynuclear aromatic hydrocarbons (PAH) per day. Total PAH (TPAH) concentrations (0.61-1.31 microg/g dry weight), composition, and spatial distributions in a lipid-rich copepod, Neocalanus were consistent with the discharge as the source of contamination. Although Neocalanus acquire PAH from water or suspended particulate matter, total PAH concentrations in these compartments were at or below method detection limits, demonstrating plankton can amplify trace concentrations to detectable levels useful for study.  相似文献   

4.
Side-by-side comparisons of polycyclic aromatic hydrocarbon (PAH) concentrations in resident blue mussels (Mytilus trossulus) and in semi-permeable membrane devices (SPMDs) were made at four sites in Prince William Sound, Alaska. SPMDs were deployed for approximately 30 days on the surface of the beach sediment at three tidal elevations on each shore and in 0.5 m deep open pits in the middle intertidal zone. Total PAH (TPAH) concentrations in mussels and in SPMDs were correlated, but the PAH compositions were different. The lower molecular weight PAH were relatively more abundant in the SPMDs than in the mussels at oiled and HA sites. TPAH concentrations in SPMDs deployed in pits and mussels collected adjacent to those pits at oiled sites were higher than in SPMDs and mussels from non-pitted SPMD locations approximately 3-15 m from the pits. Pitting released buried oil making its PAH bioavailable. SPMDs deployed in the supratidal zone (+4.0 m tidal elevation) were exposed to atmospheric contaminants for a large fraction of the deployment time and accumulated primarily pyrogenic (combustion-sourced) PAH from the atmosphere. The SPMD strips supplied by the manufacturer contained significant amounts (approximately 125 ng/strip) of primarily alkylated 2-3 ring PAH. These blank levels make SPMDs unsuitable for shoreline assessments when environmental PAH concentrations are low. Consequently, where available, mussels are recommended for use in assessments of the bioavailability of buried oil residues sequestered in intertidal sediments following an oil spill. Mussels are the preferred monitoring tool when the assessments involve food-chain effects. At locations where the absence of mussels necessitates the use of SPMDs or other passive sampling devices, their limitations need to be carefully considered in the interpretation of results.  相似文献   

5.
—In this paper we present results of body wave-form modeling of 19 earthquakes (generally m b ≥5.7) occurring from 1964 to 1983 in the vicinity and down-dip of the large asperity within the Prince William Sound region that ruptured in 1964. These data are supplemented with source parameters from studies of more recent (post-1980) events. Our results suggest that moderate earthquakes which occurred in the region between 1964 and 1984 were predominantly located in the vicinity of the Prince William Sound asperity and could be assigned to two groups. The first group consists of events occurring above the plate interface within Prince William Sound along reverse faults or low angle thrusts. The second group occurs at 35 to 60 km depth in the region north of Prince William Sound, and represents normal to normal-oblique faulting within the subducted Pacific crust or upper mantle. These earthquakes occur below the northern edge of the 1964 asperity in a region where the subducting plate undergoes a rapid change in strike and dip. A third group of events occurs in Cook Inlet well down-dip of the 1964 asperity and below the plate interface. These events exhibit a variety of mechanisms and many at depths of 50 to 70 km may be associated with complexities in the shape of the downgoing slab. Most of the Cook Inlet events occurred after 1984, whereas a few events of similar magnitude have occurred in the vicinity of the Prince William Sound asperity since 1984.  相似文献   

6.
In 2002, 13 years after the Exxon Valdez spill, mussels and clams were examined for lingering oil exposure and damage. Known oil patches were sampled at four locations, and compared to nearby reference areas (same bay), and were also compared to "hot reference" sites to verify the methods used (Cordova harbor and fresh diesel spill at Port Chalmers). Passive samplers deployed for a month at the sites, along with tissue samples, confirmed that the oiled sites were oiled (fingerprinting back to Exxon Valdez oil) and that reference sites were clean. The highest PAH loads were detected in sub-surface interstitial waters at oiled sites. Exposure at the surface was generally low level, and probably intermittent. DNA damage was assessed in blood cells using sensitive comet analyses. DNA strand breakage was detected in both mussels and clams, with the highest level of damage detected at "hot reference" sites of Cordova harbor and Port Chalmers. Bioavailability and DNA damage at the oiled sties was low, indicating there has been substantial progress in recovery from the spill 13 years before, yet low level bioavailability and damage were still detectable.  相似文献   

7.
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8.
Median levels of Coproporphyrin III (Copro III) in fecal samples of river otters (Lontra canadensis) collected from an oiled area in Prince William Sound, Alaska, USA, during 1990 were significantly higher than in samples collected from the same oiled area during 1996 (p=0.011, one way analysis of variance), a nonoiled reference area in Prince William Sound during 1996 (p=0.002) and a reference area in southeast Alaska during 1998 (p=0.004). An overall test of significance that combined probabilities from the statistical analysis of this porphyrin study with those from other biomarker studies revealed a significant difference in physiological response of river otters between oiled and nonoiled areas of the Sound for 1990 (p < 0.01). We demonstrated that changes in levels of fecal porphyrins may serve as a biomarker that may contribute to a health assessment of wild river otters.  相似文献   

9.
Delivery of dissolved chemicals to bioremediate oil from the Exxon Valdez oil spill was investigated at Beach EL056C of Eleanor Island, Prince William Sound, Alaska. The delivery technique was high pressure injection (HPI) of an inert tracer, lithium, at the approximate depth of 1.0 m into the beach near the mid‐tide line. The results revealed that the maximum injection flow rate was 3.0 L/min and the associated pressure was around 196 kPa. Therefore, exceeding any of these values would probably cause failure of the injection system. The injected tracer was monitored at multiple depths of four surrounding observation wells, and the results showed that the tracer plume occupied an area of 12 m2 within 24 h. The tracer plume traveled at the average speeds of 10 m/d in the seaward direction and 1.7 m/d in other directions. The rapid movement under HPI and the large diameter of influence (3.0 m) indicated that bioremediation of the Exxon Valdez oil on this beach via injection of chemicals is logistically feasible.  相似文献   

10.
For sixteen years following the 1989 Exxon Valdez oil spill adult returns of pink salmon in Prince William Sound, Alaska were monitored to assess spill effects on survival. No evidence of spill effects was detected for either intertidal or whole-stream spawning fish. From 1989 through 2004 mean densities for oiled and reference streams tracked each other, illustrating similar responses of oiled and reference stream adult populations to naturally changing oceanographic and climactic conditions. Hatchery fish strayed into the study streams, but similar incursions occurred in oiled and reference streams, and their presence was compensated for to eliminate their influence on determining the success of the returning natural populations. These results, showing no detectable effects of oiling on pink salmon spawning populations, are supported by published field studies on pink salmon incubation success in oiled streams.  相似文献   

11.
Delivery of dissolved chemicals to potentially bioremediate oil from the Exxon Valdez oil spill was investigated at Smith Island, Prince William Sound, Alaska. Two transects for tracer application were installed: one at a clean area and another at an oiled area. Tracer delivery occurred under ambient pressure through manifolds. Lithium in LiBr/sea water solution was the inert tracer, and the solution (82.6 mg/L of lithium) was released at a flow rate of 0.23 L/min for 58.5 h. While maintaining the flow rate, the solution was switched to sea water (i.e., 0.0 mg/L of lithium) for 16 h. The results show that the tracer moved landward with rising tides and seaward with falling tides. The plume got deeper moving landward and shallower moving seaward of the manifold. Thus, in situations where oil biodegradation is limited by the availability of nutrients or oxygen, applying these chemicals by this technique would allow them to reach entrapped oil seaward of the manifold from below. The seaward plume traveling speed (around 2.0 m/d) suggests that this technique is logistically feasible from a hydraulic point of view.  相似文献   

12.
Despite great efforts including bioremediation, the 1989 Exxon Valdez oil spills persist in many gravel beaches in Prince William Sound, Alaska, USA. To explore this mystery, a lithium tracer study was conducted along two transects on one of these beaches. The tracer injections and transports were successfully simulated using the 2-dimensional numerical model MARUN. The tracer stayed much longer in the oil-persisting, right transect (facing landwand) than in the clean, left transect. If the tracer is approximately regarded as oils, oils in the upper layer would have more opportunities to enter the lower layer in the right transect than in the left one. This may qualitatively explain the oil persistence within the right transect. When the tracer is regarded as nutrients, the long stay of nutrients within the right transect implies that the oil persistence along the right transect was not due to the lack of nutrients during the bioremediation.  相似文献   

13.
I have relocated 18 earthquakes occurring in the south-central Alaska region between 1899 and 1917 using a bootstrap relocation technique. Locations of events within the Yakutat region suggest that the 1899 sequence began on 4 September with a MS = 7.9 event within the area of the Pamplona fault zone/western Transition fault zone, rupturing the western portion of the North American/Pacific plate interface. A MS = 7.4 event on 10 September appears to have ruptured the offshore portion of the plate interface to the east of the 4 September event. This was followed by a MS = 8.0 event that likely ruptured the onshore and down-dip portion of the plate interface. A MS = 7.0 event in 1908 may have ruptured a small portion of the plate interface between the 4 September and 10 September events. Events occurring between 1911 and 1916 in the Prince William Sound region appear to be slab events occurring in similar locations to more recent seismicity. Within the Kodiak region the 1900 earthquake of MS = 7.7 has a location consistent with the rupture of the Kodiak asperity which also ruptured during the 1964 great Alaska earthquake. Other large magnitude Kodiak events appear to be associated with regions of recent seismicity, including the Karluk Lake area of southwestern Kodiak Island and the Albatross Basin located offshore southeast of Kodiak Island. Space-time seismicity patterns since 1899 indicate that magnitude 6 to7 events have occurred with regularity in the Kodiak Island region; that there has been a lack of magnitude ≥ 6 events in the Prince William Sound region since 1964, and that the Yakutat region has remained notably quiescent at the magnitude ≥ 6 level.  相似文献   

14.
Exposure to contaminants other than petroleum hydrocarbons could confound interpretation of Exxon Valdez oil spill effects on biota at Prince William Sound, Alaska. Hence, we investigated polychlorinated biphenyls (PCBs) in blood of sea otters and harlequin ducks sampled during 1998. PCB concentrations characterized by lower chlorinated congeners were highest in sea otters from the unoiled area, whereas concentrations were similar among harlequin ducks from the oiled and unoiled area. Blood enzymes often elevated by xenobiotics were not related to PCB concentrations in sea otters. Only sea otters from the unoiled area had estimated risk from PCBs, and PCB composition or concentrations did not correspond to reported lower measures of population performance in sea otters or harlequin ducks from the oiled area. PCBs probably did not influence limited sea otter or harlequin duck recovery in the oiled area a decade after the spill.  相似文献   

15.
Petroleum and PAH contamination of the Black Sea   总被引：19，自引：0，他引：19  
Concern has been expressed regarding the extent of contamination of the Black Sea. Analyses of coastal sediments taken from throughout the region indicate, however, that levels of petroleum hydrocarbons (2-300 microg g(-1) dry wt total hydrocarbons) are generally comparable to those encountered in the Mediterranean and are lower than concentrations reported for highly contaminated areas such as the Gulf, Hong Kong, Taiwan and New York Bight. Highest concentrations of total hydrocarbons (>100 microg g(-1) dry wt) were associated with discharges from Odessa, Sochi and the River Danube. Chronic/degraded petroleum was the major contributor at these sites. Samples from the Ukrainian coastline were comparatively clean (<10 microg g(-1) dry wt total hydrocarbons). Major contributions of fresh oil (as indicated by sigma n-C14-34) occur through the River Danube. Concerning total PAH, concentrations (7-638 ng g(-1) dry wt) compare to relatively unpolluted locations in the Mediterranean and are much lower than levels reported for polluted UK estuaries (e.g. Mersey, Tyne, Thames). Both pyrolytic and petrogenic PAH are present in most samples, although petroleum derived PAH are dominant at Sochi and pyrolytic sources are prevalent in the Bosphorus region. The absence of a correlation between total hydrocarbons and PAH (R2 = 0.04) indicates different primary sources for the two.  相似文献   

16.
Twenty years after the Exxon Valdez oil spill, scattered patches of subsurface oil residues (SSOR) can still be found in intertidal sediments at a small number of shoreline locations in Prince William Sound, Alaska. Some scientists hypothesize that sea otters continue to be exposed to SSOR by direct contact when otters dig pits in search of clams. This hypothesis is examined through site-specific examinations where SSOR and otter-dug pits co-occur. Surveys documented the exact sediment characteristics and locations on the shore at the only three subdivisions where both SSOR and otter pits were found after 2000. Shoreline characteristics and tidal heights where SSOR have persisted are not suitable habitat for sea otters to dig pits during foraging. There is clear separation between areas containing SSOR and otter foraging pits. The evidence allows us to reject the hypothesis that sea otters encounter and are being exposed by direct contact to SSOR.  相似文献   

17.
We compared total mercury (THg) concentrations in the fur of northern fur seals (Callorhinus ursinus) from the depleted Pribilof Islands population with those of both declining and thriving populations of Steller sea lions (Eumetopias jubatus) from Prince William Sound (PWS) and Southeast Alaska (SEA), respectively. Relatively low wet weight concentrations (ranges) of THg were detected in the fur of Steller sea lion (SSL) pups (0.90-3.14 microg/g) and juveniles (0.56-6.75 microg/g) from both areas in 1998 and 2000 compared to northern fur seal (NFS) pups (3.15-8.14 microg/g) in 2000. The mean concentration +/- SD for SSLs sampled were 1.46 +/- 0.64 microg/g for pups (n = 22) and 2.74 +/- 2.89 microg/g for juveniles (n = 6). Analyses indicated higher THg concentrations from SSL pups from PWS compared to the SEA. Mean +/- SD. THg in the NFS pups was 4.90 +/- 1.42 microg/g (n = 34) and for post-partum dams was 7.84 +/- 1.78 microg/g (n = 12).  相似文献   

18.
In 2002, 13 years after the Exxon Valdez oil spill (EVOS), 39 selected sites in Prince William Sound (PWS) were re-surveyed following established shoreline cleanup assessment team (SCAT) field observation procedures to document surface and sub-surface oiling conditions in shoreline sediments and to compare results with those from previous Shoreline Cleanup Assessment Team (SCAT) surveys and other surveys in PWS. The selected sites are locations where EVOS oil persisted in 1992, at the time the Federal and State On-Scene Coordinators determined that the cleanup was complete and that further cleanup activities would provide no net environmental benefit. These sites had been included in a 2001 NOAA survey of shoreline oiling conditions and account for 88% of the sub-surface oil residues (SSO) oil documented by that study. The 2002 field survey found isolated occurrences of residual EVOS surface oil residues (SO) in the form of weathered asphalt pavement at 15 of the 39 sites. This residual SO typically consisted of asphalt in mixed sand/gravel substrate, located within a wave shadow effect created by boulders or bedrock in the upper intertidal to supratidal zone. Residual SO, expressed as a continuous oil cover, was less than 200 m(2) within the approximately 111,120 m(2) surveyed. A total of 1182 pits were dug at locations where SSO residues were present in 1992. Six of the 39 sites and 815 (68%) of the pits contained no residual SSO. Eighty-three percent of pits with SSO residues were found primarily in middle to upper intertidal locations. SSO residues commonly occurred in a discontinuous approximately 3 cm thick band 5-10 cm below the boulder/cobble or pebble/gravel veneer. The SO and SSO occurrences in the 2002 survey closely match the locations where they were found in 1992 and earlier surveys; however, in 2002 residual SSO patches are more discontinuous and thinner than they were in the earlier surveys. These sites are biased toward SSO persistence; those that have SSO residues represent less than 0.5% of the originally oiled shorelines in PWS. Despite evidence of continued oil weathering, both at the surface and in the sub-surface, it is clear that the natural cleaning processes at these particular locations are slow. The slow weathering rates are a consequence of the oil residue being incorporated in finer sediments (fine sand, silt, mix) and isolated from active weathering processes as boulders and outcrops, shallow bedrock asperities, or boulder-armoring create wave shadows and limit effective physical action on shorelines.  相似文献   

19.
A coastal ocean extended Prince William Sound nowcast/forecast system (EPWS/NFS) has been running semi-automatically for an extended domain of Prince William Sound (PWS), Alaska for 2 years. To determine the performance of this modeling system, an assessment is conducted. EPWS/NFS and PWS/NFS (viz., its predecessor) nowcasts are compared with observed time series of sea surface temperature (SST) and coastal sea level (CSL) at a few stations, and to velocity profiles from a moored ADCP. With the extension of the model domain to include the continental shelf outside PWS and forced by an operational global ocean model (Global-Navy Coastal Ocean Model (Global-NCOM)) and a 2D tidal model at the open boundary, EPWS/NFS has achieved significant improvement over PWS/NFS, which covered only PWS per se, for most of the predicted variables in this study. In both magnitude and phase, EPWS/NFS accurately predicts the coastal tide fluctuations, as well as M2 tidal currents in Central Sound, although significant errors in coastal tides exist during some spring and neap tide cycles. Other than for the tidal motions, EPWS/NFS generally produces less energetic CSL and velocity variations than those observed. In comparison, although PWS/NFS well predicts the coastal tides, it suffers from the absence of low-frequency CSL variations, as well as misprediction of M2 tidal currents in Central Sound. For 40 h low-passed PWS/NFS and EPWS/NFS velocities, significant phase error occurs during the model–date comparison period, while EPWS/NFS nowcasts generally produce less root-mean-square-error (rmse) and smaller correlations with the observations than PWS/NFS does. Both observations and EPWS/NFS have similar vertical profiles of baroclinic velocity standard deviations, but some substantial discrepancies occur in the velocity direction. Also, in the Central Sound, EPWS/NFS predicts well the SST seasonal cycle and a major cooling event during the summer 2005. However, for periods shorter than 1 week, both PWS/NFS and EPWS/NFS SST underestimated the observed fluctuations by an order of magnitude.  相似文献   

20.
The composition, distribution and the sources of polycyclic aromatic hydrocarbons (PAHs) in the surficial sediments of the Gulf of Trieste were investigated. To document the spatial PAH input, surficial sediment samples from 17 locations throughout the Gulf were analysed. The total PAH load determined in the surficial sediment samples are between 30 and 600 ng g-1, and were the highest in the immediate vicinity of the Port of Trieste. The PAH contents decline rapidly with increasing distance from the shore. The ratios of methylphenanthrenes/phenanthrene and methylpyrene/pyrene are sensitive indicators of the origin of PAH pollution in the Gulf which is mostly pyrolitic. The phenanthrene/anthracene ratio was used to determine the approximate location and distance from the source of PAH pollution, while 1-methy 1-7-isopropylphenanthrene (retene) was used as indicator for forest fires. A sediment depth profile indicates a major increase in the PAH concentrations after the First World War.  相似文献   

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