Hydrocarbon Concentrations In Sediments Research Articles

A field experiment of the physical and chemical effects of two oils on mangroves

The effects of two different types and five levels of oil on some physical and chemical characteristics of sediments and plants were investigated in four mangrove species under field conditions. The sediments in which four mangrove species ( Rhizophora stylosa, Rhizophora mucronata, Ceriops tagal and Avicennia marina) were growing, were treated with Kuwait Crude Oil (KCO) and North West Shelf Condensate (NWSC) at application rates of 0, 1375, 2750, 5500 and 11 000 g m −2. The effects varied with species. The oil treatments usually increased concentrations of most nutrient elements in R. stylosa and R. mucronata, had mixed effects on C. tagal and mostly decreased concentrations in A. marina. KCO significantly decreased concentrations of every element examined in A. marina. The effects on sediments also varied with oil type. NWSC decreased concentrations of about half of the elements tested in the sediments and had no significant effect the others. In contrast, KCO increased concentrations of about half of the elements tested in the sediments and had no significant effect on most of the others. The concentrations of hydrocarbons in leaves increased with increasing oil application to the sediments, but the effects varied in the different species. A. marina accumulated between two and six times more hydrocarbons in leaves than the other species. The concentration of hydrocarbons in sediments treated with NWSC decreased by about an order of magnitude in the 24 weeks after application, but the rate of decrease was less for KCO than for NWSC. Sediment pH, dissolved oxygen concentration, redox potential and the salinity of interstitial water were decreased by oil treatments, causing the oiled sediments to become poorly oxygenated with strongly reducing conditions. It was concluded that these experimental oil treatments in the field caused changes in sediment characteristics and uptake of oil components by mangroves, depending on the characteristics of the oil and the mangrove species.

Effects of Persistent Shoreline Oil on Breeding Success and Chick Growth in Black Oystercatchers

To determine if Black Oystercatchers (Haematopus bachmani) were affected by persistent shoreline oil from the T/V Exxon Valdez oil spill, I identified contaminated foraging sites of oystercatchers, quantified diet and foraging behavior, assessed hydrocarbon uptake, and measured breeding success and mass gain of chicks. Hydrocarbon concentrations in sediments at foraging sites indicated that some oystercatchers potentially were exposed to shoreline oil that persisted into 1992 or 1993. Direct evidence of hydrocarbon exposure was obtained from feces of chicks raised on persistently oiled shorelines. Elevated concentrations of total hydrocarbons, even-numbered aliphatics, and unresolved complex mixtures were indicative of petroleum hydrocarbon exposure. Mussels (Mytilus trossulus) were an important component of the diet of adults and chicks. Oystercatchers foraged for mussels on low-sloping, mixed sand-and-gravel beaches that often retained oil but spent less time foraging on contaminated substrates than on unoiled substrates. Effects of persistent shoreline oil on measures of breeding success were negligible and likely were overridden by the influence of egg and chick predation. Chicks raised on shorelines that were heavily oiled in 1989 gained mass at a slower rate than did chicks raised on shorelines that were not heavily oiled; however, slower mass gain did not translate into reduced fiedging success of chicks raised on heavily oiled shorelines. Although some oystercatchers were exposed to persistent shoreline oil, areas of contamination were patchily distributed, and relatively few adults and young were exposed. The lack of a large-scale change in oystercatcher numbers inhabiting the oiled area of Prince William Sound suggests that the negative effects of oil exposure operated locally. Consequently, oiled mussel beds present little additional risk to the population of Black Oystercatchers inhabiting Prince William Sound.

THE PERSISTENCE AND EFFECTS OF NON-WATER-BASED DRILLING FLUIDS ON AUSTRALIA'S NORTH WEST SHELF: PROGRESS FINDINGS FROM THREE SEABED SURVEYS

The effects and persistence of non-water-based drilling fluids discharged into the marine environment were investigated at three locations on Western Australia's North West Shelf (NWS), namely the North Rankin 4A' (NRA) drilling platform, the Wanaea–6 production well and the Lynx–la exploration well. For the multiple-well drilling operation at NRA, acute biological effects at the completion of drilling were restricted to within 400 m in the direction of the prevailing current. High total petroleum hydrocarbon (TPH) concentrations within the NRA cuttings pile persisted between 1991 and 1993. Away from the cuttings pile itself, a consistent downward trend in TPH concentrations was evident, indicating an approximate half-life of one year for surface sediments. Three years after the completion of drilling at Wanaea–6, biological effects appeared to be limited to within 100 m of the cuttings discharge point, with background concentrations of TPH and trace metals occurring near 1,200 m in the direction of the prevailing current. Sediment hydrocarbon concentrations greater than 1 mg/kg were found to be restricted to within 200 m of the cuttings discharge point. Dramatic reductions in TPH and barium concentrations occurred in the 12-month period between the completion of drilling and the follow- up survey at Lynx–la. The reductions are attributed to sediment dispersal mechanisms which appear to play a major role in reducing sediment TPH and trace metal concentrations in mid-shelf water depths (70–80 m) on the NWS. The installation and presence of subsea production facilities may result in sediment redistribution and changed dispersal mechanisms, complicating the interpretation of the presence of contaminants within sediments.

Petroleum hydrocarbons and their effects in subtidal regions after major oil spills

The question often arises after large oil spills as to the extent and effect of oil entering the subtidal zones adjacent to heavily oiled shorelines. Estimates for a number of large spills suggest that 1 to 13% of the spilled oil can enter subtidal regions. Hydrocarbon concentrations in these subtidal zones are generally orders of magnitude lower than shoreline sediments. For example, in the Exxon Valdez oil spill, subtidal sediment hydrocarbon concentrations attributable to the spill were very low in the first year after the spill and barely detectable in the second year. The conditions necessary to produce high concentrations of hydrocarbons in the subtidal region include large amounts of oil in a semienclosed estuary or bay and high concentrations of fine particulate matter to associate with hydrocarbons to allow them to disperse and sink. Such conditions do not often occur after spills, with some exceptions, such as low energy tidal estuaries in the Amoco Cadiz spill in Brittany, France. More commonly sea floor sediment hydrocarbon concentrations, where sediment-associated hydrocarbons have settled, are generally near to background levels, due to dilution and weathering. A number of methods have been used to evaluate the biological effects of oil spills on subtidal fauna. These include toxicity to amphipods, increases in the concentrations of fluorescent aromatic metabolites in the bile of fish, histopathology of fish, increases in opportunistic species and infaunal succession. Sediments collected from the subtidal zone below heavily oiled shorelines of the Exxon Valdez spill showed low toxicity using standard amphipod bioassays. Well documented effects on the subtidal biota adjacent to heavily oiled shorelines are the increases in the number of hydrocarbon degrading microbes which are fed on by opportunistic species of meiofauna which in turn are food for macrofauna. The documented biological effects of oil in the subtidal region are generally of short duration and recovery back to an equilibrium or ‘normal’ condition is typically quite rapid.

AN OIL SPILL IN AN ILLINOIS LAKE: ENVIRONMENTAL EXPOSURE ASSESSMENT

ABSTRACT On April 27, 1985, an oil pipeline ruptured, releasing 10,775 barrels (452,550 gallons) of a Southern Louisiana crude oil into Newton Lake, a 1,750-acre electric power plant cooling lake in Jasper County, Illinois. The oil, which flowed into the northern part of the 6-mile eastern arm of the V-shaped lake, was restricted by booms to the upper third of the lake. A long-term environmental assessment program was immediately initiated and continued until October 1991. Shortly after the accident, offshore (benthic) lake sediments nearest the release site contained up to 5,000 µg/g [ppm] total hydrocarbons. A steep gradient of decreasing hydrocarbon concentrations in sediments occurred with distance from the point where the oil entered the lake. By 1989, concentrations of total hydrocarbons in offshore sediments were less than 50 μg/g in all areas (zones) except in an area of the lake within 1 mile of the release where isolated total hydrocarbons concentrations ranged from <50 μg/g to 430 μg/g. Fingerprinting of polycyclic aromatic hydrocarbon (PAH) assemblages six years after the spill revealed that traces of the spilled oil (<400 ng/g total PAHs) remained only in this uppermost part of the lake. PAH assemblages from other sources than the spilled oil were identified in offshore lake sediments as the major contributing PAHs. Low concentrations of residual oil were found in subsurface sediments in the upper 0.4 mile of the lake. Diagenetic perylene was particularly abundant in sediments (up to 2,400 ng/g) especially in the depositional (deepest) areas of the lake. Only trace amounts of a few PAHs (<50 ng/g total PAHs), most from sources other than the released oil, were found in shoreline sediments in any part of the lake. Tissues of fish collected in 1985 shortly after the spill and again in 1991 did not contain detectable levels (<10 ng/g dw) of released oil PAHs.

Hydrocarbon concentrations in sediments and clams (Rangia cuneata) in Laguna de Pom, Mexico.

Laguna de Pom is a coastal lagoon within the Laguna de Terminos system in southern Gulf of Mexico. It belongs to the Grijalva-Usumacinta basin, and is located between 18{degrees} 33{prime} and 18{degrees} 38{prime} north latitude and 92{degrees} 01{prime} and 92{degrees} 14{prime} west longitude, in the Coastal Plain physiographic Province of the Gulf. It is ellipsoidal and approximately 10 km long, with a surface area of 5,200 ha and a mean depth of 1.5 m. Water salinity and temperature ranges are 0 to 13 {per_thousand} and 25{degrees} to 31{degrees}C, respectively. Benthic macrofauna is dominated by bivalves such as the clams Rangia cuneata, R. flexuosa, and Polymesoda carolineana. These clams provide the basis of an artisanal fishery, which is the main economic activity in the region. The presence of several oil-processing facilities around the lagoon is very conspicuous, which together with decreasing yields has created social conflicts, with the fishermen blaming the mexican state oil company (PEMEX) for the decrease in the clam population. This work aims to determine if the concentration of hydrocarbons in the clams (R. cuneata) and sediments of Laguna de Pom are responsible for the declining clam fishery. 11 refs., 4 figs., 2 tabs.

Temporal and spatial changes in the concentrations of hydrocarbons and trace metals in the vicinity of an offshore oil-production platform

A 4-year multidisciplinary monitoring program was conducted between October 1986 and October 1990 to detect and quantify environmental impacts related to oil and gas drilling in the Arguello Field in southern California. As part of this program, concentrations of trace metals and petroleum hydrocarbons were determined in surface sediments and in trapped sediments before, during, and after drilling had stopped. Barium, a major component of drilling muds, was the only chemical that changed significantly during the period of study. During drilling, barium concentrations in surface sediments increased 30–40% above background. After drilling stopped, barium concentrations decreased but, after 1.5 years, had not approached background concentrations of surface sediments. In trapped sediments, barium concentrations increased 200–300% during drilling but returned to background concentrations within 1 year after drilling had stopped. Hydrocarbon concentrations in sediments from the study area were occasionally elevated, but generally were not consistent with drilling activities. Examination of the petroleum hydrocarbon and PAH distributions indicated that a distinct petroleum signal was occasionally observed in some samples; however, natural seepage rather than drilling discharges is probably responsible for the randomly-elevated hydrocarbon concentrations. The presence of seep-related particles should be recognized in characterizing the ambient hydrocarbon concentrations of sediments in the study area. During peak drilling periods, neither barium nor petroleum hydrocarbons were detected in concentrations that are likely to impact benthic biota in the vicinity of the drilling platform.

Mixed-function oxidase-specific activity in wild and caged speckled sanddabs Citharichthys stigmaeus in Elkhorn Slough, Moss Landing Harbor and nearshore Monterey Bay, California.

The goal of this study was to characterize the spatial, seasonal and annual hepatic activities of mixed-function oxidase (MFO) in the speckled sanddab Citharichthys stigmaeus, the most common fish in the Moss Landing area. In addition, techniques to monitor MFO activities in caged speckled sanddabs were developed and tested. Once the relationship between MFO activities in caged and wild fish populations is determined, caged fish could be used to monitor potential hydrocarbon impacts at Moss Landing, or other marine sites. During each of the spatial, seasonal and annual sediment samplings conducted in 1985-1987 as part of a separate hydrocarbon variability study at Moss Landing, 12 wild speckled sanddabs were collected from Moss Landing Harbor, Elkhorn Slough and nearshore Monterey Bay sites. In addition, four locations were chosen for a 14-day field caged fish experiment. The caged fish experiments successfully demonstrated the feasibility of using caged sanddabs as indicators of hydrocarbon exposure. The major source of variability in hepatic aryl hydrocarbon hydroxylase activity in wild speckled sanddabs from the Moss Landing area is due to seasonal rather than site differences. Significant relationships between caged fish MFO response and sediment hydrocarbon concentrations were found. It is possible that caged fish could be used in place of costly sediment sampling and analysis, and provide a more direct method to assess biological impacts. Many of the caging techniques demonstrated in this study can easily be transferred to other benthic flatfish, and other marine and freshwater environments.

Oil and combustion-product contamination of the Gulf marine environment following the war

FOLLOWING the Gulf war, controversy and speculation have surrounded the extent to which the massive spillage of petroleum and the burning of oil wells in Kuwait have damaged marine ecosystems in the region1–5. We report here the results of a rapid assessment survey of hydrocarbon contamination undertaken in the coastal marine environment from Kuwait to Oman during mid-1991. Our results show that severe oil pollution was restricted primarily to the Saudi Arabian coastline within ∼400 km from the spillages, and that during the four months following the conflict and preceding our survey, the spilled oil had extensively degraded. Surprisingly, concentrations of petroleum hydrocarbons in sediments and bivalve molluscs from Bahrain in June 1991 were lower than those recorded from our pre-war (1983–86) surveys at the same site, probably as a result of decreased tanker traffic and associated deballasting during and after the conflict. As for carcinogenic polycyclic aromatic hydrocarbons produced during burning of the oil wells, we found that concentrations in sediments from even the most heavily contaminated sites were relatively low, and comparable to levels reported for the Baltic Sea6, coastal locations of the northeastern United States7 and United Kingdom estuaries8.

Effects of oil/gas field produced water on the macrobenthic community in a small gradient estuary

Little is known about how climatic events (i.e., drought) inhibit or enhance movement of petroleum hydrocarbon laden sediments in estuarine systems and how this in turn effects the macrobenthic populations exposed to these sediments. Seventeen collection stations were established and monitored at New Bayou, Texas, a small gradient estuary which receives petroleum products via oil/gas field produced water discharge. Hydrographic, geologic and biotic samples were taken monthly from each station during a period of reduced rainfall. Both temperature and dissolved oxygen data taken during the study followed patterns typical for the area. Salinity values increased into the polyhaline range at near-bay stations during the reduced rain period, while upper bayou stations remained within the oligohaline range. Sediment grain sizes along the bayou were generally in the silty-clay range. Sediment hydrocarbon concentrations were highest (11.4 mg g−1 dry sediment) around the produced water discharge site and lowest at near-bay stations (0.2 mg g−1 dry sediment). Ninety-six macrobenthic species were collected during the study. General effects from produced water discharge on macrobenthic populations followed the classical pattern outlined by other research in shallow bay systems. A sediment hydrocarbon concentration of 2.5 mg g−1 dry sediment was found to reflect the average value needed to depress population abundances. Both abundance and diversity values were lowest at central stations near the discharge site. This zone of depressed macrobenthic populations extended from the discharge site at least 107 m downstream and 46 m upstream. The zone of stimulated macrobenthic populations occurred 1486 m downstream and 381 m upstream from the discharge site.

Hydrocarbon concentrations in sediments and animal tissues from the coastal waters of Karachi

Hydrocarbon concentrations in sediments and animal tissues from the coastal waters of Karachi

Hydrocarbon concentrations in sediments and water from the English Channel

Hydrocarbon concentrations in sediments and water from the English Channel

Georges bank monitoring program: hydrocarbons in bottom sediments and hydrocarbons and trace metals in tissues

Hydrocarbons in sediments and hydrocarbons and trace metals in tissues from Georges Bank were analyzed to evaluate potential changes to the henthic environment resulting from exploratory drilling operations. Sediment hydrocarbon concentrations varied with grain size: concentrations up to 2·5μg/g dry weight total aromatic equivalents occurred in the fine-grained sediments of Lydonia Canyon and the ‘Mud Patch’ area south of Martha's Vineyard, whereas concentrations were less than I μg/g dry weight in sediments from the shallow areas of Georges Bank, at a regional control site, and at the site of drilling operations. Increases in total aromatic equivalents from approximately 0·1 μg/g dry weight to 0·4 μg/g dry weight were measured in sediments from a site 0.25 km from the drill rig concurrent with drilling operations. Petrogenic hydrocarbons were detected in both drilling fluid extracts and in sediments collected during drilling operations, suggesting short-term deposition of drilling discharges in near-rig sediments. Drilling discharge residues were not observed in the near-rig sediments one month after drilling operations were terminated. Furthermore, hydrocarbon residues from drilling discharges werenot observed in sediments from stations located at distances greater than 6 km from the drill site either during or subsequent to the drilling operations.

Polycyclic aromatic hydrocarbons in sediments of the Great Barrier Reef region, Australia

At present the concentrations of polycyclic aromatic hydrocarbons in sediments from the Great Barrier Reef are remarkably low. The baseline levels range from <0.01 μg kg−1 dry wt. for benzo(k)fluoranthene and benzo(a)pyrene to <0.82 μg kg−1 for chrysene. Measurable levels of polycyclic aromatic hydrocarbons have only been found in small areas close to sites frequently visited by power boats. Sediments from Townsville and Gladstone Harbours on the coast adjacent to the reef are polluted with polycyclic aromatic hydrocarbons to a similar degree to that reported for coastal sediments in similar locations in other parts of the world.

Relationship between hydrocarbons and bacterial activity in mediterranean sediments: Part 1—nature and concentration of the hydrocarbons in the sediments

The presence of hydrocarbons in marine sediments of the Mediterranean coast was studied by two different but complementary methods. Results obtained through a technique especially adapted to sediments are given; this leads to a relatively accurate and reproducible determination of the hydrocarbon concentrations in sediments collected at many sites of the Mediterranean coast, polluted or not, by chronic petroleum input (Brusc lagoon, zones of Embiez, Fos, Carry-le-Rouet and Etang de Berre). The hydrocarbon concentrations in the non-polluted sediments are always less than 300mg/kg of dry sediment, with important variations according to season. In the polluted sediments the hydrocarbon concentrations are more than 300ppm, with variations difficult to interpret. The analytical profile of these hydrocarbons shows considerable differences from that for the hydrocarbon fraction extracted from the non-polluted sediments. These differences principally relate to concentrations of odd and even carbon numbered hydrocarbons and the presence of aromatic or polyaromatic compounds specific of petroleum fractions.

The cumulative ecological effects of normal offshore petroleum operations contrasted with those resulting from continental shelf oil spills

Assessments of the cumulative ecological effects of chronic sublethal discharges from normal (non-spill) offshore petroleum operations have been based on (1) model studies, (2) controlled laboratory and microcosm experiments, (3) studies of spills of crude oil and its refined products and of severe organic pollution, and (4) ecological field studies in areas of intensive petroleum operations. Methods (2) and (3) involve ( a ) the extrapolation of results obtained from concentrations and rates of exposure that are not representative of chronic low-level exposure, ( b ) usually a different suite of chemical contaminants, and ( c ) usually a different ecosystem. The fourth method is faced with determining the ecological effects of very low levels of contamination in the presence of larger natural environmental and biological variations and of other sources or types of contamination. This paper compares predictions based on method (3) with results obtained by using method (4) in the Gulf of Mexico. Primary data are from three studies on cumulative effects and from studies of spills in the Gulf. The response of benthic macroinfaunal communities and populations to sediment hydrocarbon concentrations are the primary basis for comparisons. Some principal environmental variables are ‘norm alized’ to facilitate quantitative comparisons.