Pyrolysis of spill oils adsorbed on zeolites with product oils recycling

Experimentally, a feasibility study for adsorption and catalytic pyrolysis of spill oils on Cu/ZSM-5 for recycling of light oils has been conducted in the present work. The adsorption and pyrolysis of model compounds such as heptane, toluene, and diesel (to stimulate the spill oils) on Cu/ZSM-5 have been investigated on a continuous fixed-bed reactor. By component fitted X-ray absorption near edge structural (XANES) spectroscopy, catalytic active species such as metallic copper (Cu) (77-84%) and Cu(2)O (6-7%) are found in the channels of ZSM-5 during pyrolysis of heptane or toluene. Pyrolysis of diesel effected by Cu/ZSM-5 yields gas (C(1)-C(5)) (32%) and light oil (68%) that can be used as auxiliary fuels.     

Photocatalytic degradation of spill oils on TiO(2) nanotube thin films

The nitrogen-doped TiO(2) nanotube (N-TNT) thin films were synthesized using ZnO nanorods as the template and doped with urea at 623K. Under ultraviolet (UV) and visible light irradiation, the efficiencies for photocatalytic degradation of methylene blue is as high as 30%. About 10% of toluene (representing aromatics in the spill oils) in sea water can be photocatalytically degraded under visible light radiation for 120 min. The aliphatic model compound (1-hexadecene) has, on the contrary, a less efficiency (8%) on the N-TNT photocatalyst. On the average, under visible light radiation, the effectnesses of the N-TNT for photocatalytic degradation of model compounds in the spill oils in sea water are 0.38 mg toluene/gN-TNTh and 0.25 mg 1-hexadecene/gN-TNTh. It is expected that spill oils in the harbors or seashores can be adsorbed and photocatalytically degraded on the N-TNT thin films that are coated onto levee at the sea water surface level.     

Photocatalytic degradation of spill oils on TiO2 nanotube thin films

The nitrogen-doped TiO₂ nanotube (N-TNT) thin films were synthesized using ZnO nanorods as the template and doped with urea at 623 K. Under ultraviolet (UV) and visible light irradiation, the efficiencies for photocatalytic degradation of methylene blue is as high as 30%. About 10% of toluene (representing aromatics in the spill oils) in sea water can be photocatalytically degraded under visible light radiation for 120 min. The aliphatic model compound (1-hexadecene) has, on the contrary, a less efficiency (8%) on the N-TNT photocatalyst. On the average, under visible light radiation, the effectnesses of the N-TNT for photocatalytic degradation of model compounds in the spill oils in sea water are 0.38 mg toluene/gN-TNT h and 0.25 mg 1-hexadecene/gN-TNT h. It is expected that spill oils in the harbors or seashores can be adsorbed and photocatalytically degraded on the N-TNT thin films that are coated onto levee at the sea water surface level.     

Interference of oil spill emulsifiers with gas chromatography

Several commercially available spill control agents interfere with gas chromatographic correlation of spilled oils with suspected sources. The effects of four such products are presented. Two of these interfere seriously. One is removable by a simple clean-up procedure, and the other is not removable in principle. In favourable cases, its interference may be minimized by extrapolation. Anticipated interference with other analytical methods is surveyed.     

Assessment of Jessica oil spill impacts on intertidal invertebrate communities

The impact of the Jessica oil-spill on intertidal macroinvertebrate communities was studied using a reference-impact design at three tidal levels at sites where oil deposits had been reported by a shoreline assessment team, and adjacent reference sites. Faunal relationships between the various sites did not show any clear pattern related to oil exposure at the time of sampling (4-11 months post-spill). Similarly, no significant differences associated with oiling were detected for total animal density nor species richness data, nor for the abundances of common taxa. We note that post-hoc studies such as this are limited by a failure to recognise different levels of oiling impacts at different sites (oiling-site interactions). Baseline information is critical if subtle effects of oiling are to be distinguished.     

Impact of adsorbed petroleum hydrocarbons on marine organisms

Adsorptions of south Louisiana crude oil from seawater by clays, non-clay minerals and sediments were conducted in the laboratory. Effect of sediment-adsorbed and water dispersed crude oil on adult oysters were investigated in aquaria. Hydrocarbons in oyster tissues and surrounding water were identified by gas chromatography. Field specimens from an area of a new oil spill and an area five months after an oil spill were also analysed. Evidence of secondary chemical effect of aged oil in sediments on oyster mortality is presented. Oil coated asbestos surfaces severely reduced recruitment of sedentary larval organisms.     

Impact of Amoco Cadiz oil spill on intertidal and sublittoral meiofauna

Changes of meiofauna densities (nematodes and harpacticoid copepods) were studied in intertidal and sublittoral fine sand heavily polluted by the Amoco Cadiz oil spill. A general decrease in the nematode abundance was obvious in intertidal sand seven months after the pollution in spite of the occurrence of the natural spring bloom. No changes in the nematode and copepod densities could be detected in sublittoral sand. Comparisons with the pre-pollution data show, however, a significant decrease in the nematode diversity, mainly due to the increase of some limited dominant species after pollution.     

Large-scale dispersant leaching and effectiveness experiments with oils on calm water

The use of dispersants to treat oil spills in calm seas is discouraged because there is insufficient ‘mixing energy’ to cause immediate dispersion of the oil. However, dispersants might be applied while the seas are calm, in the expectation that they would work later when sea states increase. The present study examined the persistence of dispersants in treated oil slicks on calm water in a large outdoor wave tank. Test slicks, pre-mixed with dispersant, were allowed to stand on static and flowing water for up to six days, after which their dispersibility was tested by exposing them to breaking waves. Results showed that thicker slicks exposed to calm water for up to six days dispersed completely with the addition of breaking waves. Thinner slicks and slicks exposed to water movement became less dispersible within two days. The loss of dispersibility was caused by dispersant loss rather than by oil weathering.     

Effects of the 'Prestige' oil spill on macroalgal assemblages: large-scale comparison

An assessment of the effects of the 'Prestige' oil spill on intertidal, macroalgal assemblages was carried out comparing abundance data obtained before and after the spill. Four zones in the North and Northwest coast of Spain were sampled, one of them located at the immediate vicinity of the spill, the zone most heavily oiled. Macroalgal assemblages had similar structure between years. Neither critical decrease in abundance of the dominant macroalgae, nor increase in opportunistic species were found. Some differences in abundance were observed, but they did not show any pattern, being more likely the result of the natural variability of the assemblage. Extensive, but not intense fuel deposition on the shores and a limited use of aggressive cleanup methods are suggested as possible causes for the lack of the effects in these assemblages after the 'Prestige' oil spill.     

Effects of oil spill on seawater infiltration and macrobenthic community in tidal flats

Tidal flat ecosystem simulators are used to clarify the effects of stranded fuel oil on tidal flat ecosystems. Results show that oil spills increase the periphyton on sediment by decreasing the predation stress caused by deposit feeders. About a month after an oil spill, the total population density of the macrobenthos recovered. The oxidation-reduction potential in the surface sediment drops to a negative value after the oil spill, and the anaerobic condition throughout the sediment seems to be responsible for the decrease in the population density of the macrobenthos. The infiltration volume of seawater into the oil-stranded sediment decreases to a third of that without the oil spill. The recovery of infiltration volume after about a month coincides with the recovery of the population density of the macrobenthos. This result suggests that the macrobenthic population is highly dependent on the infiltration of seawater.     

Effects of an oil spill on benthic community production and respiration on subtropical intertidal sandflats

This study determined effects of an oil spill on subtropical benthic community production and respiration by monitoring CO₂ fluxes in benthic chambers on intertidal sandflats during emersion before and after an accidental spill. The oil spill decreased sediment chlorophyll a concentrations, altered benthic macrofaunal community, and affected ecological functioning by suppressing or even stopping microalgal production, increasing bacterial respiration, and causing a shift from an autotrophic system to a heterotrophic system. Effects of the oil spill on the macrofauna were more severe than on benthic microalgae, and affected sedentary infauna more than motile epifauna. Despite the oil spill’s impact on the benthic community and carbon metabolism, the affected area appeared to return to normal in about 23 days. Our results suggest that the prompt response of benthic metabolism to exposure to petroleum hydrocarbons can serve as a useful indicator of the impact of an oil spill.     

Impacts of the Jessica oil spill on intertidal and shallow subtidal plants and animals

Densities of fishes, invertebrates and plants at rocky intertidal and shallow subtidal sites were censused 1-2 days prior to the Jessica oil spill and compared with information obtained for the same sites one month after the spill, both for sites impacted by oil and unaffected reference sites. While the availability of pre-spill data made this analysis one of the most powerful to date for testing impacts of oil on shoreline environments, no clear changes attributable to oiling could be identified. Discharged oil appeared to cause very little impact in the intertidal and shallow subtidal zones, with such impacts lying within the range of natural spatial and temporal variation at sites investigated. Factors considered to minimize impact in Galápagos included paucity of fully sheltered shores in spill path, moderate wave action, warm temperature, high levels of sunlight, and mixing of bunker oil with diesel.     

Impacts of the Jessica oil spill on sea lion (Zalophus wollebaeki) populations

Following the Jessica oil spill, a total of 79 oiled Galápagos sea lions (Zalophus wollebaeki) were recorded around the islands of San Cristóbal, Santa Fé, Isabela and Floreana. Almost half of these animals required washing and other treatment. One sea lion death and a high incidence of conjunctivitis and burns were detected during the period of the oil spill. Sea lion populations exhibited a tendency for decline in the first months following the spill at all three colonies monitored close to the grounding site on San Cristóbal. By comparison, declines of similar magnitude occurred at only one of six sea lion colonies monitored on islands more distant from the spill. However, no significant decreases in population numbers were detected for any colony in the year following the spill. Galápagos sea lion populations were partially recovering from the much more catastrophic impact of the 1997/98 El Ni?o.     

Effects of Kuwait oils on feeding rates of copepods

Sub-lethal toxicity and recovery tests were made on feeding rates of 4 species of copepods using Kuwait oils kept in suspension on a slowly rotating wheel. Counts of faecal pellets from individuals fed on standard algal suspension were made after 20 h at 12°C. This exposure produced only marginal effects at 1 and 2 ppm, but 10 ppm produced definite effects on planktonic species. Recoveries were generally quite good from ‘weathered’ oil treatments. Oils emulsified alone did not produce significantly different effects in these experiments from oils emulsified with dispersants.     

Impacts of a raw sewage spill on water and sediment quality in an urbanized estuary

A sewer main serving a large municipal wastewater system ruptured, discharging approximately 3,000,000 gallons (11,355,000 L) of raw human sewage into a multi-branched tidal creek estuary along the US East Coast. The biochemical oxygen demand caused severe hypoxia in the system, causing a large fish kill. The sewage load led to high fecal coliform bacteria concentrations in the creek (maximum of 270,000 CFU 100ml(-1)), which declined in an approximate logarithmic manner over the first few days. The spill caused elevated sediment fecal coliform bacteria and enterococcus counts that declined much more gradually than water column counts. Persistence of relatively high concentrations of fecal indicator bacteria in sediments for several weeks after the spill suggests that sediment sampling should be included in response to major sewage spills. The high concentration of nutrients in the spilled sewage led to several algal blooms. However, nutrient concentrations in the water column declined rapidly, demonstrating the value of conserving marshes because of their pollutant filtration function.     

Oil spill clean-up: The effect of three dispersants on three subtropical/tropical seagrasses

Three seagrasses found throughout the Greater Caribbean tropical/subtropical region as major critical habitat organisms were tested in the laboratory for toxicity limits to three dispersants commonly stockpiled in the region. At concentrations in the recommended dosage level, that is, below 1 ml dispersant with 10 ml oil in 100 000 ml seawater, even for 100 h no large mortality occurred (15–18 barrels per acre as calculated by Exxon, 1985). At an order of magnitude higher, especially for longer time periods, the more sensitive seagrasses Syringodium filiforme and then Halodule wrightii succumbed. The dispersants had widely differing effects, with Corexit 9527 and Arcochem D609 having far less toxic effect than Conco K(K) at the same exposure time and concentration. There was comparatively little difference between effects of oils (Louisiana crude versus Murban). Types and brands of dispersants should be referred to specifically in oil spill contingency plans since such widely varying ecological toxicity occurs among various dispersants. Use of the word ‘dispersant’ as a policy tool should be used with caution, realizing that dispersants vary widely in toxicity effects. Further testing of seagrasses in other ocean basins and those dispersants to be used there is highly recommended.     

Short-term effects of the prestige oil spill on the peregrine falcon (Falco peregrinus)

We have monitored the distribution, population status, breeding success, turnover rate and diet of a Peregrine Falcon population in Bizkaia (North of Spain) since 1997. On the 13th November 2002, the tanker Prestige sunk off La Coruña (NW Spain) causing an oil spill that affected the whole of the Cantabrian Coast and the Southwest of France. The total number of birds affected by the Prestige oil spill was expected to be between 115,000 and 230,000, some of them raptors. The loss of clutches during the incubation period increased significantly and was correlated with the loss of females. Moreover, the turnover rate of the population increased from 21% to 30%. The polycyclic aromatic hydrocarbon concentrations in the eggs, collected from five nests after they were deserted, ranged from 21.20 ng/g to 461.08 ng/g, values which are high enough to cause the death of the embryos and poisoning of adult birds. The effects of pollution reached inland since some inland-breeding falcons prey on shorebirds that use rivers during their migratory flights. As the Prestige oil spill has clearly resulted in increased rates of adult mortality and reduced fertility, we suggest that the environmental authorities urgently undertake measures aimed at protecting the Peregrine Falcon in Bizkaia.     

Monitoring the Prestige oil spill impacts on some key species of the Northern Iberian shelf

Selected key components of the continental shelf benthic and demersal communities were monitored for the two years following the Prestige oil spill (POS) in order to identify the possible ecological effects of the oil. This work includes the first results regarding changes in abundance, distribution and food habits of hake (Merluccius merluccius), four-spot megrim (Lepidorhombus boscii), Norway lobster (Nephrops norvegicus) and Pandalid shrimp (Plesionika heterocarpus) populations of Galician and Cantabrian Sea shelves following the POS. Significant reductions in the abundance of Norway lobster, Plesionika heterocarpus and four-spot megrim were detected in the POS maximum impact area, located over the Galician shelf. Noteworthy recoveries were observed in the 2004 abundance indices of four-spot megrim and Plesionika. On the other hand, no significant effects were detected in the abundance or distribution of hake juveniles even though the tar aggregates were bound by the same oceanographic drift events as the hake recruits were during the winter of 2003 (Navidad current) in different water column layers of the Cantabrian Sea. Feeding patterns of the four species analysed did not present apparent modifications that can be related to the POS.     

Mexican oil spill: A toxicity study of oil accommodated in seawater on marine invertebrates

The Mexican Ixtoc oil well blew out on 3 June, 1979. Since then more than 3.5 × 10⁵ tonnes of crude oil have entered the Gulf of Mexico. This is probably the largest oil spill in the world's history. Two months later (7 August, 1979), the spilled oil began moving to the Texas coastal waters and the well is not yet capped. Although laboratory tests showed that the aged oil was not acutely toxic to some marine invertebrates, further work needs to be conducted to determine its possible chronic effects on sensitive ecosystems such as the Laguna Madre.