Oil and Chemical Pollution最新文献

The ability of the marine Alteromonas sp. 17 to degrade hydrocarbon substrates was investigated. This strain effectively degraded various liquid and solid hydrocarbons. Growth on the long chain alkane eicosane was studied. The relationship between degradation efficiency of this solid hydrocarbon (80% degradation) and potential bioemulsifier production by the marine strain was investigated. Production of non-dialyzable bioemulsifier, monitored by decrease of surface tension and emulsifying capacity measurements, was observed. The bioemulsifier was able to emulsify various types of hydrocarbons. Its basic composition was 37 mg litre⁻¹ carbohydrates and 15·58 mg litre⁻¹ lipids. Major lipids were polar lipids (phospholipids, monoglycerides, glycolipids). The strain exhibited moderate adherence to liquid hydrocarbons but was non-adherent to solid hydrocarbon.

A new approach for predicting the behaviour of oil spilled on the sea has recently been developed at IKU, Sintef-Group. The approach includes an extensive laboratory investigation of an oil's properties when exposed to weathering. Parameters especially tested are the tendency of the oil to form water-in-oil (w/o) emulsion (mousse), and the susceptibility of the w/oemulsion or water-free weathered oil to disperse using oil spill dispersants. The laboratory results are transformed to field conditions in a numerical model which predicts the rate of weathering processes at sea under different weather conditions. The computer system displays graphical chartsfor the development of each property with time, and estimates the ‘time window’ e.g. for effective application of dispersants under a chosen set of sea conditions. The system may represent an important tool, for contingency planning andfor ‘on-scene’ commanders to facilitate decision-making concerning the use of different countermeasure techniques during oil spill combat operations. This approach may form the basis for a standard method for future characterization of the weathering properties of different oil types which may be spilled under a variety of environmental conditions.

Solubilities are reported for 42 crude oil and petroleum products in water as a function of temperature, salinity, oil weathering and water-to-oil volume ratio. The applicability of several analytical techniques (purge-and-trap gas chromatography, high pressure liquid chromatography, and fluorescence) for the determination of dissolved hydrocarbon concentrations is discussed critically. The effect of water-to-oil volume ratio on the apparent solubility of oils in water is discussed in detail.

A pipeline break on 23 April 1985 near Nairn, Louisiana, resulted in the release of approximately 300 barrels of Louisiana crude oil into a brackish marsh dominated by a vegetative mixture of Spartina patens, S. alterniflora and Distichlis spicata. Since the impact of oil spills on brackish marshes has received little attention, we initiated this investigation to assess the post-spill status of the vegetation. Sixty-eight randomly selected plots located on 15 transects which traverse the complete study area were sampled for various vegetative cover parameters. The major impact of the spill was confined to the 50-acre (20-ha) marsh located immediately around the pipeline rupture. The oil caused a 64% reduction in live vegetative cover (adjusted for differences in total percentage cover among plots) in this marsh 3 months after the spill. This high plant mortality from a relatively low oil dosage (estimated at 0·28 liters/m²) was probably due to the contact of the oil with a large percentage (about 30–70%) of the photosynthetic leaf surfaces of the vegetation and the penetration of the oil into the marsh substrate.

A study of the effects of the water soluble fraction of Iraq crude oil on eggs, larvae and postlarvae of gilthead sea bream, Sparus aurata is presented. The water soluble fraction of Iraq crude oil greatly affects eggs of gilthead sea bream, causing mortality, deformities, narcotic effects and reduced motility. Larvae in all water soluble fraction concentrations died after 72 h. At the start of exposure, growth and yolk sac resorption increase, but after 24 h both decrease compared to the controls. Of the early stages, postlarvae seem to be most resistant to the water soluble fraction of Iraq crude oil.

The application of fluorescence spectroscopic techniques to the uptake of aromatic hydrocarbons into the sandprawn, Callianassa kraussi, was examined. Animals were exposed to the water-soluble fraction of Qatar crude oil for up to 12 weeks, then depurated in clean seawater for up to 4 weeks. Fixed wavelength measurements showed the extent and rapidity of aromatic hydrocarbon accumulation into the hepatopancreas of C. kraussi These measurements, along with synchronous spectra, were useful in demonstrating differential accumulation of light and heavy aromatic hydrocarbons.

A common method of detecting a small leak in a pressurized underground storage tank pipeline system containing petroleum is to monitor the pressure in the line. This paper presents theoretical models to predict the pressure changes associated with leaks and product temperature changes in pressurized pipelines. These models have been validated in experiments at retail petroleum facilities and the EPA's UST Test Apparatus. A heat conduction model is used to estimate the waiting period prior to the beginning of the test that is long enough to allow the product temperature changes to be negligibly small, and an exponential pressure-decay model is used to estimate the test duration that allows the pressure drop associated with small leaks to exceed the threshold. The results suggest that a test duration of 15 to 60 min is required to detect leaks as small as 0·1 gal/h and a waiting period of up to 6 to 12 h is required for the temperature changes in a 2-inch diameter pipeline to be negligible after the last dispensing of product through the line.

Aromatic hydrocarbons were measured in Lake Burley Griffin by fluorescence spectroscopy to gain an estimate of the pollution of the lake by petroleum hydrocarbons. Aromatic hydrocarbons are reported as equivalents of m-terphenyl (T) and chrysene (C). Observed concentrations are 0·3–2·2 μg/litre (T) and 0·1–0·5 μg/litre (C). Widespread distribution of fuel distillates is evident with only a small contribution from lubricating and heavier oils.