Oil and Chemical Pollution最新文献

The results of a series of chemical dispersion tests are presented, in which three crude oils (Gullfaks, Statfjord and Arabian heavy), each at 4 states of weathering, have been dispersed at 13°C with two dispersants (Finasol OSR-5 and OSR-12) using three laboratory tests (Warren Spring Rotating Flask — WSL test, Institute Français du Pétrole flow test — IFP test and MackayNadeau—Steelman — MNS test). Effectiveness and dispersed oil droplet size distributions in the different test methods have been studied and an attempt has been made to develop correlation or mathematical models of the chemical dispersion phenomena. This mathematical treatment helps to explain the reasons that the tests give different results, but it is concluded that, at present, our understanding of the basic dispersion phenomena is not sufficient to form a basis for a reliable model. Several modelling approaches are discussed in the hope that as further data and insights become available, reliable models may be developed to describe this complex process.

Afield analysis of the effect of oil and gas derived produced water discharges on the vegetation of one freshwater and two brackish wetlands in coastal Louisiana was conducted. Aboveground biomass, plant species composition, pH and salinity were measured to determine if the produced water discharge in each marsh was related to differences in plant response. Of the three marshes investigated, only one of the brackish marshes exhibited significantly lower live aboveground biomass at the site receiving produced waters compared to its adjacent reference site. Although interstitial salinities were significantly higher at the treatment site of this brackish marsh, the salinity difference between treatment and reference sites was only 1·5 ppt in a marsh with a mean salinity of 11·9 ppt. This salinity difference should have no discernible biological effect on the brackish species inhabiting this marsh. Also, the differences in species composition between treatment and reference sites of each marsh did not indicate a produced water effect. Thus, at these three produced water discharge sites the dilution of the produced water in the discharge canals, plus the sinking of higher density produced water to canal bottoms (thus making it less available for tidal movement into the marsh), appears to prevent a biologically significant negative impact on the marsh vegetation. Whether this conclusion is valid for other produced water sites needs further evaluation.

Offshore oil exploration activity usually requires the discharge of drilling muds and formation cuttings into adjacent waters or on ice above these waters. Although dispersal of these muds is well documented in marine environments of moderate to high energy, the fate of drilling muds in shallow, low-energy Arctic environments has received little attention. This study focused on three drilling effluent disposal sites around Stefansson Sound in the Alaskan Beaufort Sea. All sites were in shallow (less than 5 m), low-energy marine environments. Sediment concentrations of six metals often present in drilling effluents (aluminum, arsenic, barium, chromium, lead and zinc) were examined. Metal concentrations obtained from replicate grab samples along 100 m transects were compared with those taken at four shallow-water offshore island control sites, and with data from other studies.

The results indicate persistence of barium, chromium, lead and zinc at certain stations at all three discharge sites, and elevated concentrations of aluminum at one of the three sites when sampled 2–4 years after the discharges. Metal concentrations, when elevated, were typically highest near the discharge points, continued in the direction of wind-induced longshore transport, and generally diminished with distance from the discharge site. However, distributions displayed some patchiness indicative of in place melting of ice-rafted muds or reworking of sediments by currents or icegouging.

Further work will be needed to evaluate the biological impacts of drilling effluents. However, the slow dispersal of these materials suggests there is a need for closer evaluation of drilling effluent persistence problems at shallow, lowenergy locations in the Beaufort Sea.

Recent increased human pressures on the environment have led to biological consequences in Lagos' coastal waters, notably in the Lagos lagoon and its drainage channel to sea. Two broad surveys were conducted in February and June 1985 and repeated in 1986 to obtain information on the distribution, habitats and communities in the Lagos lagoon in relation to environmental factors. The samples were used for biological, sediment particle size, organic matter, heavy metal and hydrocarbon analyses.

A wide variety of sediments occurred throughout the study area. These ranged from fine, medium and coarse sands to admixtures of silt and clay which provided a wide selection of habitats. The western industrialized areas contained high levels of selected heavy metals. Petroleum hydrocarbon contamination was present in most samples. The percentage of total organic matter was closely associated with the sediment types and the influence of waste inputs. The distribution of several species was influenced by the salinity regime and nature of bottom deposits. Benthic macro-infauna was dominated by molluscs, which were most common in the shallow shoal sands of the northeastern portions of the study area. Species characteristic of stressed environments, notably Capitella capitata, Nereis sp. and Polydora sp., were more abundant in the polluted western industrialized portions. Several species showed seasonal population fluctuations. Diversity indices indicated that the communities exhibited high dominance with a small number of species.

The concentration of polycyclic aromatic hydrocarbons (phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene/chrysene, benzo(a)pyrene, benzo(e)pyrene/perylene, benzo(k)fluoranthene and benzo(ghi)perylene) and n-alkanes ranging from n-hexadecane (C-16) to n-dotriacontane (C-32) in sixty sediment and water samples from the southern Baltic Sea were determined. Since hydrocarbon concentration itself cannot be used for estimation of marine environment pollution, multivariate classification and comparison using principal component analysis (PCA) has been made on the data matrices. The connection of the principal component score values with the geography of the sampling area was investigated. Some suggestions on the usefullness of the aforementioned parameters for the estimation of marine environment contamination are given.

Five lorries shipped on board the ferry Herald of Free Enterprise that sank off the Belgian coast in 1987 contained together over 100 different chemicals. During the intricate salvage operation that followed the tragedy, the environmental protection activities met with technical, scientific, legal and organizational difficulties. An assessment of the exact nature, harmfulness, and situation of the cargo had to be done while access to the casualty was limited, and information insufficient. The risks for the personnel and for the marine environment were evaluated using both simplified scenarios and sophisticated computer simulations. Environmental contamination was monitored and protective counterpollution measures were implemented under supervision of the authorities. Although more than half the dangerous cargo was lost, environmental damage was kept to a minimum.

The application of flexible polyurethane (PU) foam for the removal and recovery of priority pollutant phenols, such as phenol, anisole, guaiacol, 2,3-dimethyl, 2,4-dimethyl, 2,5-dimethyl, 2,6-dimethyl, 3,4-dimethyl, 3,5-dimethyl phenols, 1,2-dihydroxy benzene (Catechol), 1,3-dihydroxy benzene (Resorcinol), 1,2,3-trihydroxy benzene (Pyrocatechol) and 1,3,5-trihydroxy benzene (Phloroglucinol) and their mixtures, from dilute aqueous solutions was investigated. The effect of various parameters on the absorption of phenols by PUfoam was examined. Maximum absorption can be achieved at a flow rate of I ml/min in the range pH 3–9, which is marginally increased as the temperature of the effluent variesfrom 30 to 60°C. As phenol concentration is increased, though the total quantity of phenol absorbed increases, the percentage absorption decreases. It is also observed that at low concentrations of some phenols, satisfactory extraction can be achieved even with increasing volumes of aqueous phase. Based on the extraction data, an extraction mechanism was proposed. Model schemes for the removal and recovery of phenols from industrial effluents (10–100 kl), both by dynamic and static methods, are proposed.

Levels of aliphatic hydrocarbons within the boiling range of alkanes n-C₁₄ to n-C₃₄ were determined in samples of surface sediments and in two bivalve species, Unio tigridis and Pseudodontopsis euphraticus (Unionidae), from seven locations in the lower reaches of the rivers Tigris and Euphrates, and the upper Shatt Al-Arab. These levels, and data derived from them, indicate only slight pollution, mostly by degraded hydrocarbons arising from anthropogenic sources. The Shatt Al-Arab samples were most contaminated and those from the river Tigris the least contaminated.