Tanker Routes Research Articles

Tar pollution of beaches in the Indian Ocean, the South China Sea and the South Pacific Ocean

During 1978, a comparative survey was made of the degree of pollution of 265 beaches in the Indian Ocean, the South China Sea, the South Pacific and along the Southern California Bight, the Mid-Atlantic Bight and the Dutch North Sea. Part of the results were published recently and elicited a number of requests for the full data set, which is, therefore, summarized in this note. Generalized observations on tar pollution are: (1) strandings from individual spills could rarely be correlated over distances longer than a few km; (2) tar is concentrated in distinct bands parallel to the water line; (3) there is a pronounced trend of vertical zonation of tar from smaller, well-rounded and soft particles near the water line to larger, flattened and hardened lumps landward; (4) buried tar is relatively uncommon, suggesting a residence time of around 30-90 days in the tropics; (5) tar concentrations display high variability indicating the need for large numbers of samples; (6) prevailing wind regimes are the main cause for seasonal variations in tar strandings. The highest beach tar concentrations were found in areas of oil production or near tanker routes, especially in enclosed seas; Persian Gulf, Red Sea and South China Sea.

The characteristics and dynamics of tar pollution on the beaches of Trinidad and Tobago

Trinidad and Tobago beaches were periodically sampled for tar between July 1980 and September 1981. This project was carried out by the Institute of Marine Affairs in cooperation with the United Nations. The Caribbean coasts of both islands were almost pristine, whereas pollution on the Atlantic coast beaches was comparable to that of other coasts along major tanker routes. The source of high tar concentrations on the Atlantic coasts may be attributed to the residues from tanker bilge cleanings, which are carried along the South Equatorial Current, eventually to strand on the islands' beaches. In the dry season (January to April) north-westerly currents and north-easterly winds prevail and more tar strands on Trinidad than on Tobago. In the wet season (June to November), however, when currents are more northerly and south-easterly wind prevail, the reverse situation holds and more tar strands on Tobago.

Dissolved petroleum hydrocarbons along the oil tanker route in the southern Bay of Bengal : Topgi, R.S., R.J. Noronha, S.P. Fondekar and R. Sen Gupta, 1982. Indian J. mar. Sci., 11(2):175–176

Dissolved petroleum hydrocarbons along the oil tanker route in the southern Bay of Bengal : Topgi, R.S., R.J. Noronha, S.P. Fondekar and R. Sen Gupta, 1982. Indian J. mar. Sci., 11(2):175–176

Present state of oil pollution in the northern Indian Ocean

A consolidated picture of oil pollution for the northern Indian Ocean is presented. Oil slicks were sighted on 5582 observations, about 83.5% of the total observations of 6689. The range of concentrations, of the floating tar balls, is 0–6.0 mg/m 2 in the Arabian Sea. Similarly, the oil tanker route in the Bay of Bengal has the range of 0–69.75 mg/m 2. North of this route, the Bay of Bengal is comparatively free from this floating tar. Mean concentrations of dissolved and dispersed hydrocarbons for 0–20 m are 32.5 and 24.1 μg kg −1, respectively, in the Arabian Sea and the Bay of Bengal.

Dissolved petroleum hydrocarbons in some regions of the northern Indian ocean

Dissolved petroleum hydrocarbons were measured in some parts of the Northern Indian Ocean using UV absorbance technique with a clean up step. The concentration of oil ranged from 0.6 to 26.5 μg l −1. Higher values were recorded along the oil tanker route compared with the coastal region From surface to about 10 m depth the oil appeared to be well mixed with water.

Extractable organics and hydrocarbons in the Mediterranean sea

The level of tanker shipments in the Mediterranean is relatively high, being approximately 8 million barrels per day in 1972 and 1975 (Lloyds, 1972, 1975). This represents an important proportion of world-wide shipments which in 1972–1975 were approximately 30 million barrels daily. Because of the tanker traffic and the Suez Canal opening in June 1975, there was particular interest in obtaining hydrocarbon baseline data prior to changed conditions caused by this event. In response, the present study was carried out in the latter half of 1975 when 0–1m and −5m samples were collected along the tanker routes; Augusta, Sicily/Gibraltar; Augusta/Alexandria, and Augusta/Tunis. Total dispersed extractable organics (lipids) and nonvolatile hydrocarbons (C 14+) were measured. Hydrocarbons were found to be complex mixtures of normal and isoparaffins, cycloparaffins and aromatics. Surface water showed a persistent pattern of n-paraffins of carbon numbers 16, 17, 18, and 19, with a preponderance of the C 17 and C 19's. Presence of these compounds and low concentrations of aromatics indicate that an important proportion of the hydrocarbons were of biogenic origin.

A COMPARATIVE RISK ASSESSMENT TECHNIQUE FOR TANKER OIL SPILLS

ABSTRACT The tanker oil spill risk assessment model (TRAM) allows a user to investigate the way in which oil spill probabilities, and amounts spilled, vary with such factors as fleet composition, navigational aids, or particular properties of the route. Such a comparison of alternatives is generally required for an environmental impact statement. TRAM operates through multiplication of a series of matrices: P, Q, R, and S. The rows and columns of all matrices are parameterized by accident type (such as collision or grounding) and location (such as at a pier, or in a harbor). The probability of an accident (P) and of a spill following an accident (Q) are based on world tanker fleet data. The matrix S expresses the conditional probability that if there is a spill, the vessel will be a total loss. This enables catastrophic spills in which spill size can be related to vessel size to be distinguished from minor spills in which vessel size is generally not a factor. The matrix R contains most of the unique features of the model. It accounts for vessel and route-specific features that reasonably may be expected to alter the world tanker fleet data. Examples are given from the literature for the elements of R corresponding to: fleet composition (domestic/foreign carrier); navigation aids such as vessel traffic system; vessel age, and construction (double hull, inerting system, segregated ballast, etc.); and various features of the tanker route, such as channel width and traffic density, based on Macduff's causation probability formalism. The practical usage of the model is demonstrated by applying it to a hypothetical project involving tanker oil transportation. The extension of this analysis technique to other forms of risk analysis studies (including operations other than oil transport) is also discussed.

Glacier ‘retreat’ threatens Alaskan oil tanker route

Glacier ‘retreat’ threatens Alaskan oil tanker route

Computerized scheduling of seagoing tankers

AbstractComputerized Scheduling of Seagoing Tankers The tanker scheduling problem considered in this paper is that of the Defense Fuel Supply Center (DFSC) and the Military Sealift Command (MSC) in the worldwide distribution of bulk petroleum products. Routes and cargoes which meet delivery schedule dates for a multiplicity of product requirements at minimum cost are to be determined for a fleet of tankers. A general mathematical programming model is presented, and then a mixed integer model is developed which attempts to reflect the true scheduling task of DFSC and MSC as closely as possible. The problem is kept to within a workable size by the systematic construction of a set of tanker routes which does not contain many possible routes that can be judged unacceptable from practical considerations alone.