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M u . 7nur. Bid., Vol. 8, 1970, pi). 21.5 -306
THE PROBLEM OF OIL POLLUTION OF THE SEA
A. NELSON-SMITH Department of Zoology, University College of Xwansea,
I. Introduction . . .. .. .. .. .. * . 11. Sources and Control . . .. .. . . . . ..
A. Tanker Operation and General-cargo Shipping . . 3. Harbours and Marine Terminals . . . . . . C. Coastal Industry and Other Sources . . . . . .
111. Properties of Petroleum Oils .. .. .. .. A. Physico-chemical Characteristics . . .. .. B. I3ehaviour of Spilt Oil on Sea and Shore C. Detection and Identification . . . . ,. * .
IV. Effects of Oil Pollution . . . . .. . . .. A. Mode of Action and Toxicity of Oils . . .. .. B. Effects on Marine Comrnunities .. .. .. C. Carcinogenesis . . .. . . . . .. .. D. Rehabilitation of Oiled Birds . . . . .. .. E. Public Amenity and the Tourist Industry . . . .
V. Removal of Spilt Oil . . .. . . .. . . .. B. Dispersal, Sinking and Recovery at Sea . . .. C. Problems in Cleansing Shores . . .. . . ..
VI. Conclusions and Prospects . . .. . . .. ..
. . . .
A. Bacterial Degradation and Other Biological Processes
D. Mode of Action and Toxicity of Solvcnt-emulsifiers
VII. References .. .. .. . . . . . .
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.. 271 ,. 214 . . 280 .. 288 . . 290
I . INTRODUCTION The Report from the Select Committee on Science and Technology
(1968) points out that oil pollution is referred to (as " slime ") in the Book of Genesis and by Herodotus. Such natural seepages still occur in petroleum-producing areas, but elsewhere, oil pollution of the sea results mainly from its transport or use as a fuel by shipping. Possibly the first account of this was by Jonas Hanway who in 1754 complained of leakages from wooden petroleum-barges in the Caspian Sea (Hawkes, 1961); a century later, these barges were still creating a pollution problem on the Volga.
The first widespread use for petroleum products was in lamps, where mineral oil began t o replace vegetable or whale oil in the mid-
216 A. NELSON-SMITH
nineteenth century. It was shipped in barrels carried in the hold, like whale oil or any other liquid cargo, but even so was liable to spillage as with the schooner " Thomas W. Lawson )', wrecked on the Isles of Scilly in 1907 with the loss of her cargo of two million gallons of crude oil (Parslow, 1967a). Steamers did not at first engage in the petroleum trade for fear of fire, so the first true tankers were sailing vessels fitted out with wing tanks. The Anglo-American Oil Company's " Daylight )', one of the most successful, sailed on into 1921, although the steam- tankers " Gluckauf " and " Bakuin " entered the Batoum oil-service in 1886. At much the same time, the internal-combustion engine and the steam-turbine were invented. The Royal Navy turned t o oil-firing for the turbine-driven Tribal-class destroyers in 1908, while the first sea- going motor-ship '' Vulcanus )' was launched in 1910.
Much of the early pollution of European coasts was by fuel from the bilges and bunker-tanks of oil-fired or motor ships, whose numbers were increasing rapidly. Crude oil was mostly processed in petroleum- producing regions and tankers carried the refined products, many of which were clean light oils. The shipping lanes converging on the English Channel are the busiest in the world, so that the degree of pollution already became sufficient to prompt the passage in 1922 of the Oil in Navigable Waters Act, which prohibited the discharge of oil or oily water in British territorial waters. The United States followed with the Oil Pollution Act of 1924. In 1926 an international conference in Washington recommended the establishment of coastal zones 50-150 miles wide in which the discharge of oil should be prohibited ; agreement could not be reached, but the zones were recognized voluntarily by the shipowners' associations of many Western nations. The scheme formed the basis of a Convention drawn up by the League of Nations in 1935 but after the withdrawal of Germany, Italy and Japan from the League, this Convention could not be ratified and the outbreak of war in 1939 prevented further action.
I n 1938, world petroleum production was 278 million tons ; western Europe consumed 36 million tons of oil, of which the British share was 11 million tons. Rate of consumption was enormously accelerated by the 1939-45 war and subsequent industrial expansion, until by 1967 world production had reached 1 828 million tons and Britain alone consumed 85 millions tons (Select Committee, 1968 ; British Petroleum CO., 1968). During this period, the contribution made to world production by Middle East oilfields grew from nearly 4% to over 27% (Fig. 1). By 1960, the growth of the European market and the political instability of the Middle East and other oil-producing regions made it economically and politically prudent to build refineries at the point of
FIG. 1. Main oil shipments to western Europe-A, from 1963 to early 1967 ; R, in late 1967. The width of tho arrows is proportional to the tonnage carried. Compare with similar maps by the Ministry of Transport (1953) and IMCO (1964); after British Petroleum Review-( 1967).
218 A . NELSON-YMITII
consumption. Thus not only was there a great increase in the sea- transport of oil ; there was a basic change in its nature. Large tankers entering European waters now carry crude oil, while refined products (whose spillage creates less of a pollution problem) are carried overland or in small coastal tankers.
Recent governmental efforts to control oil pollution of the sea have been reviewed in a US. State Deyt. Report (1959) and by Barclay- Smith (1958, 1967). Various meetings of naturalists and wildfowlers in 1952 were followed by the appointment of the Faulkner Committee, which reported the next year (Ministry of Transport, 1953). I n 1954 an international conference in London drew up a Convention which, like that of 1935, prohibited the discharge of oil within specified coastal zones. The United Kingdom was the first to ratify the Convention, passing the Oil in Navigable Waters Act of 1955; by 1958, having been ratified by ten nations, the Convention came into force. I ts admini- stration passed to the Intergovernmental Maritime Consultative Organization (IMCO) when that body was formed by the United Nations in 1959. The United States ratified the Convention in 1961, after a further international conference in Copenhagen.
Amendments to the 1958 Convention extending the prohibited zones (to include, for example, the entire Baltic and North Seas) and regulating further classes of vessel were proposed at an IMCO conference in 1962 and eventually came into force in 1967 (IMCO, 1962, 1967) ; but by this time " Torrey Canyon " had been stranded off the coast of Cornwall, bringing to a head the apprehension felt in many quarters about the operation of increasingly large tankers. Proposals discussed at subsequent IMCO meetings include regulations governing the con- struction, navigation and routeing of tankers as well as measures directly concerned with pollution prevention and control (Goad, 1968). Legal problems arising from the " Torrey Canyon " incident, sum- marized by Marshall (1967; see also Edwards, 1968) were discussed at, an International Legal Conference on Marine Pollution Damage con- vened by IMCO in Brussels during November 1969. Procedures were laid down by which a coastal nation might act if a casualty on the high seas threatened to cause severe pollution. A Convention was drafted placing strict liability for compensation upon the owners of an oil- carrying ship from which the cargo escapes or is discharged. As an interim arrangement, nearly 60% of the world tanker fleet had already subscribed to the TOVALOP plan, which from October 1969 provided for much of the cost of cleaning up an oil spill to be covered by the owners, encouraging them to take quick action in minimizing the resultant damage.
THE PROBLEM O F OIL POLLUTION O F THE SEA 219
11. SOURCES AND CONTROL A. Tanker operation and general-cargo shipping
The largest and most dramatic spillages of oil a t sea have resulted from the collision or stranding of tankers. It has been argued that the current trend towards very large bulk carriers should reduce this risk, because fewer voyages are necessary to keep any one refinery or tank- farm supplied. Nevertheless, in the three years ending with April 1967, 91 tankers went aground and 238 were involved in collision. 19% of the groundings and 9% of the collisions resulted in cargo spillage-a total of 39 incidents. I n the first five months of 1968, a further 39 tankers were involved in various accidents, not all resulting in oil-spills (Brockis, 1967; Select Committee, 1968). When a large tanker is damaged, it is obvious that she is potentially capable of losing a great deal of oil ; modern design trends do little to minimize this possibility. Before the 1939-45 war, typical tankers carried 10 000-12 500 tons of cargo at speeds up to 12 knots. To meet wartime demands, American shipyards went into mass-production of the T2 tanker, carrying some 16 500 tons at a sustained speed of 144 knots. For some years after the war, this type formed the backbone of tanker fleets before it was ousted by " supertankers " (as they were calle