Eve Southward recounts the MBA's response to the Torrey Canyon oil spill.
The tanker Torrey Canyon struck the Seven Stones Reef off Land’s End, Cornwall in south west England, on 18 March 1967 and the cargo of about 119,000 tonnes of Kuwait crude oil started to escape from the damaged ship immediately (Fig.1). The government and armed forces took charge of clean-up operations after attempts to tow the wreck off the reef failed, and oil dispersants (detergents) were sprayed on the oil slick from Royal Navy ships and others. Ten days after running aground, the wreck was bombed by the RAF and some of the cargo was burned but the fires went out and leakage continued until, towards the end of April, the empty wreck sank. The floating slick was moved by wind and tide (see Fig. 2) and the oil fouled the shores of west Cornwall between 24 and 29 March, and the Channel Island of Guernsey on 7 April. North Brittany (France) was finally reached on 10–12 April.
Thousands of sea birds were the first victims of the oil but this spill became notable for the enormous amount of oil-spill dispersants that were applied in the Cornish marine environment. They were first used at sea to try to disperse the floating oil and were also sprayed (usually diluted with water) on the oily rocky shores and sandy beaches. The toxicity of such dispersants was not fully understood at the time of the disaster and they had a devastating effect on the fauna and flora.
Many official and voluntary bodies became involved in the subsequent clean-up and its consequences. As soon as the large-scale use of detergents became known and the pollution of large stretches of the Cornish coastline was seen to be inevitable, it was decided to divert the entire resources of the MBA laboratory to study the effects of oil and detergent pollution on intertidal and offshore marine life in the area. Work started on 26 March and continued until mid-June – although some at the laboratory continued for much longer. A report was completed by mid-September and published as a book in spring 1968.
Figure 1. The tanker Torrey Canyon on the Seven Stones reef, 18 March, 1967. Image copyright: Mariner's Museum.
On 28 March the MBA’s research vessel Sarsia (Fig. 3) set off from Plymouth to take samples of water, plankton, and fish in Mount’s Bay and the Seven Stones area. Gerald Boalch, the Chief Scientist on the cruise remembers: “When we steamed west on Sarsia the first thing we noticed before we saw the oil was the dreadful sickening smell. When we did reach the oil it was like a thick rust-red layer on the surface. Local boats were out spraying the oil with detergent and the oil was obviously being broken up and dispersing. We realized that the detergent was breaking up the oil but was probably making it more accessible to the marine life. At that time we had no information on the toxicity of the detergent. We sampled the plankton in the area where the oil was being treated and under the microscope could see that some species of the plankton were being killed.”
Local people were also involved in attempts to deal with the spill, but frequently felt that their knowledge and suggestions were ignored by the ‘experts’. When interviewed in 2011, members of local communities commented on the nauseating smell and the brown colour of the incoming oil on the sea. They feared for their livelihoods and the likely effect on the 1967 tourist season.
Figure 2. Approximate track of the oil from the Torrey Canyon and the plaaces it came ashore. Reproduced from Smith (1968).
Figure 3. The Sarsia, the MBA's research vessel at the time of the spill. Image: MBA.
My own involvement began with exploratory experiments – with Alan Southward and Eric Corner – on the toxicity of the detergents on the larvae of a common intertidal barnacle, Elminius modestus. We tested four brands of detergent employed at the time, in comparison with the laboratory detergent Teepol and with samples of Kuwait crude oil. All four brands were more toxic than Teepol or Kuwait crude. The relative toxicity of the various brands depended on the types and quantities of organic solvent components. Other researchers found similar effects on other types of planktonic larvae and phytoplankton species in culture.
Alan and I then turned our attention to the effects of oil and detergent on the ecology of the Cornish rocky shores, for which we had some 10 years’ earlier data. MBA workers visited 65 sites between mid-March and mid-May; 18 main sites were obviously heavily polluted and most of these were ‘cleaned’. It was difficult to find a shore that had been oiled and not cleaned, however, the shore at Godrevy Point (close to a seal colony) was patchily oiled and not directly treated with detergent because of objection by the National Trust. This became our control site in future years. On heavily detergent-treated shores tufts of bleached seaweeds and empty shells could be seen. The rocks looked clean, even white. In the absence of most grazing animals ephemeral green algae could settle and grow, turning the shore green within the first year, and the green algae were succeeded by a heavy settlement of brown algae. At Godrevy Point, most of the limpets survived under a light coating of oil, there was no greening and the shore returned to normal within two to three years. The recovery of dispersant-treated shores to ‘normal’ took 5 to 10 years (see Fig. 5).
Up to 50 years’ follow-up observations, including photographs, are now available for five of the major Torrey Canyon sites, showing the extent of the recovery phases and later natural fluctuations in algal cover and animal populations.
Eve Southward (firstname.lastname@example.org)
Figure 4. Drawings of barnacle larvae copied from Smith (1968).
Smith J.E. ed. (1968) ‘Torrey Canyon’ Pollution and Marine Life. Marine Biological Association of the U.K. and Cambridge University Press. 196 pages.
Green A. & Cooper T. 2015. Community and Exclusion: The Torrey Canyon disaster of 1967. Journal of Social History 48 (4), 892–909.
Corner, E.D.S, Southward A.J. and Southward E.C. 1968. Toxicity of oil-spill removers (‘detergents’) to marine life: an assessment using the larvae of the intertidal barnacle Elminius modestus. JMBA 48: 29–47. Link to JMBA vol 48?
Southward, A.J. and Southward, Eve C. 1978. Recolonization of rocky shores in Cornwall after use of toxic dispersants to clean up the Torrey Canyon spill. Symposium on Recovery Potential of Oiled Marine Environments. Journal of the Fisheries Research Board of Canada 35, 5: 682–706.