THE GREAT PATAGONIAN OIL SPILL (METULA), 41 YEARS LATER

Abstract

ABSTRACT: 2017-300 On 9 August 1974, the supertanker VLCC Metula spilled over 50,000 tons of Saudi Arabian crude oil and 2000 tons of bunker oil into the eastern portion of the Strait of Magellan in southern Chile. Oil spread over 200 km of glacially derived shorelines primarily composed of mixed sand and gravel to boulder-sized material. No cleanup was performed. Initial and follow-up investigators from Chile, U.S., U.K. and Canada reported on oiled shoreline conditions and spill persistence through 2005. This report extends the analysis to February 2015 for the primary areas noted as having remaining oil, i.e. within Puerto Espora behind Espora spit and the sheltered East Espora Marsh. Both are located along the First Narrows on the Tierra del Fuego side of the Strait. Comparisons are made to previous site visits in 1975–76, 1981 and 1995. Conditions at Puerto Espora historically showed a wide band of thick asphalted gravel pavement in a slow process of breakup. This area in 2015 has been further degraded by physical processes but mineralized asphalt remnants are still evident over a discontinuous length of 180 m (maximums: width = 8 m, thickness = 10 cm). In East Espora Marsh, oil initially entered during a very high tide such that oil settled on to channel banks and upper areas dominated by salt-tolerant plants (Salicornia, Puccinellia and Sueda). In 2015, oil remains very much in evidence as weathered asphalt in thin deposits, as a high viscosity black oil with underlying brown mousse common in thicker (>4 cm) deposits, and as oil buried up to 10 cm below a layer of fine silt/clay. Vegetation has recovered to an estimated 75% in interior marsh areas and to ~35% in the outer marsh located at the entry to the marsh. The Metula site remains of great scientific interest in terms of oil spill persistence in a cool dry environment that may be compared to other high latitude habitats such as found in the newly opening Arctic Ocean area.