Pelagic tar in the Mediterranean Sea

Abstract

Floating tar samples were collected, using neuston nets, in 101 stations in the Mediterranean Sea in August–September, 1987, by research vessels of Cyprus, Germany, Israel, and Turkey. The distribution of the tar content indicates that the most tar contaminated sea is in the northeast between Cyprus and Turkey and in the Gulf of Sirte off the coast of Libya, where the mean tar content was 1847 and 6859 μg m −2, respectively. The least polluted areas were the western Mediterranean, 236 μg m −2, and the northern Ionian Sea as far east as halfway between Crete and Cyprus with mean tar concentration of 150 μg m −2. Strongly heterogeneous but overall intermediate mean values of 1347 and 876 μg m −2 were found in the Levantine Basin west and south of Cyprus, respectively. A comparison between pelagic tar data collected in 1969, in 1974 and our data shows a sharp decline in tar concentration with time, from 37,000 μg m −2 in 1969 to 9700 μg m −2 in 1974 and to 1175 μg m −2 in 1987. The geographical distribution of tar may be explained by the severe reduction in the activity of oil terminals in Israel, Lebanon and Syria which causes a reduction in tar content in the southeastern Mediterranean. The increased activity of the oil terminal in Iskenderun Bay, Turkey, and the activity of oil loading at the terminals in Libya still leave a high level of tar pollution in the Mediterranean water off these coasts. However, recent technologies in the oil shipping industry, international conventions on oil pollution of the Mediterranean, and harsher steps to administer the anti pollution laws by various countries in the Mediterranean have caused a general decline of this problem.