Chlorinated hydrocarbons in the seawater of the German Bight and the Western Baltic in 1975

Abstract

67 water samples taken from the German Bight in 1975, and 80 samples from the Western Baltic also taken in 1975, have been investigated from the following water depths: the micrometre, the millimetre, the metre layers, and the deeper water regions. As a mean value, water of the millimetre layer contains 20 times more of the organochlorine compounds in the German Bight and 50 times more in the Western Baltic than that of waters near the bottom. These relationships, however, are not always as evident; sometimes they are even the reverse. The results show the unexpected fact that, as a consequence of the hydrological, meteorological, etc., conditions, no clear correlationship could be detected between the concentrations of organochlorine compounds on the one hand, and the amount of particulate matter, rainfall, and land distance on the other hand. Of 20 substances we were looking for, 9 could be detected. Concentrations of 7 compounds have been evaluated (in ng/l): In the German Bight: lindane: 4.8; α-BHC: 5.4; dieldrin: 0.15; p.p′-DDD: 0.13; p.p′-DDE: 0.12; p.p′-DDT: 0.26; PCB: 1.9. In the Western Baltic: lindane: 4.3; α-BHC: 6.0; dieldrin: 0.08; p.p′-DDD: 0.07; p.p′-DDT: 0.09; PCB: 1.4. The surface layers are not included in these mean figures. The analyses show a number of supposedly halogenated hydrocarbons to be present in the samples, however, these could not be identified. Their concentrations often surmount by far the concentrations of DDT.