Residues of chlorinated hydrocarbon insecticides in the North Sea environment

Abstract

1. Sandwich terns(Sterna sandvicensis) of a colony in the Dutch Wadden Sea, which were seen dying in tremors and convulsions, were analysed for their contents of chlorinated hydrocarbon insecticides. These proved to be present in considerable concentrations. 2. The concentrations found were compared to those present in chickens of hens, poisoned in the laboratory. The amounts present in the dying or dead Sandwich terns were high enough to cause their death. 3. Tern eggs from different coastal places in Ireland, Great Britain, The Netherlands and West Germany were sampled and analysed for these compounds. The amounts of dieldrin, telodrin and endrin in the eggs from the first two countries were much lower than those in the eggs from the last two ones. The amounts of DDE were quite the same. 4. Tern food fishes(Clupea sprattus, Clupea harengus andAmmodytes lanceolatus) were sampled in the Dutch Wadden Sea and analysed. They contained considerable amounts of chlorinated hydrocarbon insecticides. 5. Mussels(Mytilus edulis) were sampled at a series of locations alongside the Dutch coast. The highest concentrations of the insecticides were found on places near the mouth of the river Rhine. Also telodrin, an insecticide not used in Europe, was found. 6. A big insecticide producing industry near the mouth of the river Rhine was informed of these facts. Measures taken by this form resulted in a decrease of the amounts of telodrin in the coastal North Sea environment.