Dispersant Toxicity Test Procedures

Abstract

Abstract The toxicity of chemicals used to disperse oil is considered on the basis of British experience and in relation to effects on fisheries and marine life. It is concluded that although toxic dispersants may be of value in treating oil at sea, they should not be used in large quantities in shallow coastal water, over shellfish beds or fish nursery grounds, or in estuaries. When oil comes ashore the problem should be reduced by mechanical means and chemical methods used only on high-amenity beaches. Toxicity-testing procedures for dispersants have so far been based upon the determination of LC50 values in static-water aerated tanks at 15°C over a 48-hour period, but a continuous-flow apparatus is being devised. Test animals regularly used are Pandalus montagui, Crangon crangon, Carcinus maenas and Cardium edule, but the fish Solea solea and Limanda limanda and the lobster Homarus gammarus are now being included. A large number of commercially available dispersants have been tested and also some experimental formulations. Some recently-developed materials for use at sea have low toxicities but are of little value for treating oil which has come ashore. Tainting by oil and dispersants may affect fisheries by adding unwanted flavours to fish and shellfish and so affecting marketability over several weeks.