Integrity testing and toxicity of three dispersants to Chironomous transvaalensis Keiffer (Diptera:Chironomidae)

In-depth integrity testing of three dispersants: Corexit 9572, NalcoD4106 and Goldcrew was carried out to determine key physical characteristics of the dispersants and toxicity to the larvae of Chironomous transvaalensis Keiffer (Diptera:Chironomidae). The result revealed that Corexit 9527 and Goldcrew maintained their integrity while NalcoD4106 on the other hand deteriorated in storage. Static bioassay conducted to determine the 96hr LC50for the dispersants against the insect species showed that Corexit 9572 was the least toxic followed by Goldcrew and Nalco D4106. Furthermore, mixtures of crude oil and either Corexit 9572 or Goldcrew were less toxic to the test animals than the crude oil alone whereas dispersant – crude oil mixtures containing NalcoD4106 were more toxic. Dispersants which would be effective for particular environmental conditions is discussed.