Assessment of integrity of three dispersants and their toxicity to a Brackishwater Cichlid, Sarotherodon melanotheron (Cichlidae)

Key physical characteristics of three dispersants: Corexit 9527, NalcoD4106 and Goldcrew were studied to determine their integrity and toxicity to a brackishwater fish Sarotherodon melanotheron. The results showed that with regards to the physical properties, Corexit 9527 and to a large extent Goldcrew maintained their integrity while NalcoD4106 deteriorated. Observations of the 96h LC50 static bioassay showed that the toxicity of the dispersants to the fish in an increasing order is Corexit 9527 < Goldcrew < NalcoD4106. Crude oil – dispersant mixtures involving either Corexit 9527 or Goldcrew were less toxic than crude oil alone. On the other hand, NalcoD4106 exhibited higher toxicity than crude oil either as dispersant alone or as dispersant – crude oil mixture.