Aspects of the sensitivity of juvenile Jasus lalandii and decapod excitable tissue to the water soluble fraction of crude oil

1. A flow-through aquarium facility, for testing the toxicity of the water-soluble fraction (WSF) of crude oil is described. 2. The 24 hour median lethal concentration (LC50) of WSF of crude oil for 2 to 3 year old (30 - 45 mm cephalothorax length) juvenile Jasus lalandii ranged from 3,7 to 5,9 mg l⁻¹. 3. Behavioural experiments appear to provide a quick and convenient approach for estimating the relative toxicity of the WSF of crude oil. 4. The major effect of the WSF of crude oil on Jasus heart beat rate was bradycardia. Furthermore, the greater the initial exposure concentration the sooner the heart beat frequency decreased. 5. Exposure of Jasus muscle fibres to the WSF of crude oil resulted in a shift of the resting membrane potential of those fibres in a hyperpolarising direction. Preliminary investigations into the level of excitability of decapod neurons after exposure to the WSF, indicated a rapid increase, followed by a decrease in excitability, to a level below that of unexposed tissue. 6. Recommendations are made as to how the findings of this study could be applied to enhance the sensitivity of toxicity bioassays.

Grantor dc:publisher.institution

Department of Biological Sciences

Year dc:date.issued

1983

Author dc:creator

• Lipschitz, Steven Richard

Advisor dc:contributor.advisor

• Brown, Alec C

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/21850

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/21850