ENSC 201 Lecture Notes - Lecture 3: Botulinum Toxin, Rainbow Trout, Lt50
29 Jan 2017
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Ensc201 lecture 3: principles & methods of environmental toxicology. Toxicant: a substance that will cause a harmful effect when administered to a living organism. Toxin: a toxicant produced by a living organism: e. g aflatoxins, botulinum toxin, domoic acid [cont. in natural hazards, xenobiotic: foreign to the body, anthropogenic: human-made, (cid:862)all things are poisons, for there is nothing without poisonous qualities. It is only the dose which (cid:373)akes thi(cid:374)gs poiso(cid:374)ous(cid:863) paracelsus. Toxicity : dose and concentration, duration, route of exposure. Lt50 = median lethal time set at specific dose/ [ ] Quantal dose response used to calculate ld50 (median lethal dose, or does that kills 50% of the individuals in a population. Provides a basis for monitoring effluent quality and environment quality. Provides data for setting criteria, guidelines, objectives, standards to limit environmental levels of contaminants. Duration and frequency of exposure to toxicant (lab animals) Acute: less than 24h duration, usually single dose, e. g.
