Page 16 - Professorial Lecture - Prof Omoregie

Ladies and Gentlemen, at this juncture, it is pertinent to distil how animals in the
marine environment will deal with toxicants within their system (physiological
system). Animal physiology deals with the way an animal carries out all its
functions leading to survival within the environment. This includes nutrition,
respiration, transformation of energy, circulation, excretion, reproduction,
development, response to environmental stimuli, etc.

An animal rarely lives under constant environmental conditions. The physical,
chemical and biological environments constantly change (or fluctuate).
Environmental fluctuations when in excess of the capacity of the animal, leads to
physiological dysfunctions (or even death if environmental changes are not
reverted back to ‘normal’).

In order to survive, an organism must make adjustments or compensations, an
active attempt to come to terms with its external environment (environmental
ecophysiology). In the presence of toxicants in the environment, this adjustment /
compensation become extremely difficult to attain, thereby leading to
physiological dysfunctions.

The term Ecotoxicology was coined in 1969 by Truhaut (1977) as a natural
extension from Toxicology (which is the study of toxicants and their effect on
living organisms).

Ecotoxicology is the science of predicting effects of potentially toxic agents on
natural ecosystems and on non-target organisms (Hoffman et al., 2003).

Ecotoxicology assessments depend on results obtained from toxicity test when
animals are exposed to known contaminants (both laboratory and field
experiments). The general test methods used by Aquatic Toxicologists originated
from the 1800s (Penny and Adams, 1863) and were adapted from general
techniques used in Mammalian Toxicology.

Toxicology tests may be used to meet one or more of the following objectives as
documented by Di Giulio and Hinton (2008):
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