Page 690 - The Toxicology of Fishes

670 The Toxicology of Fishes

7
165 µg/L
174 µg/L
6.5 271 µg/L 122 µg/L 95
Percent Mortality (Probits) 5.5 107 µg/L 50% % Mortality
90
6
80
5
LT50
4.5
4
10
3.5 20
5
3
1 10 100 1000
Exposure Time (hr)
A
7
96h 72h 48h 24h 12h 9h
6.5 95
Percent Mortality (Probits) 5.5 6h LC50 50% % Mortality
90
6
80
5
4.5
4
10
3.5 20
5
3
100 200 300
Exposure Concentration (µg/L or ppb)
B
FIGURE 15.4 Cumulative percentage mortality for a fish population exposed to a range of concentrations of a chemical
in water. (A) Plot of exposure time vs. mortality at various exposure concentrations (drawn from data for low-fat fish
exposed to pentachlorophenol). (B) Plot of exposure concentration vs. mortality at various exposure times (idealized
pentachlorophenol results). (From van den Heuvel, M.R. et al., Aquat. Toxicol., 20, 235–252, 1991. With permission.)

• The test should be widely accepted.
• The test should have a sound statistical basis and should be repeatable in different laboratories;
thus, tests must be standardized and conducted according to defined protocols.
• Data should include the results of effects from a range of concentrations with realistic exposure
times.
• Laboratory tests should have predictive potential for defining field effects and should be useful
for hazard and risk assessment.
• Test procedures should be easy to carry out.
• Tests should be sensitive to be able to detect the effects under investigation.

Test methods in the laboratory are designed to examine the responses of a few individuals within a
species to chemical exposures to establish cause-and-effect relationships. These tests can also provide
data on the relationship between external and internal concentrations of a chemical, the duration of
exposure, and the biological effects. Single-species tests are straightforward and standardized and can
be replicated. Single species tests are currently conducted with species representative of broad classes