Page 118 - The Toxicology of Fishes

98 The Toxicology of Fishes

TABLE 3.2
Apparent Volumes of Distribution (V ss ) for Selected Chemicals in Fish
Temperature Reference
Chemical (°C) Species Region a V ss (L/kg) Ref.

Nitrofurantoin 25 Channel catfish Plasma 0.08 Stehly and Plakas (1993)
Sulfachlorpyridazine 22 Channel catfish Plasma 0.34 b Alavi et al. (1993)
Diethylhexylphthalate 12 Rainbow trout Plasma 0.35 Barron et al. (1987b)
Sulfadimethoxine 10 Atlantic salmon Plasma 0.39 Samuelsen et al. (1995)
Sulfadimethoxine 13 Rainbow trout Plasma 0.42 Kleinow et al. (1992)
Sulfadiazine 24 Carp Plasma 0.60 c Nouws et al. (1993)
Nalidixic acid 14 Rainbow trout Plasma 0.96 Jarboe et al. (1993)
Benzocaine 12 Rainbow trout Plasma 1.0 Ma (2000)
Paraoxon 12 Rainbow trout Plasma 1.1 Abbas et al. (1996)
Parathion 12 Rainbow trout Plasma 1.3 Abbas et al. (1996)
Chlorpyrifos 22 Channel catfish Blood 1.5 Barron et al. (1991)
Sarafloxacin 10 Atlantic salmon Plasma 2.3 Martinsen and Horsberg (1995)
Ormetoprim 10 Atlantic salmon Plasma 2.5 Samuelsen et al. (1995)
Diquat 25 Channel catfish Plasma 2.9 Schultz et al. (1995)
Oxolinic acid 5 Atlantic salmon Plasma 2.9 c Rogstad et al. (1993)
Flumequine 5 Atlantic salmon Plasma 3.1 c Rogstad et al. (1993)
Flumequine 10 Atlantic salmon Plasma 3.5 Martinsen and Horsberg (1995)
Trimethoprim 24 Carp Plasma 4.0 c Nouws et al. (1993)
Oxolinic acid 10 Atlantic salmon Plasma 5.4 Martinsen and Horsberg (1995)
Trifluralin 12 Rainbow trout Plasma 5.7 Schultz and Hayton (1993)
Trimethoprim 10 Rainbow trout Plasma 6.0 Tan and Wall (1995)
Enrofloxacin 10 Atlantic salmon Plasma 6.1 Martinsen and Horsberg (1995)
Methyltestosterone 15 Rainbow trout Plasma 6.1 Vick and Hayton (2001)
Proflavine 12 Rainbow trout Plasma 28 Yu (1996)
Acriflavine 12 Rainbow trout Plasma 31 Yu (1996)
Aminoantipyrine 20 Goldfish Water 0.55 Kaka and Hayton (1978)
Sulfapyridine 20 Goldfish Water 0.59 Lo and Hayton (1981)
Ethanol 20 Goldfish Water 0.68 Kaka and Hayton (1978)
Pentachlorophenol 12 Rainbow trout Water 478 Stehly and Hayton (1989a)
Trifluralin 12 Rainbow trout Water 3200 Schultz and Hayton (1993)
Diethylhexylphthalate 23 Sheepshead Water 19,000 Karara and Hayton (1984)
minnow
a V ss values referenced to plasma and blood were determined by collecting serial samples after intravascular administration
of the chemical. Values referenced to water were determined from whole-body concentrations during waterborne exposures.
b V ss was calculated using noncompartmental analysis as the product of mean residence time (MRT) and total body
clearance (CL).
c β-Phase volume of distribution (V β ).

One-Compartment Model
Intravascular Administration
The simplest compartment model assumes that the fish body behaves like a single, well-stirred com-
partment. In this section, the one-compartment model is developed for a toxicant that is administered
by intravascular injection. Intravascular administration is usually accomplished by injecting a solution
of the toxicant via an indwelling catheter placed in the dorsal aorta. The dose may be administered as
a rapid injection (bolus) or as a constant-rate infusion using an infusion pump. After the dose is
administered, samples of plasma are removed at various times to measure the toxicant concentration (C ).
p
Bolus Dose—For a toxicant administered as a bolus dose, its rate of elimination (dX/dt; mass/time) is:
–dX/dt = CLC p (3.28)

Division of both sides by V, followed by integration, yields an equation that predicts the time course of C :
p