Environmental Biology
for Engineers and Scientists
D.A. Vaccari, P.F. Strom, and J.E. Alleman
© John Wiley & Sons, 2005
Chapter 19 – Dose-Response Relationships
Chapter 21 – Toxicity of Specific Substances
Figure 19-1. Hypothetical dose-response relationship for
(a) a substance required at low dosages, and
(b) a nonessential substance.
Death
Irreversible damage
a
Reversible damage
Homeostasis
b
C1
C2
Exposure concentration for fixed time
Figure 19-2.
Percent mortality
(b) Normal tolerance
distribution of mortality
frequency.
100
80
Dose-response curve
(a)
60
40
20
0
-20 0
1
120
100
2
3
Log dose
Toxicity distribution
140
Slope of response
(a) Sigmoidal logarithmicdose-response relationship.
120
(b)
80
60
40
20
0
-20 0
1
2
Log dose
3
Figure 19-3. Dose-response curve for a carcinogen and extrapolation to low
dosages by linear and multistage models.
0.9
Fraction having tumors
0.8
Multistage model
0.7
0.6
0.5
0.4
0.3
Background response
0.2
0.1
Linear model
0.0
0
1
Linear
Threshold
2
3
Dosage (ppm)
4
5
6
0.12
(a) Linear relationship
for toxicity (the
inverse of LD50);
(b) Effect of mixture
fraction (l) directly on
LD50.
(a)
0.08
0.06
0.04
0.02
0.00
0
0.2
0.4
l
0.6
0.8
1
0.6
0.8
1
100
LD50mix
Figure 19-4.
1 / LD50mix
0.10
80
(b)
60
40
20
0
0
0.2
0.4
l
Figure 19-5. A hypothetical time-toxicity curve.
LD50 (mg/L)
1000
100
10
dt
1
0
1
10
Time (hrs)
100
1000
Figure 21-1. Structures of some organochlorine pesticides.
CHLORINATED INSECTICIDES
Cl
H
C
Cl
Cl
C
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Dichloro-diphenyl-trichloroethane ( DDT)
Cl
Cl
Cl
Cl
Cl
CCl2
Cl
Cl
Cl
Lindane ( a fungicide)
Chlordane
CCl2
CH2
Cl
Dieldrin
Cl
O
Figure 21-1. More structures of some organochlorine pesticides.
CHLORINATED HERBICIDES
Cl
Cl
O
O
CH2
CH2
COOH
COOH
Cl
Cl
Cl
2,4-dichlorophenoxyacetic acid
( 2,4-D)
2,4,5-trichlorophenoxyacetic acid
( 2,4,5-T)
Figure 21-2. Structures of some unchlorinated pesticides.
ORGANOPHOSPHATE PESTICIDES
S
O
C2H5
P
O
O
C2H5
NO2
Parathion
S
O
CH3
P
S
O
CH3
O
CH
H2C
C
O
C2H5
C
O
C2H5
O
Malathion
OH
O
P
OH
O
CH2
N
CH2
C
H
Glyphosate - an herbicide
OH
Figure 21-2. More structures of some unchlorinated pesticides.
CARBAMATE INSECTICIDES
NITROGEN-BASED PESTICIDES
O
O
C
Cl
NH CH3
N
N
CH3
H3C
CH2 NH
N
NH CH
CH3
Carbaryl ( Sevin)
Atrazine ( a triazine used as an herbicide)
Figure 21-3. Effect of thiophosphorus pesticides on ammonia oxidation by estuarine nitrifiers.
[Originally from Jones, RD, Hood NA: The effects of organophosphorus pesticides on estuarine ammonia oxidizers.
Can J Microbiol 26:1296-1299, 1980.]
80
Control
70
Methyl-Parathion
Percent activity
60
50
Parathion
40
Guthion
30
20
Fonofos
10
0
5
7
9
11
t (days)
13
15
Figure 21-4. The Uranium-238 decay series.
ATOMIC NUMBER
238
U-238
4.5e9 yr
4.2 MeV
234
U-234
2.5e5 yr
4.7-4.8 MeV
91 - (Pa)
Protactinium
Pa
Pa-234m
1.2 months
2.3 MeV
90 - (Th)
Thorium
Th
Th-234
24 days
0.2, 0.1 MeV
89 - (Ac)
Actinium
Ac
88 - (Ra)
Radium
Ra
87 - (Fr)
Francium
Fr
86 - (Rn)
Radon
Rn
85 - (At)
Astatine
At
84 - (Po)
Polonium
Po
83 - (Bi)
Bismuth
82 - (Pb)
Lead
92 - (U)
Uranium
230
226
MASS NUMBER
222
218
214
210
206
Alpha Decay
(helium nucleus
ejected)
Th-230
8.0e4 yr
4.6-4.7 MeV
Beta Decay
(electron
ejected)
Ra-226
1600 yr
4.8 MeV
Rn-222
3.82 days
5.5 MeV
Po-218
3.05 min
6.0 MeV
Po-214
1.6e-4 sec
7.7 MeV
Po-210
138 days
5.3 MeV
Bi
Bi-214
19.7 min
0.4-3.3 MeV
Bi-210
5.0 days
1.2 MeV
Pb
Pb-214
26.8 min
0.7, 1.0 MeV
Pb-210
22 yr
<0.1 MeV
Pb-206
Stable
Figure 21-5. Relation between forward mutation rate per locus per rad and the DNA content per
haploid genome. Line is regression through zero. Point for man estimated from DNA content.
Redrawn from data of Abrahamson, S., Bener, M.A., Conger, A.D., and Wolff, S. (1973). Uniformity of radiation-induced mutation
rates among different species. Nature 245, 460.]
Log of specific locus mutations
per locus per rad
-6.0
Tomato
Barley
-6.5
Man
-7.0
Mouse
-7.5
-8.0
Fruit fly
-8.5
Fungus
Yeast
-9.0
E. Coli
-9.5
0.01
0.1
1
DNA per haploid genome
10
100