PRINCIPLES OF TOXICOLOGY

470 RISK ASSESSMENT
TABLE 18.4b Cancer Risks for Household Exposures to Pesticides (TEAM Studies)
Pesticide Exposure (ng/m 3 ) Potency (mg/kg⋅day) –1
Lifetime Cancer Risk
(× 10 –6 Banned termiticides
)
Heptachlor71 4.5 90 (19)
Chlordane 198 1.3 70 (15)
Aldrin 13 17 60 (13)
Dieldrin 3 16 14 (3)
Heptachlor epoxide 0.4 9.1 1 (0.2)
DDE 2.2 0.34 0.2 (0.4)
DDT
Other pesticides
0.7 0.34 0.1 (0.02)
Dichlorvos 33 0.29 2.7
g-BHC (lindane) 6.6 1.3 2.5
a-BHC 0.5 6.3 1
Propoxur 100 0.0079 0.2
Hexachlorobenzene 0.3 1.67 0.1
Dicofol 2.6 0.34 0.05
o-Phenylphenol 58 0.0016 0.02
2,4-D 0.6 0.019 0.003
Atrazine 0.05 0.22 0.003
cis-Permethrin 0.4 0.022 0.003
trans-Permethrin 0.1 0.022 0.001
Source: Adapted from Wallace (1991).
TABLE 18.5 The Therapeutic and Virtually Safe Dosages (VSD) of a Few Medications
Drug
Cancer Slope Factor
(mg/kg⋅day) –1
VSD (mg/kg⋅day)
Rifampin 2.1 4.8 × 10 –7
Isoniazid 4.9 × 10 –1
2.1 × 10 –6
Clofibrate 5.4 × 10 –2
1.9 × 10 –5
Disulfiram 3.6 × 10 –1
2.8 × 10 –6
Phenobarbital 2.9 × 10 –1
3.5 × 10 –6
Acetaminophen 1.3 × 10 –2
7.6 × 10 –5
Metronidazole 4.4 × 10 –2
2.3 × 10 –5
Sulfisoxazole 1.9 × 10 –3
5.3 × 10 –4
Dapsone 1.7 × 10 –1
5.8 × 10 –6
Methimazole 4.8 × 10 –1
2.1 × 10 –6
Oxazepam 1.0 × 10 –1
9.8 × 10 –6
Furosemide 6.0 × 10 –2
1.7 × 10 –5
Dose Ratio (daily
dose/VSD)
Incremental Lifetime
Cancer Risk per
Daily Dose of Drug
(10 –6 ) a
18,000,000 704.5
2,400,000 93.9
1,500,000 58.7
1,300,000 50.9
825,000 32.3
747,000 29.2
467,000 18.3
215,000 8.4
123,000 4.8
102,000 4.0
87,700 3.4
68,723 2.7
Source: Adapted from Waddell (1996).
a Calculated by dividing Waddell’s dose ratio by the 25,550 days in a 70-year lifetime to get the incremental lifetime risk per daily
dose of drug above the 10 –6 risk representing the VSD.