Table 1

Calculated cancer risk for selected smokeless tobacco product (STP) constituents meeting GothiaTek standards

Compound	GothiaTek limit (ng/g dry weight)	Laboratory^‡ method detection limit (ng/g dry weight)	Compound TD₅₀ (mg/kg body weight/day)	Cancer potency factor ((mg/kg body weight/day)⁻¹)	Cancer risk estimate (100% transfer)	Cancer risk estimate (reduced percentage transfer)
TSNA^*	10000	230^§	0.0999	10.1	6.2×10E−3	5.3×10E−3
BaP (BaPeq)^†	20 (40)^†	0.04	0.956	1.1	2.7×10E−6	1.6×10E−7
Cadmium	1000	43.3	0.0217	46.1	2.8×10E−3	1.7×10E−4
Lead	2000	37.9	46.6	0.02	2.5×10E−6	1.5×10E−7
Arsenic	500	25	No comparable CPDB data
Chromium	3000	11.9	No comparable CPDB data
Product total risk					9.0×10E−3	8.1×10E−3

↵* TD₅₀ (chronic dose rate in mg/kg body weight/day, which would induce tumours in half the test animals at the end of a standard lifespan for the species) for NNK and NNN was used as a conservative estimate of risk for the composite of TSNAs and 85% bioavailability was assumed for each when calculating reduced percentage transfer.24
↵† Cancer risk estimates were based on concentrations using BaP equivalents (BaPeq) to represent contributions from other carcinogenic PAHs.
↵‡ These are detection limits for the selected constituents in processed tobacco as reported by the laboratory that tested the STPs used in this study.
↵§ This was based on the analysis of the tobacco ‘as received’.
BaP, benzo(a)pyrene; CPDB, carcinogenic potency database; NNK, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone; NNN, N'-nitrosonornicotine; PAH, polycyclic aromatic hydrocarbon; TSNA, tobacco specific nitrosamine.