Table 4.

Non-benzene sources of benzene urinary metabolites.

Chemical	Source	Amount	Reference
SPMA	No known endogenous or exogenous sources
ttMA	Diet (sorbitol) Europe	6–30 mg/d	Ruppert et al. (1997)
	Diet (sorbitol) USA	25 mg/d	Yu & Weisel (1996b)
	Percentage of ttMA in smokers attributed dietary sorbic acid	10–50%	Ruppert et al. (1997)
	Percentage of ttMA in non-smokers attributed to dietary sorbic acid	5–25%	Ruppert et al. (1997)
Phenol	Diet and endogenous sources	0.2 mg/kg-bw/d	McDonald et al. (2001)
	Mainstream cigarette smoke	60–140 µg/cig	Hoffmann & Wynder, (1986)
	Sidestream cigarette smoke	1.6–3.0 × mainstream smoke	Hoffmann & Wynder, (1986)
	Over the counter medicines	Not quantified	McDonald et al. (2001)
Catechol	Diet and endogenous sources	0.3 mg/kg-bw/d	McDonald et al. (2001)
	Mainstream cigarette smoke	100–350 µg/cig	Hoffmann & Wynder (1986)
	Sidestream cigarette smoke	0.6–0.9 × mainstream smoke	Hoffmann & Wynder (1986)
Hydroquinone	Diet and endogenous sources	0.1 mg/kg-bw/d	McDonald et al. (2001)
	Black and white photographic processing	Not quantified	McDonald et al. (2001)
	Mainstream cigarette smoke	110–300 µg/cig	Hoffmann & Wynder (1986)
	Sidestream cigarette smoke	0.7–0.9 × mainstream smoke	Hoffmann & Wynder (1986)