IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC ...

same products resulted in exposures below 1 ppm [4.3 mg/m 3 ] (Säämänen et al., 1991).
Application of polyester putty during cable splicing operations for a telephone company
in the USA resulted in short-term levels (3–16 min) ranging from 2 to 16 ppm
[8.5–68 mg/m 3 ] in four samples (Kingsley, 1976). In a Japanese plant where plastic
buttons were manufactured from polyester resins, the 8-h TWA concentration of styrene
for 34 workers was 7.1 ppm [30 mg/m 3 ], with a maximum of 28 ppm [119 mg/m 3 ]
(Kawai et al., 1992).
In four 100-min area air samples taken in 1982 at a college in the USA during a
sculpture class in which polyester resins were used, styrene concentrations ranged from
0.8 to 1.2 ppm [3.4–5.1 mg/m 3 ]; two personal breathing zone air samples contained 2.8
and 3.0 ppm [11.9 and 12.8 mg/m 3 ]. The concentration of methyl ethyl ketone peroxide
was below the detection limit (< 0.02 ppm) (Reed, 1983).
Taxidermists who used polyester resins during specimen preparation were shown to
be exposed for short periods (2–34 min) to concentrations of styrene ranging from 21 to
300 mg/m 3 (12 samples) (Kronoveter & Boiano, 1984a,b).
In two cooking-ware manufacturing companies in the USA where styrene-based
resins were used, the 8-h TWA concentrations of styrene ranged from 0.2 to 81 ppm
[0.85–345 mg/m 3 ]; two short-duration samples (24 min) contained 142 and 186 ppm
(605 and 792 mg/m 3 ] (Fleeger & Almaguer, 1988; Barsan et al., 1991).
1.4.3 Environmental occurrence
STYRENE 455
Human exposure to styrene has been assessed on the basis of a review of data in the
published literature (Tang et al., 2000). The authors estimated that styrene exposure for
the general population is in the range of 18.2–55.2 μg/person/day (0.3–0.8 μg/kg bw) or
6.7–20.2 mg/person/year (95.7–288 μg/kg bw), mainly resulting from inhalation and
from food intake. The inhaled styrene accounts for more than 90% of the total intake.
The styrene in food occurs mainly by migration from polymer packaging materials. The
authors also concluded that cigarette smoking is another important source of styrene
intake for smokers. The intake of styrene due to smoking 20 cigarettes was estimated to
be higher than the total daily intake from food and air.
A Canadian study estimated a daily total styrene intake for the Canadian general
population ranging from below 0.19 to over 0.85 μg/kg bw. Intakes from ambient air
ranged from 0.004 up to 0.17 μg/kg bw and those from indoor air from 0.07 up to
0.10 μg/kg bw. Intake from food was calculated to range from below 0.11 to over
0.58 μg/kg bw. The estimated intakes from drinking water and soil were negligible.
Potential exposure from cigarette smoke, on the basis of the styrene content reported for
mainstream smoke (10 μg per cigarette) and a smoking rate of 20 cigarettes per day, was
estimated to be 2.86 μg/kg bw per day for adults. The Canadian study estimated that
styrene in food may represent a major exposure source for the general population (Health
Canada, 1993; Newhook & Caldwell, 1993).