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Styrene - PSL1

4.0 Recommendations for Research and Evaluation

It is recommended that additional data be obtained on:

1. the quantities of styrene released to the environment from the production, use and disposal of styrene and styrene-containing materials in Canada (high priority);
2. current concentrations of styrene in terrestrial plants, snow, surface water and aquatic organisms, particularly near industrial sources (high priority);
3. interspecies variations in the metabolism of styrene, particularly for humans (medium priority);
4. the carcinogenicity of styrene in an adequately conducted carcinogenesis bioassay. Long-term inhalation bioassays with rats and mice are currently being conducted under the sponsorship of the Styrene Information and Research Center (Science and Technology Task Group of the Styrene Information and Research Center, 1991). When available, the results of these studies should be evaluated with respect to their implications for designation of "toxic", but in view of other priorities for assessment under CEPA;
5. the results of the large historical cohort study conducted by Wong (1990), which is currently being updated to extend the latency period by another 10 to 15 years, and of an ongoing study initiated in 1988 by the International Agency for Research on Cancer (IARC), which involves a cohort of approximately 35 000 employees in this industry. When available, the results of these studies should be evaluated with respect to their implications for designation of "toxic", but in view of other priorities for assessment under CEPA;
6. immunological effects of styrene in long-term studies in animal species (medium priority);
7. acute and chronic toxicity of dissolved styrene in aquatic organisms (using procedures appropriate for volatile substances), and of atmospheric styrene in terrestrial plants (high priority); and
8. the chronic effects of styrene on birds, preferably through a reproductive/ developmental study, as this would probably be the most sensitive end-point (medium priority).