GBF Report - Polystyrene Foam

34 Appendix 6 .3 Styrene Styrene, also known as vinylbenzene, ethenylbenzene, cinnamene, or phenylethylene, is the monomer used to produce PS. In addition to PS, styrene is also used in the production of other plastics and resins, including fiberglass in boat hulls, copolymers used in piping, automotive components, refrigerator liners, and car battery enclosures (i.e. styrene-acrylonitrile and acrylonitrile-butadiene-styrene), styrene-butadiene rubber used in car tires, industrial hoses, and shoes, styrene-butadiene latex in carpet, paper coatings, and latex paints, and other styrene copolymer used in liquid t oner for photocopiers and printers (IARC, 2002; Luderer et al., 2006; NTP, 2016). Styrene has been detected in surface water, drinking water and fish in the Great Lakes area (Environment Canada & Health Canada, 1993). Styrene in water could be due to leachates, or from air. A study collecting air samples from 1988 to 1990 found styrene concentrations were highest in industrial areas in cities across Canada, with concentrations up to 34.20 ug/m3 (Dann, 1990). Styrene has also been detected in sewage, indoor air in single family homes, cigarettes, combustion from spark-ignition engines, waste incineration, and natural sources, including by-products from fungus and microbes (Concord Environmental, 1992; Environment Canada & Health Canada, 1993). Styrene volatizes rapidly from surface waters and typically has a half-life in water ranging from 1 to 60 hours (Min and Martin, 1992; Santodonato et al., 1980; Zoeteman et al., 1980). Volatilization depends on depth of the water body and degree of turbulence (Environment Canada & Health Canada, 1993; Zoeteman et al., 1980), and deep water can prolong styrene half-life values (Zoeteman et al., 1980; Alexander, 1990). In surveys of Canadian water supplies, elevated levels of styrene have been detected in raw and treated drinking water from the Great Lakes (Environment Canada & Health Canada, 1993). The maximum concentration measured in raw water during that study was 1.7 mg/L, in Cornwall (Environment Canada and Health Canada). A study of Great Lakes fish found styrene ranging between 15 and 100 mg/kg in walleye and splake caught in the St. Clair River (Bonner and Meresz, 1981)(Bonner and Meresz, 1981). According to the International Agency for Research on Cancer (IARC), there is evidence of styrene carcinogenicity from studies in experimental animals (NTP 2016). Styrene caused lung tumors (Cruzan et al., 2001), liver damage (Carlson, 2002; Vogie et al., 2004), and genotoxicity (genetic damage such as coding errors) (Vodicka et al., 2006). In vitro studies have observed mutagenic effects in cell cultures (Bastlova and Podlutsky, 1996). For human health, evidence on exposure to styrene is from epidemiological studies of workers exposed to styrene in the plastics and rubber industries (NTP 2016). These studies show increased mortality from cancer in the lymphohematopoietic system and increased damage in lymphocytes and with increased levels of DNA adducts (Kogevinas et al., 1994; Kolstad et al., 1995, 1994). Occupational exposure to styrene in the reinforced- plastics industry in Europe experienced increased cancer risks, including malignant lymphoma and leukemia when exposed to higher levels of styrene, or longer exposures (Kogevinas et al., 1994; Kolstad et al., 1995, 1994). Two studies from workers exposed to styrene from plastics manufacturing in the USA did not find significant associations between exposure to styrene and lymphohematopoietic cancer (Ruder et al., 2004; Wong et al., 1994), however, these studies have been criticized as having low statistical power to detect an association (IARC, 2002; NTP, 2016). A slightly increased risk of miscarriage was reported in Canadian women employed in the processing of PS, however, this observation was based on small sample size with poorly characterized exposure levels (McDonald et al., 1988). Styrene, styrene polymers, and styrene copolymers are often approved for use in food packaging (FDA, 2018), although small amounts may migrate to food from styrene-based plastic food packaging (ATSDR, 2010; Environment Canada & Health Canada, 1993; FDA, 2018). Since 2018, styrene is no longer permitted in food additives (i.e. chewing gum base) (FDA, 2018). Styrene concentrations in bottled water have a limit of 0.1 mg/L in the USA (FDA, 2019). No set limits could be found for Canada, although the presence of styrene has been reported in food and drink from containers made of PS (Environment Canada & Health Canada, 1993). For more information and references, see the National Toxicology Program (NTP) Report on Carcinogens, Fourteenth Edition, Styrene: https://ntp.niehs.nih.gov/ntp/roc/content/profiles/styrene.pdf

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