Oligomers of styrene are not endocrine disruptors

Abstract

Oligomers of styrene have been identified in polystyrene (PS) polymer samples intended for food packaging. Such oligomers contribute to nonintentionally added substances (NIAS) that may migrate into food or food simulants and therefore have to be assessed for the potential risk to health. No oligomers larger than dimers and trimers of styrene have been found to be present in PS. Some in vivo and in vitro information indicative of an endocrine activity for some specific oligomers suggest concerns for their potential for endocrine disruption in humans. Data on endocrine activity available from in vitro and in vivo screening approaches and from non-guideline studies in experimental animals were evaluated. The different test methods were classified according to the OECD Conceptual Framework for Testing and Assessment of Endocrine Disruptors (OECD) and the ranking system of Borgert et al. proposed in 2014. The quality and reliability of each study is further assessed by professional judgment. The integration of the total information supports the conclusion that neither specific oligomers, nor their mixtures, potentially migrating into food are endocrine disruptors according to the definition of EFSA and WHO/IPCS.

Keywords:

• NIAS in polystyrene
• oligomers
• dimers and trimers of styrene
• assessment of endocrine activity
• (anti)estrogenicty
• (anti)androgenicity
• effects on thyroid regulation
• in vitro and in vivo screening tests

Acknowledgements

The authors gratefully acknowledge the very useful comments offered by six anonymous reviewers who were selected by the Editor. These review comments were very helpful in strengthening the manuscript and clarifying key points.

Declaration of interest

The employment affiliations of the authors are indicated on the cover page. The companies listed there for MB, GD, EL, and AY are producers and users of styrene and PS in the US, Europe, and Japan. Authors employed by these companies have written the manuscript as part of their normal employment. The preparation of the manuscript was financially supported by the Styrenics Steering Committee (SSC) of PlasticsEurope (www.plasticseurope.org). The members of the SSC are the major styrene producing and using companies in Europe. CB is the Director General of SSC. AS is the Senior Adviser of the Japanese Styrene Industry Association (JSIA) (www.jsia.jp). The members of JSIA are the styrene and PS producing companies in Japan. HPG is a private consultant working for SSC and received funding by SSC. MP is a private consultant (http://www.systox.com) working for the SSC and INEOS Styrolution Group GmbH. Within the last 5 years, none of the authors has appeared in any legal or regulatory proceedings related to the content of the paper. The authors have the sole responsibility for the writing and contents of the paper and the views expressed in the paper are not necessarily those of the authors’ employers.

Supplemental material

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