Coraline Simon

Investigation of the genotoxicity of substances migrating from polycarbonate replacement baby bottles to identify chemicals of high concern

Due to the worldwide concern that bisphenol A might act as an endocrine disruptor, alternative materials for polycarbonate (PC) have been introduced on the European market. However, PC-replacement products might also release substances of which the toxicological profile--including their genotoxic effects--has not yet been characterized. Because a thorough characterization of the genotoxic profile of all these substances is impossible in the short term, a strategy was developed in order to prioritize those substances for which additional data are urgently needed. The strategy consisted of a decision tree using hazard information related to genotoxicity. The relevant information was obtained from the database of the European Chemicals Agency (ECHA), in silico prediction tools (ToxTree and Derek Nexus(TM)) and the in vitro Vitotox(®) test for detecting DNA damage. By applying the decision tree, substances could be classified into different groups, each characterized by a different probability to induce genotoxic effects. Although none of the investigated substances could be unequivocally identified as genotoxic, the presence of genotoxic effects could neither be excluded for any of them. Consequently, all substances require more data to investigate the genotoxic potential. However, the type and the urge for these data differs among the substances.

Screening of endocrine activity of compounds migrating from plastic baby bottles using a multi-receptor panel of in vitro bioassays.

Endocrine activity of 65 compounds migrating from polycarbonate replacement plastic baby bottles was assessed using in vitro cell based assays (reporter gene assays) involving 7 nuclear receptors, i.e. human steroid hormones receptors (oestrogen, androgen, progesterone and glucocorticoid receptors), human thyroid beta and peroxisome proliferator-activated gamma receptors, and the mouse aryl hydrocarbon receptor. The chemicals were tested at 4 concentrations ranging from 0.001mM to 1mM. Only twelve chemicals did not show any activity towards any of the nuclear receptors, while fifty three compounds showed a possible endocrine activity. Most of the agonistic activities were observed towards the oestrogen receptor while the PPARγ was the target for most of the recorded antagonistic activities. Agonistic activities were recorded for several phthalates, benzophenones, aromatic hydrocarbons and phenols, while compounds such as benzaldehydes, ketones and esters of fatty acid showed antagonistic activities. Thirty five chemicals were able of agonistic activities on 1 to 4 receptors and antagonistic activities were recorded for 35 compounds as well, towards 1 to 7 receptors. Sixteen compounds were able of both agonistic and antagonistic activities, but not on the same receptors, except in 2 cases for the oestrogen receptor and 4 cases for the PPARγ.

Evaluation of the potential health risks of substances migrating from polycarbonate replacement baby bottles

Since the European Commission prohibited the use of bisphenol A in the production of polycarbonate (PC) baby bottles, many other materials have replaced PC for the manufacture of this type of food contact materials. In the present study, the potential migration risks associated with these alternative materials were investigated. First, all substances were evaluated for endocrine disruptive (ED) activity by using different existing lists of (suspected) ED chemicals. Next, the potential non-ED risks were assessed. A distinction was made between migrants listed in Annex I of European Regulation 10/2011 and the unlisted substances (e.g. non-intentionally added substances). For the listed substances, concentrations in the migration solutions were compared to their respective specific migration limits (SML) (when applicable). Migration of all substances was shown to be below their SML. The unlisted substances were evaluated using toxicological information from previous evaluations, or if not available, by applying the Threshold of Toxicological Concern (TTC) approach. In case the estimated exposure to the unlisted substance exceeded the human exposure TTC value, a more indepth risk assessment was performed. Based on the results of both parts of the study, four baby bottles were considered of high concern because of the potential toxicity of migrating compounds.

Assessment of methods of detection of water estrogenicity for their use as monitoring tools in a process of estrogenicity removal

ABSTRACT Methods of monitoring of estrogenicity in water were gathered, compared, and tested within the context of their practical use as measurement and design tools, in the development of a process of degradation of estrogenic endocrine disruptors. In this work, the focus was put on in vitro assays, with the use of analytical techniques as additional analysis when possible. Practically, from a literature review, four methods that seemed most suitable to practical use required in a process development were tested: the Yeast Estrogen Screen assay, the Lyticase-assisted Yeast Estrogen Screen assay (LYES), the MMV-LUC assay and the HPLC-UV analytical method. Dose–response curves in response to estrogenic standard 17β-estradiol were compared. Bisphenol A estrogenicity was measured by the methods as well. The model for the calculation of estradiol equivalents as measurements units was adapted. The methods were assessed in terms of ranges of detection, time of experiment, cost, ease of the experiment, reproducibility, etc. Based on that assessment, the LYES assay was selected and successfully applied to the monitoring of estrogenicity removal from 17β-estradiol and bisphenol A. More precisely, the bioassay allowed the acquisition of kinetic curves for a laboratory-scaled process of estrogenicity removal by immobilized enzymes in a continuous packed-bed reactor. The LYES assay was found to have a real methodological potential for scale-up and design of a treatment process. The HPLC-UV method showed good complementarity with the LYES assay for the monitoring of bisphenol A concentrations in parallel with estrogenicity, reporting no significant estrogenicity from degradation byproducts, among others.