Research Objectives

Food and water studies have included: 1) a comparison of the EDC concentrations in commonly consumed food items as well as in drinking water sources (bottled, water treatment plants) in Montreal and both a rural (Vhembe) and urban (Pretoria) setting in South Africa; and 2) an assessment of methods to reduce possible contaminants by food and water processing. In parallel, breast milk samples have been collected in all three geographical settings to assess maternal-infant exposure to the environmental contaminants.

Major Accomplishments since 2021

Food: In January 2022, we published the levels of plastic-related contaminants in 168 food composites. Most notably, bisphenol S (BPS) was detected in packaged fresh food (notably fish) purchased in Canada more frequently than in their non-packaged equivalents. Since then, we have tested the hypothesis that migration from the thermal labels on plastic film packaging was a major source of exposure to bisphenols and alternative color developers in food. We began by analyzing 140 packaging materials from packaged fresh food purchased in North America. The results provided evidence, for the first time, that BPS and alternative thermal label color developers migrate from packaging materials into food. Furthermore, BPS migration significantly exceeded the European Union Specific Migration Limit (50 ng/g ww), suggesting that further risk assessment studies are warranted.

We also conducted a literature review on the abiotic degradation of legacy and novel flame retardants (manuscript in preparation) and concluded there is insufficient data with regards to degradation conditions induring food processing for OPFRs, mineral and nitrogen-based flame retardants. Earlier in 2021, we completed laboratory-controlled experiments on the degradation of OPFRs in water. In 2022, we screened other matrices to find alternative models to study OPFR degradation during food processing. In this context, >100 honey samples collected in Québec were analyzed for OPFRs: traces of TBOEP and TPHP were confirmed in a few samples.

Breast milk: In 2022, a literature review on the characterization of different contaminants and current knowledge for defining chemical mixtures in human milk was finalized and submitted for publication (revisions requested). This review confirmed that hundreds of xenobiotics, with very diverse origins, have been detected in human milk, including contaminants of emerging concern, personal care products and other current-use substances reflecting lifestyle. However, the lack of reliable human milk monitoring data for some individual chemicals and, especially, for complex mixtures, is a major factor hindering risk assessment.

In the laboratory, a suitable method was applied to analyze 9 targeted bisphenols and to screen for other bisphenol-related compounds from hundreds of human milk samples (~170 completed for Montreal and 200+ for South Africa to date). BPA, BPS and BPAF were detected in breast milk, and the preliminary patterns are consistently different for Montreal (Canada), Vhembe and Pretoria (South Africa). Most strikingly, some novel contaminants detected in food packaging (thermal label color developers) were also detected in human milk.

Water: A sampling campaign was conducted at a drinking water treatment plant in Montreal to assess the efficiency of the process for the removal of 39 contaminants. The very good news is that most of the contaminants are significantly removed during treatment, which contributes to minimizing exposure to these contaminants through water. In addition, analysis of the results obtained between each treatment step (screening, sand filtration, UV disinfection and chlorination) will now allow us to identify steps which are more efficient for the various contaminants.

Major Challenges and Adaptations

Extracts of food and Montreal breast milk had been prepared (hundreds of hours of laboratory work), but their final analyses had to be put on hold in early 2020 once the COVID lockdowns began. The extracts were retrieved from the freezers in 2022 and analyzed for OPFRs and flame retardants. After 3 years of storage, many of the solvent extracts were compromised (visible decreased volume), and their analysis revealed only a small fraction can be still be used based on QC criteria.

In 2021, we made the decision to split the methodology for plasticizers and bisphenols for analysis in breast milk as we could not achieve appropriate method validation for all compounds at the same time. The analysis of bisphenols separately is now providing reliable and interesting results. However, resources are lacking to complete the analysis of other targets (plasticizers, OPFRs) in all 600+ breast milk samples.

We had to transfer our water analytical methods to a new analytical system that was purchased to replace the old one that had stopped working. This caused some delays in the work.

2023-2024 Goals

We will complete the analysis of bisphenol and bisphenol-related compounds in the remaining 200+ breast milk samples and compile/interpret the data (two manuscripts anticipated). We intend to analyze plasticizers in a small batch of samples to provide preliminary data to hopefully obtain additional resources to perform this analysis.

We are analyzing some remaining food packaging materials to identify possible correlations between the levels of plastic-related contaminants in the earlier 168 food composites and their packaging.

Several manuscripts will be submitted for peer-review on (i) OPFRs in honey, (ii) abiotic degradation of legacy and novel flame retardants, (iii) OPFR degradation in water, (iv) bisphenols and alternative color developers in packaged fresh food, (v) plasticizers in alcoholic beverages and (vi) methods for OPFR analysis in food and breast milk.

We plan to publish the recent work on EDC exposure reduction through drinking water treatment as well as to present the work at an international conference. We will also consolidate all of the raw data related to water for potential further usage. Finally, we will try to secure funding to carry out the plasticizer analyses of the breast milk samples.

We will finalize a composite database to allow for the analysis of single as well as multiple chemicals for each food, water and breast milk sample.

In South Africa, we collected infant size and health data at birth as well as at the time of breast milk collection.  We hope to be able to produce results on the determinants of early exposure to EDCs as well as associations with health and growth indicators.