Discovery Exposomics by Non-Targeted Identification of Organic Contaminants in Human and Environmental Samples

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Most organic contaminants, including those classified internationally as “persistent organic pollutants” (POPs), were only discovered in the environment after several decades of intense use. This long delay in discovery was a result of the traditional reliance on targeted analytical methods, which are often limited by lack of authentic chemical standards. Through my NSERC Discovery research program I will develop powerful screening techniques to identify new contaminants in a non-targeted fashion. In other words, I aim to discover important contaminants without any previous knowledge that they are there. A “discovery exposomic” workflow has been proposed that includes sensitive sample preparation techniques coupled to a battery of powerful instrumental methodologies capable of separating and identifying trace unknowns that are potentially bioaccumulative, persistent and toxic. Large-volume stir-bar sorptive extraction (SBSE) methods will be developed for fractionation of the hydrophobic (bioaccumulative) and polar fractions of human blood and urine, and oxidation tests will be used to identify the most persistent unknown chemicals. We will validate three analytical methods to analyze the sample fractions, including by HPLC and high-efficiency supercritical fluid chromatography linked to ultrahigh resolution mass spectrometry operating in full scan and with unique flagging modes designed to detect halogenated chemicals and toxic conjugates of glutathione. These sensitive and comprehensive methods for organic contaminant discovery will subsequently be applied to unique environmental archives, including an ice core from Ellesmere Island and archived polar bear serum from two populations. Such new screening tools will revolutionize contaminant discovery by allowing unknown chemicals to be detected in environmental samples before they become widespread global threats. The new discoveries my HQP make through this research will lead to better domestic and international chemical management and a safer environment.