Chemistry Weekly Seminar - Dr. Jonathan Challis, Toxicology Centre

Title:

Developing a novel passive sampler: Applications for understanding occurrence and fate of polar contaminants in impacted surface waters

Abstract:

Current passive sampling designs for polar organic contaminants lack the ability to easily adjust uptake rates for differing environmental conditions (e.g., temperature, flow rate). Without an extensive laboratory or in-situ calibration specific to each study, qualitative concentration estimates often result. This issue significantly reduces the overall applicability of current polar passive samplers. To improve upon these current techniques, we successfully adapted the diffusive gradients in thin films (DGT) sampler (widely popular for measuring trace metals) to effectively uptake polar organics (o-DGT) in aquatic systems. This work establishes the utility of o-DGT as an effective monitoring tool offering three main advantages over current polar passive samplers: 1) reduced flow-rate influence on sampler uptake; 2) application of temperature-specific sampling rates; and 3) a predictive diffusion-based model for simple determination of sampling rates. These factors greatly increase o-DGT’s applicability and ease-of-use by minimizing the extent of calibration required for the end-user.

This seminar will describe the development, calibration, and field validation of o-DGT for a suite of polar organic contaminants. Performance of o-DGT in surface waters and wastewaters will be demonstrated in comparison to more established sampling techniques. Additionally, the use of o-DGT as a tool for suspect and non-target screening in high-resolution mass spectrometry will be explored. This work illustrates the promise of o-DGT as an improved, widely applicable monitoring tool for organic contaminants in the aquatic environment.