PFAS, halogenated contaminants, tire-wear chemicals and other reactive and toxic chemicals
Our interests are driven by persistence, bioaccumulation potential and toxicity.
Overarching Research Interests
We study the fate of organic chemicals in the environment. Specifically, we are interested in transformation reactions of anthropogenic chemicals, how they can be precursors to other toxic contaminants, and how environmental reactions can enable long-range transport to remote regions.
Scientific Approach to Studying the Environment
Some key questions we’re interested about potential chemicals of concern are:
Are they persistent? That is, once in the environment do they degrade to innoculous chemicals, do they react to form more persistent of toxic chemicals, or do they resist all reactions? Chemicals that persist may build up to high enough concentrations that may be of concern.
We can test this in the laboratory by simulating environmental conditions where reactions occur.
We can confirm this in the field by collecting samples and looking for transformation products.
Where do they go? Once in the environment, do these chemicals stay in one place, or travel far away from their point sources of contamination? Chemicals that are globally distributed, far away from where they are initially used are much more challenging to regulate or remediate, if necessary.
We can gain insight in the laboratory by investigating physical properties of the chemicals: sorption to soils, water solubility, volatility.
We can investigate this in the field by sampling remote locations, like the Arctic, to determine if long-range transport occurs. We can also collect samples from various points near and far from known contamination sources, such as downstream of a factory or wastewater treatment plant.
Where do they come from? The sources of most contaminants are not well understood, which results in the burden of these contaminants in the environment being poorly constrained. Sometimes, this is because of trade secrets, but sometimes it is because the chemicals are unintential products - they can be transformation products, or byproducts of industrial mixtures.
We can investigate sources in the laboratory by measuring chemicals in household or industrial products directly, or after they are exposed to simulated environmental reactions. We can also study the presumed precursor chemicals, and determine if they are transformed to the expected chemical products.
We can intelligently set up field sampling locations near an expected point-source, and use complementary data to determine if certain locations, and their related activities may be sources of certain contaminants.
This research relies on understanding the chemistry of the analytes and their reactivity in the environment, and also cannot be performed without innovating analytical techniques to support our scientific questions: we need to make meaningful quantitative measurements under relevant scenarios, and thoroughly identify transformation products.
