Garrett McKay

Probing the Photochemical Formation of Hydroxyl Radical from Dissolved Organic Matter: Insights into the H2O2-Dependent Pathway This study quantifies the contribution of the H2O2-dependent pathway to hydroxyl radical (•OH) production from the photolysis of dissolved organic matter (DOM). •OH formation rates were cross-validated using benzoate and terephthalate as probe compounds for diverse DOM sources (reference isolates and whole waters). Catalase addition revealed that the H2O2-dependent pathway accounts for 10–20% of the total •OH production in DOM isolate materials, but no significant correlation was observed between ambient iron (Fe) concentrations and H2O2-dependent •OH formation. This lack of correlation was likely due to lower total Fe levels in isolated materials, thus limiting the concentration of photochemically produced Fe(II) available for reaction with H2O2. Notably, the H2O2-dependent pathway contributed 11 ± 3% to •OH formation from Pony Lake fulvic acid, which had the lowest Fe content, implicating additional H2O2-driven formation mechanisms independent of Fe. Experiments with the DOM model compounds acetophenone and p-benzoquinone indicated no •OH production from triplet DOM reactions with H2O2. However, •OH formation rate increased 6-fold when H2O2 was reduced by ketyl radicals formed from the reaction between excited triplet acetophenone and 2,4,6-trimethylphenol. This study advances the knowledge of •OH production mechanisms from DOM photolysis, providing insight into the role of H2O2 in aquatic photochemical processes.

New paper from my group investigating OH radical mechanisms from organic matter photolysis

pubs.acs.org/doi/10.1021/...

Woo hoo! Congrats!

I’m tired of people telling me I look tired. When will my 3 yo stop waking up in the middle of the night?

Trump allies begin attack on EPA and rules protecting US drinking water With about to grab reins of US, Republicans are starting an assault on the Environmental Protection Agency

Oof www.theguardian.com/environment/...

The joy of spending startup $$

"Find what makes you joyful, and schedule it into your calendar like it matters, because it does." Lots of sage advice from the wonderful Kamini in here, for all career stages.
agupubs.onlinelibrary.wiley.com/doi/full/10....

Remember all those disinfectants (QACs) you were using in 2020 and 2021? We measured their presence and removal in wastewater during that period -- pubs.acs.org/doi/full/10....

Ditto. I think I scored 50th percentile-ish on the GRE.

Friday paper submissions are the best paper submissions ✅

If you're funded by NSF, or in the middle of writing a proposal (or review!) for NSF, here's our agency's lapse plan. Basically you can still do those things but will have no help or communication from us (sorry, we hate it too!) www.nsf.gov/pubs/2023/sh...