Scholarly Publications

2025

“The Effects of Soil Moisture and pH on Soil Organic Carbon Content in Tidal Freshwater Marsh Wetlands” in the Journal for Freshwater Ecology

Authors: Ciara Dalton, , Jeffrey J. Imbrogno, Morgan M. McCue, Regina A. Easley, YuYe J. Tong, and Dejun Chen

Abstract: The carbon stock in tidal freshwater wetlands in the upper estuaries has often been overlooked and not typically included in either the teal or blue carbon accounting. It was in this context that we measured the carbon stock at three selected representative sites (one is distal and the other two are proximal to a water tributary) in a wetland sanctuary of the Chesapeake Bay, United States. The measured average organic carbon stock of 243±31 MgC ha−1 (n=5) in the top
68-cm soil is consistent with the recently reported high carbon stocks in the tidal freshwater wetlands. More intriguing and potentially more important, however, are that the latitude comparison between the data garnered from the sites distal and proximal, respectively, to a water source and the longitude comparison between the data of this and a 1993 study reveal the remarkable importance of soil moisture in keeping organic carbon. Particularly, the distal site that suffered from soil drying (i.e. had less soil moisture content) revealed a loss of ca. 57% carbon stock over a 28-year span. The measured lower soil pH at the distal site is possibly caused by the lower-moisture-enabled higher activity of oxidizing organic matters, particularly in warm seasons. Accordingly, we proposed that
a 59% soil moisture content could be used as the minimum soil-moisture-level criterion for ensuring an effective preservation of carbon stocks and a soil pH decrease in warm seasons as an indicator of potential degradation in its carbon stocking capacity.

“A Suspects Screening Workflow towards Total Per- and Poly-fluoroalkyl Substances in Cosmetics with Time-of-flight Mass Spectrometry” in the Journal of Hazardous Materials Advances

Authors: Kelsey O’Malley, Hannah Blair Hidle, Benjamin Parker Jones, Shenwei Liang, YuYe J. Tong , and Dejun Chen

Abstract: In response to growing concerns over PFAS exposure from cosmetics, this study developed a level-5a (Suspect Screening Exact Mass Match) PFAS suspect screening protocol using liquid chromatography and time-of-flight high-resolution mass spectrometry to identify PFAS in 35 U.S.-market cosmetic products. A screening workflow developed by a Native PFAS Precision and Recovery Standards Solution, containing 30 typical PFAS, enabled maximum-likelihood suspect identification against a PFAS list of 3,882 compounds from National Institute of Standards and Technology with least false-negatives and false-positives. PFAS suspects were identified in 34 of 35 samples, with 13 samples containing over 10 unique PFAS suspects. Powder-based cosmetics exhibited more PFAS suspects than cream-based products. Targeted analysis with 30 PFAS standards via Triple Quadrupole LC-MS/MS confirmed 26 of the 218 identified suspects. These results underscore the feasibility of the total PFAS suspects in cosmetics and highlight the need for stricter regulation of fluorinated ingredients and further research on dermal PFAS exposure.