Research in the McDonough lab aims to develop a comprehensive understanding of how organic contaminants impact aquatic ecosystems and human health by combining innovative environmental chemistry and bioanalytical techniques, state-of-the-art mass spectrometry, and field monitoring campaigns. Our work protects the public from exposure to harmful pollutants and draws attention to the global ubiquity of organic contaminants.
Current Research Projects
Bioaccumulation of Novel Per/Polyfluoroalkyl Substances (PFASs) from an Aqueous Firefighting Foam (AFFF) in a Mouse Model
Per- and polyfluoroalkyl substances (PFASs) are a global research priority because they have been found at levels exceeding various health advisory limits in the drinking water of millions of people. Aqueous firefighting foams (AFFFs) are a common source of complex mixtures containing hundreds of PFASs to drinking water. Understanding the full extent of human exposure to PFASs via these complex mixtures requires innovative analytical methodologies, including high-resolution mass spectrometry for suspect screening and nontarget analysis.
In this study, a mouse model was dosed with a commercial AFFF mixture. Serum and urine samples from dosed mice were analyzed by quadrupole time-of-flight mass spectrometry (QToF-MS). Suspect screening was conducted using an extensive in-house extracted ion chromatogram (XIC) list and fragmentation library for hundreds of AFFF-associated PFASs. Screening of serum revealed that several substituted perfluoroalkyl sulfonates, for which no toxicological data is available, were enriched in blood from AFFF-dosed mice.
Screening of urine revealed a mixture of PFASs distinct from those accumulating in the blood, with normalized peak areas increasing steadily over the exposure period. Additionally, non-target analysis of mouse serum revealed the presence of fluorinated compounds that were not included in the original suspect screening list and had not been detected previously in the AFFF product. This highlights the use of in vivo models as an effective tool for prioritizing novel bioaccumulative PFASs that may be overlooked because they are minor components in drinking water and AFFF products.
McDonough, C. A.; Guelfo, J. L.; Higgins, C. P. Measuring total PFASs in water: The tradeoff between selectivity and inclusivity. Current Opinion in Environmental Science & Health. 2018. 7, 13-18. DOI: 10.1016/j.coesh.2018.08.005.
McDonough, C. A., Choyke, S., Ferguson, P. L., DeWitt, J. C., Higgins, C. P. 2020. Bioaccumulation of novel per- and polyfluoroalkyl substances in mice dosed with an aqueous film-forming foam. Environ. Sci. Technol. doi:10.1021/acs.est.0c00234.
The PFAS-AWARE Study: PFASs in Drinking Water and Human Serum from an AFFF-Impacted Community in El Paso County, CO
PFASs have become ubiquitous water pollutants due to their remarkable persistence. More information is rapidly needed to understand health risks posed by widespread, long-term contamination of drinking water by PFAS-containing aqueous firefighting foams (AFFFs).
This study investigated PFAS contamination of public water systems in El Paso County, Colorado. Wells in this area were found to be contaminated with PFASs from AFFF above EPA health advisory levels between 2013 and 2016. Raw drinking water and human serum from throughout this region were collected from April to June, 2018. Serum samples were re-collected from a subset of the initial cohort one year later to track changes in PFAS levels after exposure ended. All samples were analyzed via quadrupole time-of-flight mass spectrometry (QToF-MS) suspect screening to understand the extent of PFAS contamination in human blood resulting from this exposure. Data were screened for >1000 previously characterized and theoretical AFFF-associated PFASs using a high-resolution mass spectral (HRMS) library and an extensive extracted ion chromatogram (XIC) list.
Suspect screening of drinking water samples using HRMS libraries tentatively revealed the presence of cyclic/unsaturated perfluoroalkyl sulfonates as well as sulfonamide precursors. Screening of human serum samples revealed that the average concentration of perfluorohexane sulfonate (PFHxS; 25 ng/mL) was elevated compared to the general population as well as most previous data from impacted communities, and showed that C5-C8 sulfonates were prominent and ubiquitous in blood from residents. Suspect screening suggests the presence of additional PFASs, such as chloro- and oxy-PFSAs that have previously been seen in blood from occupationally-exposed firefighters.
Barton, K.; Starling, A.; Higgins, C. P.; McDonough, C. A.; Calafat, A.; Adgate, J. Sociodemographic and behavioral determinants of serum concentrations of per- and polyfluoroalkyl substances in a community highly exposed to aqueous film-forming foam contaminants in drinking water. Int. J. Hyg. Environ. Health. 2019. In press. DOI: 10.1016/j.ijheh.2019.07.012
Depth profiles of Organophosphate Flame Retardants in the Remote Ocean
Passive sampling to Understand Contaminant Dynamics in the Great Lakes