PFAS Exposure from WWTPs to Surface Waters and Agricultural Fields

By Gabrielle Boucher, NWC student intern

Every year, the Nebraska Water Center (NWC) awards United States Geological Survey (USGS) 104b funding for projects intended to address water challenges in Nebraska. The competitive selection process includes reviews by a panel of fellow colleagues. This year, four projects were chosen and each focuses on contaminated water in Nebraska. To provide an overview of each project and the researchers behind them, the NWC will publish a series of articles on 104b awardees.

Polyfluoroalkyl Substances, or PFAS, are emerging contaminants that can stem from many different sources – the main two being manufacturing and household products such as non-stick pans, water repellent fabrics, and some cleaning supplies. Researchers note the likely source of PFAS in biosolids from Wastewater Treatment Plants (WWTPs) come from household cleaning products. Biosolids are leftover organic materials after the treatment of domestic sewage treatment and are often applied to agricultural farms. PFAS found in these biosolids are persistent and quite difficult to degrade and remove. PFAS are of concern because they are a known carcinogen that can cause various health issues, such as increased cholesterol levels. 

Dr. Tiffany Messer is a water quality engineer and assistant professor in the Biological Systems Engineering Department at the University of Nebraska-Lincoln. She will be overseeing a project named “PFAS Exposure from WWTPs to Surface Waters and Agricultural Fields” with the USGS 104b grant she has been awarded. Her team will focus on determining movement and fate of PFAS from WWTPs to agroecosystems receiving biosolids as well as quantifying PFAS in these agroecosystems. Messer decided to conduct this research to fill in significant knowledge gaps on PFAS in agriculture and how they move in agroecosystems. She notes, “there have, to our knowledge, been no studies looking at fate and transport of PFAS in agricultural settings.” She intends for this project to serve as seed data. This is likely the first study of its kind and will address one of Nebraska’s top 10 water challenges. 

The project will consist of taking biosolids from Lincoln’s Wastewater System and placing them in nearby Rogers Farm along with some controls, and assessing how much PFAS is lost from runoff when it rains. By removing and analyzing soil cores, Messer’s team will evaluate PFAS’ persistence and how it moves in the soil. The last part of the project is assessing sites upstream and downstream of a WWTP to see how PFAS concentrations vary. To analyze samples taken from the field, the team will be utilizing the Water Sciences Laboratory, and specifically its new Mass-Spectrometer which is profiled here.

Based on previous studies in manufacturing, Messer expects “we will see PFAS in the biosolids because we anticipate it is coming into the treatment plant and there isn’t much degradation or removal in processes that are currently allowing it to be removed in the system.” She also expects the PFAS to be leaving the field through water runoff. However, it’s difficult to say whether the levels are toxic since this is the first study of its kind. This project will no doubt provide valuable information about PFAS in agroecosystems and communities can move forward to address this emerging contaminant. 

This project raises a crucial question: what to do if levels are toxic? Messer has already been brainstorming ways to address this outcome and another UNL researcher, Steve Comfort, has submitted a proposal to the EPA on a method he is developing to remove PFAS from WWTPs. To gain more data regarding agroecosystems, she also plans to submit proposals for larger scale projects similar to this one.  

Messer and her team plan to start this project in early April and finish in October in line with the growing season and deliver results by winter. She will be working alongside two undergraduates who will help lead the project, as well as Dr. Shannon Bartelt-Hunt, department chair of Civil and Environmental Engineering at UNL, and Dan Snow, director of the UNL Water Sciences Laboratory. The team is excited to get started and see the impact this study will have on Nebraska.