From Wastewater to Feed: Understanding the Occurrence of PFAS in Crops Irrigated with Reclaimed Wastewater
Restricted (Penn State Only)
- Author:
- Kosiarski, Kelly
- Graduate Program:
- Biorenewable Systems
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 11, 2024
- Committee Members:
- Heather Elise Preisendanz, Thesis Advisor/Co-Advisor
Francesco Di Gioia, Committee Member
Suat Irmak, Program Head/Chair - Keywords:
- PFAS
Reclaimed Wastewater
Plant Uptake
Intake
Irrigation
Living Filter Site - Abstract:
- The beneficial reuse of human and animal wastes (i.e., wastewater, biosolids, and manure) has long been viewed as an environmentally responsible practice that reduces reliance on unsustainable depletion of freshwater resources and synthetic fertilizers. However, within the past two decades, extensive monitoring efforts have revealed that land application of human and animal wastes inadvertently introduces chemicals that may have significant adverse health effects, including endocrine disruption, into the environment, and particularly into agroecosystems. The presence of per- and polyfluoroalkyl substances (PFAS) in beneficially reused human wastes has become a topic of urgent concern in agricultural operations due to the potential for these compounds to persist in the environment, mobilize and impact water quality, be taken up by crops, bioaccumulate in the food chain, and negatively impact human, livestock, and ecosystem health. We conducted field and greenhouse studies to assess the roles of uptake pathways and evapotranspiration rates on PFAS levels in forage crops. For the field study, corn and fescue samples were collected at the time of harvest over a four-year period (2020 – 2023) at a beneficial reuse site in central Pennsylvania known as the Penn State Living Filter Research Site and analyzed for 20 PFAS following EPA Method 537.1 (modified). For the greenhouse study, soil was collected from the Living Filter site, and control soil was collected from a nearby agricultural site with no history of wastewater irrigation or pesticide applications. The greenhouse study was comprised of four treatments for each crop (corn and orchard grass): (1) PFAS-contaminated agricultural soil and watered with treated wastewater; (2) PFAS-contaminated agricultural soil and watered with tap water; (3) control soil and watered with treated wastewater; and (4) control soil and watered with tap water. Soil, water, and crop tissue samples were analyzed for 40 PFAS following EPA Draft Method 1633. Results from the greenhouse study suggested that uptake from the soil was the dominant uptake pathway, with foliar sorption from wet deposition unlikely a contributing factor to PFAS found in the crops. Evapotranspiration rates and other climate variables were not able to explain total PFAS concentrations in crop tissue harvested at the Living Filter; although, evapotranspiration may be able to partially explain PFBA uptake. Both the field and greenhouse data showed that uptake into corn was lower than forage grass, such that corn would pose a lower risk of certain PFAS entry into the food chain as compared with grass. Furthermore, short-chain compounds were more prevalent in the grass than long-chain compounds, which presents a lower risk of transferring to livestock products (meat, milk, etc.) due to lower biotransfer factors for short-chain compounds. Finally, we present the implications for management strategies that can be adopted to reduce risk of PFAS exposure to livestock and humans due to beneficial reuse of treated wastewater.