Grantee Research Project Results
2022 Progress Report: Evaluating PFAS Occurrence and Fate in Rural Water Supplies and Agricultural Operations to Inform Management Strategies
EPA Grant Number: R840082Title: Evaluating PFAS Occurrence and Fate in Rural Water Supplies and Agricultural Operations to Inform Management Strategies
Investigators: Lee, Linda S. , Pennell, Kurt , Preisendanz, Heather
Institution: Purdue University
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2020 through August 31, 2023 (Extended to August 31, 2025)
Project Period Covered by this Report: September 1, 2021 through August 31,2022
Project Amount: $1,609,344
RFA: National Priorities: Research on PFAS Impacts in Rural Communities and Agricultural Operations (2020) RFA Text | Recipients Lists
Research Category: Water , Land and Waste Management
Objective:
Our overall goal, which includes 6 objectives, is to address key data gaps in our understanding of PFAS occurrence and fate in the rural landscape and agricultural operations and their impacts on rural water supplies and agricultural products using a combination of field, laboratory and modeling activities to evaluate the following objectives.
Progress Summary:
In year 2, we made varying degrees of progress on all objectives.
For Obj. 1 (contribution of effluent and land-applied biosolids to PFAS in rural water sources), Purdue collected and analyzed 96 sets of well water samples in Tippecanoe County, IN. Total PFAS concentration (54 PFAS targeted for quantitation) ranged from 2 to 35 ng/L with 77% of the wells having concentrations < 5 ng/L. PFOS and PFOA were generally < 1.12 ng/L and 0.2 ng/L, respectively, which are the approximate LOQs or our analysis. Current assessment does not reveal any noticeable spatial trends associated with proximity to land-application of biosolids. Penn State completed sampling and analysis of 68 private wells from their rural well-owner network. PFAS levels in 72% of the samples were above the EPA’s 2022 interim health advisories for PFOA and PFOS, with concentrations up to 16 and 16.5 ng/L, respectively. Overall, current results suggest that PFAS concentrations were inversely correlated with well age, well depth, and distance from a site with an active biosolids permit, while they were positively correlated with the presence of onsite wastewater treatment (e.g., septic tank).
For Obj. 2 (PFAS fate, transport, and crop uptake in effluent irrigation), influent and effluent from the Penn State water resource recovery facility (WRRF) were sampled at six times between 10/2021 and 08/2022. Data were combined with previous years data to evaluate PFAS occurrence trends, which overall did not vary substantially. Monitoring well (MW) and crop silage samples were collected and fescue (hay) at the Penn State wastewater spray-irrigation ‘Living Filter’ (LF) site where effluent is used to irrigate the site. Overall, PFAS in MWs were found to be ubiquitous and generally increased in the direction of groundwater flow, with total PFAS concentrations as high as 155 ng/L in MWs. PFAS concentrations in the irrigated corn silage were 0.97 µg/kg dw (3x higher than the non-irrigated silage). Fescue cuttings had total PFAS concentrations of 11.3 µg/kg dw. Based on the feed rations for non-research dairy cattle raised at Penn State and PFAS concentrations obtained from fall and spring harvests, the total annual PFAS consumption was estimated to be 2.46–7.67 mg/animal/yr (dw). More than 84% of PFAS in cattle feed crops were short-chain compounds (PFBA, PFPeA, PFHxA). PFAS present in the crop samples may be from uptake and/or direct spray-irrigation.
For Obj. 3 (PFAS fate, transport, and crop uptake from land-applied biosolids) following the observations reported in year one for the VA land-reclamation field study, additional studies were carried out to evaluate the dilution effect of blending biosolids with mulch on PFAS leaching. Blending biosolids with mulch (0.75:1) reduced PFAS in leachates with the dilution effect being more pronounced for longer chain PFAS. PFAS composition in leachates were similar between the blended and non-blended biosolids and predominantly short-chain PFCAs. VA biosolids field study was delayed until March/April 2023.
For Obj. 4 (precursor occurrence and persistence), efforts focused on method development for better evaluations and comparisons of total organofluorine using modified wet bench assays and HR-CS GF MAS relative to quantifiable PFAS with HRMS.
For Obj. 5 (PFAS interfacial adsorption), unsaturated Ottawa sand or Appling soil column experiments were conducted to evaluate air-water interfacial adsorption on the transport and retention of PFAS mixtures. Increased retention of the 9 PFAS evaluated increased with decreasing % moisture (i.e., 100%, 60%, to 27%). Surface tension and batch adsorption studies were completed to provide independently measured input parameters for mathematical model development and validation.
For Obj. 6 (refine and validate mathematical models to predict PFAS leaching), PRZM and Hydrus models modified in Year 1 to incorporate a nonlinear interfacial adsorption were applied to representative field data from the Penn State LF Site to evaluate their performance. In addition, monitoring well and soil data from the LF Site were mapped using ArcGIS. Kriging interpolation of the most recent concentration data yielded estimates of PFAS concentrations. The Pros Zonal Summary geoprocessing tool was used to determine mean concentrations that would be detected at wells within the interpolated zone to examine risk if property owners used private wells for drinking water. The source code for a third unsaturated zone model (LEACHM) was obtained from Dr. John Hutson at the Flinders University (New Zealand) for evaluation.
Future Activities:
Penn State WRRF sample collection will continue throughout the remainder of the project period. Biosolids (IN) and well water sample collection and analysis (IN and PA) will continue (Obj. 1). Sampling and analysis of the monitoring wells and crops at the Penn State wastewater spray-irrigation field site will continue throughout the remainder of the project period (Obj. 2). Sampling and analysis of the VA HRSD Progress agricultural farm site will be ongoing for the remainder of the project. The manuscript for the VA land-reclamation field study will be completed and submitted. Analysis of the artificially constructed land reclamation site will be completed in Year 2. Additional unsaturated columns will be conducted using Appling soil and a field soil from PFAS-impacted biosolids application field site (Obj. 3) and an effluent water application field site (Obj. 2) at three water saturations of 30%, 60% and 100% (Obj. 5). Using additional PFAS soil profile data obtained from Obj. 5, we will simulate PFAS fate and transport in unsaturated soils using the modified version of Hydrus 1D, PRZM5 and LEACHM and independently measured input parameters. A sensitivity analysis will be undertaken to investigate effects of environmental conditions.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 19 publications | 2 publications in selected types | All 2 journal articles |
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Type | Citation | ||
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Mroczko O, Preisendanz HE, Wilson C, Mashtare ML, Elliott HA, Veith TL, Soder KJ, Watson JE. Spatiotemporal patterns of PFAS in water and crop tissue at a beneficial wastewater reuse site in central Pennsylvania. J. Environ. Quality 2022; 51(6):1282-1297. |
R840082 (2022) |
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Supplemental Keywords:
biosolids, effluent irrigation, crop uptake, transport, biotransformation, interfacial adsorptionProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.