Location: Water Management and Conservation Research
Project Number: 2020-13000-005-017-I
Project Type: Interagency Reimbursable Agreement
Start Date: Aug 1, 2023
End Date: Jul 31, 2027
Objective:
Goal 1: Investigate the absorption, distribution, and depuration of PFAS residues
in food animals for which few data exist, and determine the fate of PFAS during
carcass composting.
Goal 2: Determine the effects of dietary PFAS binding agents on PFAS
absorption/tissue accumulation and on PFAS depuration rates.
Goal 3: Examine and compare the removal of PFAS compounds by biochars and an
activated carbon typically used in water treatment.
Goal 4: Determine the effectiveness of microwave irradiation for the destruction of
PFAS compounds on biochars and activated carbon.
Goal 5: Screen a large number of biochars (50-60) from various feed stocks for PFAS
sorption from solution; select high sorbers and determine rates of desorption under
various conditions.
Goal 6: Utilize the best biochars (maximum sorption, minimum desorption) in
greenhouse studies to identify those that maintain soil health, reduce PFAS
leaching, and reduce plant PFAS uptake.
Goal 7: Use the optimal biochar in a field setting focusing on PFAS sorption,
reduction in plant uptake, and soil health endpoints.
Approach:
Goal 1. Accumulation and depletion of PFAS in edible tissues of farm animals for which few data exist (swine, turkeys, sheep, or goats) will be measured. Animals will be dosed with PFAS in water and/or feed at levels commensurate with environmental contamination (i.e. 100 parts per trillion or lower) with an emphasis on measuring residues in edible products (milk, meat, eggs, etc.). Carcasses from animals will be shared with collaborators for composting. Residues in edible tissues, composted materials, and simulated leachate will be measured using validated LC-MS/MS methods.
Goal 2. The effects of dietary PFAS-specific sorbents on the accumulation (6-8 weeks) of PFAS residues in broiler chickens will be measured. PFAS will be fortified into feed and water at environmental concentrations and feeds will contain four levels (0, .5x, 1x, 2x) of sorbent per kg of diet (w/w) where 'x' represents an 4-6 orders of magnitude excess PFAS binding capacity. Modified silica, ion exchange, algal, and biochar based sorbents will be tested. At harvest, blood, liver, and skeletal muscle will be collected for the determination
of PFAS residues by liquid chromatography-tandem mass spectrometry.
Goals 3 and 5. Cooperators will introduce biochars (~5 g) into solutions (100 mL) containing known quantities of EPA-regulated PFAS: PFOA, PFOS, PFNA, PFHxS, PFBS and HFPO-DA (GenX). Biochar mixtures will be gently stirred for 48h, followed by filtration. Solutions will be analyzed for PFAS concentrations, and removal calculated by difference between starting and final concentrations.
Goal 4. Biochars having high PFAS sorptive capacities (Goals 3 and 5) will be microwave (MW) digested to destroy sorbed PFAS in cooperating laboratories. A 2.45 GHz MW oven equipped with a cyclonic inverter will be used irradiate 5.0 g biochar samples in a ceramic crucibles. Power levels and irradiation times will be varied to assess digestive performance and biochar temperature changes. Irradiated biochars will be physically and chemically characterized, rinsed, and the destruction of PFAS assessed by measuring F- in rinse water using ion chromatography.
Goal 6. Cooperators will select 3-6 of the best PFAS sorbing biochars for addition (0, 0.5, 1, 1.5% wt:wt) to soil collected from a PFAS contamination site. PFAS concentrations in leachate collected from soils under controlled conditions, soil health endpoints, and PFAS concentrations in above ground plant materials will be measured.
Goal 7. A 2-year field trial using biochar identified under Goal 6 will be conducted by cooperators. Biochar will be incorporated in the top 6" of soil in a contamination site located in Maine using appropriate replication. Soils will be planted with a cool season grass used in greenhouse studies. Soil health, soil PFAS concentration, and biomass PFAS concentrations will be measured. Cooperators will use an in vitro method to assess PFAS risk of ingested soil or plant material.
