Characterizing and Comparing Per- and Polyfluoroalkyl Substances in Commercially Available Biosolid and Organic Nonbiosolid-based Products
By Rooney Kim Lazcano, Youn Jeong Choi, Michael L. Mashtare, and Linda S Lee
ES&T
June 29, 2020
DOI: 10.1021/acs.est.9b07281
Concerns of the presence of per- and polyfluoroalkyl substances (PFAS) in biosolids are increasing while sales in commercially available biosolid-based products used as soil-amendments are also increasing. Seventeen perfluoroalkyl acids (PFAAs) in 13 commercially available biosolid-based products, 6 organic composts (manure, mushroom, peat and untreated wood), and one food and yard wastes compost. PFAA concentration ranges observed are as follows: biosolid-based products (9.0 – 199 µg/kg) > food and yard waste (18.5 µg/kg) > other organic products (0.1 – 1.1 µg/kg). Analysis of 2014, 2016 and 2018 bags from one product line showed temporally decreasing PFAA totals (181 µg/kg, 101 µg/kg and 74 µg/kg, respectively). The total oxidizable precursor (TOP) assay revealed PFAA precursor presence in the biosolid-based products with much higher levels were evident when soluble carbon was removed with ENVI-Carb cleanup prior to the TOP assay. Time-of-flight mass spectrometry confirmed the presence of three sulfonamides, two fluorotelomer sulfonates and several polyfluoroalkyl phosphate diesters. Pore-water concentrations of water-saturated products were primarily of short-chain PFAAs and increased with increasing PFAA concentrations in the products. A strong positive log-linear correlation between organic-carbon (OC) normalized PFAA partition coefficients and the number of CFn units indicating OC is a good predictor of PFAA release concentrations.
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