Analysis of multi-class unregulated organic compounds in soil and biosolids using LC-MS/MS

Numerous unregulated organic compounds (UOCs) including pharmaceuticals, opioids, and personal care products (PCPs) end up in wastewater. UOC presence in biosolids (a wastewater treatment byproduct), which are applied to soil for different reasons raises environmental and health risk concerns. In this study, two multi-class extraction methods were developed and validated to target 111 UOCs from 8 different major families simultaneously in biosolids and biosolids-impacted soil. One method (M-SPE) is a modified version of EPA 1694, that uses triple solid-liquid extraction and solid phase extraction (SPE). The second method (EMR) is a super-fast method consisting in a single solvent extraction and EMR (enhanced matrix removal)-Lipid dispersive SPE. M-SPE performed better overall with 72 and 54 UOCs extracted with 50-130% recovery for soil and biosolids, respectively, compared to EMR for which only 49 and 43 UOCs achieved within the same range, respectively. EMR performed particularly well for the extraction of low concentration opioids from biosolids. The use of ENVI-Carb as an additional cleanup step and its potential to sorb analytes was also evaluated. Although >75% sorption of 27 UOCs occurred, ENVI-Carb (graphitized carbon) was needed to sufficiently clean extracts prior to injection to avoid precipitation and protect analytical systems. Application of these methods to environmental samples resulted in detection of some flame retardants, opioids, pharmaceuticals, PCPs and phthalates totaling 30 and 26 UOCs in biosolids and soil historically applied with biosolids, respectively. This methodology will be an asset to determining UOC concentrations in biosolids and biosolids-impacted soils.