INORGANIC AND ORGANIC CHEMICALS IN LAND-APPLIED REUSE MATERIALS (LARMS)

Land-applied waste by-products such as municipal biosolids, livestock waste (LW), and drilling-fluid waste (DW) are viewed as reusable resources and are commonly allowed for application to farmland to lessen costs associated with disposal. As part of a national study on the land-application of biosolids, LW, and DW, a team of multidisciplinary scientists is examining if the application of these reuse materials translates to an increased risk to environmental and human health. The study includes 34 reuse-material samples that were analyzed for a broad suite of inorganic and organic compounds and for any potential toxicities and health effects from contaminant exposures in individual wastes. Initial results indicate that the organic carbon content of reuse materials was as large as 45% in biosolids, 42% in livestock waste, and 11% in DW. Biosolids contained the greatest concentrations of organic chemicals, with total concentrations of pharmaceuticals and pesticides as large as 10,260 ng/g and 2,530 ng/g, respectively. Total PFAS concentration in biosolids was as large as 338 ng/g at a single site. DW contained the greatest concentrations of hydrocarbons, with a total concentration of polycyclic aromatic hydrocarbons as large as 171,000 ng/g and a total alkylbenzenes concentration as large as 46,000 ng/g. Median total inorganic nitrogen and phosphorus concentrations in LW (21 mg/g and 13.5 mg/g, respectively) and biosolids (5.3 g/g and 26.4 mg/g, respectively) were as much as three orders of magnitude greater than respective concentrations in DW. Concentrations of toxic heavy metals in all three reuse materials did not exceed U.S. EPA concentration limits set for land application of biosolids. Rare-earth elements were generally two orders of magnitude greater in DW than in biosolids and three orders of magnitude greater than LW. The results generated by this research (i.e., contaminant characterization and associated quantitative toxicological effects) will provide stakeholders, industry, and regulatory authorities insight into the potential for the beneficial uses and risks to environmental and human health of these materials.