This document provides technical background, statistical methods, and resulting estimates of pollutant concentrations in treated sewage sludge (biosolids) that represent Publicly Owned Treatment Works (POTWs) in the contiguous United States with flow rates of at least 1 million gallons per day (MGD). Estimates were produced using data from a national probability sample of 74 POTWs that statistically represent 3,337 POTWs that met the study criteria. This sampling effort is known as the Targeted National Sewage Sludge Survey (TNSSS). Estimates presented in this document are generally exploratory, and they provide important input to EPAs efforts to evaluate biosolids generated by the nations POTWs. The results also may support the development of pollutant limitations, regulatory impact analysis (RIA), and aggregate risk analysis related to biosolids under Part 503 of 40 CFR.