The U.S. Geological Survey (USGS) is conducting market research to determine the availability of qualified businesses capable of providing Particle Size Distribution analysis for soil samples. The project involves analyzing approximately 52 soil samples collected from areas variably affected by contamination with lead and other metals. The samples have been prepared for analysis by drying and sieving to less than 1 millimeter. The desired outcome is the breakdown of % sand, % silt, and % clay, as well as the distribution of particle sizes in ¼-phi intervals. Some key points to consider: • The laboratory must have experience with methods for determining particle size distribution in solid materials. • Chains-of-custody for all laboratory operations and analyses for each sample will be fully documented. • Laboratory quality assurance/control results for each analytical run, including at minimum replicates and certified reference standards, must be provided. • Results will be delivered as XLS or CSV files and must be made available by July 15, 2025.