Objective 1: Determine the absorption, distribution, metabolism, and excretion of emerging and legacy chemicals in food animals. Sub-objective 1.A: Determine the metabolism and disposition of [14C]-nitrofurazone in broiler chickens. Sub-objective 1.B: Determine the ADME of [14C]-PBDEs 47, 99, and 153 in laying turkeys. Sub-objective 1.C: Determine the ADME of 1,3,7,8-tetrabromo [14C]-dibenzo-p-dioxin in laying hens. Sub-objective 1.D: Determine the ADME of a defined mix of PFAS, including perfluorohexane sulfonic acid (PFHxS) in lactating cattle. Sub-objective 1.E: Determine the fate of PFAS originating in a contaminated water source during the life cycle of laying hens. Sub-objective 1.F: Determine the ADME of [14C]-(-)-trans-'9-tetrahydrocannabinol (THC) and/or [14C]-cannabidiol (CBD) in lactating dairy goats. Sub-objective 1.G: Determine the accumulation and depuration kinetics of THC and CBD in feedlot cattle supplemented with dietary hemp. Sub-objective 1.H: Evaluation of cellular uptake, translocation, and toxicity of microplastics using cell models. Sub-objective 1.I: Determination of the fate of microplastics in laying hens. Sub-objective 1.J: Determination of the uptake and depuration of microplastics in lactating dairy goats. Objective 2: Develop and validate sensitive and accurate rapid analytical tools to detect emerging and legacy residues in food animals and food animal systems. Sub-objective 2.A: Develop ambient ionization mass spectrometric detection and quantitation techniques of chemicals in matrices easily collected from live animals (blood, hair, urine, saliva). Sub-objective 2.B: Develop ambient ionization mass spectrometric detection and quantitation techniques of chemicals in postmortem matrices (blood, tissues). Objective 3: Determine levels and sources of emerging and legacy chemical or biological residues in the domestic food supply. Sub-objective 3.A: In cooperation with regulatory agencies, determine the levels of dioxins, furans, and PBDEs in the U.S. meat supply. Sub-objective 3.B: Determine the source(s) contributing to high background levels of PBDEs in commercial turkey.