Southern California Coastal Water Research Project Authority 1 article published in JoVE Environment Screening for Endocrine Activity in Water Using Commercially-available In Vitro Transactivation Bioassays Alvine C. Mehinto1, B. Sumith Jayasinghe2, Darcy R. Vandervort1, Nancy D. Denslow2, Keith A. Maruya1 1Southern California Coastal Water Research Project Authority, 2Department of Physiological Sciences, University of Florida A protocol to screen for endocrine activity in organic extracts of water samples, including treated wastewater effluent and surface (receiving) water, was adapted using commercially available division-arrested ("freeze and thaw") in vitro transactivation bioassays.