This is a presolicitation for a contract to provide scientific, technical, and regulatory support to the EPA's Office of Water for developing and implementing ecological and human health criteria. The Government anticipates awarding a single, five-year IDIQ contract with a maximum ordering value of $17,000,000, set aside 100% for small businesses. The contractor will perform a wide range of tasks including toxicological reviews, ecological risk assessments, laboratory and field studies, data analysis, and technical document preparation. The contract contains significant organizational conflict of interest restrictions, limiting the contractor's future business relationships with entities involved in wastewater discharge, water treatment, and related industries for three years after contract completion. The anticipated award date for the resultant contract is no later than February 1, 2026.