This document establishes ambient water quality criteria for selenium, a critical element impacting aquatic ecosystems and human health. The U.S. Environmental Protection Agency (EPA), tasked with environmental protection, presents this publication as part of its ongoing efforts to inform policy and regulation. It details the scientific basis for recommended selenium levels in water bodies, addressing both ecological toxicity and potential human exposure pathways through the environment. The criteria are derived from scientific literature and risk assessments to guide regulatory actions and water quality management.

This publication serves as a foundational scientific document for regulatory bodies and environmental managers concerned with selenium contamination in water. It provides the technical basis for setting water quality standards, reflecting the EPA's commitment to evidence-based environmental protection. The criteria outlined are intended to inform policy decisions and contribute to the preservation of aquatic life and public health. Its detailed scientific approach makes it a key reference for understanding and managing selenium pollution.