The Chesapeake Bay: A Study of Present and Furture Water Quality and Its Ecological Effects Volume I: Analysis and Projection of Water Quality

This study, prepared for the National Commission on Water Quality, is an analysis of the present and future water quality in the Chesapeake Bay from the Susquehanna River at Conowingo, Md. to the Atlantic Ocean. The objectives addressed in this volume of the study are 1.) Description of the present conditions of water quality and water quantity with respect to temperature, salinity, nutrients and dissolved oxygen. and 2.) Projection of future water quality conditions associated with the achievement of require ments and goals of the Federal Water Pollution Control Act Amendments of 1972, P.L. 92-500, 86 Stat. 816. The assessment of present and future biological and ecol ogical conditions is addressed in Volume II

Prepared by

NOTICE This technical report does not necessarily represent final EPA decisions or positions. It is intended to present technical analysis of issues using data which are currently available. The purpose in the release of such reports is to facilitate the exchange of technical information and to inform the public of technical developments which may form the basis for a final EPA decision, position, or regulatory action

U.S. EPA Authority to Use Cumulative Risk Assessments in Environmental Decision-Making

Conventionally, in its decision-making, the U.S. EPA has evaluated the effects and risks associated with a single pollutant in a single exposure medium. In reality, people are exposed to mixtures of pollutants or to the same pollutant through a variety of media, including the air, water, and food. It is now more recognized than before that environmental exposure to pollutants occurs via multiple exposure routes and pathways, including inhalation, ingestion, and dermal absorption. Moreover, chemical, biologic, radiologic, physical, and psychologic stressors are all acknowledged as affecting human health. Although many EPA offices attempt to consider cumulative risk assessment and cumulative effects in various ways, there is no Agency-wide policy for considering these risks and the effects of exposure to these risks when making environmental decisions. This article examines how U.S. courts might assess EPA’s general authority and discretion to use cumulative risk assessment as the basis for developing data in support of environmental decision-making, and how courts might assess the validity of a cumulative risk assessment methodology itself