Development and Application of Tools to Assess and Understand the Relative Risks of Drugs and Other Chemicals in Indirect Potable Reuse Water

Principal Investigators and Project Managers
Margaret H. Nellor, P.E., Nellor Environmental Associates, Inc.
Jeffrey Soller, Soller Environmental, LLC

Tools to Assess and Understand the Relative Risks of Indirect Potable Reuse and Aquifer Storage & Recovery Projects
Volume 2 

The overall objective of the project is to use existing risk assessment tools to develop new information that can be used by sponsors of indirect potable reuse projects to evaluate and explain the relative human health risks related to the use of recycled water.

The project is comprised of three tasks.The goal of Task 2, the subject of this report,  is to evaluate and explain human health risks related to the use of recycled water for indirect potable reuse projects and associated exposure to chemical contaminants. Task 2 identifies screening level target exposure concentrations or tolerable daily intakes (TDIs) and drinking water equivalent levels (DWELs) for a broad group of chemicals of interest to the recycled water community that might be present in recycled water, including prescription drugs, drugs of abuse, over-the-counter drugs, veterinary pharmaceuticals, personal care products, components of household products, endocrine disrupting compounds (EDCs), and other constituents of “emerging” concern.

This project report was prepared to support decisions by risk managers and others who may make decisions about the use of recycled water but was prepared independent of regulatory agencies. With regard to the term “safe,” it is used in the context of a risk judged to be insignificant relative to other health risks by using standard risk and exposure assessment methodologies. Task 2 also develops risk metrics that put the safe exposure concentrations into understandable terms to support risk communication, by describing relative hazards in terms of the amount of water a person would have to drink to reach the TDI level. While the focus of this evaluation was recycled water for indirect potable reuse, these TDIs are applicable to other potable water matrices, including raw and treated groundwater and surface water intended for potable use.

(2010, 340 pages, 06-018-2)