Guest Column | November 2, 2015

Thinking About Volatile Organic Compounds (VOCs) In Drinking Water

By the Water Research Foundation (WRF)

Project 4457 from WRF provides the water community with tools for understanding and communicating the risks associated with contaminants of emerging concern (CECs). As part of the initiative, WRF has created question-and-answer articles for each of four substances: VOCs, chromium, medicines and personal care products, and NDMA. The core message sheets were developed following best practices for risk communication as employed by the Centers for Disease Control and Prevention (CDC). What follows is WRF's core message sheet covering VOCs, or volatile organic compounds.

The United States has some of the safest public water supplies in the world. Our drinking water is treated and monitored to assure that the water being delivered is safe for consumption. While our water is safe, drinking water quality and management is understandably complicated. Small traces of naturally occurring or human-made substances can sometimes find their way into the tap water. One such group of substances is volatile organic compounds.

What are volatile organic compounds?
Volatile organic compounds (VOCs) are a large group of carbon‐based chemical compounds that evaporate easily at room temperature. Certain VOCs are federally regulated substances in drinking water.

Where do VOCs come from?
According to the EPA, sources of VOCs found in indoor air include home products such as paints, paint strippers, solvents, wood preservatives, aerosol sprays, cleansers and disinfectants, moth repellents and air fresheners, stored fuels and automotive products, and dry‐cleaned clothing.i VOCs can occur in drinking water sources as a result of contamination by improper disposal of products containing VOCs. Leaking underground storage tanks are a major source of VOCs in groundwater (underground drinking water sources).

Why are VOCs a concern?
The primary health concern associated with VOCs is their potential ability to cause cancer. Some VOCs are currently regulated, while others are being evaluated, including a group of 16 VOCs that are identified as carcinogenic. Consuming tap water constitutes a minor contribution to a person’s total exposure to VOCs that may be found in drinking water, because inhalation of water vapor while showering/bathing and skin absorption are the main pathways of exposure.

What solutions exist for VOCs?
Methods exist to both measure and treat VOCs.ii Many of the VOCs can be largely removed from water using existing treatment technologies found at some drinking water treatment plants.iii

In March 2010, the EPA announced a new approach to protecting drinking water and public health. One of the goals of this approach is to develop a single standard for the group of 16 VOCs identified as carcinogenic.

The EPA’s ongoing review of VOCs will provide an updated evaluation of the potential health effects of exposure to VOCs and the likelihood of significant exposure through drinking water, as well as a determination about whether changes to regulations of these substances is likely to be effective.

Source of information
This information is based on detailed technical information prepared by Dr. Shane Snyder. Dr. Snyder is a Professor of Chemical & Environmental Engineering, and holds joint appointments in the College of Agriculture and School of Public Health, at the University of Arizona. He also co‐directs the Arizona Laboratory for Emerging Contaminants (ALEC) and the Water & Energy Sustainable Technology (WEST) Center. For nearly 20 years, Dr. Snyder’s research has focused on the identification, fate, and health relevance of emerging water pollutants. Dr. Snyder has been invited to brief the Congress of the United States on three occasions on emerging issues in water quality. He has served on several US EPA expert panels and is currently a member of the EPA’s Science Advisory Board drinking water committee. He was recently appointed to the World Health Organization’s Drinking Water Advisory Panel.

i US EPA. (2012b). “An Introduction to Indoor Air Quality (IAQ): Volatile Organic Compounds (VOCs).” [Website.] Last updated 7/9/2012. Washington, DC: United States Environmental Protection Agency (US EPA), Office of Radiation and Indoor Air, Indoor Environments Division.
ii US EPA. (2011). Basic Questions and Answers for the Drinking Water Strategy Contaminant Groups Effort. EPA 815‐F‐11‐002. January 2011.
iii Kommineni, S., J. Zoekler, A. Stocking, S. Liang, A. Flores, M. Kavanaugh. (1999). Advanced oxidation processes. Chapter 3.0, In: Treatment Technologies for the Removal of Methyl Tertiary Butyl Ether (MTBE) from Drinking Water: Air Stripping, Advanced Oxidation Processes, Granular Activated Carbon, Synthetic Resin Sorbents, Second Edition. NWRI‐99‐06. Fountain Valley, California: National Water Research Institute. http://www.nwri‐