NEW REPORT URGES FOCUS
ON CHEMICAL MIXTURES IN STUDIES
OF ENVIRONMENTAL CONTAMINATION

SOUTH HADLEY, Mass . – The Military Waste Cleanup Program (MilWaste) has issued a new report on chemical mixtures authored by MilWaste science director Emily Monosson, visiting professor of environmental studies at Mount Holyoke College. Chemical mixtures, two or more toxic chemicals that occur together at the same time and place, are a key concern among communities affected by hazardous waste contamination. The report, “Chemical Mixtures: A review of the evolution of toxicology and chemical regulation from a single-chemical approach to a science and regulatory process that must address complex chemical mixtures,” shows that toxicology, and the regulations that are based on toxicological research, has evolved as a “single-chemical science” that must be restructured to address chemical mixtures.

The report, intended for use by community members, technical advisors, scientists, and students involved in environmental cleanup, is written in plain English. “Chemical Mixtures” can be used as a guide to assess the treatment of mixtures in a specific risk assessment process. The report contains six sections:

• Toxicology Basics
  
• A Brief History of Toxicology: The Study of Poisons –
• One Poison at a Time
• The Regulation of Toxic Chemicals
• Review of EPA’s Supplementary Guidance for Conducting Health Risk Assessment of Chemical Mixtures
  
• Current and Future Research on Chemical Mixtures
  
• Summary and Conclusion: Where Do We Go From Here?

The report reviews current EPA and other guidance on chemical mixtures, and offers recommendations for future directions in science and regulation to deal with the complexities of chemical mixtures. One key recommendation is for the formation of small working groups and research funding that would expand the number of creative solutions available for addressing chemical mixtures, including and in addition to the current computer modeling approaches.

"In the environment, living systems are exposed to toxic chemicals as mixtures, not individual chemicals," the report concludes. "If an understanding of chemical mixtures, rather than single chemicals, had been the driving force behind the science of toxicology, the principal science we rely upon to protect humans and the environment, would we be in a different place now?"

Monosson, author of the report, holds a doctorate in biochemical toxicology from Cornell University, and has taught as a visiting professor at MHC since 1999. Her research work includes basic research in endocrine and reproductive disruption in fish, the toxicology of PCBs and community-based learning. Monosson has published extensively in toxicological journals and is co-editor of Interconnections between Human and Ecosystem Health (Chapman & Hall, 1996). She is a recipient of numerous grants, including NSF, EPA, and the Hudson River Foundation.

The Military Waste Cleanup Program supports communities and scientists in their efforts to understand technical, environmental, and human health issues related to military and nuclear environmental cleanup. MilWaste accomplishes its goals through research, education, networking, and outreach activities. The Program is located at the Center for the Environment at Mount Holyoke College, a liberal arts college for women located in South Hadley, Massachusetts.

The report, funded through a grant from the US Environmental Protection Agency, is available in pdf format on the MilWaste website, at http://www.milwaste.org/publications/chemicalmixturesfinal.pdf