To date, U.S. EPA has not selected a metal as a high-priority chemical for risk evaluation under the Toxic Substances Control Act (TSCA). TSCA requires that 50% of all high-priority designations be drawn from the 2014 Update of the TSCA Work Plan and that EPA also gives preference to Work Plan chemicals with the following characteristics: 1) Persistence and bioaccumulation scores of three; 2) Known human carcinogens; or 3) High acute or chronic toxicity. The 2014 Update of the TSCA Work Plan identifies several metals that meet these criteria, including cadmium, lead, cobalt, and antimony. If a metal is selected as a high-priority substance, unlike other substances, the risk evaluation method is specified by statute – specifically EPA is required to use the March 2007 Framework for Metals Risk Assessment of the Office of the Science Advisor.
Metals differ from organic chemicals in a number of ways that are important to environmental and occupational health risk assessment. Key factors for consideration include the natural occurrence of metals mixtures in all environmental media and their complex environmental chemistries that strongly influence their fate and potential for toxicity. Accounting for metal’s speciation, bioavailability, and bioaccumulation is critical to proper exposure assessment. The potential hazard of a metal is governed by its toxicokinetics and toxicodynamics, which are dependent on the form of the metal, metal compound, or mixture. Furthermore, many metals are essential nutrients for living organisms, including humans, and combined nutritional and toxicological effects could occur.
ToxStrategies’ scientists have published research and systematic reviews addressing these complex metals toxicology and risk assessment issues. Our experts have applied the Framework for Metals Risks Assessment to numerous metals for various industrial, occupational, commercial, and consumer conditions of use and are ready to assist clients prepare for the risk evaluations under the TSCA program. Contact us at info@toxstrategies.com to learn more!