A new method to analyze and define chemical risk will make it easier and less expensive to manage potential risks, according researchers who have published their approach in the journal Risk Analysis.
The authors say there are more than 80,000 chemicals in commerce and the environment, and the potential human health risks for most of these remain unknown. Using quantitative high-throughput screening technologies and adverse outcome pathways (AOPs) will allow regulatory agencies — such as the EPA — to prioritize which of these chemicals are hazardous and should be further evaluated, the researchers say.
As EHS Today explains, high-throughput screening uses robotics and other technological devices, allowing researchers to quickly conduct millions of chemical tests. AOPs trace biological events leading to adverse effects, which can be used in risk assessment.
“In my opinion, this work is starting to lay the foundation that will allow risk assessors and risk managers around the world to couple high-throughput screening tests and adverse outcome pathways for risk assessment,” Dr. Lyle D. Burgoon of the US Army Engineer Research and Development Center in Research Triangle Park, North Carolina, told EHS Today.
When asked about the study, the Society of Chemical Manufacturers and Affiliates’ Dan Newton, government relations senior manager, told Environmental Leader that “integrating advances in high throughput in-vitro testing could have broad implications on the chemical manufacturing sector. Generally speaking, it is an obvious way to reduce animal testing, and increase efficiency. From a regulatory standpoint, by increasing the understanding of the effects of certain chemicals and chemical categories, it could help inform agency priorities, as well as regulatory decision making.”
While industry groups say chemical prioritization is essential, they are quick to point out that the “more than 80,000 chemicals” figure is misleading.
The Toxic Substances Control Act (TSCA), currently being updated in Congress, requires the EPA to keep a list of all chemicals manufactured or processed in the US. The TSCA Chemical Substance Inventory includes about 84,000 chemicals, but the Society of Chemical Manufacturers and Affiliates and the American Chemistry Council both say this number does not reflect chemicals that are actually being produced and used today.
A more accurate number of chemicals in commerce, according to EPA data, is closer to 7,500 — this reflects chemicals that are produced in what EPA considers “significant amounts” and are widely used in commerce.
“Chemical prioritization is critical to a modernized TSCA,” says board-certified toxicologist Richard Becker, Ph.D. Becker is also a senior director of the American Chemistry Council’s science and research division.
“Developing a chemical prioritization process will help EPA create a clear process to determine which chemicals may require further scientific evaluation, and which do not,” he told Environmental Leader. “This ensures that EPA does not waste time and resources to evaluate chemicals that are already well-understood, such as those that are known not to pose significant risk to public health or the environment.”
Becker says ACC supports the development of new methods that use high-throughput screening to improve risk-based prioritization. Such approaches provide more data in less time, and at less cost.
“As experience grows in interpreting high-throughput HTS data, developing and verifying AOPs and deriving human exposure estimates, we anticipate there will be a number of pilot approaches — like the one described in this publication — that will be developed.”
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