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Posted: Nov 22, 2016
Researchers develop hazard assessment for nanosilver products
(Nanowerk News) Researchers have adapted an ‘off-the-shelf’ hazard assessment tool for use with emerging nanomaterials in an effort to better understand threats they may pose to workers, the public and the environment. As described in the peer-reviewed, scientific journal Environmental Health ("Use of a modified GreenScreen tool to conduct a screening-level comparative hazard assessment of conventional silver and two forms of nanosilver"), researchers focused on characterizing nanosilver products already approved for use by the U.S. Environmental Protection Agency (EPA) and currently found in hundreds of products -- and discovered health and environmental hazards not previously considered by EPA during its approval process..
The study was coordinated by scientists working together through the environmental health network Coming Clean, and documents the adaptation of the GreenScreen® for Safer Chemicals comparative hazard assessment method. GreenScreen summarizes known - and missing - information on chemical hazards in an accessible, visual format. It also assigns benchmark scores to substances, and now nanomaterials, based on both known and unknown hazard information. This allows for easy hazard comparisons and an informed way to select safer substitutes to guide product manufacturing.
To demonstrate the adapted method, researchers analyzed a nanosilver product named AGS-20 which has been approved by EPA for use in textiles, such as blankets, plush toys and undergarments, and then compared those findings with an analysis of another nanosilver product EPA used to fill in missing information on AGS-20 and, finally, bulk-form silver. The comparison shows important human health hazards that appear to have been overlooked in EPA’s assessment and approval, along with numerous data gaps where health hazards are likely to exist.
This finding creates concern that EPA’s approach to regulating the rapidly emerging field of nanomaterials is inadequate, and undermines justification for EPA’s decision to fill missing information on AGS-20 with information from other forms of nanosilver--which was done against the recommendation of EPA’s Scientific Advisory Panel. It also shows that nanosilver materials, currently in hundreds of consumer products, may be harming workers, the public or the environment despite approval by EPA.
The specific findings on the nanosilver materials analyzed show they are highly persistent in the bodies of people and some evidence exists they are toxic to cells. These factors could combine to harm the health of workers who manufacture nanosilver or the consumer products it’s included in, as these workers may come in repeated contact with a persistent, toxic material. Nanosilver materials also pose a particularly high threat to aquatic life, which creates an environmental hazard as many nanosilver products may be washed repeatedly and leach nanosilver particles into rivers, lakes and streams.
“Our study demonstrates that the nanosilver product AGS-20 was approved by EPA despite missing substantial information on how it might harm workers or the public,” said Jennifer Sass, PhD, and Senior Health Program Scientist with the Natural Resources Defense Council (NRDC), who co-authored the research report. “You can’t put the genie back in the bottle, and now that nanosilver products are already on store shelves we hope EPA and manufacturers will consider this study and use it to further protect public health.”
“Nanomaterials are a different animal entirely, and as this field continues to expand it’s imperative that EPA refine its process for understanding their hazards and regulating their risks appropriately,” said Lauren Heine, PhD, and Executive Director of Northwest Green Chemistry, a co-author of the report.
“Nanomaterials are quickly infiltrating the marketplace,” said Tracy Gregoire, Director of the Learning Disabilities Association of Maine. It’s important that EPA and industry seek to better understand the hazards associated with any nanomaterial before it’s used to replace toxic chemicals in our products. Our project results can help establish common sense chemical disclosure and safer substitute practices for nanomaterials and other emerging technologies.”
“This demonstration study proves that both regulators and companies don’t have to wait for new assessment methods in order to determine the potential harm of nanomaterials. They can act now to protect the health of workers and the public by making better choices on what to include in their products,” said Elizabeth Crowe, Co-Executive Director of Coming Clean.
Coming Clean staff and the authors of the study are urging government agencies and manufacturers to do more to understand potential hazards of nanomaterials before they move to market, and working to alert workers and consumers to the potential health threats of nanosilver materials.