Summary posted by Meridian on 9/24/2010

Source: The Bureau of National Affairs' Daily Environment Report

Author: Pat Rizzuto

Water utilities in the United States are expressing concern to the U.S. Environmental Protection Agency (EPA) about the growing use of nanosilver. The utilities say that the EPA should not conditionally approve the use of nanoscale silver as a preservative in textile products as it does not have the scientific basis to conclude the use would not cause harm. The EPA proposed, in August, to conditionally approve a form of nanoscale silver as a pesticide to treat textiles. The National Association of Clean Water Agencies (NACWA), in comments on the approval, said "[T]here are no current data that can be used to support a conclusion of 'no unreasonable adverse effects' for the unique properties of nanosilver." According to Ben Horenstein, chairman of Tri-TAC, a technical advisory committee representing the League of California Cities, California Association of Sanitation Agencies, and California Water Environment Association, "EPA's primary reason for the conditional approval appears to be its concerns over market fairness and the fact that other competing products are already on the market. EPA should instead focus its efforts on the existing products to ensure it has sufficient information on their potential impacts. From a wastewater treatment perspective, the conditional approval of another nanosilver product is very discouraging. Wastewater utilities have been working diligently to reduce the input of silver in their wastestream in order to limit its presence in biosolids and wastewater effluent." NACWA disagreed with EPA's reliance on a "Down-the-Drain" model that assumed wastewater treatment would remove 88 percent of the silver, as the model is not designed to assess removal of nanosized materials. "Therefore, such a high rate of removal cannot be assumed. The wastewater treatment process is typically far more effective at removing larger particles than smaller ones, and so it is quite likely that there will be considerable pass through of small materials such as silver nanoparticles," the Association wrote. The article can be viewed online at the link below.

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