Safety of nanosilver in consumer products: many questions remain
BfR workshop confirms incomplete data on the health risks of nanoscale silver
In its statement on aspects of the toxicity of nanosilver, the Federal Institute for Risk Assessment (BfR) recommended avoiding the use of nanosilver in food and everyday products until the data situation allows a conclusive assessment of the health risks. The objection raised against this BfR assessment, particularly by industry, was that there was sufficient data available to assess the health risk of nanosilver in consumer products and in food. The BfR has therefore invited experts from research and science as well as representatives from associations and industry to a workshop to discuss existing risks and possible courses of action for comprehensive consumer protection. "The discussion confirmed the BfR's warning of caution," said BfR President Professor Dr. dr Andreas Hensel, "because there is still too little reliable scientific knowledge about the specific effects of nano-sized silver particles."
Metallic silver and various silver compounds are used, for example, in cosmetics and in various consumer products, primarily because of their antimicrobial effect. In addition to medical-therapeutic applications, hygiene aspects are increasingly playing a role for textiles. The antimicrobial finishes on the textile fibers are primarily intended to counteract the formation of odors caused by the microbial decomposition of sweat. In the meantime, nano-sized silver particles are also increasingly being used. Nanoparticles are understood to mean particles with a diameter of less than 100 nanometers.
In its Opinion No. 24/2010, the BfR pointed out that silver in nanoscale form (nanosilver) could possibly have an effect profile with additional toxic effects that had not previously been described for silver. Due to the special physico-chemical properties of the nanoparticulate form, a changed toxicological potential for many nanomaterials is known. The BfR workshop has shown that only a few toxicological data are available for nanoscale silver, which experimentally examined the material taking into account nano-specific aspects. In addition, the characterization of both the particles used and the dosage was inadequate for many years, partly because the corresponding analytical methods were not available. Many older studies on colloidal silver, now commonly considered a nanomaterial, do not meet the standards of modern toxicology. Recent studies have provided clear indications of effects previously unknown for silver. These include pathological changes in tissue in the liver after oral and inhalative administration and in the lungs after inhalative exposure, changes in organ-specific physiological parameters and an increased potency.
Only a few legal regulations define requirements for the ingredients of certain products regarding the type and scope of toxicological data that must be submitted for a health assessment before marketing or for the continuation of marketing. Silver-based biocidal products will in future be tested as part of an approval process. For the health assessment, the applicants must submit the relevant toxicological data. For consumer products such as textiles, on the other hand, there is no obligation to register or have a permit. Since the industry is not obliged to make toxicological data available to the authorities for the assessment, these are often missing, so that the health risk of products containing nanosilver can only be assessed with difficulty or not at all. As a rule, information on the release of nanosilver particles from textiles and products is rarely available. Furthermore, the data on possible effects on the spread of resistance to silver or antibiotics in the specific application context is insufficient. Uptake in the body has also not yet been adequately clarified. In particular, little is known about uptake in the respiratory tract (lungs, bronchi) and the distribution of the absorbed particles in the body (toxicokinetics) after inhalation. In addition, there is a lack of data on effects on the skin (sensitizing potential, irritation), but also on reproductive toxicity, chronic toxicity and carcinogenic potential.
By law, consumer goods and products must not pose a health hazard when used as intended and in the event of foreseeable misuse. However, since there is still no final safety assessment for humans and the environment for nanoscale forms of silver due to the data gaps, the BfR continues to advise against the widespread use of nanosilver in consumer products.
About BfR
The Federal Institute for Risk Assessment (BfR) is a scientific institution in the Federal Ministry of Food, Agriculture and Consumer Protection (BMELV). It advises the Federal Government and the states on questions of food, chemical and product safety. BfR engages in research on topics that are closely linked to its assessment tasks.
Source: Berlin [BfR]
