Silver is a metal that is known for its use in jewelry and silverware, but in its ionic form it has properties which are hazardous to the environment. Silver ions are very toxic to aquatic organisms and may cause long-term adverse effects in the aquatic environment. Fish and small crustaceans (like water fleas) are particularly sensitive. Growth or reproduction is impaired at silver ion concentrations even below 1 µg/L.
Silver is persistent and, once emitted into the environment, not reversible. To which extent silver is bioavailable, that is can be taken up by plants and animals in the environment, depends on many factors like organic matter content, in particular organo-sulfur compounds, pH and content of other metals. There is some concern that widespread use of silver could cause the development of resistant bacteria. There are reasons, therefore, to recommend precaution with regard to uses of silver which are not essentially necessary.
In the past, silver was widely used in photographic applications, but this has been reduced considerably with the switch to digital technique.
In recent years, however, silver is increasingly applied in other areas, for example in medical supplies or in water cooling systems or for drinking water disinfection. But silver is also used in common consumer products: textiles, shoes, refrigerators, toothbrushes, plastic bottles, vacuum cleaner filters, mattresses, cutting boards, etc. The market for these types of products is growing. The reason for this is that silver in ionic form has antibacterial effects.
The use of silver ions in many different consumer products contributes to diffuse spreading into the environ¬ment by sewage water and by sewage sludge. The extent to which silver is released and spread in the environment varies between different uses. The environmental impact by for example silver treated textiles through regular washing is certainly higher than by a refrigerator, which gets wiped only seldom and with far less amount of water. But some kind of environmental impact is likely for all silver containing products. It has been questioned whether the benefits of some of the silver treated products outweigh the negative environmental impact they might have.
Products which contain silver and make an antimicrobial claim like “antimicrobial”, “free of bacteria”, “for lasting freshness”, “hygienic protection”, “keeps the natural hygienic balance”, “treated against odour”, “prevents miscolouring”, etc. have to be labelled. This labeling has to include:
- that the article contains a biocidal product containing silver
- the purpose of the treatment
- the name of the silver substance(s) contained
- the name of the nanomaterial(s) contained, if relevant
- relevant instructions for use and any precautionary measures that are necessary.
Unfortunately, some products are placed on the market without correct labelling.
Read more about labelling of treated articles.
Silver used as a biocide requires approval
Silver, that is all chemical compounds releasing silver or silver ions, is considered a biocidal product that needs authorisation if the purpose of the use is to prevent bacterial growth. Silver used as a biocidal product is covered by the provisions of the Biocidal Products Regulation (EU) No. 528/2012 concerning the placing of biocidal products on the market.
Sweden has been assigned being the evaluating Member state for several different silver compounds included in the review program of the biocides legislation. The evaluation includes to assess risks to human health and the environment connected with the use of silver in different types of biocidal products. The results will be presented in an assessment report. The report forms the basis for a decision taken by the European Community regarding whether these silver compounds should be approved or not for biocidal use in the future.
After the decision regarding whether silver should be approved, biocidal products containing silver as an active substance will require approval in Sweden, as in all EU countries, before they can be sold. Biocidal products containing silver substances which are not under evaluation or have not been approved must not be sold in Sweden. Articles treated with silver may only be placed on the market in the EU after 1 March 2017 if the silver substance contained has been approved for the use in question.
Read more about which biocidal products may be released on the market.
Read more about treated articles.