The EU has decided: From 1 February 2020 in Europe, industries are no longer allowed to use more than 0.1% of siloxanes D4 and D5 in skin and hair care products that are washed off during normal use.
– A rational decision, says senior scientist Nicholas Warner, – and one that will help reduce the emissions of siloxanes from wastewater to the aquatic environment, in which high concentrations have been found.
While satisfied with this regulation (Commission Regulation (EU) 2018/35), Warner’s colleague, scientist Ingjerd S. Krogseth, emphasize that there is still a lot we do not know about siloxanes.
– And, as she says, – the big question now is how the industry will replace these siloxanes, and in what ways any new substances will affect the environment.
Chemicals of emerging Arctic concern
This news coincides with the launch of the AMAP Assessment 2016: Chemicals of Emerging Arctic Concern. In this report, Warner has written a review chapter on the knowledge we have so far regarding siloxanes’ presence within Arctic Regions.
– One of the main challenges with siloxanes is that they are very extensively used, explains Warner. – You find these silicon-based compounds in various industrial applications such as polymer production, fuel additives, building materials, surface treatment agents and detergents. While they are broadly used in polymer productions, their main use is in cosmetic and personal care products such as lotions, shampoo and deodorants, and this also results in the largest emissions to the environment.
Due to this, large amounts of siloxanes end up in wastewater and subsequently in the aquatic environment. Exactly how much depend on the level of treatment applied to wastewater influent, as well as the size of the population that treatment plan supports.
Water and air
While the main concern for siloxanes are aquatic organisms living in waters that receive wastewater effluents, the majority of siloxanes in the environment are present within the atmosphere.
Siloxanes are so volatile, most of the siloxanes in personal care products we apply to our bodies will evaporate and undergo atmospheric degradation.
However, long-range transport potential of siloxanes have been confirmed. Elevated atmospheric concentrations of both D4, D5 and D6 have been measured in air at the Zeppelin observatory on Svalbard. Monitoring data also show that annual concentration trends have remained stable in recent years.
– That siloxanes are able to undergo long-range atmospheric transport from source regions located further south, is an important criteria in assessing the risk that these chemicals pose to remote regions, Warner explains.
Regulation as a start
However, even under Arctic conditions, it is unlikely that siloxanes will deposit – because of its inherent volatility. The scientists believe that siloxanes found in Arctic regions primarily comes from local sources, such as human settlements. Due to the limited wastewater treatment in these areas, wastewater emissions of siloxanes can be extensive considering the small populations, and is the major source of siloxanes in Arctic aquatic environments.
– Reducing the use of D4 and D5 to less than 0.1% in wash-off personal care products is a start, Warner concludes. – Continuous monitoring data will be crucial to assess the changes in environmental concentrations of siloxanes, and influence any future restrictions on the use of siloxanes and their substitutes.
The projects mentioned in the articles are funded by the Research Council of Norway (project number 222259) and from the Fram Centre (High North Research Centre on Climate and the Environment) flagship program ‘Hazardous substances – effects on ecosystems and human health’.