Science

Environment

Protecting the environment is a key priority for the silicones industry. Together with our global partners, we have developed a global product stewardship programme. This includes a guide for our downstream users on how to reduce emissions of siloxanes during manufacturing. Read more about these projects in our About us section.

Our products also contribute to reducing carbon emissions across many sectors. To better understand the role of silicones in achieving greenhouse gas emissions reduction, we commissioned a study, which examined the potential contribution of the industry in specific applications. The results indicate that all examined applications showed emissions saving potential when compared to silicone alternatives.

The silicones industry is committed to a science-driven approach. We continuously evaluate the properties and environmental fate of our materials. The four sections below provide an overview of some of the most relevant peer-reviewed studies on siloxanes in the environment.

Find out more about our Decarbonisation Study

Behaviour and fate in the environment

We have collected a series of publications that address the properties and environmental fate of siloxanes.

This includes publications on the physical/chemical properties of siloxanes, their persistence and how they behave depending on whether they are exposed to air, water, soil, or sediment. We have also included general monitoring publications that address the presence of the substances in the environment.

Find out more in our resources page.

Persistence and Bioaccumulation

Persistence is a chemical property, which refers to the amount of time necessary for a substance to degrade in the environment. It is an important indicator of how long chemicals remain in the air, water, and soil.

Bioaccumulation refers to a relative increase in the concentration of a substance from the environment (food uptake, respiration, contact) to an organism in a food chain. Bioaccumulative criteria has been established to protect against substances that bio-magnify, which means that their concentrations increase as they move up the food chain.

Persistence and bioaccumulation are commonly used as part of criteria to assess whether a substance is harmful to the environment.

While some models and screening studies may identify some cyclic and linear siloxanes as bioaccumulative, robust, real-world studies have failed to observe “bio-magnifications”. The studies below assess the bioaccumulation potential of cyclic and linear siloxanes.

Selected studies

Monitoring study shows: The levels of D4, D5 and D6 are already in line with those targeted under the 2019 proposed REACH restriction

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Bioaccumulation and trophic transfer of cyclic volatile methylsiloxanes (cVMS) in the aquatic marine food webs (Norway)

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Application of multimedia models for understanding the environmental behavior of volatile methylsiloxanes: Fate, transport, and bioaccumulation

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Long-range environmental transport and back deposition

The Stockholm Convention on Persistent Organic Pollutants (POPs) was established to ensure that governments work together to protect the environment from POPs that travel over long distances. To protect remote environments such as the Arctic, it is important to assess two things: whether a substance undergoes long-range environmental transport (LRET) (that is, travels over long distances), and if so, whether it deposits back to or transfers to the earth’s surface where it can potentially cause harm. Below is an overview of recent studies on the long-range environmental transport and back deposition potential of Volatile methylsiloxanes (VMS).

Risk assessment

To understand whether a substance could be harmful to the environment, it is important to know both what the potential hazards are and the exposure. Risk assessment frameworks evaluate both hazard and exposure of a substance to assess its risks. While the criteria provide some information, it is equally important to look at real-life data, to see how substances actually behave in the environment and consider the exposure potential. Governments, scientists, and industry have all performed risk assessments for siloxanes.

In terms of cyclosiloxanes, the overwhelming majority concludes that they are safe for the environment. In addition, independent scientific studies, voluntary industry stewardship efforts, and regulatory evaluations, including from Environment Canada and Health Canada, have all demonstrated the safety of linear siloxanes, including L3 (octamethyltrisiloxane), L4 (decamethyltetrasiloxane) and L5 (dodecamethylpentasiloxane).

Visit our resources section to access the latest studies.

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