Environment

The natural environment comprises all organisms around us – from soil, to plants, to air, to living organisms. Protecting the environment is a key priority for the silicones industry.

Together with our global partners, we have developed a global product stewardship programme, which includes a guide for our downstream users on how to reduce emissions of siloxanes during manufacturing.  Read more about these projects in our “commitments and responsibilities” section. Our products also contribute to reducing carbon emissions across many different sectors. The four sections below provide an overview of some of the most relevant peer-reviewed studies on siloxanes in the environment.

Properties and Environmental Fate

Properties and Environmental Fate

All substances have a unique environmental profile. Their properties determine their environmental fate.

Bioaccumulation

Bioaccumulation

Bioaccumulation refers to a relative increase in concentration of a substance from the environment to an organism in a food chain. The bioaccumulation potential of siloxanes has been thoroughly assessed.

Long-Range Transport

Long-Range Transport

To protect remote environment, it is important to assess whether substances travel over long distances and have the potential to cause harm in distant regions.

Risk Assessment

Risk Assessment

Extensive risk assessments have been carried out by governments, industry and academics over many years.

Properties and environmental fate

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

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

Bioaccumulation

It refers to a relative increase in concentration of a substance from the environment (food uptake, respiration, contact) to an organism in a food chain.

It is commonly used as part of criteria to assess whether a substance is harmful to the environment, for example in so-called “PBT” criteria. A compound that exceeds regulatory thresholds for all three factors of Persistence (P), Bioaccumulation (B), and Toxicity (T) is considered a PBT. Regulatory thresholds for persistence, bioaccumulation and toxicity vary between regions of the world.

Bioaccumulative criteria were established to protect against substances that bio-magnify, which means that their concentrations increase as they move up the food chain. While some models and screening studies may identify some cyclosiloxanes as bioaccumulative, robust, real-world studies have failed to observe “bio-magnifications”. The studies below assess the bioaccumulation potential of cyclosiloxanes.

Risk assessment

To understand whether a substance could be harmful to the environment, it is important to know what the potential risks are. Risk assessment frameworks such as the criteria for Persistence, Bioaccumulation and Toxicity (PBT) evaluate different aspects 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. Governments, scientists and industry have all performed risk assessments for cyclosiloxanes. The overwhelming majority concludes that cyclosiloxanes are safe for the environment at the levels found or likely to be found. Below are some of the risk assessments developed over the past decade.

Long Range 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 transport (that is, travels over long distances), and if so, whether it deposits back to the earth’s surface where it can cause harm. Below is an overview of recent studies on the long-range transport and back deposition potential of Volatile Dimethylsiloxanes (VMS).

Behaviour in source regions

Siloxanes do not back deposit in remote regions