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

Sewage treatment plant

Silicones Europe commissioned ERM GmbH (Environmental Resources Management – ERM) to conduct a multi-year monitoring study to evaluate the effectiveness of the EU product use restriction of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in wash-off personal care products (PCPs). The monitoring results from the study are consistent with the goals of the EU Restriction of D4 and D5 in wash-off PCPs. Furthermore, the current mass loadings of D4, D5, and D6 from all sources are below or consistent with the proposed post-restriction goals presented in the 2019 Proposed Restriction. Therefore, the study shows that the restriction of D4 and D5 in wash-off PCPs has been effective in reducing the presence of these substances in wastewater and that the levels of D4, D5 and D6 are already in line with those targeted under the 2019 Proposed Restriction.

The restriction, published in 2018, was intended to reduce the concern for aquatic environments receiving discharges from wastewater treatment plants. In addition, the study benchmarks its findings against the goals set under the proposed EU restriction of D4, D5 and dodecamethylcyclohexasiloxane (D6) in leave-on PCPs, published in 2019. This proposal, not yet entered into force, also includes a restriction of D6 in wash-off PCPs.

The study focused on the analysis of samples collected from six representative wastewater treatment plants across the European Union and the United Kingdom receiving wastewater from primarily residential sources. Plants were sampled eight times for each of the two periods of the study, an Initial Period, running from the fall of 2017 to the summer of 2018, and a Transitional Period, from the spring of 2019 to the winter of 2020.

These samples were analysed to measure mass loadings of D4, D5 and D6, while taking into account all relevant geographic and demographic variables, as well as for uncertainty and variability in the input parameters. The analysis was performed at the Synlab laboratory (Rotterdam, NL), using a laboratory method developed and reviewed by the ERM team and analytical chemists from Silicones Europe member companies and verified by conducting a validation study. In particular, the statistical analyses were performed to assess the effectiveness of the targeted D4 and D5 product use restriction, testing for a significant difference between the Initial and Transitional Periods.

The completion report of the monitoring study is now available. Read more at this link.