Environmental risk limits for octamethylcyclotetrasiloxane in water : A proposal for water quality standards in accordance with the Water Framework Directive

Abstract

RIVM has derived environmental risk limits for octamethylcyclotetrasiloxane (D4) in water. D4 is used as an intermediate in the chemical industry, in cosmetics, skin- and hair-care products, and cleaning products. The compound is listed in Dutch legislation on monitoring and quality objectives in the context of the Water Framework Directive (WFD). The current water quality standard for D4 has to be updated according to the WFD-methodology. The ERLs derived in this report are advisory values that serve as a scientific background for the Dutch Steering Committee for Substances, which is responsible for setting those standards.

Food chain accumulation
Long-term exposure to D4 affects growth and reproduction of water organisms. The compound also accumulates from water into fish and predators. The proposed standard for long-term exposure (0.19 microgram per liter) therefore also considers exposure of humans and/or predatory birds and mammals via consumption of fish.

Improved analytics needed
It is hard to accurately measure concentrations of D4 in water. The compound strongly binds to organic matter, and is volatile as well. The use of D4 in personal care products poses a risk for accidental contamination of samples by the staff during collection and handling of samples. In addition, siloxane-like materials are sometimes applied in analytical equipment, thereby interfering with the analysis. Improved analytical methods are needed for compliance check.