Losher, C. & Mercea, P.V. (2021). Plastic Pipes Conference XX, Amsterdam. Available via the Plastic Pipes Conference Association database.
In the framework of the German Environmental Agency (UBA) requirements of plastic articles in contact with drinking water (KTW-BWGL-guideline), the compliance is verified by comparing so-called “expected concentrations at tap”, Ctap, of substances contained in the plastics with specific limits in drinking water (socalled MTCtap’s). In practice, Ctap’s are obtained by analytical determination of the substance concentrations, CW’s, in water at the end of a number of migration periods.
However, this procedure is often a challenging, time and costs intensive task. This is especially true for materials like PVC-U, where the migration levels are, in most case, far below the detection limits of the most modern analytical methods. For such situations, an UBA Guideline recommends the use of migration modelling for the estimations of CW’s.
To perform such calculations a series of input parameters are needed, among them the diffusion and partition coefficients, DP’s and KPW’s, of the migrating substances are the most challenging ones. In recent years FABES Forschungs-GmbH, by investigating migration of substances from a series of polyolefins into water, has developed methods which allow the estimation of “conservative” 𝐷𝑃 +’s and 𝐾𝑃𝑊 + ’s, for compliance migration calculations for any organic additive found in these polymers. In this presentation these results are presented in a very concise manner.
Moreover, the extension of these results for a series of substances migrating from PVC-u samples in drinking water will be also presented. Eventually it will be shown how this information was implemented in a special software MIGRAPipe-KTW with which migration estimations as stipulated in the KTW-BWGL-guideline can be performed.
