Organic micropollutants

The method on micropollutants consists of 2 documents (both in preparation). In the Waters Protection Ordinance (WPO) not all substances are regulated and the toxicity of mixtures of different substances is also not considered. Therefore, a VSA guideline for the assessment of the ecotoxicity of organic trace substances is being developed in parallel to the development of the enforcement aid.

Since April 2020, numerical requirements for organic trace substances have been included in the Water Protection Ordinance. In an implementation guide “Chemical surveys for organic trace substances – Review of numerical requirements in Annex 2”, guidance is to be provided on the procedure for surveying and assessing the numerically regulated organic trace substances in Annex 2. The module is being developed under the direction of the VSA Platform for Water Quality and the FOEN in close cooperation with an group of experts from the cantonal water protection agencies, Eawag and the Ecotox Center.

The method builds on the following reports:

  • Assessment concept for substances from municipal WWTPs
  • Assessment concept for substances from diffuse sources

Recorded parameters:

Pharmaceutical residues, biocides, plant protection products and other organic trace compounds.

Evaluation:

Comparison of the concentrations with the numerical values that must be respected at all times and the requirements that must not be exceeded over a period of two weeks (continuous exposure).

Legal assessment requirements fulfilled/not fulfilled.

A large number of organic trace compounds are found in water. However, the WPO only regulates substances, which are widely distributed and repeatedly exceed the limits. The toxicity of mixtures of different substances is also not considered. In parallel to the elaboration of the enforcement aid ” Chemical surveys for organic trace substances – Review of numerical requirements”, a VSA guideline for the evaluation of the ecotoxicity of organic trace compounds is therefore being developed. This module is being developed under the leadership of the VSA Platform for Water Quality and the FOEN in close cooperation with an group of experts from the cantonal water protection agencies, Eawag and the Ecotox Center.

The module is based on the following reports:

  • Micropollutants – Scheme for the assessment of water quality with regard to organic trace compounds from municipal sewage systems
  • Assessment Strategy for Non-Point Source Micropollutants

Recorded parameters:

All organic trace compounds (micropollutants) for which reliable ecotoxicological quality criteria are available. Toxicity of the mixtures for vertebrates, invertebrates and plants.

Evaluation:

Comparison of concentrations with chronic and acute quality standards.

Evaluation in 5 categories.