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Classification of Water Hazard WGK


LAUS can support you with scientific tests for the self-classification of substances in Water Hazard Classes (Wassergefährdungsklassen WGK) according to the German federal water act (AwSV), April 18, 2017:

Effects on the environment:

  • Acute toxicity to Daphnia (48 h EC50)
  • Algae growth inhibition (72 h IC50)
  • Acute toxicity on fish (96 h LC50)

Ready Biodegradability

  • OECD 301

Bioaccumulation Potential

  • logPOW

Physico-chemical Data

  • Water solubility

Oral and Dermal Toxicity


The classification of substances and mixtures is based on a system, which assigns evaluation points and precautionary points.

The accumulated total of points leads to the WGK classification as follows:

0 - 4: WGK 1
5 - 8: WGK 2
> 8: WGK 3

Evaluation points are being assigned depending on the result of scientific tests. If there are no experimental data, precautionary points will be assigned.

Classification based on test data:

Daphnia (48 h EC50), algae (72 h IC50), fish (96 h LC50), 2 tests out of 3 required, for animal welfare reasons, daphnia and algae are preferred, the lowest value is taken into account:
- ≤ 1 mg / L: 8 points
- 1 - ≤ 10 mg / L: 6 points
- 10 - ≤ 100 mg / L: 4 points
- > 100 mg / L: 2 points

Ready biodegradable and no increased bioaccumulation potential (applicable only for substances): Deduction of 2 points

Precautionary points are assigned for the lack of experimental data. If the data are missing, e.g. for effects on the environment, 8 points are added, if there is no acute oral or dermal toxicity: plus 4 points.

In addition, evaluation points are assigned for substances that based on scientific tests are classified with R-phrases according to Directive 67/548 / EEC or H-phrases according to Regulation (EC) No. 1272/2008. The number of points can be found in the AwSV, Appendix 1.

For mixtures, the classification can be calculated taking into account the individual components, as described in Appendix 1 of the AwSV. This can be replaced by scientific tests of the mixture. The classification is then based on the same point system as for substances, only that mixtures can't be classified as "not hazardous to water" (due to the lack of data for biodegradability and bioaccumulation, see above).

A substance is regarded as "not hazardous to water" if the following criteria apply:
- the total of points is zero
- two of the environmental impact values are below solubility
- for solids the water solubility<100 mg / L and organic substances are ready biodegradable or have no increased bioaccumulation potential
- for liquids the water solubility is <10 mg / L and organic substances are ready biodegradable
- no water-polluting substance appears during degradation
- it is not a floating liquid

The German Federal Environment Agency controls the self-classification and decides on the classification of substances, groups of substances and mixtures. For substances and groups of substances this will be published in the Bundesanzeiger.

Don't hesitate to contact us for a non-binding quotation.

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