Until June 2015, the rules for the assessment and classification of dangerous preparations were laid down in Directive 1999/45/EC, which is still applied for the derivation of water hazardous classes. In Annex III of the directive three different methods for the evaluation of environmental hazards of preparations have been described:
Normally the environmental hazards of a preparation shall be assessed by the conventional method (a and b). If the aquatic toxicity is directly determined, the tests are to be carried out in conformity with quality criteria of the methods described in Regulation (EC) No 440/2008 laying down the test methods pursuant to REACH on all three species (algae, daphnia, fish).
Since 1st June 2015, the classification criteria of the CLP Regulation (EC) No 1272/2008 for mixtures have to be applied. The classification with respect to possible environmental hazards is described in section 4. In future, also results on chronic aquatic toxicity are evaluated, in which the organisms are exposed for a longer time in relation to their life-cycle. Moreover, for highly toxic components of mixtures (EC50 <1 mg /L or NOEC <0.1 mg /L) "multiplication factors" have been introduced. These are taken into account when calculating the classification of mixtures according to the summation method.
Chemicals and preparations are classified according to their hazard potential to the environment and human heath into Water Hazard Classes. Three Water Hazard Classes (WGK) have been defined:
WGK 1: slightly hazardous to water,,
WGK 2: obviously hazardous to water,
WGK 3: highly hazardous to water.
The classification is made according to the Ordinance on facilities for handling substances that are hazardous to water (AwSV), which replaces the Administrative Regulation on the Classification of Substances Hazardous to Waters into Water Hazard Classes. The AwSV may be downloaded along with other comprehensive documents from the website of the German Environmental Agency.
The classification of substances into water hazard classes is carried out according to the hazards scheme attributed by the CLP-Regulation on classification, labelling and packaging of substances.
The classification of mixtures into water hazard classes follows either the computation rule with the water hazard class of its components or is based on test data obtained with the mixture. Hereby fixed concentration limit values were considered for the derivation of the water hazard class by means of a computation rule similar to that used for the conventional method of Annex III of the Directive 1999/45/EC.
The water hazard class of mixtures with components which are not known in detail can be derived also by direct testing of the mixture. The acute aquatic toxicity is determined on at least two species (fish, daphnia, and algae). The results lead to an allocation of evaluation points, which are considered in the specification of a water hazard class.
The classification of substances and mixtures into Water Hazard Classes is governed by Annex 1 of the AwSV, which also implements requirements of the CLP-Regulation on classification, labelling and packaging of substances and mixtures.
For the classification of substances and mixtures as "non-hazardous to water" further requirements such as ready biodegradability of liquid substances or low bioaccumulation of solid organic substances are demanded. For floating liquid substances and mixtures a new category of "substances generally hazardous to water" has been established. That includes e.g. liquid manure, slurry, silage effluents and fermentation substrates.