Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
1 000 mg/L

Additional information

No measured toxicity to micro-organisms data are available for Cashew (Anacardium occidentale) Nutshell Extract, Decarboxylated (Technical Grade), but reliable test data are available for a source substance Cashew (Anacardium occidentale) Nutshell Extract, Decarboxylated, Distilled (Distilled grade). Information from an Activated Sludge, Respiration Inhibition Test (OECD TG 209) using Distilled grade showed that no signs of toxicity were evident at any of the exposure concentrations (0, 10, 32, 100, 320 and 1000 mg/l) after 3 hours exposure (i.e. 3-hour No Observed Effect Concentration = 1000 mg/l nominal test material based on respiration rate). The study is classified as Klimisch Category 1 (Reliable without restriction) as it was performed to an internationally recognised method and was conducted to GLP.

Under Annex XI of the REACH Regulation “General rules for adaptation of the standard testing regime set out in Annexes VII to X”, in addition to the specific rules set out in Column 2 of Annexes VII to X, a registrant may adapt the standard testing regime in accordance with the general rules set out in Section 1 of the Annex. One approach that may be used is the grouping of substances and the read-across approach (Section 1.5 of Annex XI). An overall grouping and read-across rationale has been developed for the three grades of cashew nutshell extract. This has involved using data for two source substances Distilled and Distillation Residue grades to read-across the required data for Technical grade by interpolation. In this context interpolation is “the estimation of a value for a member of the group using measured values from other members on both sides of that member within the defined group spectrum”.

The justification for the read-across approach results from the commonality of the constituents and functional groups in the three grades and the common modes of action for specific localised endpoints that are manifest in physico-chemical, environmental fate and toxicological properties that are similar or follow a regular pattern as a result of structural similarity. Further details on the justification for using the interpolation based read-across approach are given in the accompanying document “Report on the development of an updated grouping and read-across rationale for the three grades of processed Cashew Nutshell extract”. The following points are relevant:

•       The three grades are manufactured using a common process in which the unprocessed cashew nutshell extract is heated, which produces Technical grade. Subsequent distillation does not result in the formation of any new constituents in the resulting Distilled and Distillation Residue grades, but rather changes in the proportion of certain constituents relative to those present in Technical grade.

•       In all the three grades the proportions of three out of the five key constituents namely the low boilers, C17 phenolics and high boilers (cardol and 2-methylcardol) are similar. Whilst the lightest, lower molecular weight non-polymeric constituents (such as cardanol) and the highest molecular weight polymeric constituents vary between the grades, Technical grade compositionally lies between Distilled and Distillation Residue grades.

•       For all the physico-chemical parameters for which measured data are available (relative density, vapour pressure, water solubility, octanol-water partition coefficient, flash point and flammability) the values estimated for the target substance Technical grade from the results generated in tests on the source substances Distilled and Distillation Residue grade are consistent with the actual measured values for Technical grade. The consistency of the estimated and measured values for these endpoints for Technical grade indicate that the read-across approach is appropriate and that reliable results can be generated by interpolation from the source substances (Distilled and Distillation Residue grades). In particular, there is consistency for the key physico-chemical parameters which influence toxicological behaviour of the three grades of processed cashew nutshell extract, namely: water solubility, octanol-water partition coefficient (logKow) and vapour pressure.

•       The environmental fate properties of aerobic biodegradation and soil absorption (log Koc) for the three grades of processed cashew nutshell extract follow a regular pattern as a result of structural similarity, supporting the interpolation-based read-across approach.

On the basis of the available data Distilled grade is not considered to cause toxicity to sewage treatment works micro-organisms at the highest test concentration. A similar conclusion is predicted for Cashew (Anacardium occidentale) Nutshell Extract, Decarboxylated (Technical Grade).