No IUPAC name is currently defined for Cashew (Anacardium occidentale) Nutshell Extract, Decarboxylated, Distilled (“Distilled Residue Grade”).

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Justification for type of information:

1. HYPOTHESIS FOR THE CATEGORY APPROACH (ENDPOINT LEVEL)
The basis for the adoption of a category approach for the three grades of processed Cashew Nutshell Extract is 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. The ECHA Final Decisions on the Annex IX and X (mammalian toxicology, ecotoxicology and environmental fate) Testing Proposals for three grades confirmed the applicability of a category approach which involves reading data across from the source substances Cashew Nutshell Extract, Decarboxylated, Distilled (Distilled Grade) and Cashew Nutshell Extract, Decarboxylated, Distillation Residue (Distillation Residue Grade) to the target substance Cashew Nutshell Extract, Decarboxylated (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”. Further details on the justification for using the interpolation based read-across approach are given in the attached document “Report on the grouping and read-across rationale for the three grades of processed Cashew Nutshell Extract”. The interpolation approach has been applied to the Annex IX and X OECD TG211 and TG218 testing on Distilled and Distillation Residue Grades. For the Annex VII and VIII endpoints a programme of testing has been carried out to provide comparative information for the three grades and develop a data matrix to support the category and read-across approaches. This has involved generating reliable data for all Annex VII and VIII physico-chemical and environmental fate endpoints and certain mammalian toxicity properties. However, based on the discussions surrounding the Final Decisions it was not considered necessary to apply this approach retrospectively to address all identified data gaps at Annexes VII and VIII. The original data used for the registration of a single substance (Cashew Nutshell Liquid, CAS Number 8007-24-7) was largely based on data for Distilled Grade since this was considered to be the most (eco) toxicologically active form, given the higher content of low molecular weight constituents (such as cardanol) and the low content of polymeric species. However, for the short-term acute aquatic toxicity endpoints the testing on algae, invertebrates and fish was carried out on Technical Grade. The measured data for the key physico-chemical properties that underpin the likely short term aquatic toxicity of the three grades, namely water solubility and octanol-water partition coefficient, are consistent. Therefore, based on the use of the category approach it is considered appropriate to read-across from the existing short-term aquatic toxicity data for Technical Grade to the other two grades.
2. CATEGORY APPROACH JUSTIFICATION (ENDPOINT LEVEL)
For the short-term toxicity to fish endpoint no test data is available for the registered substance Distillation Residue Grade. However, data is available for the compositionally similar substance Technical Grade which is part of the category of the three grades of CNSL. In the short-term toxicity to fish study on Technical Grade there were no effects on the lethality of the marine fish Cyprinodon variegatus after 96 hours exposure in a reliable with restriction (Klimisch Code 2) OECD TG203 study. In the study, loading rates up to 1000 mg/l were prepared using Water Accommodated Fractions. The highest loading rate of 1000 mg/l corresponds, in principle, to the water solubility limit given that no solvents were used in the preparation of the exposure concentrations. Therefore, it was concluded that there were no adverse effects of Technical Grade on short-term fish lethality at the substances water solubility limit. The available data for the three grades indicates that they all show low measured water solubility in the range 0.2 to 0.3 mg/l. All three substances also show high measured octanol-water partition coefficients (log Kow >6.2 in all cases). This data indicates that the measured data for the key physico-chemical properties that underpin the likely short term aquatic toxicity of the three grades are consistent. On this basis it would be expected that the three grades would show similar responses in the short-term aquatic toxicity tests. This hypothesis is currently supported by the results of the long-term OECD TG211 and TG218 ecotoxicity tests that have been conducted on both Distilled Grade and Distillation Residue Grade as part of the interpolation approach. Therefore, it is considered appropriate to read-across from the data for Technical Grade to Distillation Residue Grade with the result that it has been estimated that there will also be no adverse effects of Distillation Residue Grade on short-term fish lethality at the substances water solubility limit.

Duration:

3 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

3 h

Dose descriptor:

LL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

6 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

6 h

Dose descriptor:

LL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

24 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

24 h

Dose descriptor:

LL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

48 h

Dose descriptor:

LL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

72 h

Dose descriptor:

LL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

other: WAF loading rate

Basis for effect:

mortality (fish)

Validity criteria fulfilled:

yes

Conclusions:

It is considered appropriate to read-across from the data for Technical Grade to Distillation Residue Grade with the result that it has been estimated that there will also be no adverse effects of Distillation Residue Grade on short-term fish lethality at the substances water solubility limit.

Executive summary:

For the short-term toxicity to fish endpoint no test data is available for the registered substance Distillation Residue Grade. However, data is available for the compositionally similar substance Technical Grade which is part of the category of the three grades of CNSL. In the short-term toxicity to fish study on Technical Grade there were no effects on the lethality of the marine fish Cyprinodon variegatus after 96 hours exposure in a reliable with restriction (Klimisch Code 2) OECD TG203 study. In the study, loading rates up to 1000 mg/l were prepared using Water Accommodated Fractions. The highest loading rate of 1000 mg/l corresponds, in principle, to the water solubility limit given that no solvents were used in the preparation of the exposure concentrations. Therefore, it was concluded that there were no adverse effects of Technical Grade on short-term fish lethality at the substances water solubility limit. The available data for the three grades indicates that they all show low measured water solubility in the range 0.2 to 0.3 mg/l. All three substances also show high measured octanol-water partition coefficients (log Kow >6.2 in all cases). This data indicates that the measured data for the key physico-chemical properties that underpin the likely short term aquatic toxicity of the three grades are consistent. On this basis it would be expected that the three grades would show similar responses in the short-term aquatic toxicity tests. This hypothesis is currently supported by the results of the long-term OECD TG211 and TG218 ecotoxicity tests that have been conducted on both Distilled Grade and Distillation Residue Grade as part of the interpolation approach.  Therefore, it is considered appropriate to read-across from the data for Technical Grade to Distillation Residue Grade with the result that it has been estimated that there will also be no adverse effects of Distillation Residue Grade on short-term fish lethality at the substances water solubility limit. 

Additional information

In a 96-hour acute toxicity study, Sheepshead minnow (Cyprinidon variegatus) were exposed to Cardolite NC-603 (Technical Grade) at nominal concentrations of 0 and 1000 mg/L WAF under static conditions.

 

No mortalities occured at a concentration of 1000 mg/l nominal WAF loading rate and no sub-lethal effects were noted after 96 hours.

 

The 96-hour LL₅₀was >1000 mg/L nominal WAF.

 

Read-across justification: The read across source substance is Cashew (Anacardium occidentale) Nutshell Extract, Decarboxylated ("Technical Grade").  For a full description of the read-across case, please refer to the document "Rationale for the grouping and read-across approach for the three grades of processed Cashew Nutshell Extract" located in Section 13.