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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Short-term toxicity to fish

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Administrative data

Link to relevant study record(s)

Description of key information

Short-term toxicity to fish (Danio rerio) of the substance was determined as LC0 = 99.8 mg/L and LC100 = 438.0 mg/L. The geometric mean of both LC values gabe an EC 50 = 209.1 mg/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
209.1 mg/L

Additional information

Rational for read across

REACH regulation (Corrigendum) EC 1907/2006 on page L 136/120: “Substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity may be considered as a group, or ‘category’ of substances. Application of the group concept requires that physicochemical properties, human health effects and environmental effects or environmental fate may be predicted from data for reference substance(s) within the group by interpolation to other substances in the group (read-across approach).”

Further, ECHA guidance document “Guidance on information requirements and chemical safety assessment – Chapter R.6: QSARs and grouping of chemicals (May, 2008)” provides information on the use of read-across (page 78) as follows: “In the read-across technique, endpoint information for one chemical is used to predict the same endpoint for another chemical, which is considered to be similar in some way (usually on the basis of structural similarity). In principle, read-across can be applied to characterise physico-chemical properties, environmental fate, human health effects and ecotoxicity.”

Triethyl posphite (CAS 122 -52 -1) and diethyl phospite (762 -04 -9) are very similar in their chemical structure. However, there is a more relevant rational for the use of studies conducted with triethyl phosphite: In contact with water triethyl phosphite quickly hydrolyses with diethyl phosphite being the hydrolysis product. This product is expected to be stable for a certain time period which should be the period of an acute toxicity study. Thus, when conducting a study with triphenyl phosphite it should be the effects of diethyl phosphite that are detected instead.The other hydrolysis product phosphate can be expected not to cause any toxicity since it is an ubiquitious and inorganic compound.

Concluding, it is highly justified to use studies with triethyl phosphite to predict effects with diethyl phosphite.