Registration Dossier
Registration Dossier
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EC number: 255-003-1 | CAS number: 40615-39-2
Ecotoxicological Summary
Administrative data
Hazard for aquatic organisms
Hazard for air
Hazard for terrestrial organisms
Hazard for predators
Additional information
Conclusion on classification
Two study reports (rated as Klimisch 1) on aquatic organisms are available covering two trophic levels: a primary producer (freshwater algae, represented by the model species Pseudokirchneriella subcapitata) and a primary consumer (aquatic invertebrates, represented by the model species Daphnia magna).
D. magna was exposed for 48 hours to 5’-O-(4,4’-Dimethoxytrityl)thymidine in a static short-term GLP toxicity study (OECD 202) at a limit concentration of 2.99 mg/L (measured, limit of water solubility, loading 100 mg/L nominal). No effect on D. magna was observed. The test concentration was determined analytically by HPLC-UV. Therefore, 5’-O-(4,4’-Dimethoxytrityl)thymidine is not toxic to D. magna up to the limit of water solubility (determined water solubility according to OECD 105, see section 4.8 in the present report
The freshwater algae P. subcapitata was exposed to 5’-O-(4,4’-Dimethoxytrityl)thymidine for 72 hours in a GLP toxicity study (OECD 201). In this study the 72 h ErC20 (= 5.028 mg/L) is calculated by extrapolation slightly exceeding the solubility of the substance. The 72 h ErC50 (> 4.66 mg/L) could not be determined, as it exceeds the solubility of the test item. The ErC10 value (2.975 mg/L) is interpolated and does not exceed the water solubility of the substance. The test concentrations were determined analytically by HPLC-UV.
Taking into account that 5’-O-(4,4’-Dimethoxytrityl)thymidine is poorly soluble, and no acute toxicity (i.e. ErC50) is recorded up to the limit of water solubility and considered to be not readily biodegradable based on ThCO2 (Flach 2018), and the estimated log Kow is ≥ 4, 5’-O-(4,4’-Dimethoxytrityl)thymidine has to be classified as "Aquatic Chronic 4" (H413) following the provisions laid down in the CLP Regulation (Regulation (EC) No 1272/2008).
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