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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

Read-across substance_Phosphoric acid, mono- and di-(C8-C10) ester, compds. with C12 - 14 amine_Oncorhynchus mykiss_OECD 201: LL50(96h): 75 mg/L loading rate WSF (95 % CL: 56 - 100 mg/L loading rate WSF); NOEC(96h): 32 mg/L loading rate WSF

Key value for chemical safety assessment

LC50 for freshwater fish:
75 mg/L

Additional information

No information concerning toxic effects to fish of the target substance (Reaction products of diphosphorus pentaoxide and alcohol C7-9-iso, C8 rich, salted with 2-ethylhexylamine) is available. An experimental result in order to fulfil this endpoint is given by a study conducted with the read-across substance (Phosphoric acid, mono- and di-(C8 -C10) ester, compds. with C12 - 14 amine). Both substances represent a mixture of mono- and (di) alkyl phosphates salted with an alkyl amine. The basic structures of the target and read-across substances are the same: aliphatic ester of phosphoric acid and a primary aliphatic amine. Based on the structural sameness, it can be assumed that also the same mode of action in organisms will take place. For further details of this read-across approach, please refer to the corresponding statement by Chemservice S.A. (2013d).

The acute toxicity of the read-across substance (Phosphoric acid, mono- and di-(C8 -C10) ester, compds. with C12 - 14 amine) towards the freshwater fish Oncorhynchus mykiss was investigated according to OECD Guideline 201 (Wetton, 1999a). Based on the results in the preliminary test (after 48 h exposure at a concentration of 100 mg/L all fish were dead), the test concentrations in the definitive test were 0, 10, 18, 32, 56 and 100 mg/L. Based on the poor water solubility, the test solutions were prepared as Water Soluble Fractions (WSFs). Aqueous media are thereby prepared by mixing the test substance with water for a prolonged period (24 - 48 h). Afterwards the test substance phase is separated by filtration and the organisms are exposed to the WSF. Rainbow trout is a representative of a wide variety of natural habitats and can be considered as important non-target organism in freshwater ecosystems. The acclimatisation period last about 12 days and within this time, no mortality was observed. The mean standard length at study initiation was 4.6 cm, the mean weight was 1.16 g. For the definitive test, 10 fish per concentration were exposed in 20 L glass vessels, resulting in a biomass loading rate of 0.58 g bw/L. The vessels were covered to reduce evaporation and aeration was performed via narrow bore glass tubes. The temperature was held constant at 14 +/- 0.5 °C. The photoperiod was set as 16 h light and 8 h darkness with 20 min dawn and dusk transition periods. The water temperature, pH and dissolved oxygen concentrations were recorded daily. A semi-static test regime was employed involving a daily renewal of the preparations to ensure that the test concentrations remain near nominal and to prevent the building up of nitrogenous waste products. Total Organic Carbon (TOC) analysis of the test solutions was carried out at 0 (fresh media), 24 (old media), 72 (fresh media) and 96 hours (old media). 56 mg/L was the highest loading rate WSF resulting in no mortality, the lowest loading rate WSF resulting in 100 % mortality was 100 mg/L and the No Observed Effect Concentration (NOEC) was 32 mg/L loading rate WSF. A sub-lethal effect (i.e. swimming at the bottom of the test vessel) was recorded at 56 mg/L loading rate WSF. Using the moving average method by Thompson (1947), the LL50(96h) is given as 75 mg/L loading rate WSF with a corresponding 95 % confidence limit range of 56 - 100 mg/L loading rate WSF.