Reaction products of diphosphorus pentaoxide and alcohol C7-9-iso, C8 rich, salted with 2-ethylhexylamine

Long-term toxicity to aquatic invertebrates

Description of key information

Read-across substance_Phosphoric acid, mono- and di-(C8-C10) ester, compds. with C12 - 14 amine_Daphnia magna_OECD 202_prolonged: Immobilisation: EL50(21d): 4.6 mg/L loading rate WSF (95 % CL: 3.9 - 5.6 mg/L loading rate WSF); Reproduction: EL50(21d): 3.5 mg/L loading rate WSF (95 % CL: 3.2 - 4.0 mg/L loading rate WSF); NOEL(21d): 1.6 mg/L loading rate WSF

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.6 mg/L

Additional information

The target substance (Reaction products of diphosphorus pentaoxide and alcohol C7-9-iso, C8 rich, salted with 2-ethylhexylamine) was not investigated for its long-term toxicity effects towards freshwater invertebrates. Although this endpoint is not mandatory for a registration under REACH, an experimental result conducted with the read-across substance (Phosphoric acid, mono- and di-(C8 -C10) ester, compds. with C12 - 14 amine) is reported. The basic structure of the target and read-across substance is the same: aliphatic ester of phosphoric acid and a primary aliphatic amine. Thus, both represent a mixture of mono- and di-alkyl phosphates salted with an alkyl amine. Therefore it can be assumed that also the same mode of action in organisms will take place. For further details, please refer to the separate read-across statement of Chemservice S.A. (2013d).

Daphnia magna was exposed to the read-across substance (Phosphoric acid, mono- and di-(C8 -C10) ester, compds. with C12 - 14 amine) over a period of 21 days by a method followed OECD Guideline 202 (Wetton, 1999c). The test solutions were prepared as Water Soluble Fractions (WSFs) based on the poor water solubility. The test substance is thereby mixed with water for a prolonged period of time (24 - 48 h) with subsequent filtration to separate the test substance phase. The invertebrates (4 replicates of 10 daphnids per group) were exposed to a Water Soluble Fraction (WSF) of the test substance over a range of loading rates of 0.16, 0.50, 1.60, 5.0 and 16 mg/L. The test solutions were renewed 3 times/week. The numbers of live and dead adult Daphnia were determined daily. The numbers of young Daphnia (live and dead) were determined at each test media renewal. Each Daphnia received approximately 2.0 - 7.0 µL of a mixed unicellular algal culture (approx. 5.8 x 10E9 - 2.3 x 10E10 cells/mL) daily. Feeding was at a level of approx. 0.10 - 0.17 mg carbon/Daphnia/day, dependent on the age and size of the animals. Young daphnids were considered to be dead if no sign of movement was apparent during microscopic examination. Adult Daphnia, which were unable to swim for approximately 15 seconds after gentle agitation (i.e. immobile), were considered to be dead. An immobilisation criterion for the young daphnids was considered to be inappropriate due to the large numbers of offspring produced in the flasks.Temperature of the test solutions was recorded daily throughout the study. Dissolved oxygen concentrations, pH and temperature were recorded before and after each test media renewal. The EL50 (immobilisation and reproduction) values and associated confidence limits were calculated by the moving average method of Thompson (1947). Mortality (immobilisation) occurred predominantly at the highest loading rate of16mg/L resulting in100 %mortality by Day 5. Significant mortality (immobilisation) also occurred throughout the study in the 5.0 mg/L loading rate WSF group resulting in 8 % and 58 % mortality by days 14 and 21, respectively. No mortalities occurred at the 0.16, 0.50 and 1.6 mg/L loading rates throughout the study.It was not possible to calculate a 48-Hour EL50 as less than 50 % mortalities were observed at this time point. However, the morality pattern observed, which showed 30 % mortality at the16 mg/L loading rate WSF after 48 -Hours was considered to be consistent with the acute toxicity, 48 -Hour EL50 value of 16 mg/L loading rate WSF. Thus, as final result, the EL50(21d), based on immobilisation is given as 4.6 mg/L loading rate WSF with 95 % confidence limits of 3.9 - 5.6 mg/L loading rate WSF. The EL50(21d), based on reproduction was determined as 3.5 mg/L with a corresponding 95 % confidence limit of 3.2 - 4.0 mg/L loading rate WSF. The No Observed Effect Loading Rate (NOELR) was shown to be 1.6 mg/L. All results based on nominal concentrations.