Phosphoric acid, mono and bis-linear butyl esters, potassium salts

Endpoint summary

Description of key information

Short-term toxicity to fish: The LC50 (96 h) value was determined to be 1300 mg/L in a test perfomed using fathead minnows (equivalent or similar to OECD 203).

Short term toxicity to aquatic invertebrates: The 48 h EC50 was >100 mg/L (nominal) and the NOEC was 100 mg/L (nominal) in a test performed on Daphnia magna (OECD 202).

Toxicity to aquatic algae: The 72 h ErC50 was > 100 mg/L (nominal) and the NOEC was 100 mg/L (nominal) in a test performed using Pseudokirchneriella subcapitata (OECD 201).

Additional information

Short-term toxicity to fish: In a key study equivalent or similar to OECD 203 fathead minnows were exposed to eight nominal concentrations of test material plus well-water as the control for 96 hours under static conditions. Ten fish were placed into the test chamber for each treatment group and the control group. Nominal concentrations of test item selected were 412, 588, 840, 1200, 1720, 2450, 3500 and 5000 mg/L. Verification of test item concentration was not performed. Clinical signs observed in fish exposed to ≥ 1200 mg/L included lying on the bottom, erratic swimming, swimming at the surface, darkening colouration, gasping for air and lethargy. The highest test concentration resulting in 0 % mortality was determined to be 588 mg/L and the lowest test concentration resulting in 100 % mortality was determined to be 1720 mg/L. The LC50 (96 h) value was determined to be 1300 mg/L.

Short term toxicity to aquatic invertebrates: Acute toxicity of the test item on Daphnia magna was assessed in an Acute immobilisation test, over an exposure period of 48 hours in a static test system (OECD TG 202).

Because no toxic response was observed during the preliminary range-finding test, a Limit Test was carried out using only one test concentration (100 mg/L) and one control group in the definitive test.

The test concentration was analytically determined at the start and at the end of the experiment. Measured concentration was 105.3 mg/L at the start and 102.9 mg/L at the end of the experiment.

As the measured concentration deviated not more than 20 per cent from the nominal, biological results are based on the nominal concentration.

Twenty animals, divided into four groups (glass beaker) of five animals each were used at the test concentration and for the control.

All validity criteria were met during this study.

Under the conditions of this Daphnia magna acute immobilisation study the observed endpoints for the effect of the test item were as follows:

The 24h and 48h EC50 value: > 100 mg/L (nominal)

The 48h EC100 value: > 100 mg/L (nominal)

The 48h No-Observed Effect Concentration (NOEC): 100 mg/L (nominal)

The 48h Lowest Observed Effect Concentration (LOEC): > 100 mg/L (nominal)

Toxicity to aquatic algae: The effect of the test item was assessed on algal growth using the unicellular green alga Pseudokirchneriella subcapitata, over an exposure period of 72 hours (OECD TG 201).

Because a toxic response was not observed during the preliminary concentration rangefinding test, a Limit Test was carried out using only one test concentration of 100 mg/L (nominal) and one control group.

The test concentration was analytically determined at the start and at the end of the experiment. Measured concentration was 105.6 mg/L at the start and 106.3 mg/L at the end of the experiment. As the analytically measured concentration deviated not more than 20 per cent from the nominal, the biological results are based on the nominal test item concentration.

The test design included six replicates at test concentration and six replicates for the untreated control.

Statistical comparisons of biomass, average specific growth rates and yield in control and in treated groups were carried out using 2 Sample t-Test (α = 0.05) by TOXSTAT software.

The ErC50, EbC50 and EyC50 values of the test item were determined directly from the raw data.

Under the conditions of this algal growth inhibition test the calculated endpoints for the effect of the test item were the following:

72h ErC50 value (biomass): > 100 mg/L (nominal)

72h EbC50 value (growth rate): > 100 mg/L (nominal)

72h EyC50 value (yield): > 100 mg/L (nominal)

72h NOEC: 100 mg/L (nominal)

72h LOEC: > 100 mg/L (nominal)