Dialkyl phosphinic acid

Endpoint summary

Additional information

Short Term toxicity to fish

 

In two key studies the test item was found to cause no toxic effects to Zebrafish and Rare Minnow after 96 hours when tested with the limit concentration of 100 mg/L.

The LC50 after 96 hours is > 100 mg/L in both studies. All effect levels are given based on the nominal concentration level of the test item.The measured concentration were 97.8 mg/L and 117 mg/L.

 

Long-term toxicity to fish

 

The results showed that under valid semi-static test conditions (72 h-renewal), the LOEC for the growth rate of the test item to rare Minnow, Gobiocypris rarus, is over 100 mg/L (measured concentration 98.0 mg/L), the NOEC is 100 mg/L (measured concentration 98.0 mg/L).

 

Short-term toxicity to daphnia

 

Based on the nominal concentrations of the test item the 48-h EC50 for Daphnia magna was estimated to be 70.7 mg/L (95 % confidence limits: 50.0 – 100 mg/L). The NOEC after 48 h was 50.0 mg/L. The LOEC after 48 h was 100 mg/L.

The effects observed at the concentration level of 100 mg/L were caused by the low pH-values (pH below the recommended range of pH 6 – 9). This was confirmed by the pH-neutralized concentration level of 100 mg/L which caused no effects on Daphnia magna. Based on the pH-neutralized concentration the 48-h EC50 and the NOEC for Daphnia magna were > 100 mg/L.

 

Long-term toxicity to daphnia

 

The significant reduction of the reproductive output at the concentration levels of 33.9 and 69.3 mg/L was the most sensitive effect in this study.

Based on the significant reduction of the reproductive output at the concentration levels of 33.9 and 69.3 mg/L, the No Observed Effect Concentration (NOEC) after 21 days was assessed at 16.6 mg/L and the Lowest Observed Effect Concentration (LOEC) was assessed at 33.9 mg/L.

An EC50-value for the reduction of the reproductive output could not be calculated, because the reduction was limited to a maximum of 21 % within the tested concentration range. The EC10-value for the reduction of the reproductive output was calculated to be 9.98 mg/L.

 

Endpoints assessed Test item

Geometric mean measured test item concentration [mg/L]

EC10 Reproduction (with 95 % confidence limits) 9.98 mg/L(Not applicable)

NOEC Reproduction 16.6 mg/L

LOEC Reproduction 33.9 mg/L

 

Toxicity to algae

 

In this study the test item was found to inhibit the growth of the freshwater green alga Desmodesmus subspicatus after 72 hours with the following effect values (geometric mean measured test item concentrations). The NOEC-values for inhibition of growth rate and inhibition of yield after 72 hours were 52.3 mg/L and 14.6 mg/L, respectively. The LOEC-values for inhibition of growth rate and inhibition of yield after 72 hours were 93.5 mg/L and 31.0 mg/L, respectively. The EC50-values for inhibition of growth rate (ErC50) and yield (EyC50) with 95 % confidence intervals after 72 hours were 60.9 (53.5 – 79.2) and 59.5 (53.8 - 80.2) mg/L, respectively. The effects were caused by the low pH-values. This was confirmed by the pH-neutralized concentration level of 98.9 mg/L (geometric mean measured) which caused no effects on the algae growth. Based on the pH-neutralized concentration the NOEC-values for both the inhibition of the growth rate and the inhibition of the yield after 72 hours were 98.9 mg/L. The EC50-values for both inhibition of growth rate (ErC50) and yield (EyC50) after 72 hours were > 98.9 mg/L. All effect levels are given based on geometric mean measured concentrations of the test item.

 

Toxicity to microorganisms

 

A Respiration Inhibition Test with activated sludge according to OECD Guideline No. 209 (2010) was carried out with the test item in 2012.Test system was activated sludge of a municipal treatment plant. The test was carried out under static conditions with the limit concentration 1000 mg/L, pH adjusted. The respiration rates of the control, reference and test item replicates were measured after a contact time of three hours, and the inhibitory effects of the test and reference item were determined in comparison to the control respiration rates. The inhibition of respiration for the test item replicates ranged from 4 to 9 %.

In order to check the activity of the test system and the test conditions a reference test was carried out with copper (II) sulphate pentahydrate as reference item and the reference toxicity was determined. The EC₅₀-value for the reference item was 91.4 mg/L.

The validity criteria of the test guideline were fulfilled.