Dibutyl phosphonate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.014 mg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.144 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.001 mg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

PNEC marine water (intermittent releases):

0.144 mg/L

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

1 000 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.526 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.053 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.115 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Aquatic toxicity potential of the test item was calculated using assessments of potential hazard of the

test item to aquatic organisms (freshwater, marine water, sewage treatment plant (STP), freshwater

sediment and marine sediment), air, terrestrial organisms (soil) and predators (via secondary poisoning).

In order to assess freshwater and marine water hazard, the following data was obtained from short-term

studies on the test item over three trophic levels:

- Short-term toxicity to fish: LC₅₀ (96h) = 63.4 mg/L (45.5 to 88.7)

- Short-term toxicity to aquatic invertebrates: IC₅₀ (48h) = 20.8 mg/L (17.6 to 24.6)

- Toxicity to aquatic algae: E_rC₅₀ (72h) = 14.4 mg/L (13.6 to 15.4)

- Toxicity to microorganisms: EC₅₀ (3h) > 10000 mg/L (respiration rate)

The most sensitive species is identified as aquatic algae, and the nominal value of 14.4 mg/L was used for PNEC calculation.

The freshwater PNEC value was found to be 0.0144 mg/L; the marine water PNEC value was found to be 0.00144 mg/L.

In order to assess STP hazard, the following data was obtained from a respiration inhibition test:

- Toxicity to microorganisms: EC50 (3 h) > 10,000 mg/L

The PNEC value for microorganisms using the effect concentration of 10,000 mg/L was found to be 1000 mg/L.

Hazards to freshwater and marine water sediment were calculated using the equilibrium partitioning method due to the absence of experimental studies on sediment. The following equations were applied:

PNEC_{freshwater sediement} = K_susp-water / RHO_susp × PNEC_freshwater × 1000

PNEC_{marine water sediement} = K_susp-water / RHO_susp × PNEC_{marine water} × 1000

Hazard to terrestrial organisms was also calculated using the equilibrium partitioning method due to the absence of experimental studies on soil organisms. The following equation was applied:

PNEC_soil = K_soil-water / RHO_soil × PNEC_freshwater × 1000

In order to determine the K_susp-water /K_soil-water values, the EUSES software was used which required certain physicochemical properties of the substance. The molecular weight of the test item was 194.208 g/mol. The melting and boiling points used were -20 °C and 200 °C, as shown in the IUCLID Registration Dossier, which were determined using a structural analogue and a weight of evidence approach, respectively. Vapour pressure was interpreted to be the lowest possible value of 1^-6 Pa at 25 °C. No experimental data for water solubility or partition coefficient were available, therefore, the values were calculated using EPI Suite TM to be 5 g/L and log P_OW = 1.81, respectively. These also correspond to the QSAR values reported in the IUCLID Registration Dossier.

PNECsediment (freshwater) was calculated to be 0.526 mg/kg of sediment (dry weight);

PNECsediment (marine water) was calculated to be 0.0526 mg/kg sediment (dry weight).

PNECsoil was calculated to be 0.11456 mg/kg soil (dry weight).

Biotic and abiotic hazards for air were not considered as the vapour pressure of the test item is negligible.

Hazard for predators (via secondary poisoning) was not considered as the test item is not considered to bioaccumulate.

Conclusion on classification

According to the CLP Regulation (EC) no. 1272/2008, Part 4: Environmental Hazards, substances can be classified for hazardous to the aquatic environment when the following criteria are met:

A) Acute (short-term) aquatic hazard Category Acute 1: 96 hr LC 50 (for fish) and/or 48 hr EC 50 (for crustacea) and/or 72 or 96 hr ErC 50 (for algae or other aquatic plants) ≤ 1 mg/L.

B) Long-term aquatic hazard (iii) Substances for which adequate chronic toxicity data are not available and the substance is not rapidly degradable and/or the experimentally determined BCF ≥ 500 (or, if absent, log K_OW ≥ 4):

Category Chronic 1: 96 h LC₅₀ (fish) and/or 48 h EC₅₀ (invertebrates) and/or 72 or 96 h E_rC₅₀ (algae/other aquatic plants) ≤ 1 mg/L;

Category Chronic 2: 96 h LC₅₀ (fish) and/or 48 h EC₅₀ (invertebrates) and/or 72 or 96 h E_rC₅₀ (algae/other aquatic plants) > 1 to ≤ 10 mg/L;

Category Chronic 3: 96 h LC₅₀ (fish) and/or 48 h EC₅₀ (invertebrates) and/or 72 or 96 h E_rC₅₀ (algae/other aquatic plants) > 10 to ≤ 100 mg/L.

 

The test item is not rapidly degradable, and the available acute toxicity tests to fish, invertebrates and aquatic algae fixed effect levels that meet the criteria for the hazard category Category Chronic 3 for aquatic toxicity (ErC50 for algae = 14.4 mg/L). Therefore, in accordance with CLP Regulation (EC) no. 1272/2008, the substance is classified as Chronic Category 3, H412: Harmful to aquatic life with long lasting effects.