Tris(2-butoxyethyl) phosphate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

24 µg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.24 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

2.4 µg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

8.96 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.804 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.08 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:

165.75 µg/kg soil dw

Assessment factor:

1 000

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

4.44 mg/kg food

Assessment factor:

90

Additional information

The ecotoxicity of the substance Tris(2 -butoxyethyl) phosphate (TBEP) is summarised below.

Aquatic toxicity:

Acute data, based on international guidelines, are available for the three aquatic trophic levels: fish, invertebrates and algae.

To rainbow trout Oncorhynchus mykiss, under static condition, the 96h-LC50 value was determined at 24 mg/L. To aquatic invertebrates Daphnia magna, under static condition, the 48h-EC50 value was determined at 53 mg/L. To the freshwater green algae species Pseudokirchneriella subcapitata, under static condition, the 72h-NOEC and 72h-ErC50 values based on growth rate were 7.6 mg/L and 61 mg/L, respectively.

Among all the species tested, a toxic effect was found at the three trophic levels, and the most sensitive species was the rainbow trout.

In addition, the toxicity of TBEP to microorganisms (activated sludge) was evaluated under static condition. the 3h-EC50 value was found to be higher than 1000 mg/L and the 3h-EC10 value was calculated to be 89.6 mg/L.

Terrestrial toxicity:

Standardised acute toxicity tests were performed with TBEP, on earthworm (OECD 207) and three different plant species (OECD 208) giving an 14d-LC50 of 544 mg/kg dry soil and a 21d-ER50 = 46.8 mg/kg dry soil (corresponding to 165.75 mg/kg after organic carbon normalisation), respectively.

TBEP is readily biodegradable and doesn't have a high potential to adsorb to soil therefore consideration of degradation products and long term testing according to Annex X does not appear scientifically justified.

However, as some effects were measured on invertebrates and plants further testing is proposed on soil micro-organisms (OECD 216) in order to cover different habitats and feeding modes in the soil as well as taxonomic groups. At the time being, there are no indications that TBEP will pose a specific hazard to terrestrial arthropods.

Based on low experimental BCF in fish, bioaccumulation of TBEP is not expected. In addition, the acute mammalian toxicity is low and there are no indications that the registered substance will pose a specific hazard to birds.

Therefore, in accordance with annex XI in REACH regulation, further testing on terrestrial arthropods and birds does not appear scientifically necessary.

Conclusion on classification

TBEP is harmful to aquatic organisms with the lowest toxicity observed on fish (LC50 = 24 mg/L). In addition it is readily biodegradable and not bioaccumulable (based on low experimental BCF on fish) and therefore it is not classified for the environment.